Enhancing mechanical properties and air permeability of corundum porous materials by in situ formation of LaAl_(11)O_(18) in bonding phase |
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| Affiliation: | 1. Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441, Dammam, Saudi Arabia;2. Department of Biophysics, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441, Dammam, Saudi Arabia;3. Department of Nano-Medicine Research, Institute for Research & Medical Consultations (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, 31441, Dammam, Saudi Arabia;1. Chinese Academy of Sciences (CAS) Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China;3. University of Chinese Academy of Sciences, Beijing 100049, China;1. Department of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;2. Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China;3. University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Corundum porous materials of particle-packing type with different contents of in situ formed LaAl_(11)O_(18)were prepared using tabular corundum,reactive alumina and La_2O_3 powder as raw materials.The effects of the introduction of LaAl_(11)O_(18) on the microstructure.phase composition and properties of the porous materials were investigated.The specimens were characterized by scanning electron microscopy.X-ray diffraction and mercury porosimetry.Results show that platelet-like LaAl_(11)O_(18) is formed in situ by the reactions of La_2O_3 and Al_2O_3.With a certain amount of La_2O_3 added.the cold crushing strength,cold modulus of rupture and hot modulus of rupture(1400 x 0.5 h) of the specimens are increased,and the air permeability is improved simultaneously.However.upon further increasing the amount of La_2O_3 added,the mechanical properties and air permeability of the porous materials then decrease gradually owing to the increased numbers of pores and cracks in the bonding phase.The enhanced mechanical properties of the specimens with La_2O_3 added are attributed to the strengthening effects of plate-like LaAl_(11)O_(18) in the bonding phase and to the activated sintering of both Al_2O_3 powder and corundum coarse aggregate for the diffusion of La~(3+)in Al_2O_3 lattice.In addition,the improved air permeability of the specimens should be related to the decreased content of pores in the bonding phase and the reduced number of interfacial cracks. |
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| Keywords: | Porous materials of particle-packing type Lanthanum hexaluminate Mechanical strength Strengthening mechanism Air permeability Rare earths |
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