Oxide laminated composites with aluminum phosphate (AlPO_4) and alumina platelets as crack deflecting materials

摘要

Oxide-oxide laminated composites with aluminum phosphate (AlPO_4) and alumina platelets as crack deflecting interphases were developed by the tape casting method. Dense bodies of Al_2O_3, mullite, 50 vol% Al_2O_3·50 vol% YAG in situ composite, and 3Y-TZP were sintered and characterized. Tape casting formulations for different oxides with solid contents of 25.1 and 30 vol%, respectively, were developed. XRD indicated compatibility between alumina, mullite, zirconia and AlPO_4. Laminated, matrix-interphase composite systems consisting of Al_2O_3-AlPO_4, mullite-AlPO_4, 50 vol% Al_2O_3·50 vol% YAG in situ composite-AlPO_4, and 50 vol% Al_2O3·50 vol% YAG in situ composite-alumina platelets were made. The 50 vol% Al_2O_3·50 vol% YAG in situ matrix-alumina platelet composite showed 'quasi-elastic' load-displacement behavior under the conditions of fabrication, and had a 3-point bending strength and work of fracture of 188 ± 8 MPa and 0.65 ± 0.02 kj/m~2, respectively. The 3Y-TZP-AlPO_4 laminated composite could not be made because of delamination due to thermal expansion mismatch.