The Basics of Silver Plating

Gold and silver share a lot of similarities. Both have almost the same chemical and physical properties and both have soft, ductile and malleable characteristics and have melting points of 1,065°C as well as 961°C. Because of this, the process of Silver Plating is pretty much similar to Gold Plating, except for some minor differences.

Silver is considered a coinage metal. Because of this characteristic, it has become one of the most sought after metals since the ancient times. Much of the recorded history involves silver and they have since been considered the most precious metal used for monetary and decorative usage.

Early Application

Early application of the Silver Plating would require fire gilding and leafing especially if used mostly for decorative purposes. When the electronics and electrical industries have become popular especially in the 19th until the 20th centuries, various applications were created by means of Silver Electro Plating. It is due to its chemical inertness, conductivity, resistance to arcing, as well as low and stable contact resistance.

Early applications of gold plating and its predecessors, fire gilding and leafing, were almost exclusively decorative. The rise of the electrical and electronics industries in the latter half of the 19th and throughout the 20th centuries created applications for gold based on its chemical inertness, low and stable contact resistance, conductivity, and resistance to arcing.

Silver-Brightened Gold

Silver is the first commercially successful brightening agent that was used for gold. The early formulations of this system, including the similar formulations that employ antimony or tin, has made use of a large concentration of free cyanide, that has caused staining problems and have attacked some printed circuit board laminates when in use. The Silver Plating solutions were re formulated along with electrolytes that are similar to those with color flash baths. The Silver Electro Plating is based on phosphate and comes with free cyanide that was reduced to 0 up to 7.5 grams per Liter. The deposits that come with silver content that ranges from 4 to 9 weight percent are often more durable as a sliding friction, though it is still commonly used for slide wire as well as with rotary switch applications.

Silver Plating

Although the complex cyanides of gold is stable at a certain pH value that is low enough to allow the use of electrolytes through Silver Electro Plating, the complex cyanide of the Silver is unstable below the neutrality. It therefore hydrolyzes to release the insoluble AgCN which imposes a requirement to fully maintain at least some of the free cyanide within the system and set a minimum operating pH for the Cyanide Silver Plating solutions of at least 8.0 up to 8.5. Within the general class of the Cyanide silvers, there are several variations available.

Recently, a series of the silver complexes with the hydantoin as well as the substituted hydantoins are being prepared and are readily available for use. These types of Silver Electro Plating solution promise an improved pH stability as well as solution control, along with higher brightness and greater resistance to tarnishing.

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