Manufacturing of Al2O3/Ni/Ti Composites Enhanced by Intermetallic Phases

Study on Manufacturing via Slip Casting and Properties of Alumina-Titanium Composite Enhanced by Thialite Phase

This paper aims to study the Al₂O₃/Ti ceramic-metal composite obtained by the slip casting method. Samples containing 50% volume of the solid phase, including 10% volume of the metallic phase, were investigated. The rheological properties were analyzed. Thermogravimetric analysis was performed. The properties of the obtained composite determined the phase composition using and SEM/EDS microstructural analysis and the XRD method. The size of the titanium particles equals 20.6 ± 10.1 mm, which corresponds to 27.5% of the initial size and indicates significant fragmentation of the titanium powder during the manufacturing of the composite. The relative density of the fabricated composites was equal to 99%. The slip casting method allows to obtain the proposed composite additionally enhanced by the presence of TiO₂ and Al₂TiO₅ (thialite). Research results revealed a non-Newtonian character of the composite suspension flow with clear thinning under the influence of increasing shear forces. The obtained composites are characterized by the lack of visible defects (cracks, microcracks and delamination) on the surface.

Properties of Al2O3/Ti/Ni Composite Obtained by Slip Casting with Different Metal Phase Content

This work analyzed ceramic-metal composites from the Al₂O₃/Ti/Ni system produced by the slip casting method. As starting powders, nanometric Al₂O₃, Ni and Ti of submicron size were used. Three series of composites were obtained and tested with the same solid phase content (50% vol.) and different metallic phase content: 5, 10 and 15% vol. The influence of the metallic phase content on the basic properties of the proposed composites was examined by determining the phase composition of the produced samples using the XRD method, rheological measurements, and microstructural analysis (SEM/EDS). Additionally, before the sintering process, the slip stability was analyzed. A study of the fractography of samples after the sintering process was also carried out. It was shown that the appropriate manufacturing process allowed to obtain NiTi intermetallic phases in the structure of composites.

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

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.