Microstructure and properties of HVOF thermal sprayed NiWCrBSi coatings

Preliminary studies have been conducted in order to characterize plain carb on steel samples which have been HVOF thermal sprayed using commercial NiWC rBSi powder. The structure; morphology and size distribution of the powder were determined prior to the deposition process. The influence of both spra ying distance and feed powder rate at psi [equivalence ratio]= 1 on the mor phology of the coatings and their properties are assessed. The coatings are characterized by means of X-ray diffraction, optical and scanning electron microscopy. Results regarding porosity, microhardness and corrosion resist ance in 5% NaCl solution and their relationship with the spraying parameter s are also reported. (C) 1999 Published by Elsevier Science S.A. All rights reserved.