Copper Plating Services
ProPlate® provides acid and cyanide copper plating services for industrial, aerospace, semiconductor, and electronics applications, to ASTM, MIL, and AMS specifications.
ProPlate® provides copper plating services for a wide range of industrial components and applications. Copper is the second most common metal plated and serves a variety of functional roles depending on the application, from a highly conductive final finish to a critical underplate or build-up layer beneath subsequent metal deposits. ProPlate plates copper using both barrel and rack methods on small and large parts, and offers high-thickness copper plating for applications requiring significant deposit build-up.
Copper provides a soft, ductile, solderable surface with excellent electrical and thermal conductivity. Because copper tarnishes easily in open-air environments, it is more commonly used as an underplate or intermediate layer beneath a more corrosion-resistant final finish such as nickel, gold, or tin. However, copper can also serve as a final finish in specific applications where its conductivity, leveling properties, or heat stop-off characteristics are the primary requirement.
ProPlate Copper Bath Systems
ProPlate operates two copper plating bath systems to accommodate the full range of industrial copper applications. Selecting the appropriate bath depends on substrate type, part geometry, adhesion requirements, and the intended function of the copper layer.
Acid Copper
Acid copper plating uses an acidic sulfate bath to deposit a bright, fine-grained copper layer with excellent leveling and throwing power. Acid copper produces smooth, uniform deposits across most geometries and is well suited for applications requiring a bright finish, high conductivity, or a smooth underplate for subsequent metal layers. Acid copper is compatible with most metallic substrates but is not recommended for direct plating onto active metals such as steel without a prior strike layer.
Cyanide Copper
Cyanide copper plating uses an alkaline cyanide bath to deposit a fine-grained copper layer with excellent adhesion to a wide range of substrates including steel and other active metals. Cyanide copper provides superior throwing power compared to acid copper, making it well suited for complex geometries, deep recesses, and parts where uniform coverage across all surfaces is critical. Cyanide copper is also used as a strike layer before acid copper on substrates where direct acid copper adhesion is inadequate. ProPlate handles cyanide copper plating with strict process controls and waste treatment protocols.
Not sure which copper bath system is right for your application? Our experts can help.
Anti-Diffusion and Multi-Layer Plating
Metallic Copper diffuses very rapidly through metallic Gold. However, Copper will not diffuse through Nickel or Palladium. For this reason, a layer of nickel or Palladium should always be considered between Copper and Gold. Copper, which has diffused through Gold, will appear on the outer surface of the gold electro-deposit and will quickly begin to form a partial oxide layer on the surface of the electro-deposited part.
Nickel is generally suggested as the anti-diffusion layer owing to its lower material cost. However, nickel is a magnetic metal, whereas Palladium is not. So in applications where non-magnetic performance is required, Palladium would be the anti-diffusion layer of choice. It could also be considered a non-magnetic, non-oxidizing application as a replacement for Gold.
High-Thickness Copper Plating
ProPlate offers high-thickness copper plating for applications requiring significant deposit build-up beyond standard specification classes. High-thickness copper deposits are used for a variety of functional applications where the copper layer itself must perform a specific engineering role rather than simply serving as an underplate.
Common Applications for High-Thickness Copper
High-thickness copper plating is specified for heat treatment stop-off, where a thick copper deposit acts as a barrier to prevent carburizing or nitriding of specific surfaces during heat treatment. It is also used for electroforming applications where the copper deposit itself forms a structural component, for build-up and repair of worn or undersized metallic components, and for applications requiring enhanced thermal or electrical conductivity through increased deposit mass.
Process Considerations
Achieving uniform high-thickness copper deposits requires careful control of bath chemistry, current density, and agitation throughout the plating cycle. ProPlate’s in-house chemistry lab monitors bath parameters in real time to ensure consistent deposit quality across the full thickness range. Custom fixturing and masking are developed in-house for applications requiring selective high-thickness coverage on specific surfaces only.
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Copper Properties
Copper can fill sharp corners and surface imperfections, allowing smooth and uniform coverage of the base metal. The throwing and leveling properties of Copper ensure that pinholes and subsequent blistering of finish metals will be avoided.
