作者：M.A.L. BRAULIO;L. R. M. BITTENCOURT;J.PQIRIER;

作者单位：Federal University of Sao Carlos, Materials Engineering Department, Materials' Microstructural Engineering Group (GEMM), Am 235, Rod. Washington Luis, 13565-905, Sao Carlos, SP, Brazil;Federal University of Sao Carlos, Materials Engineering Department, Ma

刊名：Journal of the Technical Association of Refractories

ISSN：0285-0028

出版年：2008-01-05

卷：28

期：3

起页：180

止页：184

分类号：TQ175

语种：英文

关键词：

内容简介

Alumina-magnesia castables commonly present microsilica in their composition, due to its ability to promote better flowability, to inhibit the MgO hydration during curing and drying steps and to compensate the expansion related to in-situ spinel formation. Because these castables are commonly bonded with calcium aluminate cements, it is also important to control two other expansive reactions, involving CA_2 and CA_6 formation. In this paper, compositions containing different microsilica content were produced and analyzed by an assisted sintering technique, creep resistance and microstructural evaluation. Microsilica performed in different ways for spinel, CA_2 and CA_6 formations. The silica containing phases formed speeded up and counterbalanced the in-situ spinel formation. Conversely, microsilica addition reduced CA_2 expansion, but led to a greater CA_6 expansion rate. Due to the expansive behavior of these reactions, silica content could be a feasible way to attain a designed expansion based on previous microstructural engineering of alumina-magnesia castables, as long as the refractoriness drawbacks are kept under control.