Plasma resistant yttrium aluminum oxide body
Disclosed herein is a sintered ceramic body comprising from 90% to 99.9% by volume of polycrystalline yttrium aluminum garnet (YAG) as measured using XRD and image processing methods and a volumetric porosity of from 0.1 to 4% as calculated from density measurements performed in accordance with ASTM B962-17. The sintered ceramic body may have a total purity of 99.99% and greater and a grain size of from 0.3 to 8 μm. A method of making the sintered ceramic body is also disclosed.
1 . A sintered ceramic body comprising from 90 to 99.9% by volume of polycrystalline yttrium aluminum garnet (YAG) as measured using XRD and image processing methods and a volumetric porosity of from 0.1 to 4% as calculated from density measurements performed in accordance with ASTM B962-17, wherein the sintered ceramic body has a greatest dimension of from 350 mm to 622 mm and has an average hardness of from 13.5 to 14.5 GPa using an applied load of 0.2 kgf as measured in accordance with ASTM Standard C1327, wherein the average hardness is calculated from 8 measurements.
2 . The sintered ceramic body of claim 1 wherein the volumetric porosity is from 0.1 to 0.5%.
3 . The sintered ceramic body of claim 1 wherein the sintered ceramic body comprises pores having a maximum pore diameter of from 0.1 to 0.6 pm as measured using SEM and image processing methods.
4 . The sintered ceramic body of claim 1 wherein the polycrystalline yttrium aluminum garnet is present in an amount of from 90 to 99.4% by volume.
5 . The sintered ceramic body of claim 1 having a purity of 99.995% or higher as measured using ICPMS methods.
6 . The sintered ceramic body of claim 5 wherein the purity is 99.999% or higher.
7 . The sintered ceramic body of claim 1 wherein the total impurity content is 10 ppm or less relative to the total sintered body mass as measured using ICPMS methods.
8 . The sintered ceramic body of claim 1 wherein the sintered ceramic body comprises silica in an amount of about 14 ppm relative to the total mass of the sintered ceramic body as measured using ICPMS methods as disclosed herein.
9 . The sintered ceramic body of claim 1 further comprising at least one crystalline phase selected from the group consisting of yttrium aluminum perovskite (YAP) and yttrium aluminum monoclinic (YAM) and combinations thereof, wherein the at least one crystalline phase is present in an amount of from 0.1 to 2% by volume.
10 . The sintered ceramic body of claim 1 having an arithmetical mean height (Sa) of about 12 nm or less on a surface as measured in accordance with ISO standard 25178-2-2012, section 4.3.2.
11 . The sintered ceramic body of claim 10 wherein an arithmetical mean height (Sa) is about 20 nm or less on the surface when exposed to an etch method having a pressure of 10 millitorr, a bias of 600 volts, ICP powder of 2000 watts, the etch method further comprising a first etch step having a CF 4 flow rate of 90 standard cubic centimeters per minute (sccm), an oxygen flow rate of 30 standard cubic centimeters per minute (sccm), an argon flow rate of 20 standard cubic centimeters per minute (sccm), and a second etch step having an oxygen flow rate of 100 standard cubic centimeters per minute (sccm) and an argon flow rate of 20 standard cubic centimeters per minute (sccm) wherein steps one and two are performed for 300 seconds each and repeated for a combined duration of 6 hours.