Disclosed herein are a ceramic particle comprising a ceramic core substrate and a conformal coating of a sintering aid film on a surface of the core substrate, wherein the conformal coating includes a plurality of distributed islands of the sintering aid film across the surface of the core substrate; methods for producing the ceramic particle by ALD or MLD; and methods of using the coated ceramic particles in additive manufacturing or in solid oxide fuel cells. In one example, the film may have a thickness of less than three nanometers. The disclosed ceramic particle may be non-reactive with water.