# US 2020/0400028 A1 · Reactive thermal barrier coating

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- Number: US 2020/0400028 A1
- Document ID: US20200400028A1
- Status: Published application
- Kind: A1
- Application number: 16/906,298
- Filed: 2020-06-19
- Published: 2020-12-24
- Earliest claimed: 2019-06-21
- Assignees: Rtx Corporation
- Applicants: Raytheon Technologies Corporation
- Inventors: Brian T. Hazel; Elisa M. Zaleski; Kaylan M. Wessels
- Web page: https://patentgrep.com/patent/US20200400028A1

## CPC

- F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments}
- B32B 15/04: comprising metal as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042)}
- B32B 18/00: Layered products essentially comprising ceramics, e.g. refractory products
- C23C 4/11: Oxides
- C23C 4/134: Plasma spraying
- C23C 4/18: After-treatment
- C23C 14/06: characterised by the coating material ({C23C14/0021} , C23C14/04 take precedence)
- C23C 14/08: Oxides (C23C14/10 takes precedence)
- C23C 14/081: {of aluminium, magnesium or beryllium}
- C23C 14/082: {of alkaline earth metals}
- C23C 14/083: {of refractory metals or yttrium}
- C23C 14/086: {of zinc, germanium, cadmium, indium, tin, thallium or bismuth}
- C23C 14/088: {of the type ABO3 with A representing alkali, alkaline earth metal or Pb and B representing a refractory or rare earth metal}
- C23C 14/22: characterised by the process of coating
- C23C 14/28: by wave energy or particle radiation (C23C14/32 - C23C14/48 take precedence)
- C23C 14/30: by electron bombardment
- C23C 14/34: Sputtering
- C23C 14/3492: {Variation of parameters during sputtering}
- C23C 16/40: Oxides
- C23C 16/405: {of refractory metals or yttrium}
- C23C 16/409: {of the type ABO3 with A representing alkali, alkaline earth metal or lead and B representing a refractory metal, nickel, scandium or a lanthanide}
- C23C 16/45525: {Atomic layer deposition [ALD]}
- C23C 28/04: only coatings of inorganic non-metallic material
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- C23C 28/30: {Coatings combining at least one metallic layer and at least one inorganic non-metallic layer}
- C23C 28/3215: {at least one MCrAlX layer}
- C23C 28/345: {with at least one oxide layer}
- C23C 28/3455: {with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer}
- C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence)
- C23C 30/005: {on hard metal substrates}
- F01D 5/28: Selecting particular materials; {Particular measures relating thereto;} Measures against erosion or corrosion
- F01D 5/284: {Selection of ceramic materials}
- F01D 5/288: {Protective coatings for blades}
- F01D 25/005: {Selecting particular materials}
- F01D 25/08: Cooling (of machines or engines in general F01P); Heating; Heat-insulation (of blade-carrying members, of blades F01D5/00)
- C04B 2237/34: Oxidic
- C04B 2237/343: Alumina or aluminates
- C04B 2237/348: Zirconia, hafnia, zirconates or hafnates
- Y10T 428/1259: Oxide
- Y10T 428/12597: Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]
- Y10T 428/12611: Oxide-containing component
- Y10T 428/12618: Plural oxides
- Y10T 428/2495: Thickness [relative or absolute]
- Y10T 428/24967: Absolute thicknesses specified
- Y10T 428/265: 1 mil or less
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A calcium-magnesium-alumino-silicate (CMAS)-reactive thermal barrier coating includes a ceramic coating and a CMAS-reactive overlay coating, wherein the CMAS-reactive overlay coating conforms to a surface of the ceramic coating and comprises a compound that forms a stable high melting point crystalline precipitate when reacted with molten CMAS at a rate that is competitive with CMAS infiltration kinetics into the thermal barrier coating. The ceramic coating phase is stable with the CMAS-reactive overlay coating.

## Claims

### Claim 1

A calcium-magnesium-alumino-silicate (CMAS)-reactive thermal barrier coating comprising:
a ceramic coating; and
a CMAS-reactive overlay coating, wherein the CMAS-reactive overlay coating conforms to a surface of the ceramic coating and comprises a compound that forms a stable high melting point crystalline precipitate when reacted with molten CMAS at a rate that is competitive with CMAS infiltration kinetics into the thermal barrier coating;
wherein the ceramic coating phase is stable with the CMAS-reactive overlay coating.

