Microstructure and Properties of TiB(2) Composites Produced by Spark Plasma Sintering with the Addition of Ti(5)Si(3)

Titanium diboride (TiB(2)) is a hard, refractory material, attractive for a number of applications, including wear-resistant machine parts and tools, but it is difficult to densify. The spark plasma sintering (SPS) method allows producing TiB(2)-based composites of high density with different sintering aids, among them titanium silicides. In this paper, Ti(5)Si(3) is used as a sintering aid for the sintering of TiB(2)/10 wt % Ti(5)Si(3) and TiB(2)/20 wt % Ti(5)Si(3) composites at 1600 °C and 1700 °C for 10 min. The phase composition of the initial powders and produced composites was analyzed by the X-ray diffraction method using CuK(α) radiation. The microstructure was examined using scanning electron microscopy, accompanied by energy-dispersive spectroscopy (EDS). The hardness was determined using a diamond indenter of Vickers geometry loaded at 9.81 N. Friction–wear properties were tested in the dry sliding test in a ball-on-disc configuration, using WC as a counterpart material. The major phases present in the TiB(2)/Ti(5)Si(3) composites were TiB(2) and Ti(5)Si(3.) Traces of TiC were also identified. The hardness of the TiB(2)/Ti(5)Si(3) composites was in the range of 1860–2056 HV1 and decreased with Ti(5)Si(3) content, as well as the specific wear rate W(v). The coefficient of friction for the composites was in the range of 0.5–0.54, almost the same as for TiB(2) sinters. The main mechanism of wear was abrasive.