Title

Development of Cordierite Coatings for Low Thermal Expansion Refractory Concretes

Abstract

Stoichiometric cordierite (2MgO-2Al2O3-5SiO 2) with additions of titania have been investigated for use as coatings on low thermal expansion refractory concretes. These concretes have coefficients of thermal expansion on the order of 2 ppm/°C. Titania additions of up to 8 mole percent were investigated and the effect of titania in the crystallization of cordierite was examined. Cordierite coatings were air plasma sprayed and both glass and crystalline coatings were produced. The crystalline structure of the coating was found to be dependent upon the preheat temperature of the substrate. Preheats greater than 700°C produced a mixture of a quartz solid solution and indialite whereas glass coatings were produced at preheats less than 700°C. Coefficients of thermal expansion for the cordierite materials were dependent upon titania addition and generally increased with addition of titania. In the glass state, the thermal expansion was modestly increased (4.6 to 4.9 ppm/°C) with titania additions, but the quartz and indialite forms of the cordierite increased from 1.2 to 4.7 ppm/°C as the titania addition increased from 0 to 8 mole percent.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Cordierite Coatings; Refractory Concrete; Thermal Cycling; Thermal Expansion

Library of Congress Subject Headings

Coatings

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2000 ASM International, All rights reserved.

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