Because of their high specific strength, carbon fiber reinforced plastics (CFRPs) are widely used in the aerospace industry. Metallization of CFRP by cold spraying as a surface modification method can improve the low thermal resistance and electrical conductivity of CFRP without the need for high heat input. Herein, we cold spray a Sn coating on cured CFRP substrates and examine the Sn/epoxy interface. The results suggest that the Sn coatings are successfully obtained at a gas temperature of 473 K and indicate no severe damage to the CFRP substrates. The stress and plastic strain distributions at the cross-section of the Sn/CFRP interface when a Sn particle is impacted onto the CFRP substrate are obtained using the finite element method.

Cold-sprayed copper coatings tend to be brittle and their electrical conductivity is inferior to that of the bulk material. In order to solve these problems, conventionally, it has been attempted to recover the metallic structure by heat treatment. This study, however, focuses on the effects of phosphorus and tin with the aim of improving cold spray copper coatings by optimizing the impurity content of Cu powder. It is shown that, by adjusting the content of P and Sn, dense copper coatings can be obtained with high ductility and electrical conductivity equal to that of the bulk material.

Dilute aluminium alloys with additions of tin and indium when deposited by thermal spraying no longer behave as barrier coatings but demonstrate sacrificial corrosion properties when they exist on corrodible substrates. The degree to which the sacrificial attack occurs depends upon the spraying conditions and the tin or indium contents of the coating. The form in which the tin and/or indium exists in these coatings has not been specified but both elements are known to be sparingly soluble in aluminium. A series of experiments have been carried out using Al-12wt%Sn alloy powder as a feedstock for high velocity oxy-fuel (HVOF) spraying on to a steel substrate. The as-sprayed coatings were highly reactive in distilled water and dissolved in a few minutes. Heat-treatment of the coatings at 450°C for increasing amounts of time up to 20 hours reduced the reactivity to water but did not influence the corrosion rate in 0.1M NaCl solution. SEM/TEM observations on the coating provided evidence of the coarsening of tin particles from 15nm (as sprayed) to 0.5-2µm (as heat-treated). A second alloy with a copper addition i.e. Al-12wt%Sn-1wt%Cu was also sprayed to form coatings. The copper addition prevented reaction in water but did not influence the high corrosion rate of the as-sprayed coating in 0.1M NaCl. Heat treatment at 450°C reduced the corrosion rate and allowed passive films to form over limited ranges of electrode potential. The size and distribution of the tin phase was different in the copper containing coatings and this influenced the corrosion rate.

An experimental study was done of the impact and solidification of tin droplets falling on a stainless steel surface. The surface temperature was varied from 25°C to 240°C. Measurements were made of droplet diameters and contact angles during droplet spread. At a surface temperature of 240°C there was no solidification, and a simple model of liquid droplet impact successfully predicted the extent of droplet spread. Droplets impacting on surfaces at 25°C and 150°C solidified before spreading was complete.