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Pore Structure Of Forsterite Light-weight Material Synthesized By Molten Salt Method

Posted on:2016-10-06Degree:MasterType:Thesis
Country:ChinaCandidate:X J ZhangFull Text:PDF
GTID:2181330467991241Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
The lightweight material with higher porosity and strength can be prepared by themolten salt method. Pore structure is one of the most important characteristics oflightweight materials and have a close relationship with properties such as porosity,thermal conductivity and strength. Therefore, using appropriate characterizationtechnique to explore the mechanism and characteristics of pore have great significancefor the preparation of lightweight refractory.NaCl and NaCl-Na2CO3were used as the molten salt medium to synthesize theforsterite porous light-weight materials sintered at1000,1050,1100and1150℃. Themechanism of pore formation in the materials were studied. The pore size distributionand pore structural parameters of samples were studied by mercury intrusion porosimetry,nitrogen adsorption-desorption method and fractal dimension. The relationship ofbetween pore structure and strength of insulating material was studied by gray systemtheory.(1) NaCl was used as the molten salt medium to synthesize the forsterite porouslight-weight materials. The NaCl evaporation and dissolved in water are the main sourcesof pore. But dissolved in water formatting pores is the main pore forming. with sizelarger than4.6μm. With the temperature increasing from1000℃to1100℃, the poresize less than4.6μm formed by particle accumulation disappeared gradually and the poreformed by evaporation salt occupied the main form. When temperature reached1150℃.The pore size less than4.6μm disappeared. The fractal dimension of sample decreased bythe increasing of temperature and content of molten salt and the pore structure tend to besample. With the sample temperature and different molten salt content, the light-weightmaterials of compressive strength have the maximum correlation of pore size whichbetween4.6-46μm, and the other is fractal dimension. At different temperatures, thelight-weight of compressive strength have the maximum correlation of pore sizedistribution and fractal dimension.(2)NaCl-Na2CO3were used as the molten salt medium to synthesize the forsteriteporous light-weight materials.The formation of pores are mainly due to the action ofdecomposition of Na2CO3and the NaCl dissolved in water. The nitrogen adsorption-desorpion isotherms of sample are belong to II type. The formation ofhysteresis loop shape are belong to B type. When the temperature is1000℃and the thecontent of Na2CO3is30%, the pore of uniformity, distribution and the aperture sizeachieve the best. The fractal dimension of pore show the different change because of thethe mechanism of pore forming. With the sample temperature and different molten saltcontent, the light-weight of compressive strength have the maximum correlation offractal dimension and porosity. At different temperature, the light-weight materials ofcompressive strength have the maximum correlation of pore size between6.6-66μm,porosity and fractal dimension.
Keywords/Search Tags:forsterite, molten salt, pore structure, fractal dimension, gray theory
PDF Full Text Request
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