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The thermal fatigue behavior of alumina-magnesia based and alumina-chromia based purging plug materials are comparatively studied. By comparing thermal shock parameters, the changes of elastic modulus and hot modulus of rupture after thermal shock cycles, we come to a conclusion that microcracks emerge in the alumina-magnesia based material, which hinder the crack growth during thermal shock cycles. The fine-grained and network structure of alumina-magnesia based material are also helpful to improve thermal shock resistance. However, cracks are difficult to form in the alumina-chromia based material but it tends to fracture damage quickly once the cracks nucleation due to coarse-grained structure of alumina-chromia based material.

A SO2 sensor based on Na-b-Al2O3 interfaced with an auxiliary electrode of Na2SO4 formed in situ and a solid mixture of Fe3O4, Fe2O3, 3Na2O.5Fe2O3 as the reference electrode was developed. The sensor displayed a Nernstian response to changes in the partial pressure of SO2.

Hydration resistance of three commercially available high-purity MgO-CaO clinkers were investigated and compared in the present paper. The results show that, as well as CaO content, microstructural morphology of MgO–CaO clinker affects its hydration resistance. The microstructure in which CaO is present at the grain boundaries of MgO leads to poorer hydration resistance, whereas the one in which CaO and MgO are distributed alternately confers much improved hydration resistance on the clinker, especially when MgO level is high enough to cover most of the CaO crystals.

The isothermal oxidation behaviors of MgAlON/Si3N4 composite which was synthesized by pressureless nitridation reaction sintering have been investigated in flowing air at 1100°C, 1200°C and 1300°C respectively. The results show that the composite represents excellent self-healing property of oxidation at 1300°C, which might be attributed to the formation of protective silicate film with reasonable viscosity, good spreading power and very low oxygen diffusion coefficient, and to the formation of compact surface resulted from the expansion effect of forming mullite from SiO2 and Al2O3. However, the self-healing property of it is relatively poor at 1100°C and 1200°C as compared to 1300°C.

Heterogeneous-nucleation formation of Al2O3 coatings on graphite powders via a controlled hydrolysis process of aluminum chloride was investigated, and surface morphology and properties of the coated graphite were examined. The formed Al2O3 coatings were uniform and essentially amorphous. They were bonded well with graphite via chemical interaction between their O atoms and C atoms on graphite surface. Graphite particle size increased from 7.61 µm (as-received graphite) to 9.53 µm (the coated graphite), revealing that average thickness of the coating was ~1µm. Compared with those of as-received graphite, specific surface area and fractal dimension of the coated graphite also increased, which was caused by the porosity present in the coating. The isolectric point (IEP) of the coated graphite (~9) was close to that of pure Al2O3, indicating that the electro-kinetic behavior of the coated graphite was similar to that of Al2O3.

Study on rheological properties of gunned refractory is an effective way to optimize the quality of repaired layer and gunning operation. The fluidity of refractory was quantitatively evaluated as well as the rheological behavior of refractory particle-water suspensions. The relationship between the fluidity of refractory particle-water suspension and that of gunned refractory, and the relationship between the fluidity and adhesion ability of gunned refractory were studied. The experiments were carried out with a special rheometer and gunning machine. The results show that there is strong influence of some parameters on the rheological behavior of gunned refractory and gunning process. Interactions between particles and water that lead to the formation of gelatinous structures in this suspension are discussed.

ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66. 67% of reactant changed into ZrB2, and the other form Al203, which could optimize the properties of carbon-containing materials. Therefore, the method of in-situ synthesizing ZrB2 acting as antioxidant in carbon-containing materials is considered as one of best ways to reduce the cost and ZrB2 as refractories is used on a largescale.

Mg ion conductors, MgAl2O4 and MgZr4(PO4)6, were prepared by solid state reaction. Their electrical properties were measured and their application in electrochemical sensors for on-line determination of Mg in molten Al in the refining process and alloying process was examined. The activation energies for Mg ion conduction in MgAl2O4 and MgZr4(PO4)6 are 2.08 eV and 1.7 eV, respectively. The sensors have been found to respond rapidly to the change of Mg content in molten aluminium around 1000 K.

The corrosion behavior of BF slag to sialon bonded corundum refractories using reaction nitriding technology at 1500°C was investigated by crucible test method. The results show that the reaction products of slag corrosion are anorthite, magnalium-spinel and glass phases. The corundum grains can react with MgO in the slag to produce magnalium-spinel, accompanying by expansion and liquating stepwise by slag. Erosion mechanism is oxidation-erosion-dissolving. This study is very necessary and useful to improve the property of BF slag resistance and to yield better overall properties of sialon bonded corundum refractories.