Study on chemical nickel gold process

- Aug 28, 2018-

Chemical nickel gold coating is a wet process of PCB panel with single treatment but multipurpose, which has the functions of welding, contact conduction, wire drawing and heat dissipation.There is no other process to contend with.But the process has been difficult for a long time. Problems often occur and are difficult to deal with.For this, I will work in the process of quality problems with the industry before

Chemical nickel gold coating is a wet process of PCB panel with single treatment but multipurpose, which has the functions of welding, contact conduction, wire drawing and heat dissipation.There is no other process to contend with.But the process has been difficult for a long time. Problems often occur and are difficult to deal with.In this regard, I will work in the process of quality problems with industry predecessors to discuss.

Starting from the reaction mechanism of chemical nickel gold.

A nickel,

Nickel salt: mainly nickel sulfate, also nickel chloride, nickel acetate

Reducing agent: sodium dihydrogen hypophosphate, NaH2PO2

Reaction mechanism:

Note: phosphorous ions of resultant sodium dihydrogen phosphate hydrolyze and oxidize to phosphate and release two active hydrogen atoms to adsorb on the palladium surface of the copper base.

The nickel is rapidly reduced and plated on activated palladium surface.

A small fraction of this material, stimulated by catalytic hydrogen, produces phosphorus atoms and deposits them in the nickel layer.

In the catalytic environment, some of the phosphates themselves oxidize and form hydrogen gas that emerges from the nickel surface.