Analysis of quality parameters of fused cast AZS refractories for glass-making furnaces

A comprehensive analysis of the quality parameters of fused-cast aluminum-zirconium-silicate (AZS) refractories for glass furnaces has been carried out. It is shown that the assessment of the quality of AZS refractories by the content of ZrO2 and density in them does not give an objective idea of their operational properties. Of fundamental importance are the chemical composition and behavior of the glass phase, which determine the volume and temperature of the onset of exudation. Among the most important conditions for obtaining high-quality AZS refractories, characterized by a melting volume of 2‒3 % of the glass phase and a melting start temperature above 1400 °C, include the oxidative melting technology and the content of impurities in the chemical composition of the refractory no more than 0,25‒0,30 %. The conditions for the service of AZS refractories in the melting basin and the working space of glass-melting furnaces are formulated. Their influence on the course of the exudation process, the corrosion resistance of refractories and the formation of defects in glass is shown. Ill. 2. Ref. 30. Tab. 4.

HOT COMPACTION PROCESS OPTIMIZATION FOR IMPROVEMENT TRIBOLOGY BEHAVIOR OF ZIRCONIUM SILICATE STRENGTHENED BMCS

The paper describes the optimization of the hot compaction process to simultaneously increase hardness and decrease the wear coefficient of zirconium silicate reinforced BMCs. L9 orthogonal array is chosen for setup the experiment. Examining the influencing parameters is carried out on factors such as pressure, temperature, particle size, and particle content. Grey relation analysis is used to investigate to produce an optimal combination of parameter levels. The transmission electron scanning is used to study the morphology of zirconium silicate. The wear coefficient of the specimen was investigated by using the weight loss method. A scanning electron microscope was carried out to evaluate the wear track surface of the composite. The test results show that the particle size is the most influential hot compaction parameter. The optimal conditions for the hot compacting process are the temperature level at 350 °C, the pressure level at the 400 MPa level, the particle content level at 12 % weight, and the particle size level at 80 µm. In this optimal condition, the prediction GR-Grade value is 0.695. The validation test results showed that the GR-Grade value increased by 0.15, the hardness increased by 25%, and the wear coefficient decreased by 53%. This optimization method with Gray Relational Analysis has proven to be effective in the hot compaction process for improving the tribology behavior of the composites.

Non-Metallic Modified Thermal Barrier Coatings

The radiation resistance and optical properties of zinc and zirconium silicate doped with cerium ion obtained by the hydrothermal microwave method are investigated. To study the radiation resistance of materials, the samples were irradiated with electrons energy of 4 MeV and a dose of 1016 el/cm2. X-ray diffraction (XRD) technique was used to characterize the phase composition of materials. To study the optical properties of materials, photoluminescence spectra were studied. Using the comparative section method, the thermal conductivity of the materials was measured. The results show that thermal barrier coatings made of cerium-doped zinc and zirconium silicate can be excellent candidates for use in space crafts and not only.

Mixed metal oxide pigments

Mixed metal oxide (MMO) pigments, also knowns as complex inorganic color pigments (CICPs), are an important class of inorganic pigments. They are representatives of the blue, green, yellow, brown, and black pigments. These pigments are called mixed complex because they contain two or more different metals in the composition. Their main advantages are high opacity, heat stability, useful infrared properties, light- and weather fastness, and chemical resistance. MMOs are solid solutions of metal oxides, which are homogenously distributed in their crystal lattices. They are based on different types of crystal structures, such as rutile, spinel, inverse spinel, hematite, priderite, and pseudobrookite. Other products belonging to the CICPs besides the rutile and spinel type MMOs are pigments based on zirconium silicate (zircon, ZrSiO4). Such compositions belong to the class of ceramic pigments (color stains for glazes).