Oxidative and Frictional Behavior of a Binary Sodium Borate-Silicate Composite in High-Temperature Lubricant Applications
Copyright 2019 American Chemical Society. Alkaline borate-silicate composites provide desirable protection for the machinery moving contacts in high-temperature coating and lubricant applications, but their behavior depends closely on the composition of the interacting surface and working conditions. In this study, the capability of binary alkaline borate-silicate mixtures is investigated in terms of antifriction, wear resistance, and antioxidation. A Si-B-1 lubricant, composed of a mixture of sodium silicate/sodium borate (9:1 by weight), shows a significant reduction in friction (0.17) and disc wear loss volume (1 mm3) at 800 °C, as compared to that of sodium silicate alone (0.5 and 6 mm3, respectively). The elemental migration and segregation across the interface were observed in response to temperature during the isothermal treatment, whereas excellent lubrication originated from the adaptively constructed tribofilm under coupled effect of the stressed shearing and thermal process. This study can be extended to optimize relevant glass lubricants at an optimum composition, which will demonstrate effective lubrication properties for industrial engineering applications.