| abstract |
A powder of a metal oxide except for α-alumina, which is constituted of at least six-sided polyhedral particles and has a number-average particle diameter of 0.1-300 µm and a particle size distribution of 10 or less in terms of D90/D10 (wherein D10 and D90 represent the particle diameters corresponding to the cumulative amount of, respectively, 10 % and 90 % as determined from the finer particle side in the cumulative size distribution curve for the particles constituting the powder); and a powder of rutile titanium oxide constituted of at least eight-sided polyhedral particles. These powders are reduced in the content of aggregated particles and have a narrow particle size distribution and uniform particle shapes. |