What is Metal Conductivity？A basic guide

 

Many engineers and product designers struggle when selecting materials for electrical applications. Choosing the wrong metal can lead to high resistance, overheating, or costly failures in critical components. This is especially true for industries relying on precision metal CNC machined parts, where conductivity directly impacts performance. The good news is that by understanding metal conductivity, you can make better choices that improve efficiency, reduce costs, and extend product life.

• Tip: Selecting a metal without analyzing its conductivity may increase your project’s machining and maintenance costs. Always consult CNC machining factories for material recommendations before finalizing your design.

 

Most metals conduct electricity because of their free electrons. The best conductors are silver, copper, and gold, followed by aluminum and brass. Factors such as temperature, impurities, and alloying can affect conductivity. For precision applications, CNC machining services can help manufacture conductive parts with the right balance of strength and electrical performance.

 

Now that we’ve answered the central question, let’s dive deeper. This article will explain what metallic conductivity is, why some metals conduct electricity better than others, and which metals rank highest in performance. We’ll also look at practical applications—from wiring to heat transfer—and how CNC machining factories can support industries that depend on reliable electrical materials.

 

 

 

What is Metallic Conductivity?

 

Metallic conductivity refers to a material’s ability to allow electric current to pass through it. In metals, the outer electrons (valence electrons) are loosely bound and can move freely, forming what is known as an “electron cloud.” This mobility enables metals to conduct both electricity and heat efficiently. Conductivity is usually measured in siemens per meter (S/m) or by comparison to copper (100% IACS = International Annealed Copper Standard).

 

For manufacturers designing metal CNC machined parts, understanding conductivity is crucial. Poorly chosen materials may cause electrical losses, heating issues, or even equipment failure. This is why industries such as electronics, aerospace, and automotive often consult CNC machining services to ensure that the material’s electrical and mechanical properties meet the intended function.

 

• Tip: Always confirm conductivity values when sourcing materials; even small variations can impact large-scale electrical systems.

 

 

 

 

 

 

Why Are Metals Highly Conductive?

 

Metals are highly conductive because their atomic structure allows electrons to move freely. Unlike nonmetals, where electrons are tightly bound, metals feature delocalized electrons in their crystal lattice. This “sea of electrons” allows for minimal resistance, making current flow more efficient. Additionally, metals often have closely packed atoms, which further enhances conduction.

This property not only benefits electrical wiring but also improves thermal conductivity, which is why many conductive metals are used in heat exchangers and cooling systems. When machining these materials into metal CNC machined parts, conductivity must be preserved by minimizing surface oxidation and avoiding contaminants. Experienced CNC machining factories employ advanced processes, such as precision milling and protective coatings, to ensure parts retain their desired conductivity.

 

• Tip: Be cautious when machining; overheating during CNC cutting can alter conductivity in sensitive metals.

 

 

 

Do All Metals Conduct Electricity?

 

In general, all metals conduct electricity, but not equally well. The reason lies in their atomic structure—every metal has free electrons, which allow current to pass through. However, conductivity levels vary widely. For example, silver and copper are excellent conductors, while stainless steel and titanium are much poorer conductors due to their higher resistivity and tendency to form oxides.

 

This difference is critical in product design. For applications like power transmission, copper and aluminum are widely used because they balance high conductivity with mechanical strength and cost-effectiveness. On the other hand, metals with lower conductivity, such as stainless steel, are often chosen when corrosion resistance or structural integrity is more important than electrical performance. When producing metal CNC machined parts, engineers must carefully evaluate whether conductivity or durability should be prioritized, as the wrong choice can lead to unnecessary costs and reduced efficiency.

 

For industries that rely on CNC machining services, such as electronics, automotive, and aerospace, understanding the conductivity of different metals helps ensure that the right material is chosen for the application. By consulting experienced CNC machining factories, customers can receive guidance on which metals conduct electricity most effectively while still meeting strength, weight, and cost requirements.

 

• Tip: Never assume all metals have “good” conductivity. Some, like lead or stainless steel, conduct poorly and may increase resistance in your system—leading to overheating and performance loss.

 

 

 

Which Metals Conduct Electricity?

 

Almost all metals conduct electricity, but their conductivity levels vary significantly. The most conductive metals are silver, copper, and gold, followed by aluminum and brass. Other metals such as iron, zinc, and stainless steel also conduct electricity, but their efficiency is lower. Each metal’s conductivity depends on its electron structure, purity, and how it reacts under different conditions such as temperature or oxidation.

 

For example, silver is the most conductive metal but is rarely used in wiring due to its high cost. Copper is the most practical choice for electrical wiring and components, offering excellent conductivity and affordability. Aluminum is lighter and less expensive, making it ideal for high-voltage transmission lines. Other metals like brass and bronze are commonly used when moderate conductivity is acceptable but mechanical strength or corrosion resistance is more critical.

 

When designing metal CNC machined parts, choosing the right conductive material ensures reliability and efficiency in end-use applications. Electronics, automotive, aerospace, and energy industries often rely on CNC machining services to produce conductive parts such as terminals, housings, and connectors. Trusted CNC machining factories can also recommend cost-effective alternatives, ensuring performance without overspending.

 

• Tip: Always match your material choice with the application. For high-precision parts, copper and aluminum are often preferred, but for structural strength with moderate conductivity, brass or bronze may be better.

 

 

 

Electrical Conductivity, Resistivity, and Thermal Conductivity of Metals

 

 

Understanding the relationship between electrical conductivity, resistivity, and thermal conductivity of metals is critical in both material science and precision engineering. Conductivity measures how easily a material allows electrons to flow, resistivity is its opposition to current, and thermal conductivity reflects its ability to transfer heat. Together, these properties determine how suitable a metal is for applications such as wiring, heat exchangers, and metal CNC machined parts.

