An article (10a, 10b) comprising: a substrate; and a coating system (14a, 14b) on the substrate, the coating system comprising: an environmental barrier coating, EBC, layer (18a, 18b) including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer (18a, 18b) comprising a plurality of subsurface voids (32a, 32b), wherein respective subsurface voids of the plurality of subsurface voids (32a, 32b) define respective subsurface void volumes; an abradable EBC layer on the EBC layer (18a, 18b), 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 (18a, 18b) and within at least some of the respective subsurface void volumes of the EBC layer (18a, 18b), 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 (18a, 18b) and in at least some of the respective voids of the abradable EBC layer. a substrate; and a coating system (14a, 14b) on the substrate, the coating system comprising: an environmental barrier coating, EBC, layer (18a, 18b) including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer (18a, 18b) comprising a plurality of subsurface voids (32a, 32b), wherein respective subsurface voids of the plurality of subsurface voids (32a, 32b) define respective subsurface void volumes; an abradable EBC layer on the EBC layer (18a, 18b), 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 (18a, 18b) and within at least some of the respective subsurface void volumes of the EBC layer (18a, 18b), 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 (18a, 18b) and in at least some of the respective voids of the abradable EBC layer. an environmental barrier coating, EBC, layer (18a, 18b) including at least one of a rare-earth oxide, a rare-earth silicate, an aluminosilicate, or an alkaline earth aluminosilicate, the EBC layer (18a, 18b) comprising a plurality of subsurface voids (32a, 32b), wherein respective subsurface voids of the plurality of subsurface voids (32a, 32b) define respective subsurface void volumes; an abradable EBC layer on the EBC layer (18a, 18b), 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 (18a, 18b) and within at least some of the respective subsurface void volumes of the EBC layer (18a, 18b), 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 (18a, 18b) and in at least some of the respective voids of the abradable EBC layer.