Mechanical and Tribological Behaviors of Hot-Pressed SiC/SiCw-Y2O3 Ceramics with Different Y2O3 Contents

• Published in: Coatings (Basel) Vol. 13; no. 5; p. 956
• Main Authors: Zhang, Shaohua, Wang, Jinfang, Zhang, Meng, Ding, Longqi, Chan, Huijun, Liu, Xiyu, Wu, Fengqing, Tu, Zhibiao, Shao, Ling, Ye, Nengyong, Dai, Sheng, Zhu, Liu, Chen, Shichang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19.05.2023
• Subjects: Additives; Ceramics; Coefficient of friction; Densification; Density; Diamond pyramid hardness; Energy consumption; Flexural strength; Fracture toughness; Mechanical properties; Microstructure; Nanoparticles; Scanning electron microscopy; Silicon carbide; Sintering; Specific gravity; Tribology; Wear rate; Wear resistance; Whisker composites; Yttrium oxide; Beijing China; United States > US; China
• ISSN: 2079-6412; 2079-6412
• DOI: 10.3390/coatings13050956

Sintering additives are commonly used to reduce the conditions required for densification in composite ceramics without compromising their performances simultaneously. Herein, SiC/SiCw-Y2O3 composite ceramics with 10 vol.% SiC whiskers (SiCw) and different Y2O3 contents (0, 2.5, 5, 7.5, and 10 vol.%) were fabricated by hot-pressed sintering at 1800 °C, and the effects of Y2O3 content on the microstructure, mechanical properties, and tribological behaviors were investigated. It was found that the increased Y2O3 content can promote the densification of SiC/SiCw-Y2O3 composite ceramics, as evidenced by compact microstructure and increased relative density. The Vickers hardness, fracture toughness, and flexural strength also increased when Y2O3 content increased from 2.5 vol.% to 7.5 vol.%. However, excessive Y2O3 (10 vol.%) aggregated around SiC and SiCw weakens its positive effect. Furthermore, the Y2O3 additive also reduces the coefficient of friction (COF) of SiC/SiCw-Y2O3 composite ceramics, the higher the Y2O3 content, the lower the COF. The wear resistance of SiC/SiCw-Y2O3 composite ceramics is strongly affected by their microstructure and mechanical properties, and as-sintered SiC ceramic with 7.5 vol.% Y2O3 (Y075) shows the optimal wear resistance. The relative density, Vickers hardness, fracture toughness, and flexural strength of Y075 are 97.0%, 21.6 GPa, 7.7 MPa · m1/2, and 573.2 MPa, respectively, the specific wear rate of Y075 is 11.8% of that for its competitor with 2.5 vol.% Y2O3.