Finishing coating Hard Gold

Hard Gold is a galvanic hard/thick nickel gold coating. The technology is used as a finishing coating for knife connectors and lamellas of printed circuit boards. Total technological coating thickness: 3-7.25 um (Ni + Au). Before applying, the material undergoes a complex quality check using the methods of electrical testing (Fly-probe and/or by an adapter). The impedance control values do not exceed ± 10%.

Hard Gold features

Galvanic thick gold coating is a reliable method of detachable connection. Since the general durability of printed circuit boards primarily depends on the thickness of gold and the hardness of the contacts, then the maximum operational period of mating contact coatings is achieved by using two materials of different strengths. In this case, Hard Gold hardness is determined by the thickness of nickel/gold layers and varies from 1400 N/mm2 to 2400 N/mm2.

The only disadvantage of applying solid gold coating is a high cost associated with a special item of the production process (the cost of collecting/disposing of wastes) and a significant gold content (maximum thickness Au: 1.25 um).

Advantages of application

  • Improved durability and electrical conductivity of printed circuit boards.
  • Durability of the coating.
  • Effective protection from the harmful environmental effects (moisture, dust, ultraviolet radiation) and the occurrence of a corrosive effect.
  • Wide temperature range of application. Maximum operating temperature + 300˚.

Technological characteristics

Technology opportunities


Period of storage, months


Solderability quality


Multiple solderability


Availability of gold welding process compatibility

It is available, but if necessary, soldering with melting below 240˚ - the board requires pre-drying. This process removes moisture delamination of fiberglass. 

Availability of aluminum welding process compatibility


Finishing coating thickness, μm

2,5-6 Ni/0,5-1,25 Au

Optimum pitch of landing areas, mm


Process temperature characteristics, ˚С


Torsion, bending and dimensional stability problems


Complanarity state of landing areas


Surface cleanness state


Corrosion resistance index


Visual defects


Qualitative risks

The possibility of the emergence of black areas

Solder reliability index


Compatibility with lea -free methods


Index of the environmental damage, safety for the human body


Cost characteristics


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