Dry Sliding Wear Behavior of Al₂O₃-TiC Ceramic Composites Added with Solid Lubricant CaF₂ by Cold Pressing and Sintering

Abstract

The solid lubricant CaF₂ was added in Al₂O₃/TiC ceramic composites to reduce the friction coefficient and improve the wear resistance of the latter. The Al₂O₃/TiC/CaF₂ composites were prepared by cold pressing and sintering. Experiments on friction and wear properties were conducted using a wear-and-tear machine. The wear surfaces were observed by scanning electron microscopy and energy-dispersive spectroscopy. The wear resistance properties and self-lubricating effect of samples were analyzed. Results show that the Al₂O₃/TiC/CaF₂ composites have a lower friction coefficient than the Al₂O₃/TiC ceramic composites subjected to the same processes. The good wear resistance of the Al₂O₃/TiC/CaF₂ ceramic composites stems from the low friction coefficient and wear rate. These parameters have a self-lubricating effect on wear surfaces. The mechanism of wear resistance is that smooth self-lubricating films form when CaF₂ is applied on wear surfaces. CaF₂ particles spread on friction pairs and fill micropits, thereby improving and smoothening worn regions.

KEY WORDS:

• Ceramic-Matrix Composite
• Sliding Friction
• Solid Lubricant
• Surface Analysis

ACKNOWLEDGEMENTS

We are grateful for the testing and computing resources provided by the University of Jinan. We thank the teachers and our colleagues who helped in the course of this research.

FUNDING

This project was supported by grants from the National Natural Science Foundation for Young Scholars of China (Grant No. 51005100), China Postdoctoral Science Foundation (Grant No. 20110491572), Scientific and Technological Development Programme of Shandong Province (Grant No. 2012GGX10324), and Science and Technology Development Program of Shandong University (J11LD14).