Microstructure and wear resistance of WC-Co by three consolidation processing techniques

Tungsten carbide-cobalt (WC-Co) has been extensively employed as an abrasion/wear protective material. However, carbon loss (decarbutization) of WC-Co powders during processing reduces the efficiency of the material against abrasive wear. This paper examines the efficiency of three consolidation processing techniques to obtain coatings and bulk samples from WC-Co powder. In this work, high velocity oxy-fuel (HVOF) spray forming and laser engineered net shaping (LENS') were applied to make WC-Co coatings; spark plasma sintering (SPS) was used to produce bulk WC-Co samples for comparison. The microstructures of two types of coatings and one bulk sample were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) to recognize material modification. In addition, porosity and tribological properties of the WC-Co samples were tested. The ultra-microindentation technique was applied to measure the universal hardness and the elasto-plastic properties of the samples. Experiments using a tribometer (ball on disc configuration) under dry conditions have been performed in order to evaluate the friction and wear properties of the different systems. (C) 2008 Elsevier Ltd. All rights reserved.