US 12,076,886 B2
Transparent alumina-based plate and method of making thereof
Jeffrey Paul Youngblood, West Lafayette, IN (US); Rodney Wayne Trice, West Lafayette, IN (US); Andrew Schlup, West Lafayette, IN (US); and William Costakis, West Lafayette, IN (US)
Assigned to PURDUE RESEARCH FOUNDATION, West Lafayette, IN (US)
Filed by Purdue Research Foundation, West Lafayette, IN (US)
Filed on Dec. 15, 2020, as Appl. No. 17/121,840.
Claims priority of provisional application 62/983,816, filed on Mar. 2, 2020.
Prior Publication US 2021/0362369 A1, Nov. 25, 2021
Int. Cl. B28B 3/02 (2006.01); C01F 7/027 (2022.01); C04B 35/115 (2006.01); C04B 35/626 (2006.01); C04B 35/645 (2006.01)
CPC B28B 3/025 (2013.01) [C01F 7/027 (2013.01); C04B 35/115 (2013.01); C04B 35/62605 (2013.01); C04B 35/645 (2013.01); C01P 2002/72 (2013.01); C01P 2004/03 (2013.01); C01P 2004/20 (2013.01); C04B 2235/5292 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method of preparing a transparent platelet alumina-based plate by hot-pressing platelet alumina, wherein the method comprises:
(a) providing a sample consisting of a platelet alumina powder, wherein the platelet alumina powder sample is optionally purified by washing with an organic solvent and then by heating to remove the organic solvent;
(b) providing a die for hot-pressing, wherein the die is placed in a furnace chamber;
(c) loading the platelet alumina powder sample into the die;
(d) uniaxially pressing the platelet alumina powder sample to initially consolidate the platelet alumina powder;
(e) providing a low pre-load pressure of 0-8 MPa onto the die before a maximum sintering temperature is reached;
(f) providing a pressure to the sample until a maximum pressure of 2-90 MPa is reached;
(g) holding the maximum sintering temperature and the maximum pressure for about 5-7 hours to densify the sample; and
(h) cooling the sample and removing the pressure to provide a hot-pressed alumina-based plate with at least 60% in-line transmission for a light with a wavelength of 645 nm.