氮化硅在水和乙醇中的摩擦化学机理研究

fRIBOCHEMICAL MECHANISM OF SILICON NITRIDE WITH WATER AND ETHANOL LUBRICANTS

在往复试验机上考察了Si_3N_4在干摩,水和乙醇润滑条件下的摩擦磨损性能,用SEM,XRD和XPS研究了Si_3N_4在水和醇中的摩擦化学反应机理。结果表明,Si_3N_4的摩擦系数和磨损体积随润滑环境的不同有如下顺序:干摩擦>水润滑>乙醇润滑。Si_3N_4在水中的摩擦化学机理涉及两个方面,一是Si_3N_4与水直接反应生成SiO_2;二是Si_3N_4与溶于水中的氧反应生成无定形Si-O化合物。Si_3N_4在醇中的摩擦化学机理为:Si_3N_4先与乙醇反应生成SiO_2,部分SiO_2与乙醇进一步反应生成硅酯。

The friction and wear properties of silicon nitride （Si3N4） under dry sliding, water and ethanol lubricating conditions were investigated using a reciprocating pin-on-block tester. The tribochemical mechanism of Si3N4 with water and ethanol lubricants was studied by means of SEM, XRD, XPS. From the results, the decreasing order of the friction coefficients and the worn volume ot Si3N4 in various lubricating conditions are summarized as follows: dry sliding; water lubrication; ethanol lubrication. The proposed tribochemical mechanism of Si3N4 in water involves two aspects: Si3N4 reacts with water and forms crystal SiO2; also Si3N4 reacts with oxygen dissolved in water, forming the amorphous Si-O compounds. The proposed tribochemical mechanism of Si3N4 in ethanol includes that Si3N4 reacts with ethanol and produces crystal SiO2, which esterificates to form soluble silicon esters.