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Study On The Preparation Process And The Properties Of Alumina Honeycomb Ceramic Regenerator

Posted on:2005-03-27Degree:MasterType:Thesis
Country:ChinaCandidate:H L XueFull Text:PDF
GTID:2121360122990433Subject:Materials science
Abstract/Summary:PDF Full Text Request
In the dissertation high-temperature corundum honeycombed ceramic regenerative body was prepared by an extrusion process, a-Al2O3 minute powder as main raw material, clay, CMC etc as plasticizers, tung oil etc as lubricator. The plastic performance was tested on a plastic measure apparatus. During preparation added MgO etc as mineralization were added to decreases sintering temperature of Al2O3, control the mineral composion and microstructure, optimize the performance of heat and mechanics, etc, resulting in its use in regenerative combustion field. The result of experiment show that the best content of water is in the range of 10%~20%, and the CMC is about 3-7%. Dropping of MgO etc can decrease sintering temperature of Al2O3 efficaciously, and make Al2O3 sintered at 1450 C for 1 hour.Mineral compositions and the microstructure were investigated by XRD and SEM; the result show that The second phase and liquid phase are produced during sintering, and the second phase and liquid phase were filled in space of the Al2O3 crystals, which can control the microstructure efficaciously. Density, porosity, thermal expansion coefficient and intensity were tested by Archimedes-method, show the distance and bend resist of three point etc. Heat-conducting coefficient and specific heat etc were tested on a TC700OH laser heat constant measure apparatus, The fire-resistant performances were tested by triangle thermoscope, Thermal shock property was tested by simulating the fact, the results show that the material's thermal expansion coefficient can be decreased less than 62.5 10-7 C-1, the density of the wall of bore more than 2.40 g/cm3, the sop rate range in 9-16%, the pore rate less than 38%, the intensity were more than 40MPa, the heat-conducting coefficient were 1.015 101 W/ (m-K) (18 C) and 5.802x10 W/ ( m-K ) ( 1300 C ) , specific heat were 8.836 10-1 J/ ( g-K ) ( 18 C ) and 1.960 10 J/ (g-K) (1300 C) . the fire-resistant temperature were more than 1790 C.,and the samples' thermal shock resistance times were over 40 times during tested by simulating the fact(l100 C-cold water which temperature is less than 10 C).The experiment results show that the samples can not be sintered when the addition phases were in a very low level, and their strength and thermal shock resistance performance were neither, there were too much liquid phase created when the addition phases were in a high level, it can decrease the pore rate of the samples, and the space for structure adjusting during thermal shock, resulting in the decrease of their thermal shock resistance performance. Adding SiC can decreases sintering temperature of Al2O3 efficaciously, but also can make the Al2O3 crystal growth as flake, strengthen the coalescent of the Al2O3 crystals, and the residual SiC during sintering can strengthen the Al2O3 ceramics. Because the reaction between SiC and Al2O3 begins from the surface of samples, there is a compact protecting field on the surface of the samples to restrain O2 enter into the samples, and leave more pore in them to decrease the thermal expansion coefficient and increase their the Al2O3 ceramics' thermal shock resistance times.The results of experiment show that the samples have good regenerative conduction of heat, good heat-conducting, good heat-shock resistant, refractoriness property, and have higher strength and density, and it can be used as a kind of ideal high-temperature regenerative body.
Keywords/Search Tags:honeycombed ceramics, Al2O3 ceramic, extrusion process, regenerative body, high-temperature
PDF Full Text Request
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