Gold Plating Services (Electroplating) per MIL-G-45204, ASTM B488, AMS 2422
Advanced Plating Technologies is an industry leader in functional gold plating services to MIL-G-45204, ASTM B488 or AMS 2422. Our sixty years of expertise in providing precision barrel, rack and vibratory gold plating services is currently employed in numerous industries including the medical, telecommunications, aerospace and electronics industries.
APT offers a complete range of gold plating services including Type I, II and III purity deposits in both soft and hard gold formulations. Advanced Plating Technologies has the ability to underplate with our various nickel plating services including both bright electrolytic nickel, sulfamate electrolytic nickel and electroless nickel deposits as well as copper plating or silver plating if required.
Gold plating has excellent electrical and thermal conductivity, offers exceptional solderability and is a superb reflector of infrared radiation. In addition, gold is a noble metal that does not oxidize or chemically react under normal conditions. For this reason gold plating it is an exceptional choice for numerous engineering requirements where electrical conductivity (especially at low voltages), solderability and corrosion resistance are design requirements.
Advanced Plating Technologies offers gold plating services in both 99.7% pure “hard” gold and 99.9% pure soft gold electrodeposits. Hard gold plating services are commonly employed in applications where repeated sliding or connection wear is a design consideration, such as in female to male interconnect pins or sprung contacts. APT offers hard gold plating that is alloyed with a small amount of cobalt to achieve the required deposit properties.
Soft gold plating services are commonly used where the highest of gold purity is required for soldering, wire bonding, high temperature or high corrosion resistance applications. The soft gold plating deposit provides an extremely pure deposit of gold, which maintains the low hardness, and high corrosion resistance of gold consistent with its elemental form. Soft gold plating is preferred for high temperature applications due to the fact that alloying elements of hard gold plating can oxidize at elevated temperatures.
The appearance of gold plating is very much a function of the underplate that is applied prior to deposition of the final gold layer. If a matte nickel such as sulfamate nickel is applied, the final gold deposit will have more of a matte appearance. If a brightened nickel such as bright electrolytic nickel is utilized, the gold plating will have a bright appearance. As with any deposit, the luster of the basis material has a large degree of correlation to the luster of the final gold plating.
The three most common gold plating services certified by Advanced Plating Technologies are MIL-G-45204, ASTM B488 and AMS 2422. APT can provide Type I, II and III gold deposits per these industry standards. Gold plating services to AMS 2425 as well as most company-specific gold specifications can also be provided as detailed in our specification database. A summary of gold plating services to ASTM B488, MIL-G-45204 and AMS 2422 is provided below:
Gold Plating Services to ASTM B488-01
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 the ASTM and MIL specs are synonymous. The Types listed below are per the current 2001 revision of ASTM B488.
Type I: 99.7% pure gold with a hardness ranging from A (90 HK25 max) to C (130-200 HK25).
Type II: 99.0% pure gold often referred to as hard gold with a hardness ranging from B (91-129 KH25) to D (> 200 HK25).
Type III: 99.9% pure gold often referred to as soft gold with a hardness of A only (90 HK25 Max).
Code A: 90 HK25 Maximum
Code B: 91-129 HK25
Code C: 130-200 HK25
Code D: > 200 HK25
Relationship Between Purity and Hardness (ASTM B488-01 and Newer)
I A, B and C
II B, C and D
III A Only
Class Minimum Thickness [um]
6.5.1 Nickel Underplating – For thickness classes except 5.0, a nickel underplating shall be applied before the gold coating when the product is made from copper or copper alloy. Nickel Underplating is also applied for other reasons (see Appendix X6).
Appendix X6: Some Reasons for Using a Nickel Underplate
X6.1 Diffusion Barrier (E.g. migration of zinc into the gold layer from a brass substrate)
Gold Plating Services to MIL-G-45204
Type I – 99.7 percent gold minimum
Type II – 99.0 percent gold minimum
Type III – 99.9 percent gold minimum
Grade A – Knoop hardness 90 max
Grade B – Knoop hardness 91-129, incl.
Grade C – Knoop hardness 130-200, incl.
Grade D – Knoop hardness 201 and over.
