Wear Assessment Of Tin And Tin Alloy Coatings
Free (open access)
W. P.-W. Lam, K. Mao, C. Kerr & T. A. Stolarski
Tin and tin alloys have traditionally been used as coating materials for a variety of functions, e.g. decorative, solderable and corrosion resistant, but rarely in applications that require physical durability, owing to the soft nature of tin. Although it has been reported that some alloys of tin are comparatively harder, these materials have traditionally been used as corrosion resistant coatings and there has been little research conducted on exploring their physical properties. This paper aims to demonstrate the range of durability augmentation achieved from alloying tin with copper and nickel in coatings electrodeposited onto steel by assessing the degree of coating removal caused by wear from a sliding ceramic ball contact on the coating surface. The degree of wear is measured by the level of iron detected (i.e., where coating removal has resulted in the exposure of the underlying steel), via EDX, and this is correlated with 1) different loads (10 – 50 N at ten Newton increments) at which the ceramic ball is applied; 2) the thickness of the tin/tin alloy deposits (2, 5 & 10 microns) and 3) the wear testing duration (1 – 8 hours at one hour increments). The results are then presented in the form of a matrix. The study confirmed that tin performed poorly, and revealed significant improvements when tin is alloyed with nickel or copper. Keywords: sliding wear, coating, SEM/EDX, tin, tin-nickel, tin-copper. 1 Introduction This paper assesses the possibility of using tin and tin alloy coatings in an application not previously considered before. The suitability of the materials in question is evaluated using a novel method, where the degree of coating removal is quantified. Concluding comments and suggestions for further work are presented at the end of the paper.
sliding wear, coating, SEM/EDX, tin, tin-nickel, tin-copper.