Electrolytic Boronizing of Titanium in Na2B4O7-20%K2CO3

Abstract

Using Na2B4O7-20%K2CO3 as molten salt, the electrolytic boronizing process was used to prepare TiB whiskers on the surface of the titanium. X-ray diffraction (XRD) and electron probe micro analysis (EPMA) techniques were applied to determine the phases and their contents in boride layer. The cross-section morphology of the boride layer was measured by scanning electron microscope (SEM). The results showed that the boride layer was composed of TiB2 and TiB, with continuous phase TiB2 as the outer layer and TiB whisker as the intermediate layer. The maximum length of TiB whisker could reach 230 µm, with an aspect ratio of over 1,000. The TiB whiskers were embedded into titanium substrate. The hardness of boride increase from 2,049.7 MPa to 3,270.6 MPa.