M. Yandouzi, B. Jodoin, University of Ottawa, Ottawa, ON, Canada; L. Pouliot, A. Nadeau, Tecnar Automation Ltee, Saint-Bruno, QC, Canada; F. Nadeau, J. Blain, Tecnar Automation Ltée, St-Bruno, QC, Canada
WC-Co-Cr cermet coatings are widely used for wear protection and their properties depend largely on the carbide grain size, volume fraction, as well as the binder mean free path. In an attempt to minimize decarburization, oxidation and dissolution/reaction between the WC and Co during spraying the present work uses a new process, the Pulse Cold Gas Dynamic Spraying process (P-CGDS) developed at the University of Ottawa.
The objective of this work is to determine the effect of the spraying parameters, namely the gun length and diameter, pulse frequency, propellant gas nature, pressure and temperature, and feedstock powder size as well as substrate temperature, on the quality of the WC-Co-Cr coatings deposited using the P-CGDS. In particular, the effect of these parameters on the particle impact velocity is determined by monitoring the impact particle velocity using a laser diagnostic system, the Cold Spray Meter developed by Tecnar Automation Ltée. This allows correlating the particle impact velocity to the coating quality and spraying parameters.
The resulting coatings are analysed using OM, SEM, and image analysis to assess the coatings quality (such thickness and porosity level). Phase analyses are conducted, using XRD, to asses the level of decarburization, oxidation and reaction of the deposited materials compared to the feedstock powder.
