Understanding Influence of MoSi2 Addition (5 Weight Percent) on Tribological Properties of TiB2

Abstract

In densifying engineering ceramics such as TiB 2 using nonmetallic sinter additives, it is important to assess the influence of the addition of sinter-aid on the properties of TiB 2 . The present article reports how a small addition of MoSi 2 (5 wt pct) sinter-aid enhances the wear resistance of TiB 2 at mode-I fretting contact. This has been confirmed using a series of unlubricated wear tests on hot-pressed ceramics using two different counterbodies, viz. bearing steel and WC-6 wt pct Co cemented carbide, under identical testing conditions. Steady-state coefficient of friction (COF) against steel counterbody has been found to noticeably vary in the range of 0.5 to 1, with variation in load or MoSi 2 addition. However, insignificant variation in COF (~0.5) has been recorded during fretting against WC-Co. Furthermore, lower wear rate (~10 -6 mm 3 /Nm) is measured against the cemented carbide, as compared to that against steel (~10 -5 mm 3 /Nm). It has been observed that the material removal of TiB 2 -based ceramics against steel involves tribochemical wear as well as abrasive wear, and the occurrence of tribochemical wear is explained in terms of various feasible reactions at the tribological interface. Lower contact area, resulting in reduced adhesive wear, along with the absence of additional tribochemical wear, has been attributed to lower wear rate as observed after fretting against the harder (WC-Co) counterbody. A number of possible reactions along with their thermodynamic feasibility are discussed to explain the tribochemical wear at the interface of the mating couple. Irrespective of counterbody or material composition, the measured wear volume exhibits linear dependency on abrasion parameter, confirming the role of material parameters on the contribution of abrasive wear to the material removal/damage of the investigated materials.

Engineered Role of SiC Particle Size on Multi‐Length‐Scale Wear Damage of Spark Plasma Sintered Zirconium Diboride

“…[ 17,18 ] In this context, reinforcement with a suitable secondary phase, such as SiC, B 4 C, ZrC, and MoSi 2 , has improved not only densification but also mechanical properties, such as hardness and fracture toughness, oxidation resistance, thermal properties, and wear resistance as well. [ 16,18–21 ] Among these reinforcements, B 4 C and SiC possess low density (2.52 and 3.16 g cm −3 , respectively [ 16,22 ] ) and are attracting more interest in enhancing the performance of UHTCs. Enormous research has been carried out to study the effect of reinforcements on the mechanical, oxidation, and thermal performance of ZrB 2 .…”

Microstructure, Thermo-Physical, Mechanical and Wear Properties of in-Situ Formed Boron Carbide - Zirconium Diboride Composite

“…Refractory metal borides, carbides and their composites are natural candidates for these tribological applications due to their exceptional hardness, elastic modulus and thermal stability at elevated temperatures [32][33][34][35][36][37][38]. Among these, boron carbide is one of the potential materials for wear resistant applications [25].…”

Achieving uniform microstructure and superior mechanical properties in ultrafine grained TiB2–TiSi2 composites using innovative multi stage spark plasma sintering

“…TiB 2 -based materials have attracted considerable interest in recent years owing to their high melting point (∼3200 • C), good thermal and electrical conductivities, high wear resistance, high hardness and strength retained at high temperatures [1][2][3][4][5]. The combination of the above stated properties make TiB 2 as one of the potential material for high temperature structural applications, cutting tool, armour, electrodes in metal smelting and heavy duty wear applications [1][2][3][4][5].…”

“…The combination of the above stated properties make TiB 2 as one of the potential material for high temperature structural applications, cutting tool, armour, electrodes in metal smelting and heavy duty wear applications [1][2][3][4][5]. However, the widespread applications of monolithic TiB 2 are rather limited, because of its poor sinterability coupled with moderate mechanical properties, in particular low fracture toughness.…”