Various structural ceramic materials have been developed for tribological applications. Among them, silicon carbide ceramics exhibit excellent properties, making them a good candidate for different tribological applications. Currently, the application of silicon carbide ceramics as triboelements is mainly concentrated on specific industries such as manufacturing, chemical, aviation, automobile, among others. The need to expand their application in other fields such as biomedical and electronics have attracted significant research interest. Nevertheless, SiC ceramics exhibits poor friction characteristics under unlubricated sliding contacts, thus limiting their applications. Poor friction significantly deteriorates the durability and reliability of tribosystems, and its reduction is imperative. One way of reducing the friction coefficient is by improving wear resistance.
The complex tribological performance of silicon carbide ceramics is dependent on material characteristics such as surface and microstructural features and external factors such as load and temperature. However, more extensive research and understanding on the tribological behaviors of silicon carbide ceramics is still necessary. In a recent paper published in the Materials and Design journal, Dr. Wei Zhang, Dr. Seiji Yamashita, and Professor Hideki Kita from Nagoya University presented an expert opinion review of tribological research progress of silicon carbide ceramics. In addition to proposing future trends on tribology of silicon carbide ceramics, the authors also hoped to provide design reference for silicon carbide ceramics with low friction and high wear resistance.
According to the authors, the review focused more on microstructural characteristics, surface characteristics, self-lubrication methods, and external factors. Enhancing tribological properties for silicon carbide ceramics can reduce friction and prevent wear loss. The authors reported four main approaches for improving the tribological performance of silicon carbide ceramics. For instance, controlling microstructural characteristics is necessary. This includes controlling crack propagation, reducing grain sizes, acquiring elongated grains, hardening intergranular phases, among others. Good self-lubrication properties can be achieved in various ways: annealing heat treatment, adding secondary phase, or producing porous silicon carbide ceramics. Also, ensuring proper surface processing or modification can also improve the tribological performance of silicon carbide ceramics. Lastly, the external factors affecting the tribological performance needs to be controlled in the most effective way possible.
Furthermore, research trends of silicon carbide ceramic tribology in the future were explored in different aspects. Current studies mostly focus on the tribological performance of SiC ceramics with large amounts of sintering additives. However, future studies should also focus on small amounts of sintering additives since the materials are subjected to different conditions. Moreover, small amounts of sintering additives can help improve tribological performance by helping form clean grain boundaries without secondary phases. Next, there is a great need to develop solid lubricants for various temperature ranges. Considering the different effects of surface texture on the tribological properties of SiC ceramics, a detailed investigation of the impact of different surface parameters is highly desirable. The authors also noted that the study of the tribological performance of SiC ceramics at low temperatures is limited and should be addressed to expand their applications.
In summary, the critical review summarized the tribological research progress of SiC ceramics. Based on the results, the increasing application of SiC ceramics necessitates the need for more studies and research about their tribological performance.
Zhang, W., Yamashita, S., & Kita, H. (2020). Progress in tribological research of SiC ceramics in unlubricated sliding-A review. Materials & Design, 190, 108528.