### Claim 2 (depends on 1)

The CMAS-reactive thermal barrier coating of claim 1, wherein the CMAS-reactive overlay coating comprises a material selected from a group consisting of a pure rare earth oxide and a mixed rare earth oxide.

### Claim 3 (depends on 1)

The CMAS-reactive thermal barrier coating of claim 1, wherein the CMAS-reactive overlay coating is a rare earth aluminate.

### Claim 4 (depends on 2)

The CMAS-reactive thermal barrier coating of claim 2, wherein the ceramic coating comprises a fully stabilized zirconate or hafnate structure.

### Claim 5 (depends on 2)

The CMAS-reactive thermal barrier coating of claim 2, wherein the ceramic coating comprises gadolinium zirconate.

### Claim 6 (depends on 2)

The CMAS-reactive thermal barrier coating of claim 2, wherein the ceramic coating comprises yttrium zirconate.

### Claim 7 (depends on 2)

The CMAS-reactive thermal barrier coating of claim 2, wherein the ceramic coating comprises a plurality of vertically-oriented gaps and wherein the CMAS-reactive overlay coating extends into the gaps and is deposited on inner walls of the ceramic coating, and wherein the plurality of vertically-oriented gaps remain open.

### Claim 8 (depends on 7)

The CMAS-reactive thermal barrier coating of claim 7, wherein the CMAS-reactive overlay is deposited in pores open to the vertically-oriented gaps.

### Claim 9 (depends on 8)

The CMAS-reactive thermal barrier coating of claim 8, wherein the thickness of the CMAS-reactive overlay ranges from 10 to 500 nanometers.

### Claim 10 (depends on 8)

The CMAS-reactive thermal barrier coating of claim 8, wherein the CMAS-reactive overlay extends into the vertically-oriented gaps to a depth of at least one-third of a thickness of the ceramic coating from an outer surface of the ceramic coating.

### Claim 11 (depends on 10)

The CMAS-reactive thermal barrier coating of claim 10, wherein the CMAS-reactive overlay extends into the vertically-oriented gaps to a depth of at least one-half of a thickness of the ceramic coating from an outer surface of the ceramic coating.

### Claim 12 (depends on 1)

The CMAS-reactive thermal barrier coating of claim 1, wherein the CMAS-reactive overlay has a material composition that will react with molten CMAS to form an oxy-apatite phase.

### Claim 13

A method of forming a CMAS-reactive thermal barrier coating, the method comprising:
depositing a ceramic coating on a substrate; and
depositing a CMAS-reactive overlay on the ceramic coating, wherein the CMAS-reactive overlay coating conforms to a surface of the ceramic coating and comprises a compound that forms a stable high melting point crystalline precipitate when reacted with molten CMAS at a rate that is competitive with CMAS infiltration kinetics into the thermal barrier coating;
wherein the ceramic coating phase is stable with the CMAS-reactive overlay coating.

### Claim 14 (depends on 13)

The method of claim 13, wherein the CMAS-reactive overlay is deposited using atomic layer deposition.

### Claim 15 (depends on 14)

The method of claim 14, wherein the ceramic coating is applied by electron beam-physical vapor deposition.

### Claim 16 (depends on 14)

The method of claim 14, wherein the ceramic coating comprises a plurality of vertically-oriented columnar microstructures extending in a thickness direction of the ceramic coating and wherein the CMAS-reactive overlay conforms to surfaces along a length of the columnar microstructures, and wherein the CMAS-reactive overlay extends into the vertically-oriented gaps to a depth of at least one-third of a thickness of the ceramic coating from an outer surface of the ceramic coating.

### Claim 17 (depends on 15)

The method of claim 15, wherein the CMAS-reactive overlay has a thickness ranging from 10 to 500 nanometers.

### Claim 18 (depends on 16)

The method of claim 16, wherein the plurality of vertically-oriented columnar microstructures are separated by a plurality of vertically-oriented gaps and wherein the gaps remain open to a surface of the coating follow deposition of the CMAS-reactive overlay.

### Claim 19 (depends on 14)

The method of claim 14, wherein the CMAS-reactive overlay coating comprises a material selected from a group consisting of a pure rare earth oxide, a mixed rare earth oxide, and a rare earth aluminate.

### Claim 20 (depends on 14)

The method of claim 14, wherein the ceramic coating comprises a fully stabilized zirconate or hafnate structure.