Journal of the American Ceramic Society, Vol.84, No.10, 2445-2447, 2001
Mechanical properties of CoAl materials with the combined additions of ZrO2(3Y) and Al2O3
Intermetallic CoAl powder has been prepared via self-propagating high-temperature synthesis (SHS). Dense CoAl materials (99.6% of theoretical) with the combined additions of ZrO2(3Y) and Al2O3 have been fabricated via spark plasma sintering (SPS) for 10 min at 1300 degreesC and 30 MPa. The microstructures are such that tetragonal ZrO2 (0.3 mum) and Al2O3 (0.5 mum) particles are located at the grain boundaries of the CoAl (8.5 mum) matrix. Improved mechanical properties are obtained; especially the fracture toughness and the bending strength of the materials with ZrO2(3Y)/Al2O3 = 16/4 mol% are 3.87 MPa(.)m(1/2) and 1080 MPa, respectively, and high strength (> 600 MPa) can be retained up to 1000 degreesC.