 

When industries partner with CNC machining services, they need to choose metals that balance conductivity with strength, corrosion resistance, and machinability. For example, copper excels in conductivity, while stainless steel is less conductive but highly resistant to corrosion. By consulting with experienced CNC machining factories, manufacturers can make informed material decisions that save costs and improve product performance.

• Tip: Resistivity increases with temperature, so metals used in high-heat environments must be carefully chosen to avoid efficiency losses.

 

 

 

Silver

 

Electrical Conductivity: Silver is the most conductive metal (about 63 × 10⁶ S/m, rated 106% IACS).

Resistivity: Very low (1.59 µΩ·cm), making it ideal for precision electronics.

Thermal Conductivity: Silver also has the highest thermal conductivity of all metals (~429 W/m·K).

 

Because of its superior properties, silver is used in high-end electrical contacts, solar panels, and aerospace applications. However, due to its cost, silver is rarely used in large-scale wiring. In CNC machining, silver is often selected for metal CNC machined parts that demand maximum conductivity, such as connectors or high-frequency components. Specialized CNC machining services can machine silver to precise tolerances without losing its conductive qualities.

• Tip: Avoid using silver in environments prone to tarnishing, as surface oxidation can reduce conductivity.

 

Copper

 

Electrical Conductivity: Copper ranks second only to silver, with 100% IACS (58 × 10⁶ S/m).

Resistivity: 1.68 µΩ·cm, making it the standard benchmark for electrical conductivity.

Thermal Conductivity: High (~401 W/m·K), enabling efficient heat dissipation.

 

Copper is the most widely used conductive metal, applied in power transmission, motors, transformers, and electronic components. It strikes the perfect balance between performance and cost, making it the go-to choice for industries worldwide. When processed into metal CNC machined parts, copper requires skilled handling, as it is soft and can deform if not machined precisely. Reputable CNC machining factories use advanced tooling and cooling techniques to ensure high-quality copper components for both electrical and thermal applications.

• Tip: For projects requiring both conductivity and durability, consider annealed copper or copper alloys to enhance mechanical performance while maintaining good conductivity.

 

 

 

Brass

 

Electrical Conductivity: Brass (an alloy of copper and zinc) has lower conductivity than pure copper, typically around 28% IACS.

Resistivity: 6–7 µΩ·cm, which makes it suitable for moderate-conductivity applications.

Thermal Conductivity: Moderate (~120 W/m·K), depending on the zinc content.

 

Brass is commonly used in connectors, fittings, and components where both mechanical strength and moderate conductivity are required. It also offers good corrosion resistance, making it a practical choice for marine and plumbing industries. For metal CNC machined parts, brass is highly machinable, allowing CNC machining services to produce detailed components with tight tolerances.

• Tip: Brass is excellent when both conductivity and machinability are required, but for high-power electrical systems, copper remains the better choice.

 

 

 

Bronze

 

Electrical Conductivity: Bronze, primarily a copper-tin alloy, has conductivity around 15% IACS.

Resistivity: ~10 µΩ·cm, higher than brass due to alloying with tin.

Thermal Conductivity: Around 60 W/m·K, lower than brass and copper.

 

Bronze is not as conductive as copper or brass, but it provides superior wear resistance and durability. It’s often used in bearings, bushings, and marine hardware, where mechanical performance is more important than conductivity. For CNC machining factories, bronze is an excellent material when producing durable parts that must withstand friction and corrosion while still conducting some electricity.

• Tip: Choose bronze when durability is more important than electrical performance, especially in moving components.

 

Annealed Copper

 

Electrical Conductivity: Annealed copper is the reference standard at 100% IACS.

Resistivity: 1.724 µΩ·cm.

Thermal Conductivity: Around 390–401 W/m·K.

 

Annealed copper is pure copper that has been heat-treated to improve ductility without significantly changing conductivity. It’s widely used in electrical wiring, motors, and transformer windings. For metal CNC machined parts, annealed copper offers the highest combination of conductivity and workability. CNC machining services often recommend it for components where flexibility, conductivity, and machinability are all required.

• Tip: Annealed copper is softer than hard-drawn copper, so CNC machining requires careful control of cutting forces to prevent deformation.

 

Gold

 

Electrical Conductivity: Gold conducts electricity well, at around 70% IACS (45 × 10⁶ S/m).

Resistivity: 2.44 µΩ·cm, slightly higher than copper.

Thermal Conductivity: About 318 W/m·K.

 

Gold is highly valued for its corrosion resistance. While not as conductive as silver or copper, gold’s resistance to tarnishing makes it ideal for critical components like electrical contacts, aerospace electronics, and medical devices. In metal CNC machined parts, gold is often applied as a plating over copper or nickel components rather than used in bulk due to its high cost. CNC machining factories can prepare precise base components that are later coated with gold for conductivity and longevity.

• Tip: Gold plating is often the most cost-effective solution for ensuring long-term conductivity in critical connections.

 

Aluminum

 

Electrical Conductivity: Aluminum has about 61% IACS (35 × 10⁶ S/m).

Resistivity: 2.82 µΩ·cm.

Thermal Conductivity: ~237 W/m·K, making it excellent for both electrical and thermal uses.

 

Aluminum is the second most widely used conductor after copper. Its lightweight nature makes it ideal for overhead power lines, heat exchangers, and electronic housings. For metal CNC machined parts, aluminum offers an excellent balance of conductivity, machinability, and cost-effectiveness. CNC machining services often recommend aluminum for parts requiring high strength-to-weight ratio along with good electrical performance.

• Tip: Aluminum forms a natural oxide layer that can reduce conductivity at contact points—always ensure surfaces are treated or coated for reliable conductivity.

 

 

Iron

 

Electrical Conductivity: Iron has much lower conductivity than copper or aluminum, around 17% IACS.

