Method for producing nano-scale theta phase alumina microparticles
AssigneeNational Cheng Kung University
InventorsFu-Su Yen, Rung-Je Yang
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Abstract
A method for producing nano-scale theta (θ)-phase alumina microparticles is disclosed. The nano-scale θ-phase alumina microparticles are uniform in particle size and highly phase-pure. They are obtained by controlling the ratio of boehmite mixed with the θ-phase alumina initial powders, followed by at least one phase transformation. Therefore, the nano-scale θ-phase alumina microparticles produced by the present method have more uniform particle size and highly purer phase. As such for the production of nano-scale θ-phase alumina microparticles, the present method saves more process time and cost, and it provides an advantage such as the clean production.
Claims21
A method for producing nano-scale theta (θ)-phase alumina microparticles, *comprising:
- providing an alumina mixed powder, the alumina mixed powder comprises θ-phase alumina powder and boehmite, wherein an amount of the θ-phase alumina powder in the alumina mixed powder is in a range from 30 percent to 95 percent by weight, and an alumina equivalent of the boehmite in the alumina mixed powder is in a range from 5 percent to 70 percent by weight;
- heating the alumina mixed powder to a first temperature and keeping it at the first temperature for a first period, so as to trigger a first phase transformation of the alumina mixed powder for forming α′-phase alumina microparticles;
- and
- quenching the α′-phase alumina microparticles to room temperature and heating it to a second temperature and keeping it at the second temperature for a second period, so as to trigger at least a second phase transformation of the α′-phase alumina microparticles for forming the nano-scale θ-phase alumina microparticles, wherein a particle size of the nano-scale θ-phase alumina microparticles is in a range from 30 nanometers (nm) to 150 nm.
A method for producing nano-scale θ-phase alumina microparticles, comprising:
- providing an alumina mixed powder, the alumina mixed powder comprises θ-phase alumina powder and boehmite, wherein an amount of the θ-phase alumina powder in the alumina mixed powder is in a range from 30 percent to 95 percent by weight, and an alumina equivalent of the boehmite in the alumina mixed powder is in a range from 5 percent to 70 percent by weight;
- heating an alumina mixed powder to a first temperature and keeping it at the first temperature for a first period, so as to trigger a first phase transformation of the alumina mixed powder for forming α′-phase alumina microparticles;
- and
- quenching the alumina mixed powder to a second temperature and keeping it at the second temperature for a second period, so as to trigger at least a second phase transformation of the α′-phase alumina microparticles for forming the nano-scale θ-phase alumina microparticles, wherein a particle size of the nano-scale θ-phase alumina microparticles is in a range from 30 nm to 150 nm.
Dependencies are inferred from the claim text.