Friction and Wear Properties of Spark Plasma Sintering NiCr–SrSO4 Composites at Elevated Temperatures in Sliding Against Alumina Ball
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- 作者：Yu-Feng Li ; Hong Yin ; Xin-Liang Li ; Chong-Chong Mao
- 关键词：NiCr alloy ; SrSO4 ; Self ; lubricating composites ; High temperature
- 刊名：Tribology Letters
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：64
- 期：2
- 全文大小：2,018 KB
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Chemistry
Tribology, Corrosion and Coatings
Surfaces and Interfaces and Thin Films
Theoretical and Applied Mechanics
Physical Chemistry
Nanotechnology - 出版者：Springer Netherlands
- ISSN：1573-2711
- 卷排序：64
文摘
Nickel-based self-lubricating composites with SrSO4 as a high-temperature solid lubricant have been prepared by spark plasma sintering method. Their friction and wear properties were evaluated using a high-temperature friction and wear tester in dry sliding against alumina ball up to 600 °C. NiCr–10 wt% SrSO4 composite exhibits satisfactory mechanical properties and tribological properties from room temperature to 600 °C (except for 200 °C) as contrasted with unmodified Ni–Cr alloy. The friction coefficients of NiCr–10 wt% SrSO4 at 400 and 600 °C are 0.32 and 0.20, respectively. The corresponding wear rates are 1.44 × 10−5 and 2.4 × 10−5 mm3/(Nm). The unmodified Ni–Cr alloy exhibits friction coefficients of 0.41 and wear rates in order of 10−4 mm3/(Nm) in a temperature range of 400–600 °C. At elevated temperatures, a dense and protective glaze layer is generated on the worn surface of composites. The glaze layer was then investigated by means of scanning electron microscopy and XPS. Tribo-chemical reaction during high-temperature wear tests is responsible for the formation of the protective glaze layer. The newly formed oxides (NiO and Cr2O3) and some self-lubricating oxysalts (SrSO4 and SrCrO4) can promote the densification of oxide glaze layer, and finally generate a dense lubricating film to effectively reduce friction and wear at elevated temperatures.