If the hardness grade for the gold coating is not specified, Type I shall be furnished at hardness Grade A (90 Knoop max) and Type II shall be furnished at hardness Grade C (130 to 200 Knoop)
Purity (Type) and hardness (grade) relationship:
Type I A, B or C
Type II B, C or D
Type III A only
Class 00 – 0.00002 inch thick, minimum
Class 0 – 0.00003 inch thick, minimum
Class 1 – 0.00005 inch thick, minimum
Class 2 – 0.00010 inch thick, minimum
Class 3 – 0.00020 inch thick, minimum
Class 4 – 0.00030 inch thick, minimum
Class 5 – 0.00050 inch thick, minimum
Class 6 – 0.00150 inch thick, minimum
Underplate Requirements per section 6.3: a copper, nickel, or copper plus nickel underplate may be used, depending on the application and the environment. Silver or copper plus silver may not be used unless required by item specification. A soft gold strike from a separate plating tank should follow any other undercoating and precede the final gold coating to improve adhesion and prevent contamination of the main gold plating solution by metallic impurities. When applied to a copper rich surface such as brass, bronze or beryllium copper or a copper plate or strike, an antidiffussion underplate such as nickel shall be applied.
Gold Plating Services 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 22.214.171.124.
126.96.36.199 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.
3.2.2 Nickel Flash or Nickel Strike: A nickel flash or nickel strike shall be electrodeposited from a suitable nickel plating solution over the copper, copper alloy containing less than 15% zinc, copper flash or copper strike as applicable.
188.8.131.52 Copper Flash or Strike: Not less than 0.0001 inch (2.5um)
184.108.40.206 Nickel Strike: Not less than 0.0001 inch (2.5um)
220.127.116.11 Gold Plate: Note less than 0.00005 inch (1.27um) on all surfaces on which gold plating is specified.
3.4.4 Purity: Gold, as plated, shall be not less than 99.0% pure, determined by a method acceptable to purchaser.
APT provides expertise in gold plating services to fulfill even the most demanding applications. From prototyping and PPAP qualification to full production processing, it is our goal to exceed your expectations. The following points highlight why Advanced Plating Technologies is a leader in gold plating services:
- Diversity of Substrates: Advanced Plating Technologies provides gold plating services on nearly any metallic substrate such as copper & copper alloys including beryllium, chromium and tellurium coppers, hardened and alloyed steels, stainless steels, Inconels, Hastalloys, Monels, ductile & cast iron and metalized plastics.
- Delicate and Difficult Geometries: Advanced Plating Technologies specializes in gold plating services on delicate parts employing patented oscillating, rock-and-roll, compartmentalized, vibratory and minimum part movement barrel technologies as well as custom-engineered rack fixturing when required to ensure even the most delicate parts are handled properly. APT has a working R&D relationship with several tooling manufactures that has led to several patented designs.
- RoHS and REACH Compliance: Advanced Plating Technologies is at the forefront of environmental compliance and can certify our gold plating services as needed to the current RoHS, ELV and REACH regulations.
- Competitive Pricing: Advanced Plating Technologies has been providing quality gold plating services for over sixty years. Competitive pricing in gold plating services is paramount to gaining and maintaining our customers in today’s competitive global marketplace.
- Reliable Lead Times: With inventories leaner than ever, dependable turn-around is a core competency that we value highly to ensure the service our customer’s need.
- Value Added: Advanced Plating Technologies prides itself in meeting our customer’s needs. Whether it’s custom engineering packaging, vacuum or nitrogen sealed packaging to enhance storage, Kanban inventory management, light subassembly or multiple finishing combinations, APT will work with you to ensure we meet your needs in gold finishing services.
- Extensive in House Analytical and Quality Lab Services: SPC is employed in all wet-lab work surrounding our gold plating services to ensure baths are analyzed and adjusted at optimum frequencies to ensure operation between critical upper and lower control points. Our quality lab employs the latest in x-ray, coloumetric and spectrophotometer technologies to inspect your parts and will work to your requirements to provide testing as needed. Our quality lab can certify salt spray performance to ASTM B117, adhesion to ASTM B571 and solderability to ASTM B678. Mounted cross sections of parts are also available.