Alumina-Mullite Refractories: Prototypal Components Production for Thermal Shock Tests

Abstract:

Alumina-mullite refractory tiles are used as liners in gas turbines for power production, for the thermal insulation of the combustion chambers. The typical microstructure is characterized by a coarse fraction, in order to increase porosity (and hence thermal insulation) and improve thermal shock resistance (by grain bridging mechanism). A mixture of alumina and ceramic wastes was optimized to manufacture prototypal components, by cold isostatic press (CIP). On sintering at 1600°C, a final composition of 40% mullite and 60% alumina was obtained. For the production of refractory tiles with dimensions similar to the commercial ones, an appropriate mould was CAD-CAM designed and produced, using aluminium and silicone. 115 x 95 x 30 mm3 tiles were obtained and utilized for thermal shock tests. Samples were heated up to 1000°C and quenched to 20°C: this cycle was repeated 30 times before inspecting the macroscopic cracks. The results were compared with those obtained with a standard test for advanced technical ceramics based on MOR measurements. Two different pressing conditions were tested (60 and 150 MPa) in order to get data about a possible industrial production by uniaxial pressing.

• Periodical: Advances in Science and Technology (Volume 70)
• Pages: 53-58
• DOI: https://doi.org/10.4028/www.scientific.net/AST.70.53
• Online since: October 2010
• Authors: Alida Brentari, Martino Labanti, Francesca Mazzanti, Claudio Mingazzini, Sergio Sangiorgi, Matteo Villa, Stefano Martelli, Daniela Olevano
• Keywords: Alumina-Mullite, Cold Isostatic Press, Refractory Tile, Thermal Shock Resistance

References

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DOI: 10.4028/www.scientific.net/ast.70.9

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DOI: 10.3403/03102635u