Resistivity: 9.71 µΩ·cm.

Thermal Conductivity: ~80 W/m·K.

 

Iron is not typically chosen for electrical efficiency but is widely used for structural and magnetic applications, such as transformers and electric motors. For metal CNC machined parts, iron is cost-effective and strong, but its poor conductivity limits it to specialized roles. CNC machining factories may use iron when magnetic properties or structural integrity are more critical than electrical flow.

• Tip: Use iron in magnetic cores, but not in applications where high electrical conductivity is required.

 

 

 

Carbon Steel

 

Electrical Conductivity: Carbon steel has relatively poor conductivity, around 3–10% IACS depending on composition.

Resistivity: ~10–20 µΩ·cm, much higher than copper.

Thermal Conductivity: ~50 W/m·K, significantly lower than copper or aluminum.

 

Carbon steel is valued for its strength and cost-efficiency rather than conductivity. It is often used in structural parts, mechanical tools, and components requiring high wear resistance. For metal CNC machined parts, carbon steel offers excellent machinability but is rarely chosen for electrical systems where efficient conductivity is needed. Instead, it finds applications in mechanical housings and fixtures. CNC machining factories often recommend carbon steel when strength and durability are prioritized over electrical performance.

• Tip: Avoid carbon steel in circuits or conductive pathways—it is better suited for structural roles.

 

 

 

Stainless Steel

 

Electrical Conductivity: Stainless steel is a poor conductor, with only ~2–3% IACS.

Resistivity: ~60–70 µΩ·cm, very high compared to copper.

Thermal Conductivity: ~16 W/m·K, making it one of the poorest thermal conductors among metals.

 

Despite its low conductivity, stainless steel is used in industries where corrosion resistance, hygiene, or mechanical properties matter more than electrical flow. Applications include medical devices, food equipment, and aerospace hardware. For metal CNC machined parts, stainless steel is a favorite due to its strength and resistance to corrosion, even though it does not conduct electricity efficiently. CNC machining services often use grades like 304 or 316 stainless steel in parts exposed to harsh environments.

• Tip: Use stainless steel for durability and corrosion resistance—not for electrical applications.

 

 

 

Calcium

 

Electrical Conductivity: Calcium is a fair conductor but not widely used, around 29% IACS.

Resistivity: ~3.3 µΩ·cm.

Thermal Conductivity: ~200 W/m·K.

 

Calcium’s conductivity is higher than that of stainless steel, but it is too chemically reactive to be used in most applications. In practice, calcium appears in specialized alloys or as a reducing agent in metallurgy rather than in direct conductive applications. It is not commonly used in metal CNC machined parts, as its reactivity makes it unstable. CNC machining factories typically avoid calcium unless producing research-grade alloys.

• Tip: Calcium is not practical for conductive parts—consider copper or aluminum for stability and reliability.

 

Beryllium

 

Electrical Conductivity: Beryllium has conductivity of about 20–25% IACS.

Resistivity: ~4 µΩ·cm.

Thermal Conductivity: ~200 W/m·K, relatively high.

 

Beryllium is valued for its stiffness, light weight, and thermal properties, but its toxicity makes handling dangerous. It is usually used in alloy form, such as beryllium copper, which combines high conductivity (20–60% IACS) with excellent strength. In metal CNC machined parts, beryllium copper is popular for springs, connectors, and aerospace components. Experienced CNC machining services are required due to strict safety measures when handling beryllium-containing materials.

• Tip: Never machine pure beryllium without proper precautions—it is toxic. Use beryllium copper instead for safe, conductive components.

 

Rhodium

 

Electrical Conductivity: Rhodium conducts moderately well, about 38% IACS.

Resistivity: 4.3 µΩ·cm.

Thermal Conductivity: ~150 W/m·K.

 

Rhodium is a rare, expensive metal often used for plating due to its corrosion resistance, hardness, and decent conductivity. While not as conductive as copper or silver, it provides durability in high-wear contact points such as electrical connectors. For CNC machining factories, rhodium is rarely machined in bulk; instead, base components are produced by CNC machining services and then plated with rhodium for added longevity.

• Tip: Rhodium plating is ideal for extending the lifespan of electrical contacts in harsh environments.

 

Magnesium

 

Electrical Conductivity: Magnesium has conductivity of about 39% IACS.

Resistivity: 4.45 µΩ·cm.

Thermal Conductivity: ~160 W/m·K.

 

Magnesium is lightweight, with moderate conductivity and excellent machinability. It is often used in aerospace and automotive industries where weight reduction is critical. While not as conductive as copper or aluminum, magnesium alloys provide a balance of strength, conductivity, and lightness. CNC machining services frequently produce magnesium CNC machined parts for housings, enclosures, and components that need both electrical and thermal performance.

• Tip: Magnesium is flammable in fine chips or dust—CNC machining factories must follow strict safety protocols.

 

Molybdenum

 

Electrical Conductivity: About 31% IACS.

Resistivity: ~5.7 µΩ·cm.

Thermal Conductivity: ~138 W/m·K.

 

Molybdenum is best known for its high melting point and strength at elevated temperatures. While its conductivity is moderate compared to copper or aluminum, it is extremely valuable in high-heat environments such as furnace components and aerospace parts. For metal CNC machined parts, molybdenum is difficult to machine due to its hardness, but experienced CNC machining factories can produce critical parts like electrodes or semiconductor components.

• Tip: Molybdenum is best for high-temperature strength, not for maximum conductivity applications.

 

Iridium

 

Electrical Conductivity: ~19% IACS.

Resistivity: 5.3 µΩ·cm.

Thermal Conductivity: ~150 W/m·K.

