Using analytical pure Al（ OH）3 , SiO2 , TiO2 as raw materials, effect of TiO2 on the sinterability and microstructure of mullite synthesized from Al （ OH）3 and SiO2 was investigated in this paper by XRD , SEM and ...Using analytical pure Al（ OH）3 , SiO2 , TiO2 as raw materials, effect of TiO2 on the sinterability and microstructure of mullite synthesized from Al （ OH）3 and SiO2 was investigated in this paper by XRD , SEM and EPAX. Results show that TiO2 can promote the sintering property when the amount is below 6%, the sinterability of samples becomes better with the increase of the amount of TiO2, microstructure of samples densify gradually, and the best effect can be achieved when the amount of TiO2 is 6%. It was shown by XRD analysis that no Al2TiO5 present when the amount of TiO2 is below 6%, TiO2 existed in the form of solid-solution and glass phase; When the amount of TiO2 is up to 6%, the sinterability of samples becomes worse with the increase of TiO2 added, microstructure of samples began to loosen, Al2TiO5 can be observed in samples and its amount increase with the increase of TiO2.展开更多
The effects of sintering atmosphere on the properties of symmetric TiO2 membranes are studied with regard to sintering behavior, porosity, mean pore size, surface comPosition. and surface charge properties. The exerim...The effects of sintering atmosphere on the properties of symmetric TiO2 membranes are studied with regard to sintering behavior, porosity, mean pore size, surface comPosition. and surface charge properties. The exerimental results show that the symmetric TiO2 membranes display better sintering activity in the air than in argon, and the mean pore diameters and porosities of the membrane sintered in argon are higher than those of the membrane sintered in the air at the same temperature. The surface compositions of the symmetric TiO2 membrane sintered in the air and in argon at different temperatures, as studied by X-ray photoelectron spectroscopy, are discussed in terms of their chemical composition, with particular emphasis on the valence state of the titanium ions. The correlation between the valence state of the titanium ions at the surface and the surface charge properties is examined.It is found that the presence of Ti^3＋, introduced at the surface of the symmetric TiO2 membranes by sintering in a lower partial pressure of oxygen, is related to a significant decrease in the isoelectric point. TiO2 with Ti^4＋ at the interface has an isoelectric point of 5.1, but the non-stoichiometric TiO2-x with Ti^3＋ at the interface has a lower isoelectric point of 3.6.展开更多
文摘Using analytical pure Al（ OH）3 , SiO2 , TiO2 as raw materials, effect of TiO2 on the sinterability and microstructure of mullite synthesized from Al （ OH）3 and SiO2 was investigated in this paper by XRD , SEM and EPAX. Results show that TiO2 can promote the sintering property when the amount is below 6%, the sinterability of samples becomes better with the increase of the amount of TiO2, microstructure of samples densify gradually, and the best effect can be achieved when the amount of TiO2 is 6%. It was shown by XRD analysis that no Al2TiO5 present when the amount of TiO2 is below 6%, TiO2 existed in the form of solid-solution and glass phase; When the amount of TiO2 is up to 6%, the sinterability of samples becomes worse with the increase of TiO2 added, microstructure of samples began to loosen, Al2TiO5 can be observed in samples and its amount increase with the increase of TiO2.
基金Supported by the National-Basic Research Program of China （2003CB615707） and the National Natural Science Foundation of China （20636020）.
文摘The effects of sintering atmosphere on the properties of symmetric TiO2 membranes are studied with regard to sintering behavior, porosity, mean pore size, surface comPosition. and surface charge properties. The exerimental results show that the symmetric TiO2 membranes display better sintering activity in the air than in argon, and the mean pore diameters and porosities of the membrane sintered in argon are higher than those of the membrane sintered in the air at the same temperature. The surface compositions of the symmetric TiO2 membrane sintered in the air and in argon at different temperatures, as studied by X-ray photoelectron spectroscopy, are discussed in terms of their chemical composition, with particular emphasis on the valence state of the titanium ions. The correlation between the valence state of the titanium ions at the surface and the surface charge properties is examined.It is found that the presence of Ti^3＋, introduced at the surface of the symmetric TiO2 membranes by sintering in a lower partial pressure of oxygen, is related to a significant decrease in the isoelectric point. TiO2 with Ti^4＋ at the interface has an isoelectric point of 5.1, but the non-stoichiometric TiO2-x with Ti^3＋ at the interface has a lower isoelectric point of 3.6.
