Articles with enhanced temperature capability

An article comprising:

• a substrate comprising a silicon-including material;
• an environmental barrier coating (EBC) disposed over the substrate;
• a bondcoat disposed between the substrate and the EBC, the bondcoat comprising elemental silicon, silicon carbide, silicon nitride, a metal silicide, a silicon alloy, or mixtures thereof or the bondcoat comprising oxide phases of silicon including silica, rare earth silicates, rare earth aluminosilicates, and/or alkaline earth aluminosilicates;
• an oxide adjacent the bondcoat comprising silicon and at least 0.1% boron;
• and
• a boron selected from the group consisting of elemental boron in solid silicon solution, boron nitride, boron carbide boron oxide, a metal boride, and combinations thereof source disposed to provide boron to the oxide during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius, wherein the substrate, the EBC, or both of these, include the boron source.

An article comprising:

• a substrate comprising a silicon-including material;
• an environmental barrier coating (EBC) disposed over the substrate;
• a bondcoat disposed between the substrate and the EBC, the bondcoat comprising elemental silicon;
• and
• a boron selected from the group consisting of elemental boron in solid silicon solution, boron nitride, boron carbide boron oxide, a metal boride, and combinations thereof source disposed to provide an effective amount of boron to form an oxide comprising silicon and at least 0.1 weight percent boron during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius, wherein the substrate, the EBC, or both of these, include the boron source.