 

Iridium is one of the densest and most corrosion-resistant metals. Although its electrical conductivity is lower than silver, copper, or gold, it excels in harsh environments where durability is essential. It is often used in electrical contacts, spark plugs, and high-performance alloys. In CNC machining, iridium is rarely produced in bulk due to cost but can be applied in specialized metal CNC machined parts that demand exceptional longevity.

• Tip: Iridium is expensive—use it only where corrosion resistance and extreme durability are required.

 

Tungsten

 

Electrical Conductivity: ~31% IACS.

Resistivity: 5.6 µΩ·cm.

Thermal Conductivity: ~173 W/m·K.

 

Tungsten is famous for its high melting point, making it essential for filaments, welding electrodes, and aerospace applications. Its conductivity is moderate but stable at extreme temperatures. For CNC machining services, tungsten presents machining challenges due to its hardness and brittleness. However, CNC machining factories produce tungsten parts for defense, medical imaging, and electronics.

• Tip: Tungsten machining requires specialized tools—be prepared for higher costs when specifying tungsten parts.

 

 

 

Zinc

 

Electrical Conductivity: ~27% IACS.

Resistivity: 5.9 µΩ·cm.

Thermal Conductivity: ~116 W/m·K.

 

Zinc’s moderate conductivity makes it suitable for galvanization and as a base material for alloys like brass. It is not used for high-performance conductive parts but is valuable in protecting steel from corrosion. For metal CNC machined parts, zinc alloys (like Zamak) are easier to machine and widely used in automotive, consumer goods, and hardware industries. CNC machining factories often recommend zinc alloys for cost-effective, corrosion-resistant components.

• Tip: Use zinc in alloy form for cost efficiency; pure zinc is rarely chosen for conductive roles.

 

Cobalt

 

Electrical Conductivity: ~17% IACS.

Resistivity: ~6.2 µΩ·cm.

Thermal Conductivity: ~100 W/m·K.

 

Cobalt is more valued for its magnetic properties and wear resistance than its conductivity. It is used in magnets, cutting tools, and high-performance alloys. For CNC machining services, cobalt alloys are difficult to machine due to hardness but provide outstanding durability. Metal CNC machined parts made of cobalt alloys are common in aerospace engines and medical implants.

• Tip: Choose cobalt when strength and magnetism matter more than conductivity.

 

Cadmium

 

Electrical Conductivity: ~24% IACS.

Resistivity: 7.3 µΩ·cm.

Thermal Conductivity: ~96 W/m·K.

 

Cadmium is moderately conductive and often used in electroplating to protect other metals from corrosion. It is not used in bulk for CNC machining due to toxicity and softness. However, cadmium coatings are sometimes applied to metal CNC machined parts in aerospace and defense industries for wear and corrosion protection.

• Tip: Cadmium is toxic—use cadmium-plated parts only when absolutely required by specifications.

 

Nickel (Electrolytic)

 

Electrical Conductivity: ~22% IACS.

Resistivity: ~6.99 µΩ·cm.

Thermal Conductivity: ~90 W/m·K.

 

Nickel is moderately conductive and highly corrosion resistant. Electrolytic nickel is widely used in plating, batteries, and electronics. It is machinable and often chosen for metal CNC machined parts that require corrosion protection with some conductivity. CNC machining factories also produce nickel alloys (like Inconel) for high-temperature and aerospace applications, though these alloys reduce conductivity compared to pure nickel.

• Tip: Nickel plating is a cost-effective way to combine corrosion resistance with moderate conductivity.

 

Ruthenium

 

Electrical Conductivity: ~19% IACS.

Resistivity: 7.1 µΩ·cm.

Thermal Conductivity: ~120 W/m·K.

 

Ruthenium is a rare platinum-group metal with good conductivity, high hardness, and excellent corrosion resistance. It is often used as a coating on electrical contacts to improve durability and reduce resistance. While pure ruthenium is rarely machined due to brittleness, CNC machining factories often produce copper or nickel parts that are later ruthenium-plated for conductivity and wear resistance.

• Tip: Use ruthenium as a plating solution for long-lasting contacts rather than as a bulk conductive material.

 

Lithium

 

Electrical Conductivity: ~17% IACS.

Resistivity: 9.28 µΩ·cm.

Thermal Conductivity: ~85 W/m·K.

 

Lithium is lightweight, soft, and highly reactive. While it is conductive, its main applications are in batteries rather than traditional electrical components. Pure lithium is rarely machined into parts because of its reactivity. Instead, it is used in compounds and alloys. CNC machining services typically do not work directly with lithium, but lithium-containing alloys may be processed under controlled conditions.

• Tip: Lithium is best for energy storage applications—avoid specifying it for conventional conductive components.

 

Platinum

 

Electrical Conductivity: ~16% IACS.

Resistivity: 10.6 µΩ·cm.

Thermal Conductivity: ~72 W/m·K.

 

Platinum is not as conductive as copper or silver but is highly valued for its corrosion resistance and stability at high temperatures. It is commonly used in thermocouples, laboratory equipment, and medical devices. For metal CNC machined parts, platinum is rarely used in bulk due to cost but can be precisely machined for critical aerospace, medical, and research applications. CNC machining factories often work with platinum in specialized industries where reliability outweighs cost.

• Tip: Platinum is an excellent choice for high-temperature sensors, not for large-scale wiring.

 

Palladium

 

Electrical Conductivity: ~16% IACS.

Resistivity: 10.8 µΩ·cm.

Thermal Conductivity: ~72 W/m·K.

 

Palladium has moderate conductivity but outstanding corrosion resistance, making it useful for plating electronic connectors and circuits. It is also widely used in catalytic converters. In CNC machining, palladium is typically applied as a thin coating rather than bulk-machined. CNC machining services produce base parts that are later palladium-coated for conductivity and corrosion resistance.

