Abstract:

In this study, DIN 1.2738 steel was boronized at temperatures of 1123, 1173 and 1223 K and for 3, 6 and 9 hours using a boronizing mixture containing boric acid, which can be an alternative to commercial boronizing mixtures. The morphology and thickness of the boride layer formed on the surface of the substrates after boronizing processes were investigated by OM and SEM. The boride layers with a sawtooth morphology, homogeneously distributed on the surface of the material and with thicknesses ranging from approximately 33 to 148 μm were obtained. Chemical analysis of the layer was performed by XRD and EDS analyses. The formation of a single-phase layer containing only Fe2B phase was detected in all samples. The growth kinetic parameters were obtained by making calculations about the diffusion kinetics of the boronized samples. An empirical equation was obtained using these parameters. With this equation, the studies were carried out on the predictability of layer thickness depending on different process parameters. In addition, a regression model was created by evaluating the process parameters and another equation was obtained for the estimation of the layer thickness. The value of activation energy for the substrate was estimated as 204.07 kJ/mol. Contour diagrams were drawn to estimate the thickness of the layer as a function of temperature and time. The adhesion characteristics of the layers were investigated by the Daimler-Benz Rockwell-C adhesion test. As a result, it was determined that the interfacial bond between the substrate material and the layers was strong.

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