Papers by Keyword: Porous Ceramic Materials

Abstract: In order to lay raw materials foundation for increasing the performance of insulating brick with the low grade quartz sand along the Yangtze River, the quartz porous ceramic materials was researched in this paper. The results show the porosity of the porous quartz ceramics decreased with an increase in the sintering temperature. The pore is like the bowl shape, and the pore is closed pore, which is help to improve the heat insulation property of quartz porous ceramics. The CaSiO₄ is produced in the ceramics after sintering processing. The shape is better, and the microstructure is circular and symmetrical pore, which is help to improve the mechanical property of quartz porous ceramics.

Abstract: In this paper, based on the study of effects of various physical mechanisms on the fracture strength of porous ceramic materials, a thermo-damage strength theoretical model applied to each stage of temperature is established. Using the model, the sensitivities of fracture strength to relevant parameters and their variation with temperature are studied in detail. The results show that under low temperature the strength is sensitive to the changes of porosity, pore size and pore shape factor, while under high temperature the effects of porosity, pore size and pore shape factor on the strength compared to the temperature are negligible, yet the strength is very sensitive to the Young’s modulus, thus the Young’s modulus is the dominant of strength under high temperature. This study will provide a theoretical basis and guidance to the design and application of porous ceramic materials.

Abstract: The problems of thermomechanical phenomena, which occur in low stability – porous ceramic material (LS-PCM) submitted to thermal shock, are discussed. The authors tried to answer the question concerning the usefulness of Hot Distortion tests (HD) for estimation of parameters necessary in data base of simulation codes, which permit to simulate the phenomena in casting-mould system. These parameters should be accessible as temperature function, especially in high temperature range of LS-PCM used as mold heating using poured casting. The new methodology and equipment, based on British Cast Iron Association (BCIRA) method, allowed to study LS-PCM specimen feature called Hot Distortion method. In this paper the modified HD methodology, are shown. The modified apparatus DMA includes two thermal sources (electric and gaseous) used to 114 x 25 x 6 mm and 120 x 22 x 22 mm sample heating were tested and analyzed. The measurement and recording of chosen parameters, i.e. deformation (distortion) during heating and variability of surface temperature fields in heated sample, by use of pyrometer and thermal camera are presented. The virtual volume temperature field in heating sample was simulated. The comparative analysis of both, experimental and virtual results are realized. This permitted also to estimate the substitute thermo-physical coefficients using inverse solution by try & error method for predefined boundary conditions on bottom and upper specimen surfaces.

Abstract: In foundry technology the modeling of heat transfer in materials containing exothermic components must take into consideration the presence of heat sources in the Fourier–Kirchhoff equation. The aim of this investigation was the identification of real and effective thermophysical parameters of the insulating and insulating –exothermic materials used as riser sleeves containing these exothermic heat sources. The experiments of liquid steel or cast iron pouring into the mould, containing different insulating and exothermic sleeves were carried out, using thermocouples meas-urement systems (thermal analysis of casting–mould system). Then the thermo-physical coefficients of these materials were calculated using inverse problem solution. The numerical system Calcosoft and its Inverse Solution procedure were applied.