Tribology of naturally occurring boric acid films on boron carbide

摘要: Abstract In this paper, we describe the formation and self-lubricating mechanisms of naturally occurring boric acid films on boron carbide (B 4 C) substrates. The sliding friction coefficients yttria/partially stabilized zirconia pins against plain B C substrates are quite high at 0.3–0.4, but 6–10 times lower subjected to annealing 800°C. We determined that low was result a thin film forms surface. During 800°C, exposed surface undergoes oxidation layer oxide. cooling, secondary chemical reaction with moisture in air form is responsible for ultralow reported here. As previous literature, low-friction mechanism associated its layered-triclinic-crystal structure. atoms each closely packed strongly bonded other layers widely separated held together by van der Waals forces. sliding, these atomic can align themselves parallel direction relative motion slide over one another ease provide 0.03–0.05 Raman spectroscopy used elucidate bond structure bulk lubricious surfaces.