• Tip: Palladium plating is a cost-effective alternative to gold plating for electronic connectors.

 

Tin

 

Electrical Conductivity: ~15% IACS.

Resistivity: 11 µΩ·cm.

Thermal Conductivity: ~67 W/m·K.

 

Tin is moderately conductive and best known for its use in soldering. It creates reliable joints in electrical circuits by bonding conductive metals. In metal CNC machined parts, tin is often used as a coating for copper components to improve corrosion resistance. CNC machining factories frequently recommend tin plating for terminals, connectors, and circuit parts.

• Tip: Tin-based solders are widely used, but avoid pure tin in structural conductive components as it is too soft.

 

Selenium*

 

Electrical Conductivity: Selenium is a semiconductor, not a good conductor like metals. Its conductivity varies with light exposure.

Resistivity: Extremely high in dark conditions, dropping under illumination.

Thermal Conductivity: Very low (~2 W/m·K).

 

Selenium is primarily used in photocells, solar panels, and electronics. It is not machined into bulk components due to brittleness. Instead, it is deposited as thin films or coatings. While not relevant for most metal CNC machined parts, selenium has niche applications in electronics that depend on light-sensitive conductivity.

• Tip: Selenium is not a true conductor—use it for semiconducting or photovoltaic applications only.

 

Tantalum

 

Electrical Conductivity: ~13% IACS.

Resistivity: 13.6 µΩ·cm.

Thermal Conductivity: ~57 W/m·K.

 

Tantalum has poor conductivity compared to copper but is extremely corrosion resistant, even to strong acids. It is widely used in capacitors, medical implants, and aerospace parts. For CNC machining factories, tantalum is expensive but machinable with care, making it valuable in high-end, corrosion-critical applications.

• Tip: Use tantalum in electronics or medical parts where corrosion resistance is more critical than conductivity.

 

Niobium

 

Electrical Conductivity: ~11% IACS.

Resistivity: 15.2 µΩ·cm.

Thermal Conductivity: ~54 W/m·K.

 

Niobium is moderately conductive but highly valued for its superconducting properties at low temperatures. It is used in superconducting magnets, aerospace alloys, and medical implants. While pure niobium is rarely used in CNC machined parts, it is commonly alloyed with steel to improve strength and toughness. CNC machining factories that serve aerospace and medical industries sometimes machine niobium alloys for specialized applications.

• Tip: Niobium is ideal for superconducting technology, not everyday conductive parts.

 

Cast Steel

 

Electrical Conductivity: Low compared to copper (~2–3% IACS).

Resistivity: ~60 µΩ·cm (varies by alloy).

Thermal Conductivity: ~50 W/m·K.

 

Cast steel is primarily a structural material, not a conductive one. While it conducts electricity, its resistivity is much higher than copper or aluminum, making it inefficient for wiring or circuits. However, CNC machining services use cast steel extensively for mechanical components, housings, and fixtures where strength and durability matter more than conductivity.

• Tip: Use cast steel for strength—not for conductivity-based applications.

 

Chromium

 

Electrical Conductivity: ~7.9% IACS.

Resistivity: 12.7 µΩ·cm.

Thermal Conductivity: ~94 W/m·K.

 

Chromium is moderately conductive and best known for its excellent corrosion resistance. It is commonly used as a plating material on steel and other metals to improve surface hardness and resistance. In metal CNC machined parts, chromium is not typically used in bulk form but applied as a coating. CNC machining factories often provide chrome plating on steel parts for durability and aesthetics.

• Tip: Chromium is excellent for protective coatings, not for primary conductive use.

 

Lead

 

Electrical Conductivity: ~7% IACS.

Resistivity: 20.6 µΩ·cm.

Thermal Conductivity: ~35 W/m·K.

 

Lead has relatively poor conductivity compared to copper but is still used in specialized applications, such as radiation shielding and batteries. Due to its toxicity, its use in electrical applications has declined. In CNC machining, lead is rarely machined directly, but leaded alloys (like brass with lead) are easier to machine and still used in some industries.

• Tip: Avoid lead for conductivity needs—consider safer alternatives like copper or tin.

 

Vanadium

 

Electrical Conductivity: ~6% IACS.

Resistivity: 20 µΩ·cm.

Thermal Conductivity: ~30 W/m·K.

 

Vanadium has poor conductivity but is widely used as an alloying element in steels to increase hardness and strength. It is not commonly used in electrical applications. For CNC machining factories, vanadium-containing steels are very common in aerospace and tool industries where wear resistance is critical.

• Tip: Vanadium is excellent in alloys for strength, not as a conductor.

 

Uranium

 

Electrical Conductivity: ~4% IACS.

Resistivity: 28 µΩ·cm.

Thermal Conductivity: ~28 W/m·K.

 

Uranium is weakly conductive and radioactive, making it unsuitable for most commercial conductive applications. It is primarily used in nuclear fuel rather than electrical systems. CNC machining factories do not generally handle uranium due to safety and regulatory restrictions.

• Tip: Uranium is an energy source, not a viable conductive material for machining.

 

Antimony

 

Electrical Conductivity: ~3% IACS.

Resistivity: 39 µΩ·cm.

Thermal Conductivity: ~24 W/m·K.

 

Antimony is a poor conductor but is often alloyed with lead to improve hardness in batteries and solders. It is brittle and not used as a bulk material in CNC machining parts. Instead, CNC machining services may process alloys containing antimony for specific industrial needs.

• Tip: Antimony improves alloy performance but is not suitable as a standalone conductor.

 

Zirconium

 

Electrical Conductivity: ~3% IACS.

Resistivity: 42 µΩ·cm.

Thermal Conductivity: ~23 W/m·K.

 

Zirconium has low conductivity but excellent corrosion resistance, especially in chemical processing and nuclear industries. For CNC machining factories, zirconium alloys are machinable and valuable for specialized chemical equipment, not electrical wiring.

