An article includes a substrate and a coating on the substrate. The coating includes a compound of aluminum, boron and nitrogen in a continuous chemically bonded network having Al—N bonds and B—N bonds. Also disclosed is an article wherein the substrate is a plurality of fibers and the coating is a conformed coating of a compound of aluminum, boron and nitrogen having Al—N bonds and B—N bonds. The fibers are disposed in a matrix. Also disclosed is a method of protecting an article from environmental conditions. The method includes protecting a substrate that is susceptible to environmental chemical degradation using a coating that includes a compound of aluminum, boron and nitrogen having Al—N bonds and B—N bonds.