Abstract
In this paper, the calcium-hexaluminate/gehlenite (CA6/C2AS) composites have been synthesized by traditional high temperature solid state method using magnesium slag as a source of calcium and silicon. The phases, micromorphology and physical properties of the samples were characterized and analysized. The results show that the CA6 and C2AS grains formation starts at 1300oC, the main reaction has completed above 1450oC. The granular particles of C2AS are distributed in CA6 grain boundaries. With the sintering temperature increased, the amount and the grains of CA6 grow up gradually, while the amount of C2AS reduces. The CA6 grains don?t growth excessively for the space hindrance function. With the sintering temperature increased the body density, linear shrinkage and flexural strength increases, while the apparent porosity decreases.
Highlights
Calcium hexaluminate (CaAl12O19 or CaO·6Al2O3), often denoted as CA6, occurs in nature as the mineral hibonite
The high surface energy and lattice defects were generated after the raw material powers of magnesium slag and Al2O3 were attrition milled, which provided a certain sintering driving force
The high -melting point phase CA6 can formed at the low sintering temperature (1300oC)
Summary
Calcium hexaluminate (CaAl12O19 or CaO·6Al2O3), often denoted as CA6, occurs in nature as the mineral hibonite. This phase is the most alumina-rich intermediate compound of the CaO-Al2O3 system. The micromorphology of CA6 grains shows preferential growth along their basal plane [1]. Because of its excellent anti-hydration property, slag resistance, thermal shock resistance and high refractoriness [2], CA6 has a certain potential in application in high temperature refractory material field. The previous study on CA6 composites are mainly focused on CA6 and Al2O3 composite [3,4,5,6,7]. The study on CA6/MgO·Al2O3 composites are started in recent years [8, 9]
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