ZrO2对热压AlN陶瓷的显微结构与力学性能的影响

通过添加纳米ZrO2粉体,并结合Y2O3烧结助剂,采用热压烧结制备了AlN陶瓷.结果表明,加入ZrO2后,热压AlN陶瓷的物相包含AlN主相、Al5Y3O12晶界相以及ZrN新相.随着ZrO2的加入,热压AlN陶瓷的维氏硬度基本没有变化,然而其断裂韧性逐渐提高.这主要是由于添加的ZrO2与AlN发生高温反应生成了ZrN,导致AlN陶瓷从单一的沿晶断裂模式转变为包含沿晶和穿晶的混合断裂模式,强化了晶界,进而改善了断裂韧性.

Effect of ZrO2 on Microstructure and Mechanical Properties of AlN Ceramics Prepared by Hot-Pressing Sintering

The AlN ceramics were hot pressed by the addition of nanoscale ZrO2 power as second phase and Y2O3.The results show that AlN ceramics mainly comprise main phase AlN phase, grain boundary phase Al5Y3O12 and new phase ZrN.With the addition of ZrO2, the Vickers hardness of AlN ceramics has no significant change, while fracture toughness gradually increase.This is because the transformation of fracture mode from intergranular fracture to mixed fracture including intergranular fracture and transgranular fracture which is induced by the formation of ZrN due to the reaction between ZrO2 and AlN, strengthened the grain boundary and then improved fracture toughness.