Ion assisted deposition for rare-earth oxide based thin film coatings on process rings

1. A method of manufacturing an article comprising:

loading a ring shaped body into a deposition chamber, wherein the ring shaped body is a sintered ceramic body comprising a top flat region, a ring inner side and a ring outer side, wherein the ring inner side comprises a step and a vertical wall and the ring outer side is rounded;

performing ion assisted deposition to deposit a protective layer on at least the top flat region, the ring inner side and the ring outer side of the ring shaped body, wherein the protective layer is a plasma resistant rare earth oxide film having a first thickness of less than 300 μm on the top flat region and a second thickness on the vertical wall of the ring inner side, wherein the second thickness is 45-70% of the first thickness, and wherein the protective layer is a conformal layer having a porosity of less than or equal to about 0.1%; and

flame polishing the protective layer on the ring shaped body to an average surface roughness of below 6 micro-inches.

2. The method of claim 1 , wherein the protective layer is a ceramic film having a thickness of approximately 5-15 μm that comprises at least one of Y 3 Al 5 O 12 , Y 4 Al 2 O 9 , Er 2 O 3 , Gd 2 O 3 , Er 3 Al 5 O 12 , Gd 3 Al 5 O 12 , YF 3 , Nd 2 O 3 , Er 4 Al 2 O 9 , ErAlO 3 , Gd 4 Al 2 O 9 , GdAlO 3 , Nd 3 Al 5 O 12 , Nd 4 Al 2 O 9 , NdAlO 3 , or a ceramic compound comprising Y 4 Al 2 O 9 and a solid-solution of Y 2 O 3 —ZrO 2 .

3. The method of claim 1 , further comprising:

performing the flame polishing to polish the protective layer to a roughness of 2-3 micro-inches.

4. The method of claim 1 , wherein the protective layer has a thickness of 10-12 μm, and where a deposition rate of 1-2 Angstroms per second is used to deposit the protective layer.

5. The method of claim 1 , further comprising:

heating the ring shaped body to a temperature of at least 150° C. prior to performing the ion assisted deposition; and

maintaining the temperature during the ion assisted deposition.

6. The method of claim 1 , wherein the ion assisted deposition is an electron beam ion assisted deposition, wherein a voltage of 150-270V and a current of 5-7 A are used to perform the electron beam ion assisted deposition.

7. The method of claim 1 , further comprising:

performing the ion assisted deposition to deposit a second protective layer on the protective layer, wherein the second protective layer is an additional plasma resistant rare earth oxide film having a thickness of 5-15 μm.

8. The method of claim 7 , wherein the protective layer comprises a coloring agent that causes the protective layer to have a different color than the second protective layer.

9. The method of claim 7 , wherein the protective layer is an amorphous layer comprising Y 3 Al 5 O 12 or Er 3 Al 5 O 12 and the second protective layer is a crystalline or polycrystalline layer comprising Er 2 O 3 or a ceramic compound comprising Y 4 Al 2 O 9 and a solid-solution of Y 2 O 3 —ZrO 2 .

10. The method of claim 1 , wherein the article is usable at a temperature of 300° C. without causing cracking of the protective layer.

11. The method of claim 1 , wherein the protective layer is an amorphous layer after performing the ion assisted deposition, the method further comprising:

performing a heat treatment of the article after performing ion assisted deposition, wherein the heat treatment causes the protective layer to convert from the amorphous layer into a crystalline layer.

12. The method of claim 11 , wherein the heat treatment cause a transition layer to form between the ring shaped body and the protective layer.

13. The method of claim 1 , wherein the protective layer has a porosity of less than or equal to about 0.01%.