Gold Plating Services
Precision gold electroplating for industrial, medical, semiconductor, and aerospace applications. Hard, soft, and proprietary biocompatible gold bath systems available
ProPlate® provides gold plating services for industrial, medical, semiconductor, electronics, and aerospace applications. Gold is one of the most versatile and widely specified precious metal finishes, valued for its exceptional corrosion resistance, electrical conductivity, biocompatibility, and radiopacity. ProPlate offers three gold bath systems to meet the full range of application requirements, from hard gold for wear-resistant connector contacts to soft and proprietary biocompatible gold for medical device components.
GOLD(Au)
Gold is a chemical element with a bright, slightly reddish yellow color in its purest form. As a precious metal and one of the least reactive chemical elements, it does not oxidize in air, remaining stable under standard conditions, and its electrical conductivity is constant over long periods.
Gold plating can enable metal pieces to be soldered together in situations where this would not have been previously possible and increase wear resistance when mixed with cobalt. Its corrosion resistance makes gold electroplating suitable for connector pins, electrical switch contacts, and other applications where electrical contacts occur intermittently.
For medical device specific gold plating requirements including biocompatible finishes and radiopaque marker applications, visit our Medical Gold Plating page.
Underplate Recommendations
Metal ions from base metals such as brass, bronze, or beryllium copper, can disseminate into a gold layer applied on top and degrade the non-oxidizing and hardness properties of the gold. An anti-diffusion underplate, such as nickel, applied to the surface of the metal can prevent such occurrences and create a bright finish.
Purity and Coating Thickness
Gold of the highest purity is preferred for selective gold plating as impurities in the deposit can make soldering more difficult. Gold electroplating coatings should range between 50 and 100 micro inches for the most robust soldering.
Gold Properties
Gold provides highly uniform coverage over complex geometries and fine features, producing a smooth, consistent plated surface when properly applied. Its excellent throwing power allows gold to coat recessed areas and intricate details effectively, helping to minimize porosity and reduce the risk of pinholes that can compromise the final finish.
Because gold deposits are dense, non-porous, and resistant to oxidation, gold serves as a reliable functional and decorative plating layer rather than a sacrificial undercoat. Gold’s ductility allows it to maintain surface integrity without cracking, and it can be polished to a smooth, lustrous finish, making it ideal for applications where electrical performance, corrosion resistance, and surface quality are critical.
| Gold- Au | |||
|---|---|---|---|
| Atomic Number | 79 | Thermal Conductivity - W/(m*K) | 320 |
| Atomic Weight - g/mole | 197 | Electrical Resistivity - (Ohm*m) | 2.44E-08 |
| Density - g/cm³ | 19.28 | Electrical Conductivity - (S/m) | 4.50E-07 |
| Melting Point - C° | 1064.18 | Hardness - Hv | 216 |
| Melting Point - F° | 1747.52 | Specific Heat Capacity - J/(kg*K) | 129.1 |
ProPlate Gold Bath Systems
ProPlate operates three gold plating bath systems to accommodate the full range of industrial and medical application requirements. Selecting the appropriate bath depends on the required purity, hardness, biocompatibility, and end use of the component.
Hard Gold
ProPlate’s hard gold bath deposits 99.7% pure gold hardened with cobalt. The cobalt co-deposit increases the hardness and wear resistance of the gold layer, making hard gold the preferred choice for high-cycle electrical contacts, connector pins, and other applications where surface durability is critical. Hard gold is not biocompatible and is not used for implantable or body-contact medical device applications.
Soft Gold
ProPlate’s soft gold bath deposits 99.9% pure gold with no hardening additives. Soft gold is biocompatible and is used in applications requiring high purity, excellent solderability, and compatibility with sensitive substrates or regulatory requirements. It is commonly specified for wire bonding, semiconductor components, and select medical device applications.
Vizi-Band® Gold
ProPlate’s Vizi-Band Gold bath is a proprietary 99.9% pure gold plating solution developed in-house by ProPlate’s engineering team for specialized medical device applications. Like soft gold, the Vizi-Band® Gold bath is biocompatible. Learn more about Vizi-Band® radiopaque marker technology.
Have question about which gold plating is right for your application? Our experts are ready to help.
