Types and Features
|Alkaline||9 – 13||Good throwing power; retards co-deposition of base metals.|
|Neutral||6 – 8||Permits alloys via base metal co-deposition; little attack on delicate substrates.|
|Acid||3 – 6||Permits alloys via base metal co-deposition; no attack on delicate substrates; can produce purest commercial gold deposits.|
Three types of gold plating baths are available for use today. The alkaline bath, at a pH of 9.0 to 13.0, provides good throwing power and reduces co-deposition of base metals.
The neutral bath, pH 6.0 to 8.0, will permit alloy formation through base metal co-deposition and will cause little or no attack on delicate substrates.
The acid type bath, pH 3.0 to 6.0, will permit alloy formation via base metal co-deposition and will not attack delicate substrates. The acid type bath produces the purest commercial gold deposit.
Generally, most gold electroplating baths are proprietary and covered by patents. This listing will not be specific, but will outline those which are in greatest use today. All of the baths listed can be used both rack (still) and barrel plating. The choice of which bath to use will depend upon the functional requirements of the gold coating and the substrate upon which it is plated. The features of each system will be discussed when the system is described.