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研究了用加压氮化法（ｉｎｃｒｅａｓｉｎｇｐｒｅｓｓｕｒｅｎｉｔｒｉｄａｔｉｏｎ，简称ＩＰＮ法）制备高活性、高纯度的氮化硅超细粉。用这种超细粉在一定温度范围内原位生长出“无缺陷”的α－Ｓｉ＿３Ｎ＿４晶须，其截面直径×长的尺寸分别为（０．１～０．３μｍ）×（１０～３０μｍ）；（０．０２～０．０８μｍ）×（５０～１００μｍ）。在氮化硅基体中加入“无缺陷”α－Ｓｉ＿３Ｎ＿４晶须后，材料的断裂韧性Ｋ＿（Ｉｃ）达１０．５±０．９ＭＰａ·ｍ￣（１／２）；室温强度σ＿（ｆＲＴ）达９２７±２９ＭＰａ；１３００℃时强度σｆ＿（１３００℃）达５５６Ｍｐａ。
We studied the preparation of ultra-fine silicon nitride powder with high activity and high purity by increasingpressure nitridation (IPN). With this kind of ultra-fine powder, the “defect-free” α-Si_3N_4 whiskers were grown in situ within a certain temperature range. The cross-sectional diameters × long dimensions were 0.1 ~ 0.3μm × 10 ~ ; (0.02 ~ 0.08μm) × (50 ~ 100μm). The fracture toughness K_ (Ic) of the material is 10.5 ± 0.9MPa · m ~ (1/2) after adding “defect-free” α-Si_3N_4 whisker into the silicon nitride matrix; the room temperature strength σ_ (fRT) 927 ± 29MPa; the strength at 1300 ℃ σf_ (1300 ℃) up to 556Mpa.