Gold Plating Specifications
ProPlate provides services per the certified ASTM B488, MIL-G-45204, and AMS 2422 plating specifications. Our services include Type I, II, and III deposits. Company specific specifications can also be accommodated upon request.
NOTE: ASTM B488 underwent a major revision from 1995 to 2001. The Type callout of the ASTM was revised to parallel that of MIL-G-45204 such that the Type and Codes of ASTM and MIL specs are synonymous. The Types listed below are per the current 2001 revision of ASTM B488.
Gold Plating to ASTM B488-01
Type: Gold Purity
- Type I – 99.7% gold minimum
- Type II – 99.0% gold minimum
- Type III – 99.9% gold minimum
Code: Knoop Hardness
- Code A – 90 HK25 maximum
- Code B – 91-129 HK25
- Code C – 130-200 HK25
- Code D – > 200 HK25
Gold Plating to MIL-G-45204
Type: Gold Purity
- Type I – 99.7% gold minimum
- Type II – 99.0% gold minimum
- Type III – 99.9% gold minimum
Grade: Knoop Hardness
- Grade A – 90 max
- Grade B – 91-129
- Grade C – 130-200
- Grade D – 201 and over
Gold Plating to AMS 2422
3.2.1: Copper Flash or Copper Strike: a copper flash or copper strike shall be electrodeposited from a suitable plating solution, except as exempted in 3.2.1.1.
3.2.1.1: When parts to be plated are made of copper or copper alloy containing less than 15% zinc, the copper flash or copper strike may be omitted.
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Medical Gold Plating Applications
Gold is the most widely specified precious metal finish in the medical device industry due to its biocompatibility, radiopacity, and corrosion resistance. ProPlate’s soft gold and Vizi-Band® Gold bath systems are specifically suited for medical device applications including catheter-based components, radiopaque marker bands, implantable contacts, and electrophysiology electrodes.
For detailed information on ProPlate’s medical gold plating capabilities, specifications, and prototype products, visit our dedicated Medical Gold Plating page.
Gold Plated Prototype Components
ProPlate offers ready-to-order gold plated prototype components for engineers in early-stage development. Products include gold plated marker bands, electrodes, pull ring assemblies, and gold plated NdFeB magnets.
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Frequently Asked Questions About Gold Plating Services
What is gold plating and how does it work?
Gold plating is an electroplating process that deposits a thin, uniform layer of gold onto the surface of a component using an electrolytic bath. The part acts as the cathode in the circuit, and gold ions from the bath solution are reduced and deposited onto the surface. The thickness, purity, and hardness of the deposit are controlled by bath chemistry, current density, and process time.
What gold plating specifications does ProPlate plate to?
ProPlate provides gold plating services to ASTM B488, MIL-G-45204, and AMS 2422 specifications. Type I, II, and III deposits are available. Company-specific specifications can also be accommodated upon request.dion Content
What is the difference between hard gold and soft gold?
Hard gold contains cobalt as a co-deposit, which increases hardness and wear resistance. It is specified for high-cycle electrical contacts and connector applications. Soft gold is 99.9% pure with no hardening additives, making it biocompatible and suitable for wire bonding, semiconductor applications, and medical device components. ProPlate also offers a proprietary Vizi-Band® Gold bath, a 99.9% pure biocompatible gold developed in-house for specialized medical device applications.
What thickness of gold plating does ProPlate offer?
ProPlate offers gold plating across the full range of ASTM B488 thickness classes, from 0.25 microns (~0.000010 inch) through 5.0 microns (~0.000200 inch). For soldering applications, gold electroplating coatings of 50 to 100 microinches provide the most robust results. Custom thickness requirements outside standard classes can also be accommodated.
What underplate does ProPlate recommend for gold plating?
For components made from copper, brass, bronze, or beryllium copper, an anti-diffusion underplate such as electroless or sulfamate nickel is recommended before gold plating. Nickel prevents metal ions from the base material from diffusing into the gold layer and degrading its non-oxidizing and hardness properties. It also acts as a leveling layer, pore corrosion inhibitor, and tarnish creepage inhibitor.
Does ProPlate offer gold plating for medical devices?
Yes. ProPlate’s soft gold and Vizi-Band® Gold bath systems are biocompatible and suited for medical device applications. For detailed information on medical gold plating capabilities visit our Medical Gold Plating page.