Si_3N_4－ZrO_2陶瓷中ZrN的生成及其对性能的影响

FORMATION OF ZrN IN Si_3N_4-ZrO_2 COMPOSITE AND ITS INFLUENCE ON MECHANICAL PROPERTIES

研究了ＺｒＮ在Ｓｉ＿３Ｎ＿４－ＺｒＯ＿２复相陶瓷中的形成及其对材料性能的影响，结果表明：在１．５ＭＰａＮ２气压烧结条件下，ＺｒＮ的形成温度约为１６００℃，提高Ｎ＿２的压力有利于抑制ＺｒＮ的生成，以稳定的ｔ－ＺｒＯ＿２加Ｓｉ＿３Ｎ＿４基体中，对抑制ＺｒＮ的生成有明显作用。当复相陶瓷中生成一定量的ＺｒＮ时，力学性能明显下降，而ＺｒＯ＿２分布均匀且以ｔ－ＺｒＯ＿２，ｃ－ＺｒＯ＿２形式存在时，复相陶瓷具有较高的强度（７４０ＭＰａ）和断裂韧性（８．８ＭＰａ·ｍ￣（１／２））。

The formation of ZrN in Si_3N_4-ZrO_2 composites and its influence on the mechanical propertleswere investigated. The formation temperature of ZrN is about 1600℃ in sintering of 1. 5MPa gas pressure, In-crease of N_2 gas pressure is helpful to restrain the formation of ZrN. Addition of t-ZrO_2 (3.0% Y_2O_3 , inmole) in Si_3N_4 matrix is effective obviously for inhibiting the formation of ZrN. The mechanical properties ofSi_3N_4- ZrO_2 composites are degraded when some ZrN are formed. If ZrO_2 distributes homogeneously and existsas t-ZrO_2 or c-ZrO_2, the composites possess higher bending strength (740MPa) and higher fracture toughness( 8. 8MPa·m￣(1/2)).