三元共晶成分Al2O3/YAG/ZrO2粉体及陶瓷的制备与组织性能研究

Preparation, microstructure and properties of ternary Al2O3/YAG/ZrO2 ceramics hot pressed with eutectic composition powders

摘要:

本文采用醇水共沉淀法制备了三元共晶成分Al₂O₃/YAG/ZrO₂粉体,在600-1350_oC温度范围煅烧后研究其物相转变过程。经1300_oC煅烧后Al₂O₃/YAG/ZrO₂共晶成分粉体的物相由α-Al₂O₃、c-ZrO₂和YAG构成,且具有α-Al₂O₃相包裹c-ZrO₂相的特殊结构。将煅烧粉体在1550_oC下热压烧结,制备具有内晶型结构的共晶成分Al₂O₃/YAG/ZrO₂复相陶瓷,其致密度、室温抗弯强度、断裂韧性和高温(1000_oC)抗弯强度分别为98.8%、420 MPa、3.69 MPa.m_1/2和464 MPa,并对复相陶瓷组织结构的形成机理进行了探讨。

Abstract:

Al₂O₃/YAG/ZrO₂ powders with eutectic composition have been synthesized by the chemical co-precipitation in acohol-water aqueous solution and calcination method, and are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The precursors were calcined at temperatures of 600_oC-1350_oC in air, and the phase transition process was then revealed with increasing the calcination temperature. Al₂O₃/YAG/ZrO₂ powders calcined at 1300_oC for 1h consist of α-Al₂O₃, YAG and c-ZrO₂ phases. Al₂O₃/YAG/ZrO₂ ceramics with eutectic composition were hot-pressed at 1550_oC with the above-mentioned powders. The Al₂O₃/YAG/ZrO₂ ceramic sintered at 1550_oC contains an intragranular microstructure, and exhibits a relative density of 98.8%, a room-temperature flexural strength of 420 MPa, a fracture toughness of 3.69 MPa.m_1/2 and a high-temperature (1000_oC) flexural strength of 464MPa, respectively. The formation mechanism of an intragranular microstructure in the Al₂O₃/YAG/ZrO₂ ceramic has been proposed.