Gold Electrolytes for Rack and Barrel Plating

Soft Gold Electrolytes

Auruna® 550 neutral electrolyte deposits pure gold coatings with a matte yellow appearance. It was engineered for use where lifting of fully aqueous resists is an issue and where excellent bondability and solderability are required. Deposits exhibit excellent ductility, hardness below 90 HK25, low contact resistance, and 99.9% purity. Auruna 550 deposits meet ASTM B488 Type III, Code A.

Auruna 551 mildly acidic electrolyte deposits thin, pure gold (0.05-0.1 μm) as gold strike layers for neutral or alkaline gold plating baths. It also provides adhesive activation of the basic material and protection of the main gold bath from contamination.

Auruna 553 neutral fine gold electrolyte produces silk-matte coatings of exceptional ductility. Deposits are up to 200 μm; hardness is approximately 90 HV 0.01. Auruna 553 has excellent soldering and bonding properties and meets ASTM B488-01, Type III, Code B.

Plating technician rack plating in Uyemura gold electrolytes

Auruna 556 neutral electrolyte deposits hard and bright pure gold with a high current efficiency of 90%. 556 is well suited for use with PCBs where lifting of the resist by hydrogen should be avoided.

Auruna 5000 neutral electrolyte deposits a fine gold matte yellow microcrystalline coating. It was developed for use on flexible PCBs and rigid substrates.

PCBs are plated in matte nickel, strike gold plated, then coated in Auruna 5000. Gold layers exhibit excellent bondability and solderability, high ductility and low electrical resistance. Auruna 5000 layers are 99.95% pure gold, with as-plated hardness of 70-85 HV 0.025. Coating meets the requirements of ASTM B-488-01, Type III, Code A/B.

Hard Gold Electrolytes

Auruna 215 hard gold electrolyte was developed for decorative applications, particularly parts contacting skin (jewelry, watches). Coating is free of nickel and cobalt, thus eliminating potential skin sensitivities.

Auruna 232 weakly acidic electrolyte for the deposition of gold coatings shows a standard “2N” color, according to ISO 8654. Process is used for decorative applications; deposits are bright with constant color and up to 5 μm thick.

Auruna 241 weakly acidic electrolyte deposits yellowish-grey gold coatings. Process is used for decorative applications up to 1 μm thick. Bath is compatible with both rack and barrel plating.

Auruna 311 gold-cobalt electrolyte was engineered for the direct gold plating of tungsten, stainless steel, nickel and other difficult-to-plate substrates. This RoHS-compliant coating is ductile, low porosity, corrosion-resistant – and cyanide-free.

Auruna 311 is suitable for both strike gold layers and thick coatings. It has excellent throwing power, and activates without halogenides. It is suitable for rack, barrel and continuous lines; a cobalt-free version is also available.

Auruna 500 neutral electrolyte deposits red 18-carat gold-copper coatings. Coatings are very hard and abrasion-resistant and resist tarnishing and corrosion.

Auruna 500 LC neutral electrolyte deposits red 18-carat gold-copper coatings. Bath uses low gold content and has stable pH-value. Coatings are very hard and abrasion-resistant; they also resist tarnishing and corrosion.

Plating technician rack plating in Uyemura hard gold-nickel electrolytes

Auruna 527 hard gold-nickel electrolyte minimizes gold consumption, and delivers excellent throwing power in barrel plating operations.

Long-life, room temperature bath is mildly acidic, highly stable and impurities-tolerant; low deposition speed facilitates good thickness distribution, particularly for hollow parts.

Coatings exhibit excellent abrasion resistance and low contact resistance. Low gold content can be reduced from 4 g/to 2 g/l, to further reduce drag-out. Ideal for connector applications where masking is impractical.

Auruna 528 hard gold-nickel electrolyte provides high current efficiency, hardness of 150 HV 0.025. Solution can be run with high current density or reduced gold content; maximum coating thickness is 10 μm. Ideal for connectors, PCB with sensitive resists, and decorative applications.

Auruna 529 hard gold-cobalt electrolyte provides high current efficiency, hardness of 180 HV 0.025. The process has a high efficiency (65%) and a mildly acidic pH. Coating offers excellent abrasion resistance, with a maximum thickness of 10 μm.

Auruna 530 hard gold-cobalt electrolyte was developed for electrical contacts. Process provides high current efficiency, hardness of 170 HV 0.01. Bath is mildly acidic. Coating offers excellent abrasion resistance, with a maximum thickness of 5 μm.

Auruna 539 hard gold-cobalt electrolyte produces gold alloy deposits of 99.7% gold, alloyed with cobalt. Baths have excellent throwing power. Ultra-bright deposits have excellent corrosion and abrasion resistance, and a hardness of 200 HV.

Auruna 539 was developed for technical and decorative applications with low coating thickness requirements. It is well suited for pregilding and barrel gold plating. Process provides excellent deposit uniformity and a maximum thickness of 2 μm.

Auruna 539 LC weakly electrolyte with a low gold content of 2 g/l and a deposition speed of 1 μm within approximately 8 minutes (5 micro-inches per minute). Bath is preferably used for decorative and technical applications with a low coating thickness up to 2 μm.

Gold Salts

Auruna 6700 Gold Salts are used for cyanide-based gold plating products whether electrolytic, immersion, or electroless gold plating. The product is specially formulated for proper purity ensuring optimum performance. Salts are a white, granular, free pouring powder containing 67% gold metal, supplied in 1 Troy ounce or 5 Troy ounce jars.

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