Preparation of high-hardness nickel-based alloy powder for laser cladding

Purpose The purpose of this study is to develop a high-hardness nickel-based alloy powder to prevent crack propagation in laser cladding. The technique can present a good molding effect and excellent corrosion resistance to meet the needs of industrial production. Design/methodology/approach An initial nickel-based alloy powder was designed through the addition of ferroboron and ferrosilicon along with Molybdenum, Tungsten Carbide and Yttrium Oxide at different ratios, which reduced the low-melting-point eutectic phase, improved the high-temperature performance and increased the hard phase. The microstructural morphology, microhardness and phase composition of the cladding layers were respectively evaluated by scanning electron microscopy, microhardness tests and X-ray diffraction. Findings The results indicated that after adding 2 Wt.% Mo, the laser cladding layer had no macro-cracks, and the microhardness increased from 374.8 to 440.7 HV. The addition of Mo transformed the grain morphologies from coarse and massive to fine and dense bars and flakes, and the phases were Chromium Carbide, Iron Nickel, Chromium Carbide, Molybdenum Boron Carbide, Chromium Boride and Molybdenum Nickel. The addition of 1.0 Wt.% Y₂O₃ and 15 Wt.% WC also resulted in no macro-cracks, and the microhardness was enhanced to 510.0 HV. Meanwhile, the addition of Y₂O₃ and WC caused the organization to be finer, and the overall properties were significantly promoted. Originality/value A high-hardness nickel-base alloy powder, Ni50L, was prepared, with “L” denoting that it is specifically prepared for laser cladding. The cladding layer using Ni50L has a good molding effect and excellent corrosion resistance.