Influence of MoSi2 Addition on Load-Dependent Fretting Wear Properties of TiB2 Against Cemented Carbide

• Published in: Journal of the American Ceramic Society 2009-09, Vol.92 (9), p.2059-2066
• Main Authors: Raju, G. Brahma, Basu, Bikramjit
• Format: Article
• Language: English
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.2009.03173.x

In an earlier work, it was observed that the use of MoSi2 (up to 10 wt%) enhanced the densification and mechanical properties of TiB2. Therefore, the motivation of this study is three‐fold: (a) to assess whether a small amount of MoSi2 addition can enhance wear resistance property, (b) to study whether the MoSi2 addition will influence the formation of a tribochemical layer, and (c) to correlate the wear resistance with material properties in TiB2–MoSi2 materials. In order to address these issues, a series of fretting experiments were conducted systematically by varying load (2, 5, and 10 N) at an oscillating frequency of 4 Hz and a 100 μm linear stroke, for a duration of 100 000 cycles with a cemented carbide (WC—6 wt% Co cermet) ball as a counterbody. The average coefficient of friction of the TiB2 samples varied within a narrow range (0.50–0.54), without being much affected by either the sintering additive or the load. The wear volume increased with increasing load, while the specific wear rate of all the TiB2 compositions falls within a mild wear regime (1.1–3.4 × 10−6 mm3/Nm). Based on the experimental results, it can be said that the addition of MoSi2 degrades neither the wear resistance properties nor the frictional properties of TiB2, within the investigated load regime. The microcracking‐induced spalling has been found to be the dominant mechanism and, consequently, the wear volume is observed to have a linear dependency on the abrasion parameter. It is noteworthy that the tribo‐oxidation as well as the formation of finer wear debris particles occurs to a limited extent.