Abstract: The modified alumina with different elements, such as zinc, magnesium, phosphorus and silicon,respectively,were prepared by saturation impregnation method, and the wear resistance of the modified alumina microspheres was determined by turbidity analysis. The results showed that the physical wear resistance of modified alumina microspheres was not changed, but the wear resistance of the modified alumina microsphere was improved under hydrothermal condition, among them, the wear resistance of silicon-modified alumina with tetraethyl orthosilicate as raw material was the best. X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy were used to analyze the cause of the difference, it was found that the silicon hydroxyl group formed by silicon modification could replace the aluminum hydroxyl group on the surface of alumina to form Al-O-Si bond, which weakened the adsorption of water and improved the hydration resistance of alumina, furthermore, the wear resistance of silicon-modified alumina microspheres was improved under hydrothermal condition.

Key words: alumina, tetraethyl orthosilicate, modification, wear resistance