Sulfamate plating chemistry is the most popular way to plate indium. A properly maintained bath can last for years with the addition of only a small volume of bath solution to replenish the tank.
Sulfamate electroplating solution is available in small bottles, 55-gallon drums, or larger totes.
Indium sulfamate is preferred indium plating bath for the following reasons:
- The bath is a high throwing power formulation. It is stable, easy to maintain and operate, and has a wide latitude of operational parameters, which allows for heavy industrial use.
- The bath uses soluble indium anodes. This eliminates the need to “bail out” the excess plating bath from concentrate additions and the resultant waste disposal. Other baths require inert anodes that necessitate the use of an expensive liquid concentrate to maintain the indium concentration.
- No costly additives are needed for the operation. Grain refiners and leveling agents are present in sufficient quantities to last the life of the bath.
- The only additive required with an indium plating bath is sulfamic acid when the pH rises above 3.5 and the solution begins to turn milky white.
- Recovery of the spent plating bath solution only requires raising the pH of the solution to precipitate the indium.
- There is no need to incur disposal costs caused by the development of high toxicity or the formulation of cyanide.