| 摘要 |
PURPOSE:To easily and inexpensively produce the Si3N4 whiskers having a BN coating layer which is excellent in adhesive property and small in surface roughness by holding the molten borax added with a specific catalyst at a specific temp., immersing the Si3N4 whiskers therein to thinly coat the whiskers with the BN, there subjecting the whiskers to a heat treatment. CONSTITUTION:The molten borax added with, for example, Cr, and other elements of III to IV and VIII groups in periodic table as a catalyst is held at 650 to 800 deg.C and the Si3N4 whiskers are immersed into the molten borax. The Si3N4 whisker having the BN coating layer on the surface are pulled up from the molten borax, are cooled and are subjected to a heating treatment at about 1,400 deg.C in, for example, a gasseous N2 atmosphere after the surfaces are washed with hot water. The Si3N4 whiskers having the BN coating layer of the small thickness corresponding to 5 to 25% of the diameter of the Si3N4 whiskers are easily produced. Such Si3N4 whiskers are compounded in the ceramics matrix and are sintered, by which the composite ceramics having the excellent bending strength and toughness is obtd. |
