The Effect of Chemical Composition and Thermal Sprayed Method on the Chromium and Tungsten Carbides Coatings Microstructure

Maria W. Richert, Borys Mikułowski, Pawel Pałka, Agnieszka Hotloś, Malgorzata Perek-Nowak

Faculty of Non-Ferrous Metals, AGH, University of Science & Technology, Kraków, Poland.

DOI: 10.4236/jsemat.2013.31001                

Abstract

The microstructure, phase consistence and microhardness of thermal sprayed coatings were investigated. The tungsten and chromium carbide coatings and also composite NiCrSiB coating were analyzed. The microstructure of coatings were observed by using optical microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Almost equiaxial carbide particles settled inside the surrounded material of coating were found. The cracks propagating thorough the particles and along boundaries between the particles and surrounded material were observed. This phenomenon was connected with the porosity of coatings. The decarburization process was detected in coatings by phase composition investigation using X-ray method. The decarburization process was the reason due to which beside initial Cr₃C₂ the Cr₇C₃ and Cr₂₃C₆ particles were found. In the tungsten coatings beside the initial WC carbides the W₂Cones were found.

Keywords

Thermal Spraying Methods; Coatings; Chromium and Tungsten Carbides; Composite; Microstructure; Microhardness; Porosity

Conflicts of Interest

The authors declare no conflicts of interest.

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