Toughening alumina with both nickel and zirconia inclusions

Preparation of Al2O3–ZrO2–Ni nanocomposite by pulse electric current and pressureless sintering

“…The elastic modulus of the specimens, d , was determined by using an ultrasonic method. 5 The fracture toughness was determined by using an indentation technique at the load of 196 N. The following equations were used to calculate the toughness: 16…”

“…Recent studies suggested that the toughness of the brittle material can be increased by adding zirconia and metallic particles simultaneously. [5][6][7] For example, the toughness of an Al 2 O 3 /(5 vol.% ZrO 2 + 5 vol.% Ni) composite could reach a value as high as 8 MPa m 0.5 . 5 However, the strength of the composite is only marginally enhanced.…”

“…[5][6][7] For example, the toughness of an Al 2 O 3 /(5 vol.% ZrO 2 + 5 vol.% Ni) composite could reach a value as high as 8 MPa m 0.5 . 5 However, the strength of the composite is only marginally enhanced. The size of the Ni inclusions in the composite is relatively large, 2.3 m. The size may be large enough to induce micro-crack at interface for the presence of thermal expansion mismatch between Al 2 O 3 and Ni.…”

“…The size of the Ni inclusions in the composite is relatively large, 2.3 m. The size may be large enough to induce micro-crack at interface for the presence of thermal expansion mismatch between Al 2 O 3 and Ni. 5 By reducing the size of Ni particles to ∼100 nm, the strength of Al 2 O 3 may be enhanced significantly. 4 In the present study, both nanometer-sized Ni and submicrometer-sized ZrO 2 powders are added into an Al 2 O 3 matrix.…”

The Peculiarities of Structure Formation and Properties of Zirconia-Based Nanocomposites with Addition of Al2O3 and NiO

“…As engineering material, the composite Al 2 O 3 –Ni is more studied. In the studies [16, 17], it was shown that addition of nickel inclusions in alumina and zirconia matrix leads to increase in the fracture toughness of alumina or zirconia ceramic material. In this work, it has found two facts which addition of NiO during sintering promotes to (i) stabilization of a cubic phase of zirconia and (ii) destabilization of tetragonal phase and a formation of monoclinic phase.…”