微波烧结ZrO_(2(n))/Al_2O_3复合陶瓷工艺与组织

以纳米ZrO2、微米Al2O3为原料,采用微波烧结方式制备ZrO2/Al2O3复相陶瓷。探讨了烧结温度和保温时间对试样线收缩率、相对体积密度、硬度和断裂韧性的影响。结果表明,烧结温度1550℃,保温时间10 min,可得到较高的硬度(13 350 MPa)和较好的断裂韧度(6.41 MPa.m1/2),烧结过程中发生了m-ZrO2转变为t-ZrO2相变,nano-ZrO2的加入使Al2O3形成內晶型结构;试样的断裂方式为沿晶断裂和穿晶断裂并存;ZrO/AlO复合陶瓷主要通过应力诱导相变和内晶型结构进行增韧。

Microwave sintering technology and microstructure of ZrO_(2(n))-Al_2O_3 composite ceramics

ZrO_2/Al_2O_3 composite ceramics were prepared by microwave sintering method using nano-ZrO_2 and micron-Al_2O_3 powder as raw materials.The influences of sintering temperature and duration on the properties of ZrO_2/Al_2O_3 composite ceramics were investigated,which including linear shrinkage rate,relative bulk density,hardness and fracture toughness.The results show that the high hardness (13 350 MPa)and fracture toughness(6.41 MPa·m~(1/2))can be obtained for the composite ceramics sintered at 1550 ℃ for 10 min.The phase transformation of m-ZrO_2 into t-ZrO_2 occurs during sintering process,and intragranular structure is formed in Al_2O_3 matrix with addition of nano-ZrO_2.Fracture mode of the samples is intergranular and transgranular coexisting.The ZrO_2/Al_2O_3 composite ceramics are toughened mainly by the stress induced phase transformation and the intragranular formation of zircoina.