Effect of Grain Size on the Sliding Wear and Friction of Alumina at Elevated Temperatures

Abstract

The sliding friction and wear of three different grain-size aluminas were studied from room temperature through 1000°C. The coefficient of friction revealed two distinct regions of decrease with increased temperature, with a transition at ∼700°C. Below 700°C, the coefficient of friction decreased rapidly with increased temperature (∼10 −3 /°C). However, above 700°C, the decrease was more gradual (∼10 −5 /°C). This was believed to be related to a brittle-toductile transition at the wear surface. The coefficient of friction was only weakly dependent on grain size, because the largest grain sizes exhibited slightly higher friction coefficients. However, the specific wear loss of the aluminas increased with increased grain size at room temperature and at 600°C, both below the 700°C transition. The primary mechanism of wear was ascertained to be brittle microfracture along grain boundaries. At 1000°C, above the 700°C transition, the specific wear loss was significantly decreased and appeared to be independent of the alumina grain size. At 1000°C, the wear surfaces developed a thin layer of fine grains formed by dynamic recrystallization. The grain size within the thin layer was in agreement with the previously reported grain-size/Zener-Hollomon parameter relationship.

Sliding wear of Cr–Al2O3–ZrO2 and Mo–Al2O3–ZrO2 composites

“…In most cases, a finer grain size of alumina leads to lower specific wear rates. 13,14 However, this phenomenon appears to be highly dependent on test configuration, as is indicated by other data showing a decrease in specific wear rate with increasing grain size. 15 Choosing a reactive sintering route for metal-ceramic composites has the advantage that the materials can be sintered pressureless to high densities.…”

Dynamic Friction of SiC Surfaces: A Torsional Kolsky Bar Tribometer Study

“…A large amount of experimental research work [1][2][3][4][5][6][7] has been done to investigate the friction and wear properties of ceramics, such as alumina and silicon carbide under different temperature [5], environmental media [6], and surface topography [7]. The conventional types of tribometer of pin-on-disk, roller on disk or plate on plate technique are usually used to carry out the friction test along unidirection or reciprocation.…”

Effects of Temperature on Tribological Properties of Al2O3-TiO2 Coating

“…The worn surfaces of coatings were covered with a discontinuous compact layer. The EDS analysis revealed that the compact layer contained large amounts of silicon but no nitrogen, suggesting that silicon nitride was oxidised and transferred to the worn surface of the coatings 7,18 . There were many cracks existing on the worn surface of the coatings and the compact layer was in the process of delamination as flake-like debris, due to the effect of the cyclic stress.…”

“…The presence of adsorbed moisture and the formation of oxide films can decrease the wear of ceramics 13 . The wear rate of alumina-based ceramics increases with the temperature, increasing 12 up to 600 o C. Tetsuya 7 , et al found grain size also has an important effect on the wear resistance of alumina at elevated temperatures. Therefore, an interest has been shown by the researchers in the wear of plasma sprayed ceramic coatings at elevated temperatures.…”

“…The tribological behaviour of ceramics is also greatly influenced by test conditions, such as, contact load, environment, and temperature [7][8][9][10][11][12][13] . The presence of adsorbed moisture and the formation of oxide films can decrease the wear of ceramics 13 .…”