| 摘要 |
A method for reducing the particle size of an initial silicon carbide powder to a milled powder having an average particle size of below 1 micron but greater than an average of about 0.2 micron, without grinding media contamination. The method comprises milling the larger particles in a vibratory mill in the presence of sintered silicon carbide media comprising silicon carbide pellets having both curved and flat surfaces and a maximum dimension of from about 0.5 to 5 centimeters. The grinding occurs in the presence of a fluid, preferably a liquid, for a sufficient time and at a sufficient vibrational energy to obtain said milled powder having such smaller average particle size. At least 90% of the pellets in the silicon carbide media have a specific gravity (density) greater than 3.05 g/cm3. The invention includes the unique media, which may be used for various grinding operations, and includes unique milled powders. One of the unique powders has particles which have an average length to width ratio of greater than 2.5. Another of the unique powders is black silicon carbide containing from 200 to 2,000 parts per million of aluminum in solid solution. |
