石墨烯/氧化锆复相陶瓷的等离子活化烧结及其力学性能

Plasma Activated Sintering and Mechanical Properties of Graphene Reinforced Zirconia Ceramics

以N,N-二甲基甲酰胺(DMF)为分散剂制备不同石墨烯(GNPs)含量的GNPs/3Y-TZP复合粉体,并采用等离子活化烧结工艺制备系列GNPs/3Y-TZP复相陶瓷。研究了GNPs含量对复相陶瓷物相、显微结构的影响;建立了材料显微结构与其断裂韧性的相互关系,讨论了GNPs/3Y-TZP复相陶瓷的增强/增韧机制。结果表明:制备的GNPs/3Y-TZP复相陶瓷均为四方相;当烧结温度为1300℃、GNPs质量分数为0.01%时,其致密度高达99.4%,且GNPs分散均匀,同时断裂韧性达到最大15.3 MPa·m1/2,比3Y-TZP提高了61%,显微硬度为12.94 GPa。GNPs的均匀分散及与3Y-TZP晶粒的紧密结合使得穿晶断裂比例增大,石墨烯的晶粒细化、拔出、裂纹桥联及微裂纹最终促使3Y-TZP陶瓷的断裂韧性大幅提高。

3 mol% yttria stabilized zirconia(3Y-TZP) with different contents of graphene nano-platelets(GNPs) powder mixture was produced by ball milling using dimethyl formamide as dispersion media. GNPs/3Y-TZP ceramics with full density were prepared by plasma activated sintering. The fabricating process, microstructure and mechanical properties of GNPs/3Y-TZP ceramics were investigated. Tetragonal phase is presented in all the sintered samples and GNPs are dispersed uniformly. The trans-granular becomes increasingly dominant by adding GNPs. The relative density of 3Y-TZP with 0.01%(mass content) GNPs is up to 99.4% and the hardness of that is 12.94 GPa. The fracture toughness achieves 15.3 MPa·m^(1/2), wherein a 61% increase compared to 3Y-TZP ceramics without GNPs. The improvements of fracture toughness are mainly owing to grain refinement, micro-cracks, crack bridging and pulling out of GNPs.