| 摘要 |
<p>A method for preparing an oxide powder, which comprises holding in a fluidized state a base material powder comprising a first oxide and having an adsorbed water content of 0.1 to 50 %, an average particle size of 0.005 to 0.5 μm and a number of surface hydroxyl groups of 0.1 to 25 μmol/m2, contacting the base material powder held in a fluidized state with a halide or an alkoxide containing a metal or semi-metal being the same as or different from that of the first oxide together with an inert carrier gas while heating it to a temperature of 25 to 800°C, to thereby coat the base material powder with a coating film comprising a second oxide, and then heating reaction by-products comprising a hydrogen halide or alcohol formed by the above contacting to a temperature of 200 to 1000°C, to thereby remove the by-products. The method can be employed for forming, on the surface of the base material powder of a first oxide, a coating film comprising a second oxide being the same as or different from the first oxide, with homogeneity and at a low cost by a chemical procedure, and thus for providing a base material powder and a coating film layer having satisfactory physical and chemical characteristics.</p> |
