Environmental barrier coatings and methods therefor

An article, comprising:

• a ceramic matrix composite substrate comprising a continuous surface;
• a bondcoat overlying the continuous surface of the substrate, the bondcoat being formed of a material containing elemental silicon;
• one or more silicon alloys;
• silicon carbide;
• silicon nitride;
• transition metal silicides;
• silica;
• rare earth silicates;
• rare earth aluminosilicates;
• alkaline earth aluminosilicates;
• and mixtures thereof, the bondcoat comprising surface features, the surface features comprising depressions, protuberances, or combinations thereof
• at least one outer layer overlying the bondcoat and the continuous surface of the substrate;
• and
• a constituent layer on the bondcoat and between and contacting the bondcoat and the at least one outer layer, the constituent layer being formed by constituents of the bondcoat and being susceptible to creep deformation within an operating environment of the article, the constituent layer comprising surface features corresponding to the surface features of the bondcoat, and the surface features physically interlocking the at least one outer layer with the bondcoat through the constituent layer, wherein the surface features extend from or into the surface of the bondcoat by about 40 to about 160 μm.