Plasma oxynitrocarburizing of 40Cr steel in an atmosphere of gasoline and air

Abstract

A new plasma oxynitrocarburizing process in an air and gasoline atmosphere was developed. The influences of the atmosphere with different ratios of gasoline/air on the microstructure, surface hardness, and phase composition of 40Cr steel were characterized using optical microscope, scanning electron microscope (SEM), microhardness tester, and X-ray diffractometer (XRD), respectively. The experimental results showed that the plasma oxynitrocarburized layer was composed of bright layer and diffusion layer. It was found that the thickness, hardness, and Fe 3 N concentration of the plasma oxynitrocarburized layer increased with the increment of ratio of gasoline/air. © 2007 Elsevier B.V. All rights reserved.