A ceramic component is generally provided that includes a silicon-based layer comprising a silicon-containing material (e.g., a silicon metal and/or a silicide) and about 0.001% to about 85% of a Ga-containing compound. For example, the silicon-based layer can be a bond coating directly on the surface of the substrate. Alternatively or additionally, the silicon-based layer can be an outer layer defining a surface of the substrate, with an environmental barrier coating on the surface of the substrate. Gas turbine engines are also generally provided that include such a ceramic component.

A ceramic component is generally provided that includes a silicon-based layer comprising a silicon-containing material (e.g., a silicon metal and/or a silicide) and about 0.001% to about 85% of a Ga-containing compound. For example, the silicon-based layer can be a bond coating directly on the surface of the substrate. Alternatively or additionally, the silicon-based layer can be an outer layer defining a surface of the substrate, with an environmental barrier coating on the surface of the substrate. Gas turbine engines are also generally provided that include such a ceramic component.

A coated member includes a heat-shielding coating layer made of a zirconia-dispersed silicate in which ytterbia-stabilized zirconia is precipitated as a dispersed phase in a matrix phase which is any one of a rare earth disilicate, a rare earth monosilicate, and a mixed phase of the rare earth disilicate and the rare earth monosilicate. The rare earth disilicate is a (Y.sub.1-a[Ln.sub.1].sub.a).sub.2Si.sub.2O.sub.7 solid solution wherein Ln.sub.1 is any one of Sc, Yb, and Lu, or a (Y.sub.1-c[Ln.sub.2].sub.c).sub.2Si.sub.2O.sub.7 solid solution wherein Ln.sub.2 is any one of Nd, Sm, Eu, and Gd. The rare earth monosilicate is Y.sub.2SiO.sub.5, [Ln.sub.1].sub.2SiO.sub.5, a (Y.sub.1-b[Ln.sub.1]b).sub.2SiO.sub.5 solid solution wherein Ln.sub.1 is any one of Sc, Yb, and Lu, or a (Y.sub.1-d[Ln.sub.2].sub.d).sub.2SiO.sub.5 solid solution wherein Ln.sub.2 is any one of Nd, Sm, Eu, and Gd.

A coated member includes a heat-shielding coating layer made of a zirconia-dispersed silicate in which ytterbia-stabilized zirconia is precipitated as a dispersed phase in a matrix phase which is any one of a rare earth disilicate, a rare earth monosilicate, and a mixed phase of the rare earth disilicate and the rare earth monosilicate. The rare earth disilicate is a (Y.sub.1-a[Ln.sub.1].sub.a).sub.2Si.sub.2O.sub.7 solid solution wherein Ln.sub.1 is any one of Sc, Yb, and Lu, or a (Y.sub.1-c[Ln.sub.2].sub.c).sub.2Si.sub.2O.sub.7 solid solution wherein Ln.sub.2 is any one of Nd, Sm, Eu, and Gd. The rare earth monosilicate is Y.sub.2SiO.sub.5, [Ln.sub.1].sub.2SiO.sub.5, a (Y.sub.1-b[Ln.sub.1]b).sub.2SiO.sub.5 solid solution wherein Ln.sub.1 is any one of Sc, Yb, and Lu, or a (Y.sub.1-d[Ln.sub.2].sub.d).sub.2SiO.sub.5 solid solution wherein Ln.sub.2 is any one of Nd, Sm, Eu, and Gd.

A heat insulator including a porous sintered body having a porosity of 70 vol % or more, pores having a pore size of more than 1000 m in a proportion of 10 vol % or less of all pores and pores having a pore size of 0.8 m or more and less than 10 m occupy 50 vol % or more and 80 vol % or less of pores having a pore size of 1000 m or less, while pores having a pore size of 0.01 m or more and less than 0.8 occupy 10 vol % or more and 30 vol % or less pores having a pore size of 1000 m or less. The porous sintered body is formed from MgAl.sub.2O.sub.4 raw material and includes a fibrous layer formed from inorganic material fibers, the heat conductivity of the heat insulator at 1000 C. or more and 1500 C. or less being 0.40 W/m.Math.K) or less.

A heat insulator including a porous sintered body having a porosity of 70 vol % or more, pores having a pore size of more than 1000 m in a proportion of 10 vol % or less of all pores and pores having a pore size of 0.8 m or more and less than 10 m occupy 50 vol % or more and 80 vol % or less of pores having a pore size of 1000 m or less, while pores having a pore size of 0.01 m or more and less than 0.8 occupy 10 vol % or more and 30 vol % or less pores having a pore size of 1000 m or less. The porous sintered body is formed from MgAl.sub.2O.sub.4 raw material and includes a fibrous layer formed from inorganic material fibers, the heat conductivity of the heat insulator at 1000 C. or more and 1500 C. or less being 0.40 W/m.Math.K) or less.

An article may include a substrate comprising a matrix material and a reinforcement material, a layer formed on the substrate, an array of features formed on the layer, and a coating formed on the layer and the array of features. The article may have improved thermal and/or mechanical stress tolerance compared to an article not including the array of features formed on the layer.

An article may include a substrate comprising a matrix material and a reinforcement material, a layer formed on the substrate, an array of features formed on the layer, and a coating formed on the layer and the array of features. The article may have improved thermal and/or mechanical stress tolerance compared to an article not including the array of features formed on the layer.

An article may include a substrate defining a surface imperfection and a coating deposited over the substrate. The coating does not substantially reproduce the surface imperfection, and the coating comprises mullite and at least one rare earth silicate, rare earth oxide, alumina, boron oxide, alkali metal oxide, alkali earth metal oxide, silicon, barium strontium aluminosilicate, barium aluminosilicate, strontium aluminosilicate, calcium aluminosilicate, magnesium aluminosilicate, or lithium aluminosilicate. In some examples, the coating may be a first coating deposited from a slurry over the substrate, and a second coating may be deposited over the first coating. In other examples, a first coating that substantially reproduces the surface imperfection may be deposited over the substrate, and the coating that does not substantially reproduce the surface imperfection may be deposited over the first coating.

An article may include a substrate defining a surface imperfection and a coating deposited over the substrate. The coating does not substantially reproduce the surface imperfection, and the coating comprises mullite and at least one rare earth silicate, rare earth oxide, alumina, boron oxide, alkali metal oxide, alkali earth metal oxide, silicon, barium strontium aluminosilicate, barium aluminosilicate, strontium aluminosilicate, calcium aluminosilicate, magnesium aluminosilicate, or lithium aluminosilicate. In some examples, the coating may be a first coating deposited from a slurry over the substrate, and a second coating may be deposited over the first coating. In other examples, a first coating that substantially reproduces the surface imperfection may be deposited over the substrate, and the coating that does not substantially reproduce the surface imperfection may be deposited over the first coating.