Characterization of Al2O3 Matrix Composites Fabricated via the Slip Casting Method Using NiAl-Al2O3 Composite Powder

Abstract

This work aimed to characterize Al2O3 matrix composites fabricated by the slip casting method using NiAl-Al2O3 composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al2O3, was obtained by mechanical alloying of Al2O3, Al, and Ni powders. The composite powder was added to the Al2O3 powder to prepare the final powder for the slip casting method. The stained composite samples presented high density. EDX and XRD analyses showed that the sintering process of the samples in an air atmosphere caused the formation of the NiAl2O4 spinel phase. Finally, the phase composition of the composites changed from the initial phases of Al2O3 and NiAl to Al2O3, Ni, and NiAl2O4. However, in the area of Ni, fine Al2O3 particles remaining from the initial composite powder were visible. It can be concluded that after slip casting, after starting with Al2O3 and the composite powder (NiAl-Al2O3) and upon sintering in air, ceramic matrix composites with Ni and NiAl2O4 phases, complex structures, high-quality sintered samples, and favorable mechanical properties were obtained.

Particle-Reinforced Ceramic Matrix Composites—Selected Examples

“…For samples using initial pre-compopowder (5 vol.% of (NiAl + Al 2 O 3 )), the fracture toughness was equal to 6.19 MPa•m 0.5 . In addition, the fracture toughness value for pure Al 2 O 3 ceramics was 5.18 MPa•m 0.5 [70].…”

Microstructure and Mechanical Characterization of Novel Al2O3–(NiAl–Al2O3) Composites Fabricated via Pulse Plasma Sintering

“…The samples were made via the pulse plasma sintering method (PPS). Four operations were carried out during the PPS method: preparing the working atmosphere, setting the press pressure, sintering, and chamber discharge [43][44][45][46][47]. In the first step the required low vacuum level equal to 1 Pa and a high vacuum equal to 10 −3 Pa were achieved.…”

“…In previous research, Al 2 O 3 matrix composites have been fabricated by the slip casting method, using NiAl-Al 2 O 3 powder as the initial powder [44]. A composite powder consisting of NiAl + 30 wt.% Al 2 O 3 has also been obtained by mechanical alloying of Al 2 O 3 , Al, and Ni powders.…”

“…A composite powder consisting of NiAl + 30 wt.% Al 2 O 3 has also been obtained by mechanical alloying of Al 2 O 3 , Al, and Ni powders. The composite powder mixed with Al 2 O 3 powder after slip casting caused the formation of a high-density bulk composite [44]. After the sintering process of the samples in an air atmosphere the NiAl 2 O 4 spinel phase appeared.…”

“…Finally, a three-phase ceramic composite consisting of Al 2 O 3 , Ni, and NiAl 2 O 4 was obtained. Important is the fact that in the area of Ni, fine Al 2 O 3 particles remaining from the initial composite NiAl-Al 2 O 3 powder were located, which makes the complex structure of the composite [44].…”