• Tip: Zirconium is better for chemical resistance than for conductivity.

 

Titanium

 

Electrical Conductivity: ~3% IACS.

Resistivity: 42 µΩ·cm.

Thermal Conductivity: ~22 W/m·K.

 

Titanium is a poor conductor compared to copper or aluminum, but it excels in strength, lightness, and corrosion resistance. It is widely used in aerospace, medical implants, and high-performance engineering applications. In CNC machining factories, titanium alloys are popular for CNC machined parts that require high durability and biocompatibility, but not for electrical conductivity.

• Tip: Titanium is chosen for strength and weight reduction, not for conductivity.

 

 

 

Mercury

 

Electrical Conductivity: ~1% IACS.

Resistivity: 96 µΩ·cm.

Thermal Conductivity: ~8.3 W/m·K.

 

Mercury is a liquid metal at room temperature and a very poor conductor compared to solid metals. It has been historically used in switches, thermometers, and scientific instruments, though its use has declined due to toxicity. CNC machining services do not handle mercury, but machined housings for scientific equipment may integrate mercury as part of specialized assemblies.

• Tip: Mercury’s liquid state limits its use in conductive applications.

 

Germanium

 

Electrical Conductivity: ~2.1 S/cm (semiconductor, not a true metal).

Resistivity: ~0.47 Ω·cm (varies with doping).

Thermal Conductivity: ~60 W/m·K.

 

Germanium is not a good conductor by metallic standards but is a critical semiconductor material. It is widely used in electronics, solar cells, and fiber optics. Since it is brittle, CNC machining factories do not process it as bulk material; instead, it is refined for use in wafers and microelectronics.

• Tip: Germanium is valuable for electronics, not structural or conductive machining.

 

Silicon

 

Electrical Conductivity: ~1.6 S/cm (semiconductor).

Resistivity: ~2.3 Ω·cm (varies with doping).

Thermal Conductivity: ~150 W/m·K.

 

Silicon, like germanium, is a semiconductor rather than a true metal. Its conductivity depends heavily on doping with other elements, making it the backbone of modern electronics. It is not used for structural CNC machining parts, but CNC machining services may fabricate housings and precision components for semiconductor equipment.

• Tip: Silicon powers electronics, but it is not a usable conductor for machining applications.

 

 

 

 

 

 

 

Which Metals Have the Highest Electrical Conductivity? What Are Their Uses?

 

 

Metals with the Highest Electrical Conductivity

 

Electrical conductivity is usually measured relative to IACS (International Annealed Copper Standard, 100% = pure copper). Here are the top performers:

 

 

 

 

Detailed Explanation & Uses

 

Silver (Ag) –

• Conductivity Champion: The best electrical conductor of all metals.
• Uses: Often applied in coatings for electrical contacts, solar panels, high-frequency electronics, and specialty aerospace components. Expensive, so used selectively.

Copper (Cu) –

• Industry Standard: Nearly as conductive as silver but much cheaper and abundant.
• Uses: The backbone of electrical wiring, power transmission, motors, generators, PCBs, and CNC machined copper parts.

Gold (Au) –

• Corrosion Resistant: Doesn’t tarnish or oxidize, ensuring reliable long-term conductivity.
• Uses: Found in connectors, circuit boards, aerospace electronics, medical devices where reliability is critical.

Aluminum (Al) –

• Lightweight Conductor: About 60% as conductive as copper, but only one-third the weight.
• Uses: Overhead transmission lines, busbars, automotive wiring harnesses, and CNC machined aluminum components.

Beryllium (Be) –

• Specialty Conductor: Pure beryllium is toxic, but beryllium-copper alloys combine good conductivity with excellent strength and fatigue resistance.
• Uses: Precision springs, relays, connectors, aerospace and defense parts.

Magnesium (Mg) –

• Decent Conductivity, Lightweight: Conductivity lower than aluminum but much lighter.
• Uses: Specialty lightweight housings, aerospace structures, and some magnesium alloys in electronics.

 

Summary:

• Silver = Best conductor (used in high-value applications).
• Copper = Most widely used (wiring, power, CNC machined parts).
• Gold = Corrosion-proof conductor (used in electronics & aerospace).
• Aluminum = Lightweight and cost-efficient (power lines, busbars).

 

 

 

 

Why Are Some Metals More Conductive Than Others?

 

 

The electrical conductivity of a metal depends mainly on how easily its electrons can move. Three major factors explain the differences:

 

 

1. Number of Free Electrons (Valence Electrons)

• Metals conduct because of their “sea of free electrons”.
• Metals like silver (Ag), copper (Cu), and gold (Au) have just one valence electron per atom in the outer shell.
• These electrons are very loosely bound, so they move freely → higher conductivity.
• Metals like iron, stainless steel, or titanium have more complex electron structures, so their conductivity is lower.

 

2. Atomic Structure & Electron Scattering

 

In good conductors, the atomic lattice is very uniform, so electrons can travel without bumping into atoms.

In poorer conductors, atoms scatter electrons more due to irregularities.

Example: Copper vs. Brass

• Pure copper is highly conductive.
• Brass (copper + zinc alloy) has mixed atoms, which cause electron scattering, reducing conductivity.

 

3. Temperature Effect

• Higher temperature = more atomic vibration = more electron collisions = lower conductivity.
• That’s why silver and copper are used in high-performance applications → they retain conductivity better under heat.

 

Quick Analogy

 

Think of electricity like cars on a highway:

• Silver & Copper = Wide, smooth highways with few obstacles → cars (electrons) move freely and quickly.
• Steel & Alloys = Highways full of bumps and traffic → cars (electrons) keep colliding, slowing down.

