核壳型硼酸钙／SiO2复合微球的制备及摩擦学性能研究∗

摘要

以硼砂、硝酸钙和正硅酸乙酯为原料，在温和条件下制备核壳型硼酸钙／SiO2复合微粒。利用透射电镜（ TEM）、 X射线衍射（ XRD）和红外光谱（ FT⁃IR）研究复合微球的结构，发现SiO2包覆于硼酸钙的表面。将油酸修饰的复合微粒分散于液体石蜡中，利用四球摩擦试验机在载荷392 N、转速1450 r／min、时间30 min的条件下考察其摩擦学性能。结果表明，该复合微粒具有良好的摩擦学性能，其中质量分数1�0％的复合微粒可使液体石蜡的磨斑直径从0�7 mm降低到0�5 mm，摩擦因数从0�09降低到0�05。含硼酸钙／SiO2复合微粒的液体石蜡润滑时，磨痕表面生成含B、 Fe和Si的摩擦膜，从而起到减摩抗磨的作用。%Core⁃shell calcium borates/SiO2 composites were synthesized by a facile way, using borax, calcium nitrate and tetraethoxysilane ( TEOS) as row materials. The structure and morphologies of calcium borate were investigated by TEM, XRD and FT⁃IR, finding that SiO2 shell was covered on the calcium borates. The oil acid ( OA) modified compos⁃ites were mixed into liquid paraffin and the tribological properties of the oleic acid modified calcium carbonates were evalu⁃ated on four⁃ball tester at 392 N load, 1 450 r/min for 30 min. The results show that the composites possess excellent tri⁃bological properties. The wear scare diameter is decreased from 0�7 mm to 0�5 mm and the friction coefficient is dropped from 0�09 to 0�05 as 1�0% composites are added into base oil. The wonderful friction reducing and anti⁃wear properties of calcium borates/SiO2 composites are attributed to the formation of tribological film containing B, Fe and Si on the worn surface.