Investigation of Surface Properties and FeB-Fe2B Layer Formation in Pack Boronizing of Cementation Steel

Abstract

In this study, cementation steel was boronized at 1050∘C for 6h, 8h, and 10h. Microstructural change on the surface of the samples after boronization was detected by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD), and electron back scatter diffraction (EBSD) analyses. Also, surface roughness, microhardness, and layer thickness were measured. FeB, Fe2B phases, and saw tooth morphology expected in iron-based metals during boring process occurred in the entire process time. The average layer thickness of the boronized samples at 1050∘C for 10h was measured as 222μm and the surface roughness value was 3.40μm. The hardness of boride phases acquired on the samples varied between 1700 HV and 1730 HV. As a result, while the ratio of chromium carbide is the highest in the base metal, the boron level was the highest in the coating. Compounds 49wt.% Cr7C3 and 47wt.% B were identified as the most intensely concentrated.