Plasma Spray for Difficult-To-Braze Alloys

Nickel plating on surfaces makes brazing easier for some alloys. Sometimes nickel plating may not be feasible because of manufacturing sequence, size of hardware, or lack of suitable source for nickel plating. Alternative surface preparation in such cases is to grit-blast surface lightly and then plasma-spray 1 1/2 to 2 mils of fine nickel powder or braze-alloy material directly on surface. Powder is sprayed from plasma gun, using argon as carrier gas to prevent oxidation of nickel or braze alloy.