MICROSTRUCTURE AND PITTING CORROSION OF PLASMA-SPRAYED Ni–Al NANOCOMPOSITE COATING

Abstract

Ni-Al nanoparticles coating (NAN) was manufactured via atmospheric plasma spraying (APS) and thermal treated under hydrogen atmosphere at 1300[Formula: see text]C (TNAN) remained 1 h, and NiAl microparticles coating (NAM) was manufactured as a reference. Nanoscale particles were observed in NAN by TEM, and these nanoscale particles disappeared in TNAN. Many pores and cracks were observed in NAM. Few pores and cracks were observed in NAN, and no pores and cracks were found in TNAN with SEM. A scanning electrochemical microscopy (SECM) testing in 3.5% (wt.) NaCl solution for 3 h revealed that NAM underwent several pitting corrosion, NAN pitting corrosion was relatively minor, and TNAN had no pitting corrosion.