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Heat-induced structural transformations of anodic porous alumina formed in phosphoric acid
- Source :
- Microporous and Mesoporous Materials. 265:77-83
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- An anodic porous alumina prepared in phosphoric acid electrolyte was heat-treated under various conditions and structural transformations were investigated. Heating the anodic porous alumina resulted in crystallization from amorphous phase to transition alumina at ∼900 °C; subsequently, aluminum phosphate was formed in the anion-incorporated layer at ∼1000 °C, and finally, phase transition from transition alumina to α-alumina occurred above 1350 °C. The aluminum phosphate particles grew, and sintering of the alumina and phase transition to α-alumina was promoted with increasing temperature and total quantity of heat. When the temperature and total quantity of heat were further increased, aluminum phosphate passed into the gaseous phase and the gas migrated through straight pores to the membrane surface along with sintering of the α-alumina. By removing the aluminum phosphate particles, the introduction of mesopores inside the pore walls and expansion of the surface area can be easily achieved.
- Subjects :
- Phase transition
Materials science
Sintering
02 engineering and technology
Electrolyte
010402 general chemistry
01 natural sciences
law.invention
chemistry.chemical_compound
law
Phase (matter)
General Materials Science
Crystallization
Porosity
Phosphoric acid
technology, industry, and agriculture
General Chemistry
equipment and supplies
021001 nanoscience & nanotechnology
Condensed Matter Physics
0104 chemical sciences
chemistry
Chemical engineering
Mechanics of Materials
0210 nano-technology
Mesoporous material
Subjects
Details
- ISSN :
- 13871811
- Volume :
- 265
- Database :
- OpenAIRE
- Journal :
- Microporous and Mesoporous Materials
- Accession number :
- edsair.doi...........b0a38133e4ee5de6ca0cd880e07478c3
- Full Text :
- https://doi.org/10.1016/j.micromeso.2018.01.008