Because Copper has excellent leveling properties and very high throwing efficiency, it makes an excellent undercoat for most other metals. In addition, because Copper is ductile, it polishes easily to a high shine so that it supports a bright, shiny finishing metal above it.
| Copper - Cu | |||
|---|---|---|---|
| Atomic Number | 29 | Thermal Conductivity - W/(m*K) | 400 |
| Atomic Weight - g/mole | 63.55 | Electrical Resistivity - (Ohm*m) | 1.70E-08 |
| Density - g/cm³ | 8.93 | Electrical Conductivity - (S/m) | 5.90E-07 |
| Melting Point - C° | 1084.62 | Hardness - Hv | 369 |
| Melting Point - F° | 1984.32 | Specific Heat Capacity - J/(kg*K) | 384.4 |
Copper Plating Specifications
ProPlate provides services per the certified ASTM B734, MIL-C-14550, and AMS 2418 plating specifications. Our services include Type 1 and 2 deposits. Company specific specifications can also be provided if requested.
Copper Plating to ASTM B734
Type of Copper Plating bath is not specified. Classes of copper plating services as follows:
- Class 25 – 25µ minimum coating thickness
- Class 20 – 20µ minimum coating thickness
- Class 12 – 12µ minimum coating thickness
- Class 5 – 5µ minimum coating thickness
- Class x – Thickness as specified (µ)
Copper Plating to MIL-C-14550
Type of Copper Plating bath is not specified. Classes of copper plating services as follows:
- Class 0 – 0.001-0.005 inch minimum thickness
- Class 1 – 0.001inch minimum thickness
- Class 2 – 0.0005 inch minimum thickness
- Class 3 – 0.0002 inch minimum thickness
- Class 4 – 0.0001inch minimum thickness
Copper Plating to AMS 2418
- Type 1: (Engineering Plating) Shall designate a thickness of 0.0005” to 0.0007”
- Type 2: (Plating for Masking) Shall be nominally 0.002” with no area having a plate thickness of less than 0.0007”
Frequently Asked Questions About Copper Plating
What is copper plating used for?
Copper plating serves several functional roles depending on the application. It is most commonly used as an underplate or intermediate layer beneath subsequent metal deposits such as nickel, tin, or silver, where its excellent leveling and adhesion properties improve the performance of the final finish. Copper is also used as a final finish in applications where its electrical conductivity, thermal conductivity, or solderability are the primary requirement. High-thickness copper plating is used for heat treatment stop-off, electroforming, and build-up applications.
What copper bath systems does ProPlate offer?
ProPlate operates acid copper and cyanide copper bath systems. Acid copper produces bright, fine-grained deposits with excellent leveling and is suited for most metallic substrates and applications requiring smooth, uniform coverage. Cyanide copper provides superior throwing power and adhesion to active metals such as steel, making it well suited for complex geometries and substrates where direct acid copper adhesion is inadequate. Cyanide copper is also used as a strike layer before acid copper on challenging substrates.
What copper plating specifications does ProPlate plate to?
ProPlate provides copper plating services to ASTM B734, MIL-C-14550, and AMS 2418 specifications. Type 1 and Type 2 deposits are available. Company-specific specifications can also be accommodated upon request.
Why is a barrier layer needed between copper and gold?
Copper diffuses very rapidly through gold, which can cause copper ions to appear on the outer surface of the gold deposit and form a partial oxide layer over time. To prevent this, a nickel or palladium barrier layer should always be applied between copper and gold. Nickel is the most commonly specified barrier layer due to its lower material cost. In applications where non-magnetic performance is required, palladium is the appropriate barrier layer choice since nickel is magnetic and palladium is not.
Does ProPlate offer high-thickness copper plating?
Yes. ProPlate offers high-thickness copper plating for applications requiring significant deposit build-up including heat treatment stop-off, electroforming, and component build-up and repair. Custom fixturing and masking are available for applications requiring selective high-thickness coverage on specific surfaces only.
What plating methods does ProPlate use for copper plating?
ProPlate plates copper using both barrel and rack methods. Barrel plating is suited for high volumes of small, robust parts. Rack plating is used for larger components, parts requiring precise thickness control, or geometrically complex components where barrel tumbling would cause damage or uneven coverage.
What industries use copper plating services?
Copper plating is widely used in aerospace and defense, semiconductor and electronics, energy technology, and general industrial manufacturing. Common applications include underplating for subsequent precious metal or nickel finishes, electrical and thermal conductivity enhancement, heat treatment stop-off, electroforming, and build-up of worn or undersized components.