An overview of inorganic polymer as potential lubricant additive for high temperature tribology

Hot metal manufacturing process involves high temperature tribology. A class of high temperature lubricants of inorganic polymers have been developed for hot metalworking operations. Borax-, silicate- and polyphosphate-additives are polymeric in nature that deliver the appropriate friction and wear properties, their emergence will help to minimize materials loss, ensure control and stability of the hot metalworking process, and meet ever-increasing demands for surface quality, from the perspective of tribology on an industrial scale. Polyphosphate salt is a cost effective lubricant that can adapt to a wide range of temperatures, while borate can impart very stable friction at the mating surfaces and silicate additives embodies excellent restoration of rubbing surface with less friction. This overview includes much data mainly from the testings at ambient temperature, and scientific evidence is presented to support their effective function at elevated temperature. Some challenges and the potential breakthroughs are further highlighted in high temperature tribology applications.