季铵盐修饰磷钼酸铵纳米微粒作为液体石蜡添加剂的摩擦学性能

采用共沉淀法在溶液中原位合成了季铵盐修饰磷钼酸铵(NH4)3PMo12O40]纳米微粒，采用透射电子显微镜、X射线衍射仪、示差扫描热分析仪及热重分析仪等观察分析了表面修饰(NH4)3PMo12O40纳米微粒的形貌和热稳定性，并在四球摩擦磨损试验机上考察了其作为液体石蜡添加剂的摩擦学性能。结果表明：表面修饰(NH4)3PMo12O40纳米微粒大小均匀，平均粒径约为20nm；(NH4)3PMo12O40纳米核在300℃左右分解；(NH4)3PMo12O40。纳米微粒作为液体石蜡添加剂，在中低负荷下具有较好的抗磨性和一定的减摩作用，并可提高液体石蜡的极压负荷，采用扫描电子显微镜和X射线光电子能谱对磨斑表面形貌和化学组成进行观察分析发现，(NH4)3PMo12O40纳米微粒在摩擦副接触表面发生了摩擦化学作用，并形成由多种含氧化合物组成的表面保护膜，从而起到减摩抗磨作用。

Friction and Wear Behavior of Quaternary Ammonium Modified (NH_4)_3PMo_(12) O_(40) Nanopaticles as Additive in Liquid Paraffin

(NH4)3PMo12O40 nanoparticles modi fied with quaternary ammonium were synthesized in the mixture solvent of water- ethanol through co-precipitation. The morphology, structure, and thermal stabil ity of the synthetic nanoparticles were examined by means of transmission electr on microscopy, X-ray diffraction, differential scanning caloremetry, and therma gravimetric analysis. The tribological behavior of the synthetic nanoparticles a s additive in liquid paraffin was evaluated with a four-ball machine. As the re sults, the synthetic nanoparticles have a uniform size distribution and an avera ge diameter about 20 nm. They have (NH4)3PMo12O40 inorganic core s and start to decompose at about 300 ℃. The modified (NH4)3PMo12 O40 nanoparticles as additive in liquid paraffin improve the antiwear and friction-reduction ability to some extent and increase the load-carrying capac ity of the base oil significantly. This is attributed to the generation of a sur face protective film composed of various O-containing compounds such as (NH4) 2Mo2O7, Fe2O3, and ［P2O7］4-, on the worn steel surface, by way of tribochemical reaction.