Preparation of Ba1−xSrxWO4 and Ba1−xCaxWO4 films on tungsten plate by mechanically assisted solution reaction at room temperature

Preparation of the alkaline earth tungstate films such as Ba1−xSrxWO4 and Ba1−xCaxWO4 on the tungsten substrate was studied with a simple solution process assisted with the ball rotation at room temperature. The solid solution formation and limitations, the effect of oxidizing agent H2O2 and alkaline earth ions concentration on the dissolution of W substrate and the growth of Ba1−xSrxWO4 and Ba1−xCaxWO4 films were studied in detail. The ball rotation assistance plays a very important role to enhance the dissolution of the W substrate and mass transport of the reactant species such as alkaline earth ions and WO42− ions onto the solid/solution interface region, where precipitation occurs. Therefore, the rate of film formation was accelerated by the ball rotation assistance to the reaction system. Ba-rich Ba1−xSrxWO4 and Ba1−xCaxWO4 films were formed without high energy or high temperature treatment.