Crack-Healing Effectiveness of Nano Ni + SiC Co-Dispersed Alumina Hybrid Materials
Crack-healing effectiveness of nano-Ni+SiC co-dispersed Al2O3 hybrid materials by heat treatment was studied as well as oxidation behavior. The starting powder mixture was prepared by drying slurry consisting of distilled water, Al2O3, SiC powder and nickel nitrate. After reduction, the powder mixture was densified by pulsed electric current sintering. Cracks were introduced by a Vickers indenter. Specimens were exposed into air at temperature ranging from 1000 and 1300°C for 1 and 48 h. Thickness of oxidized zone in SiC+nano-Ni/Al2O3 thinner than nano-Ni/Al2O3. Cracks of SiC+nano-Ni/Al2O3 disappeared completely, for example, by oxidation at 1200°C for 6 h, as same as nano-Ni/Al2O3. Bending strength of crack-disappeared SiC+nano-Ni/Al2O3 showed 519 MPa and was comparable with that of as-sintered one. SiC+nano-Ni/Al2O3 pocesses crack-healing effectiveness with improved high-temperature oxidation resistance.
T. Chandra, N. Wanderka, W. Reimers , M. Ionescu
D. Maruoka et al., "Crack-Healing Effectiveness of Nano Ni + SiC Co-Dispersed Alumina Hybrid Materials", Advanced Materials Research, Vols. 89-91, pp. 365-370, 2010