Microabrasion Wear Behavior of VC and CrC Coatings Deposited by Thermoreactive Diffusion Technique

Abstract

Thermal reactive diffusion (TRD) coating on a DIN 1.2367 die steel substrate was performed in a powder mixture consisting of ferrovanadium, ferrochromium, ammonium chloride, alumina, and naphthalene at temperatures of 1000, 1050, and 1100 degrees C for 2-4h. The carbide layers were characterized using the microstructure, microhardness, X-ray diffraction, and chemical analysis. Wear scars were analyzed on scanning electron microscopy (SEM) micrographs with an energy-dispersive X-ray spectroscopy module. Depending on the coating process time and temperature, the thicknesses of the vanadium carbide and the chromium carbide layers formed on the substrate were obtained in a range from 7 to 30 mu m and 5 to 17 mu m, respectively. The maximum hardness values of vanadium carbide and chromium carbide layers were measured as 2537 and 1973 HV, respectively. The test samples coated using the TRD method were analyzed with regard to abrasive wear behavior using three different loads (1, 2, and 3N) and speeds of 40, 80, and 160rpm in fixed-ball micro-abrasion tests. Depending on the load and speed values applied, the grooving and rolling mechanisms were found to be predominant abrasion mechanisms on the worn surfaces.