	US 12,486,202 B2
	Multilayer sintered ceramic body and method of making
Luke Walker, Chandler, AZ (US); Matthew Joseph Donelon, Chandler, AZ (US); Saurabh Waghmare, Chandler, AZ (US); and Lillian Thompson, Chandler, AZ (US)
Assigned to Heraeus Covantics North America LLC, Chandler, AZ (US)
Appl. No. 18/248,489
Filed by Heraeus Covantics North America LLC, Chandler, AZ (US)
PCT Filed Oct. 13, 2021, PCT No. PCT/US2021/054773 § 371(c)(1), (2) Date Apr. 10, 2023, PCT Pub. No. WO2022/081700, PCT Pub. Date Apr. 21, 2022.
Claims priority of provisional application 63/216,356, filed on Jun. 29, 2021.
Claims priority of provisional application 63/160,666, filed on Mar. 12, 2021.
Claims priority of provisional application 63/092,451, filed on Oct. 15, 2020.
Prior Publication US 2024/0158301 A1, May 16, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. C04B 35/119 (2006.01); C04B 35/626 (2006.01); C04B 35/645 (2006.01); C04B 38/00 (2006.01)

CPC C04B 35/119 (2013.01) [C04B 35/62645 (2013.01); C04B 35/645 (2013.01); C04B 38/0054 (2013.01); C04B 2235/3222 (2013.01); C04B 2235/3225 (2013.01); C04B 2235/3246 (2013.01); Y10T 428/24355 (2015.01); Y10T 428/249953 (2015.04)]

15 Claims

1. A multilayer sintered ceramic body comprising:

at least one first layer comprising at least one crystalline phase of YAG, wherein the at least one first layer has at least one surface; and

at least one second layer comprising alumina and at least one of stabilized zirconia and partially stabilized zirconia,

wherein the at least one surface of the at least one first layer comprises pores wherein the pores have a maximum size of from 0.1 to 5 μm as measured by SEM, and wherein each of the at least one first layer and the at least one second layer has a coefficient of thermal expansion (CTE), wherein the CTE of the at least one first layer and the CTE of the at least one second layer differ from 0 to 0.6×10⁻⁶/° C. as measured in accordance with ASTM E228-17.

12. A method of making a multilayer sintered ceramic body, the method comprising the steps of:

a. combining yttria and alumina powders to make a first powder mixture;

b. combining alumina and zirconia powders to make a second powder mixture, wherein the zirconia is selected from the group consisting of partially stabilized zirconia and stabilized zirconia;

c. calcining the first and second powder mixtures by applying heat to raise the temperature of the powder mixtures to a calcination temperature and maintaining the calcination temperature to perform calcination to form first and second calcined powder mixtures;

d. separately disposing the first and second calcined powder mixtures inside a volume defined by a tool set of a sintering apparatus to form at least one layer of the first calcined powder mixture and at least one layer of the second calcined powder mixture and creating vacuum conditions inside the volume;

e. applying pressure to the layers of the first and second calcined powder mixtures while heating to a sintering temperature and performing sintering to form the multilayer sintered ceramic body, wherein the at least one layer of the first calcined powder mixture upon sintering forms at least one first layer and the at least one layer of the second calcined powder mixture forms at least one second layer; and

f. lowering the temperature of the multilayer sintered ceramic body,

wherein the at least one first layer comprising at least one crystalline phase of YAG, wherein the at least one first layer has at least one surface; and at least one second layer comprising alumina and at least one of stabilized zirconia and partially stabilized zirconia,

wherein the at least one surface of the at least one first layer comprises pores wherein the pores have a maximum size from 0.1 to 5 μm as measured using SEM and image processing methods, and wherein each of the at least one first layer and the at least one second layer has a coefficient of thermal expansion (CTE), wherein the CTE of the at least one first layer and the CTE of the at least one second layer differ from 0 to 0.6×10⁻⁶/° C. as measured in accordance with ASTM E228-17.