The influence of sintering temperature on properties of Al2O3-Ni composites
Magdalena Gizowska, Aleksandra Miazga, Katarzyna Konopka, Mikołaj Szafran
Quarterly No. 1, 2012 pages 33-38
DOI:
keywords: ceramic-metal composite, alumina, nickel, slip casting, stereology
abstract The main advantage of ceramic-metal composites is the increase in fracture toughness of the brittle ceramic matrix. The slip casting moulding method is widely used in the ceramic industry, which gives the possibility to obtain products of complicated shapes without green machining. Good quality and homogeneity of powder consolidation are crucial in the ceramic and ceramic matrix composite fabrication process as they influence the properties of the material. In the paper, the results concerning ceramic matrix ceramic-metal composite fabrication via the slip casting method are presented. Composites were formed from a slurry containing alumina and metallic nickel particles. For the studies nickel powder of average particle diameter below 1 µm was used (Aldrich; d = 8.9 g/cm3). Two types of alumina powder were applied. The materials formed from alumina powder of an average particle diameter of 0.4 µm (α-Al2O3, A16SG, Almatis; d = 3.9 g/cm3) were sintered at a temperature of 1550°C (above nickel melting point; TmNi = 1455°C), whereas composites obtained from alumina powder of an average particle diameter of 0.2 µm (α‑Al2O3, TM‑DAR, Tamei, Japan, d = 3.8 g/cm3) undergo densification already at 1300°C (below nickel melting point). The mechanical properties of the composites are dependent on the processes occurring in the sintering process, during which coalescence may lead to the growth of nickel particles. Stereological analysis of the nickel particles in the alumina matrix (in composites sintered below and above nickel melting point) was performed. The description of nickel particle growth in accordance to the sintering temperature was correlated with mechanical properties of the composites.