Composition variation of borax salt during the process of vanadizing by thermal diffusion

Abstract

Vanadium pentoxide, borax, boron carbide and sodium fl uoride were used to grow vanadium carbide coating on surface of Cr12 steel at 950 °C by TD process. The coating of vanadium carbide (VC) extended the serve-life period of Cr12 steel as punching die. Kinetics of vanadium carbide coating growth was brought forward and verified by comparison of the mathematical model with the experimental results. The thickness of coating was illustrated by SEM. The chemical constituent of coating and remnants were tested by X-ray diffraction (XRD) and X-ray energy dispersive spectroscopy (EDS). To increase the thickness, rare earth silicon powder (FeSiRe23) was added to the borax salt bath. The analysis of XRD revealed that FeSiRe23 increased the depth of vanadium car-bide coating as reducing agent and catalysis.

Keywords

thermal diffusion / borax salt bath / vanadizing / FeSiRe23

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