 

Summary

• Best conductors (Silver, Copper, Gold, Aluminum): Few valence electrons, stable crystal structure, minimal scattering.
• Poorer conductors (Steel, Titanium, Alloys): More complex electron interactions and scattering.

 

 

Table: Why Some Metals Are More Conductive Than Others

 

 

 

Key Takeaway:

• Silver > Copper > Gold > Aluminum are the top conductors.
• Alloys (brass, stainless steel, bronze, carbon steel) have much lower conductivity because of electron scattering from mixed atomic structures.

 

 

 

 

Factors Affecting Electrical Conductivity of Metals

 

 

Electrical conductivity determines how efficiently a metal allows electric current to pass through it. For industries such as CNC machining, electronics, and aerospace, choosing the right material is critical to ensure performance, durability, and cost-effectiveness. Several factors influence conductivity, from the type of material itself to external conditions like temperature and processing methods.

 

 

Material

 

Each metal has a unique number of free electrons available for conduction.

• Silver, copper, and gold have the highest conductivity due to their single valence electron and low resistivity.
• Steel and alloys have reduced conductivity because their complex structures cause more electron scattering.

 

Cross-Sectional Area

 

A thicker conductor provides more pathways for electrons to move, reducing resistance.

• Larger diameter wires or machined parts conduct electricity better.
• This is why high-voltage power lines use thick aluminum conductors.

 

Conductor Length

 

The longer the conductor, the greater the resistance.

• Resistance increases linearly with length.
• For critical applications, shorter connections or parallel conductors are preferred.

 

Temperature

 

As temperature rises, metal atoms vibrate more, causing electron scattering.

• Most metals’ conductivity decreases with heat.
• Some special alloys (like constantan) are designed to maintain stable conductivity across temperatures.

 

Impurities and Defects

 

Any imperfection in the crystal lattice—such as voids, dislocations, or trapped elements—disrupts electron flow.

• High-purity copper and silver show superior conductivity.
• Industrial grades with impurities are less efficient.

 

Alloying

 

Mixing metals creates alloys (e.g., brass, bronze, stainless steel) that are stronger but less conductive.

• Alloying increases electron scattering.
• This trade-off makes alloys suitable where strength > conductivity is required.

 

Processing

 

Manufacturing techniques like annealing, cold working, or CNC machining can alter conductivity.

• Annealed copper has higher conductivity than work-hardened copper.
• Surface finish in CNC machining can also impact electrical contact efficiency.

 

Key Insight for Customers:

 

When selecting materials for CNC machined parts, always balance conductivity with strength, corrosion resistance, and cost. Pure metals like copper or silver excel in conductivity, while alloys like stainless steel are preferred for mechanical durability.

 

 

Table: Factors Affecting Electrical Conductivity of Metals

 

 

     

Takeaway for Customers:

 

When choosing materials for CNC machined parts or electrical applications, prioritize pure, well-processed metals like copper or silver if conductivity is critical. For structural strength or corrosion resistance, alloys may be better even though they sacrifice conductivity.

 

 

 

 

Which Metal is Best Used to Increase the Conductivity of Alloys?

 

When designing alloys for electrical applications, the goal is usually to improve conductivity while maintaining mechanical strength, corrosion resistance, or other desirable properties. Not all metals are equally effective as additives.

 

 

1. Copper (Cu) – The Most Common Conductivity Enhancer

 

Why: Copper has excellent electrical conductivity (~100% IACS), good ductility, and compatibility with many metals.

Uses:

• Brass (Cu + Zn): Copper dominates conductivity.
• Beryllium-copper alloys: Copper maintains high conductivity while beryllium adds strength.
• Aluminum-copper alloys: Used in aerospace and high-strength electrical components.

CNC Machining Insight: Copper-rich alloys are preferred for CNC machined parts that require both strength and electrical performance.

 

 

2. Silver (Ag) – High-End Conductivity Booster

 

Why: Silver is the most conductive metal, but very expensive.

Uses: Specialty alloys for aerospace, medical, or microelectronics where maximum conductivity is critical.

Trade-off: Cost limits wide industrial use, but small additions can significantly improve conductivity.

 

 

3. Aluminum (Al) – Lightweight Conductivity Enhancer

 

Why: Aluminum has ~61% of copper’s conductivity but is much lighter.

Uses: Power transmission lines, busbars, and some aluminum alloys for lightweight conductive CNC parts.

 

 

Key Insight for Engineers & Manufacturers

• Copper is the most practical metal to increase conductivity in alloys.
• Silver is used only when cost is less critical, but performance is paramount.
• Aluminum is ideal for weight-sensitive applications.
• The exact proportion must balance strength, corrosion resistance, and machinability, especially for CNC machining services and metal CNC machined parts.

 

 

Table: Metals Used to Increase Alloy Conductivity

 

 

 

 

Customer Tip:

 

When designing CNC machined parts or alloys for electrical components, copper is usually the most practical metal to enhance conductivity. Silver or gold are used selectively for high-performance or corrosion-resistant applications, while aluminum is excellent when weight savings are critical.

 

 

 

 

Why is Electrical Conductivity Important?

 

 

Electrical conductivity is a fundamental property that defines how easily a metal allows electrons to flow. For engineers, designers, and manufacturers, understanding conductivity is critical when selecting materials for metal CNC machined parts, electrical systems, and thermal applications. High conductivity ensures efficiency, safety, and durability in a wide range of applications.

 

 

Electrical Wiring

• Importance: Conductive metals reduce energy loss, prevent overheating, and ensure reliable power transmission.
• Applications: Copper and aluminum are widely used in wiring for homes, industrial equipment, motors, transformers, and high-voltage power lines.
• CNC Machining Insight: CNC-machined copper or aluminum busbars and connectors are highly conductive, precise, and efficient, making them ideal for custom electrical assemblies.
• Tip: Using low-conductivity alloys for wiring increases resistance, heat generation, and energy cost. Always select metals with high conductivity for electrical components.

