Thermal and environmental barrier coating for ceramic substrates

Patent metadata

Field	Value
Publication number	US-10647618-B2
Application number	US-201514666745-A
Country	US
Kind code	B2
Filing date	Mar 24, 2015
Priority date	Sep 19, 2014
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A thermal and environmental barrier coating composed of ceramic hollow microspheres sintered together. In one embodiment the microspheres are sintered together with a powder of another material that acts as a binder, or with a powder of a material that may be the same as the material of the hollow microspheres, forming a matrix in which the hollow microspheres are embedded. The hollow microspheres may be composed of a material with a high temperature capability, and with a low coefficient of thermal expansion.

First claim

What is claimed is:

1. An article, comprising:
a ceramic substrate;
a thermal barrier coating covering a surface of the ceramic substrate, the thermal barrier coating having:
a void volume fraction of at least 60% and a major part of the void volume being closed porosity,
the thermal barrier coating comprising, as a major component, a plurality of hollow particles, the plurality of hollow particles comprising, as a major component, a rare-earth silicate,

each of the plurality of hollow particles having:
a maximum interior dimension less than 1 millimeter (mm) and greater than 5 micrometers, and
a maximum wall thickness less than 1/10 of the maximum interior dimension,

wherein the plurality of hollow particles are embedded in a matrix and the material of the matrix is selected from the group consisting of: rare-earth gallates, hafnium titanates, zirconium titanates, scandium tantalates, and combinations thereof; and
a capping layer covering a portion of a surface of the thermal barrier coating, the capping layer having a porosity less than 10% and a thickness less than 1/10 of the thickness of the thermal barrier coating, and wherein the capping layer comprises the same rare-earth silicate as the plurality of hollow particles, and wherein the same rare-earth silicate is selected from the group consisting of yttrium monosilicate (Y 2 SiO 5 ), yttrium disilicate (Y 2 Si 2 O 7 ), ytterbium monosilicate (Yb 2 SiO 5 ), ytterbium disilicate (Yb 2 Si 2 O 7 ), and scandium disilicate (Sc 2 Si 2 O 7 ).

2. The article of claim 1 wherein a portion of an exterior surface of each of the plurality of hollow particles is coated with a binder coating, the binder coating securing the hollow particles together.

Assignees

• Hrl Lab Llc

Inventors

• Schaedler Tobias A

Classifications

• C04B41/009

  characterised by the material treated · CPC title

• F05D2300/603

  Composites; e.g. fibre-reinforced · CPC title

• F05D2250/241

  spherical · CPC title

• C04B41/86

  Glazes; Cold glazes · CPC title

• C04B41/5024

  Silicates (C04B41/5022 takes precedence; silico-fluorides C04B41/5018) · CPC title