Method for producing ceramic coatings containing layered porosity

• US 6,365,236 B1
• Filed: 12/20/1999
• Issued: 04/02/2002
• Est. Priority Date: 12/20/1999
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Maloney, Michael J.
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US09/468,026
• Time in Patent Office: 834 Days
• Field of Search: 427/250, 427/255.28, 427/255.7, 427/404, 427/419.2, 427/585
• US Class Current: 427/585
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium
• CPC Class Codes: C23C 14/541 Heating or cooling of the substrates
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

Methods of producing layered ceramic coatings in which some layers contain porosity are described, as are the coatings produced. The different layers are applied at different temperature conditions by periodically inserting a heat blocking shield between the heat source and either the evaporation source and/or an external heater. As applied, some of the layers have a Zone I structure and some have a Zone II type structure. Heat treatment may be used to increase the porosity in the Zone I structure layers.

Claims

1. A method of applying a layered ceramic coating on a substrate including the steps of:

electron beam physical vapor depositing a plurality of ceramic layers from at least one evaporant source and onto the substrate; and

alternating the temperature during vapor depositing by periodically positioning a heat blocking screen between the evaporant source and the substrate to reduce heat flow to form alternating layers of ceramic material with at least one layer being deposited at a first temperature and at least another layer being deposited at a second temperature different than the first temperature, wherein at least one of said layers has a Zone I microstructure and at least one of said layers has a Zone II microstructure.

2. A method as in claim 1, further comprising the step of:

heat treating the layer to produce porosity in one or more of the layers having a Zone I microstructure.

3. A method as in claim 1, wherein the layer deposited at the lower temperature is the layer having the Zone I type microstructure.

4. A method as in claim 1, wherein a single evaporant source is used.

5. A method as in claim 1, wherein the single evaporant source is composed of a stabilized ceria.

6. A method as in claim 1, wherein the single evaporant source is composed of a stabilized zirconia.

7. A method as in claim 1, wherein said substrate has a surface layer comprised primarily of alumina.

8. A method as in claim 7, wherein said alumina layer has a thickness of 0.1-2.0 microns.

9. A method as in claim 1, wherein said substrate has a bond coat selected from the group consisting of MCrAlY and aluminide layers and combinations thereof and said alumina layer is located on the surface of the bond coat.

10. A method as in claim 1, wherein the total thickness of the layers is from about 0.05 to about 5000 microns.

11. A method as in claim 1, wherein the substrate is composed of a material capable of forming an adherent alumina layer, and further comprising the step of forming an alumina layer on the substrate.

12. A method as in claim 1, wherein the step of vapor depositing includes vaporizing at lease two sources of ceramic material.

13. A method as in claim 12, wherein the sources of ceramic material have different compositions.

14. A method as in claim 1, wherein the substrate defines a gas turbine engine component.

15. A method as in claim 1, wherein the substrate is composed of a superalloy material capable of forming an adherent alumina layer, and further comprising the step of forming an alumina layer on the substrate.