Pretreatments effects on mechanical and morphological features of copper coatings

Abstract

In order to exploit the aluminum potential in industrial environments, the application of alloying is fundamental. Anyway, this entails drawbacks such as decrement of mechanical bulk properties and corrosion phenomena. The surface engineering, and particularly the surface coatings, allows the local modification of the samples properties to overtake these criticisms. Copper it is often applied as a viable alternative to aluminum in several applications. Indeed, combinations of both have already broadly exploited for functional components. However, surface pretreatments strictly affect the production of coatings. This article proposes a study on the effects of some of the pretreatments of major industrial interest on the deposits created through the electrodeposition process. The results achieved demonstrate how the samples preparation effectively affects the growth of the copper grain as well as the coatings performance. In fact, different grains morphologies were observed as well as different performance of the coatings in terms of wear and scratch resistance. In particular, smooth and extremely corrugated surfaces did not lead to the formation of a continuous copper coatings when low thickness is considered. To bridge the gap among several grains, the copper core deposited has a planar growth in opposition to the other pretreatment, which allowed a compact coating and a columnar growth. Furthermore, the larger are the grain the less adherent is the coating. Also, different breakage mechanisms were identified as a function of the coating thickness.