TRIBOLOGICAL PROPERTIES OF BORIC-ACID AND BORIC-ACID-FORMING SURFACES .1. CRYSTAL-CHEMISTRY AND MECHANISM OF SELF-LUBRICATION OF BORIC-ACID

An in-depth understanding of the atomic-scale structure and chemistry of self-lubricating solids and how they relate to the efficiency and endurance of large-scale tribosystems is critically important. Of particular interest is the use of this understanding in developing mechanistic models that can increase our ability to assess and predict the capabilities of self-lubricating solids. Accordingly, a comprehensive investigation was conducted of the boric acid-forming surfaces. This paper describes the fundamentals of the crystal chemistry of boric acid and proposes a mechanism for its self-lubrication action. Pin-on-disk tests, performed on cold-pressed boric acid pins and AISI 52100 steel disks, showed that the friction coefficient of this tribosystem is approximately 0.1. The results of this investigation indicate that the boric acid, owing to its unique crystal structure and bond characteristics, is a promising solid lubricant for a wide range of tribological applications.