Optimization of ceramic content in nickel–alumina composite coatings obtained by low pressure cold spraying

The paper describes the technology of nickel-alumina composite coatings obtained by low-pressure cold spray (LPCS). content alumina reinforcement was optimized mixing commercial K32, being a mechanical mixture Al2O3 + 50 wt% Ni, with Ni-cladded powders developed in present study. cladded were prepared hydrogen reduction method. Two including Ni-films covering particles developed: 70 Ni (powder # 1) and 80 2). morphology powders, analyzed using scanning electron microscope (SEM), showed porous, cauliflower-like layer powder 1 dense nickel 2. measurements granulometry enabled finding size distribution pure having mean value about ?m which increased cladding to 65 mixed K32 sprayed LCPS onto mild steel substrate. microstructure characterized SEM, energy dispersive X-ray spectroscopy (EDXS) backscatter diffraction (EBSD). graphical analysis coatings' cross-sections determining deposits. This from 7% 9–13% its mixtures 2 up 20–30% for 1. microhardness as well coating only slightly greater than HV 0.1 > 150. microhardnesses ? 200 reached K32. Finally, bond strength coatings, measured test ISO 14916, range 1.7 5.9 MPa. greatest