Sample substrates of SAE 1010 steel were connected as vacuum arc anodes and exposed to the plasma and particle flux produced from source electrodes connected as arc cathodes. Source electrodes, and hence coating materials, of Ni, Al, and 316 stainless steel were investigated. A sequence of six 70-ms half-amplitude full-width arc pulses were applied, with peak currents ranging from 300 to 900 A. Interelectrode gaps of 3 and 6 mm, and axial magnetic fields of 0 and 0. 01 T were utilized. The resultant coatings were analyzed using metallographic, SEM, EDAX, and salt-spray diagnostics. The coating thickness was up to 30 mu m, indicating effective coating rates of up to 72 mu m/s. The thicker coatings were observed at higher currents and short gaps. The coatings were generally well bonded to the substrate. Best corrosion protection was afforded by the Al coatings, followed by 316 stainless steel. Increased corrosion protection is obtained using the higher currents and the shorter gaps, in agreement with the increased thickness measured metallographically.
|Number of pages||5|
|State||Published - 1986|