In printed circuit board technology, different gold surfaces are used for different applications. Here one distinguishes mainly between:
chemical nickel / gold surface
Application: Aluminum wire bonding and / or multiple soldering with flat pad surface.
Reductive gold surface
Application: Gold wire bonding (single case application)
galvanic nickel / hard gold surface
Application: mechanical contact (wear resistance) with simultaneous solderability.
galvanic nickel / bondgold surface
Application: Gold wire bonding (main application)
In the following list, the gold surfaces mentioned above are to be assigned to the typical fields of application. More detailed information about advantages, properties, etc. can be found in the respective subtopics. Of course, an overlap of application areas can not be ruled out and is required for special applications.