Effect of powder feed rate on the mechanical properties of WC-5 wt%Ni coatings deposited using low pressure cold spray

WC-5 wt%Ni coatings were fabricated onto 3CR12 stainless steel plates using low pressure cold spray deposition. The powder feed rate of the volumetric feeder was varied at 50% (23.6 rpm, 6.8 +/- 1 g min(-1)), 75% (35.7 rpm, 10.1 +/- 0.9 g min(-1)), and 100% (58.9 rpm, 15 +/- 1.1 g min(-1)), and the resulting influence on the mechanical properties of the coatings was investigated. The results were analyzed using a two-parameter Weibull distribution and linear regression analysis. A new parameter to quantify WC particle refinement is proposed. A powder feed rate of 75% produced the best coating properties, achieving a high hardness (2.56 GPa), low porosity (0.55%), high interfacial toughness (12.61 MPa m(0.5)), high Young's modulus (69.23 GPa), and good fracture toughness (2.81 MPa m(0.5)). This feed rate appeared to be the optimum deposition parameter to produce dense coatings, achieving a high level of Ni plastic deformation and a high amount of refined WC particles, which are too small to cause significant erosion during impact, and are therefore better able to be retained by the ductile binder. (C) 2016 Elsevier Ltd. All rights reserved.