Magnesia-spinel microcomposites

• Published in: Journal of the European Ceramic Society Vol. 24; no. 10-11; pp. 3119 - 3128
• Main Authors: AKSEL, Cemail, WARREN, Paul D, RILEY, Frank L
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 01.09.2004
• Subjects: Applied sciences; Basic refractories; Building materials. Ceramics. Glasses; Cermets, ceramic and refractory composites; Chemical industry and chemicals; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Other materials; Physics; Refractory products; Specific materials; Ceramic matrix composite; Scanning electron microscopy; Aluminium Magnesium Oxides Mixed; Mechanical properties; Experimental study; Precursor; Oxide ceramics; Composite material; Powder; Hot pressing; Additive; Aluminium Oxides; Spinel; Thermal shock resistance; Chemical preparation; Fracture surface; Manufacturing; Microstructure; Basic refractory; Magnesite refractory; Magnesium Oxides
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2003.10.036

A model system of fully dense high purity MgO, incorporating micron size spinel, was prepared by hot-pressing. Spinel powder was obtained from two sources: (i) 0.5 micron alumina powder was incorporated into MgO by in-situ reaction, and (ii) preformed 3 micron spinel powder. The thermal expansion mismatch between MgO and spinel particles led to the intergranular and intragranular crack development, with consequent loss of strength and Young's modulus. The extent of interlinking of the microcracking was determined to be a function of spinel particle size and volume fraction; the reasons for this were examined. The mechanical properties and R"" parameter values of the microcomposites are reported. The thermal shock resistance of in-situ formed 20% 0.5 micron and preformed 30% 3 micron spinel composites, in terms of the R"" parameter, was predicted to be 4 to about 5 times better than that of pure MgO, respectively. 60 refs.