Wettability and lubricity of borosilicate glass to H13 steel and TZM alloy at 900 ℃

Abstract

Lubrication can reduce friction, wear and oxidation of mechanical moving parts to achieve the purpose of maintaining the working stability, high efficiency and long life of the device. Melt lubricants have excellent anti-friction, anti-wear and anti-oxidation properties and are used in the hot metal forming process for steels. TZM alloy is a promising forging die to replace H13 steel in the hot metal forming process. In this study, the high temperature wettability and high temperature tribological performance of borosilicate glass on H13 steel and TZM alloy were studied. The results suggest that the glass has good wettability on the hot H13 steel and promising lubricating with coefficient of friction of 0.06 at 900 ℃. However, the same glass shows poor wettability and lubricating for the TZM alloy. It indicates that high temperature wettability is also one of the key parameters that influence the tribological performance, rather than the well-known high temperature viscosity. Surface and interface characterization indicates that the Fe₂O₃ induced enrichment of the network modifier Na⁺ near the substrate surface, the dense and shearable low-oxygen permeable glass film led to the excellent oxidation resistance and lubrication properties in the friction system of H13 steel (pin). The erosion of the borosilicate melt by MoO₃ leads to poor adhesion, the phase separation behavior of the glass polymerization zone and the molybdate depolymerization zone. The melting state of the low melting point species make the TZM alloy (pin) friction system exhibit complex friction behavior. This work will provide some guideline for the structure and wettability control for promising high temperature lubricating.