Dilution phenomenon during coating of titanium alloys by Plasma Transferred Arc (PTA) process

Optimization of the process parameters presumes on the one side obtaining of a suitable layer/substrate adhesion and on the other side, the smallest dilution degree of the addition material with the base material in order to avoid the degradation of functional properties. Applying the factorial method, the paper analyses the dependence of the dilution degree obtained through PTA process as linear function of 8 process parameters. The obtained data permitted the interpretation and hierarchization of the factors which cause the increasing (plasmagen gas flow, welding speed, welding current, generator-piece distance) and decreasing (current intensity of pilot arc, shielding gas flow, carrier gas flow, powder flow) of the dilution degree.