Combined centrifugal-slip casting method used for preparation the Al2O3-Ni functionally graded composites

• Published in: Composites. Part B, Engineering Engineering, 2018-05, Vol.141, p.158-163
• Main Authors: Zygmuntowicz, Justyna, Miazga, Aleksandra, Wiecinska, Paulina, Kaszuwara, Waldemar, Konopka, Katarzyna, Szafran, Mikolaj
• Format: Article
• Language: English
• Subjects: Ceramic-matrix composites (CMCs); Microstructures; Rheological properties; Slip casting
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2017.12.056

The centrifugal-slip casting method was used for producing the Al2O3-Ni composites with a gradient distribution of the Ni phase. The final products had the shape of hollow cylinders. The casting slurries were water-based and contained alumina and nickel powders with two different particle sizes. The cast samples were then subjected to sintering at a temperature of 1400 °C in an N2/H2 reducing atmosphere with heating and cooling rates of 1 °C/min, and the dwell time - 4 h. The rheological properties of the water-based slurries were examined. It appeared that the presence of the Ni particles strongly affected the slurry properties which was probably associated with the strong interactions between the Ni and α-Al2O3 particles. The Al2O3-Ni composites with a gradient distribution of the Ni particles were examined using the X-ray diffraction method. No new phases such as the nickel aluminate spinel were identified in the sintered composites. The microstructure of the samples was analyzed using Scanning Electron Microscopy (SEM). The observations revealed that the samples were composed of three zones with different distributions of the Ni particles on their cross-section. Finally, the Ni particle distribution in the functionally graded materials was described quantitatively.