Tribology

Chemisorption and Tribochemical Reaction Mechanisms of HFC-134a on Nascent Ceramic Surfaces

“…However, when ceramics are rubbed, destruction and bond cleavage of the surface layer occur at the ceramic interfaces due to mechanical stimulation and resulting in formation of nascent surfaces, on which there are many lattice imperfections, radical or ionic sites, and coordinatively unsaturated metal cations. 1 It has been found that there are many types of active sites on the rubbing surfaces of the oxide ceramics, and many kinds of organic compounds, even saturated hydrocarbons, are chemisorbed on these nascent surfaces. 2 It is considered that tribochemical reaction of lubricants occurs on the frictional surface of ceramics due to the high chemical activity of these sites.…”

“…Ceramics, which have high thermal and chemical stability and excellent mechanical properties, have been attracting great attention for tribomaterial applications in precision machines and engines. However, when ceramics are rubbed, destruction and bond cleavage of the surface layer occur at the ceramic interfaces due to mechanical stimulation and resulting in formation of nascent surfaces, on which there are many lattice imperfections, radical or ionic sites, and coordinatively unsaturated metal cations . It has been found that there are many types of active sites on the rubbing surfaces of the oxide ceramics, and many kinds of organic compounds, even saturated hydrocarbons, are chemisorbed on these nascent surfaces .…”

Friction between Individual Microcontacts

“…Sliding friction between two macroscopic solids often follows Amontons law, F = µL, where the friction coefficient µ is constant (1)(2)(3). Here, F is the friction force required to slide one solid over the other and L is the load or normal force applied.…”