Effect of loading on the friction and interface microstructure of lubricated steel tribopairs. (December 2017)

• Record Type: Journal Article
• Authors: Cui, Shaogang; Zhu, Hongtao; Wan, Shanhong; Tieu, Kiet; Tran, Bach H.; Wang, Liping; Zhu, Qiang
• Is Part Of: Tribology international. Volume 116(2017)
• Page Start: 180
• Page End: 191
• Publication Date: 2017-12
• Subjects: Sodium metaphosphate -- Phosphate tribofilm -- Ball-on-disc -- Na-Fe orthophosphate; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2017.07.007
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: In this study, the tribological behavior and interfacial evolution of GCr15/Mild steel tribopairs lubricated by inorganic sodium metaphosphate was investigated under different applied loads at 800 °C. The results show that sodium metaphosphate lubricates the contact effectively at the load ranging from 5 to 30 N, with higher loads causing increased friction and wear. A layer of glassy phosphate film formed between the contacts is responsible for the improved tribological performance. FIB/TEM and XRD analysis reveals that the phosphate film was mainly composed of amorphous Na-Fe orthophosphate matrix filled up with fine oxide wear debris. Highlights: Alkali metaphosphate lubricant can effectively lubricate the steel/steel tribopairs at high temperature. A layer of phosphate tribofilm on wear track was responsible for the improvement of tribological performance. Polyphosphate interacted tribochemically with iron oxide into NaFePO4 and Na3 Fe2 (PO4 )3 . Fine oxide debris is retained at the interface and incorporated within the phosphate tribofilm.