Effects of Cu Feedstock on Intermetallic Compound Formation in Cold Sprayed Cu-Sn Coatings

Cu-Sn composite coatings were deposited using various Cu feedstock powders with different sizes and shapes, and the formation of intermetallic compounds (IMCs) in the coatings was investigated. IMC formation by post-annealing of composite coatings could be affected. In addition, when Cu-Sn composite particles were employed, not only the Cu-Sn composites but also Cu-Sn IMCs (Cu6Sn5 and Cu3Sn) were observed at the interfaces between Cu and Sn particles in the as-sprayed state. In the case of the annealed Cu-Sn coatings, the Cu6Sn5 formed in the as-coated coatings was transformed into the Cu3Sn phase, and the embedded Sn particles were fully changed into the Cu3Sn phase. However, the intermetallic compound formation of Cu3Sn was different, depending on the shape and size of the Cu feedstock. Therefore, the deposition of Cu-Sn composite coatings using different Cu particles could have an influence on the formation of IMCs.