An article comprising: a substrate ; and a coating system on the substrate, the coating system comprising: an environmental barrier coating, EBC, layer including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer comprising a plurality of subsurface voids , wherein respective subsurface voids of the plurality of subsurface voids define respective subsurface void volumes; an abradable EBC layer on the EBC layer , the abradable EBC layer including a plurality of voids; and a nucleating agent , wherein the nucleating agent is on a surface of the EBC layer and within at least some of the respective subsurface void volumes of the EBC layer , and wherein the nucleating agent is on a surface of the abradable EBC layer and within at least some of the plurality of voids of the abradable EBC layer , wherein the nucleating agent is configured to induce crystallization of molten Calcium-Magnesium-Alumino-Silicate, CMAS, in at least some of the respective subsurface void volumes of the EBC layer and in at least some of the respective voids of the abradable EBC layer . a substrate ; and a coating system on the substrate, the coating system comprising: an environmental barrier coating, EBC, layer including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer comprising a plurality of subsurface voids , wherein respective subsurface voids of the plurality of subsurface voids define respective subsurface void volumes; an abradable EBC layer on the EBC layer , the abradable EBC layer including a plurality of voids; and a nucleating agent , wherein the nucleating agent is on a surface of the EBC layer and within at least some of the respective subsurface void volumes of the EBC layer , and wherein the nucleating agent is on a surface of the abradable EBC layer and within at least some of the plurality of voids of the abradable EBC layer , wherein the nucleating agent is configured to induce crystallization of molten Calcium-Magnesium-Alumino-Silicate, CMAS, in at least some of the respective subsurface void volumes of the EBC layer and in at least some of the respective voids of the abradable EBC layer . an environmental barrier coating, EBC, layer including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer comprising a plurality of subsurface voids , wherein respective subsurface voids of the plurality of subsurface voids define respective subsurface void volumes; an abradable EBC layer on the EBC layer , the abradable EBC layer including a plurality of voids; and a nucleating agent , wherein the nucleating agent is on a surface of the EBC layer and within at least some of the respective subsurface void volumes of the EBC layer , and wherein the nucleating agent is on a surface of the abradable EBC layer and within at least some of the plurality of voids of the abradable EBC layer , wherein the nucleating agent is configured to induce crystallization of molten Calcium-Magnesium-Alumino-Silicate, CMAS, in at least some of the respective subsurface void volumes of the EBC layer and in at least some of the respective voids of the abradable EBC layer . <EOS>