An article for service at high temperatures comprises a substrate comprising a first region and a second region; and a coating disposed over the substrate. The coating comprises a first portion disposed over the first region of the substrate and a second portion disposed over the second region of the substrate. The coating includes a layer comprising a ceramic material and further including a quantity of surface-connected voids, and a protective agent is disposed within at least some of the surface-connected voids of the layer. Within the first portion, the agent is present within the layer at a concentration of less than or equal to 4 percent by volume of the layer exclusive of the voids, while, within the second portion, the agent is present within the layer at a concentration up to the carrying capacity of the layer. Methods for forming the article are also presented.