Thermal decomposition of silver flake lubricants

There is a thin layer of organic lubricant on commercial silver flake surfa ces. This lubricant layer is a fatty acid salt formed between a fatty acid and silver flake surfaces. Thermal decomposition behavior of the silver fla ke lubricant is investigated in this study. The heat flow and mass loss of a silver flake are studied using differential scanning calorimetry (DSC) an d thermogravimetry (TG), respectively. The silver flake is also oven heated to different isothermal temperatures (150, 190, 250 and 300 degrees C) for one h. Then chemical nature of the lubricant of the heated silver flake sa mple are studied using diffuse reflectance infrared Fourier transfer spectr oscopy (DRIFTS). Based on the results, a mechanism of thermal decomposition of the silver flake lubricant is proposed. It is found that decomposition of the lubricant - the fatty acid salt - includes the release of the fatty acid, formation of short chain acids by decomposition of hydrocarbon moiety of the fatty acid, and formation of alcohols through decarbonation of the short chain acids.