 

Heat Transfer

• Importance: Metals that conduct electricity well often conduct heat efficiently. This makes them essential for thermal management in electronics, machinery, and industrial systems.
• Applications: Heat sinks, thermal pads, electrodes, and CNC-machined components in electronics often use copper or aluminum for optimal heat dissipation.
• CNC Machining Insight: Machining high-conductivity metals for thermal applications requires careful control of cutting speed and tooling to prevent surface defects that reduce heat transfer efficiency.
• Tip: Avoid alloys with low conductivity in heat-sensitive parts to prevent overheating and equipment failure.

 

Welding and Soldering

• Importance: Metals with high electrical conductivity allow efficient current flow during resistance welding or electrical soldering processes.
• Applications: Copper electrodes, aluminum busbars, and gold-plated contacts are commonly used for precise and reliable joining of electrical components.
• CNC Machining Insight: CNC-machined parts with high conductivity reduce energy loss during welding, improve joint quality, and minimize thermal deformation.
• Tip: For welding conductive metals, ensure proper surface finish and material purity to maintain conductivity and joint strength.

 

Summary:

 

High electrical conductivity is crucial for:

• Efficient power transmission in wiring and connectors.
• Effective heat dissipation in electronics and machinery.
• Reliable welding and soldering in manufacturing and assembly.

Selecting the right metals ensures energy efficiency, durability, and performance in CNC machined parts and electrical systems.

 

 

 

 

Conclusion

 

Understanding electrical conductivity is essential for selecting the right metals for both industrial and precision applications. Metals like silver, copper, and gold excel in conductivity, making them ideal for CNC machined parts, electrical wiring, connectors, and heat-sensitive components. Alloys can provide additional strength, corrosion resistance, or lightweight properties, but often at the cost of reduced conductivity.

 

Factors such as material purity, cross-sectional area, length, temperature, alloying, and processing all influence how effectively a metal conducts electricity. Engineers and manufacturers must balance these factors to ensure optimal performance, energy efficiency, and durability in their designs.

 

For applications where maximum conductivity is critical, metals like copper or silver should be prioritized, while aluminum and specialty alloys are better suited for weight-sensitive or mechanically demanding parts. In CNC machining services, choosing the right conductive material ensures precision, reliability, and long-term performance for both standard and custom components.

 

By understanding the properties and uses of conductive metals, businesses can make informed decisions that reduce costs, improve efficiency, and enhance the quality of metal CNC machined parts and electrical assemblies.

 

 

 

 

 

 

 

Frequently Asked Questions (FAQs)

 

 

1. Is gold a better conductor of electricity than copper?

 

Gold has slightly lower conductivity than copper (~70% IACS vs 100% IACS), but it is highly corrosion-resistant. Gold is preferred in connectors and electronics where reliability is critical, while copper is used for general wiring and power transmission.

 

 

2. Is brass conductive?

 

Yes, brass conducts electricity, but its conductivity (~28% IACS) is much lower than pure copper. It is often used for decorative or mechanical parts rather than high-performance electrical applications.

 

 

3. Is copper conductive?

 

Absolutely. Copper is one of the best electrical conductors (~100% IACS) and is widely used in wiring, motors, transformers, and CNC machined parts.

 

 

4. What are the uses of copper?

 

Copper is used in electrical wiring, busbars, motors, transformers, heat sinks, plumbing, and CNC machined components that require high conductivity and durability.

 

 

5. Which material has a conductivity of 98%?

 

High-purity copper can achieve ~98–100% IACS, making it one of the most conductive commercially available metals.

 

 

6. What is a good value for electrical conductivity?

 

For high-performance applications, metals with >90% IACS (copper, silver) are excellent. For general applications, 50–70% IACS (aluminum, gold) is sufficient.

 

 

7. Which metals don't conduct electricity?

 

Non-metals like rubber, glass, plastics, and ceramics do not conduct electricity. Some metalloids (e.g., silicon, germanium) have very low conductivity.

 

 

8. What causes high electrical conductivity?

 

High conductivity results from free electrons, uniform crystal lattices, low impurities, and minimal electron scattering.

 

 

9. What makes metals good conductors?

 

Metals with loosely bound valence electrons, simple atomic structures, and minimal alloying tend to be excellent conductors.

 

 

10. Why do only metals conduct electricity?

 

Metals have delocalized electrons that can move freely throughout the lattice, unlike non-metals, which have tightly bound electrons.

 

 

11. What can increase electrical conductivity?

 

Using pure metals, reducing impurities, minimizing defects, proper annealing, and adding highly conductive elements (like copper or silver in alloys) can improve conductivity.

 

 

12. What determines the conductivity of a metal?

 

Factors include material type, temperature, alloying, processing, cross-sectional area, and purity.

 

 

13. What are the different types of electrical conductivity?

• DC conductivity: Conductivity under direct current.
• AC conductivity: Conductivity under alternating current, affected by frequency and skin effect.
• Ionic conductivity: In electrolytes, not common in metals.

 

 

14. What is the difference between electrical conductivity and electrical conductivity?

 

Often this refers to specific vs. bulk conductivity:

• Specific conductivity (σ): Conductivity per unit area or material property.
• Bulk conductivity: Actual current-carrying capability in a given component.

 

 

15. How is electrical conductivity measured?

 

Using instruments like four-point probes, Wheatstone bridges, or conductivity meters, which measure resistance and calculate conductivity.

 

 

16. Which metal has the highest thermal conductivity?

 

Silver has the highest thermal conductivity (~429 W/m·K), followed by copper (~401 W/m·K), making them ideal for both electrical and thermal applications.