Cold atmospheric plasma spraying is used to produce thin coatings of copper and tin between 20-80 μm thickness for use in diffusion soldering. This study presents an alternative process to apply composite solders directly onto power electronic bare dies. The formation of intermetallic phases may be promoted by the homogeneous distribution of the Cu and Sn particles as they are presented not in a layered structure but as a pseudo alloy within the coating. The Cu and Sn powder is mixed in situ using two powder conveyors, enabling adjustable mix ratios. The presented approach has been shown to produce a homogeneous particle distribution within the coating. Furthermore, preliminary experiments indicate the feasibility of the technology for applications in diffusion soldering.

Assemblies containing fiber-reinforced plastic (FRP) and metal parts are typically fastened together via mechanical joining or adhesive bonding. Mechanical joining processes tend to weaken FRP parts by cutting fibers, while adhesives require long cures and often lead to inseparable material compounds. This paper evaluates a new joining method in which plastic parts are laser treated, then metallized via wire-arc spraying, and finally soldered to mating metal parts using a low-temperature process. Due to the effective increase in interface area resulting from laser structuring, bond strengths of up to 15.5 MPa can be achieved.

In this study, cold sprayed Cu approximately 40 to 60 μm in thickness is deposited on 6063 and LD10 aluminum plate to improve wettability for low temperature soldering and to serve as a barrier layer to protect the substrate from gallium diffusion originating in the solder paste. The effect of the coating on wettability, diffusion, solder joint interface microstructure, and shear strength is investigated in detail.

In this work, steel columns are metallurgical bonded to tempered glass with the aid of atmospheric plasma spraying and low-temperature soldering. Glass surfaces were sandblasted using different grain sizes, then multilayer (Al 2 O 3 -Cu) coatings were applied at various power levels and spraying distances. Sn-Ag-Cu solder paste was then painted on the metallized glass and steel structures were set in place and soldered in a reflow oven. The interfacial bond strength of the alumina layer was measured along with the strength of the solder joint. The results are presented and correlated with sandblasting grain size and spraying heat input.

Innovative short arc technology is gaining high interest for low temperature joining strategies exemplified by the soldering of zinc coated steels and the joining of steel/aluminum hybrid joints. Controlled short arc allows on one hand a very low heat input in the component, so that melting of the base material can be limited. On the other hand it is possible to use low temperature melting filler wires, as for example zinc wire. New development in controlling short arc have been performed in the last year and reached its maturity for welding production (e.g. Cold Metal Transfer (CMT) of Fronius or Cold Arc in EWM). In both cases the short arc is controlled after drop transfer. One way to perform control is a high dynamic wire feed, which allows high dynamic retracting wire end. Another possibility represents a new type of highly dynamic inverter switching, combined with very fast digital current control, to reduce drastically the peak power in the arc when the short arc is reignited. The consequence of this is a no-sputter, low heat processing procedure. The arc is considerably colder due to the power reduction on re-ignition, which means that a lower heat input is possible.

Thermal spraying for joining and filling of aluminum substrates under atmospheric conditions represents an enrichment in soldering technology. In a respective process, rod-, wire- or cored wire type, zinc-aluminum-based spray materials are applied for joining components or area filling of substrate and fused simultaneously. The advantages, in contrast to soldering, result from the direct application of the spray material, in particular also in constraint positions, and an uncomplex processing, which enables a conditioned inline capability and the use as a comparatively simple procedure for construction-site services or repairs. The aluminum substrate surface and spray material passivation, which would prevent a successful fusing, can be effectively suppressed by the use of a flux in the cored wires as well as straight on the substrates or a brushing activation.

Application of cold gas spraying for deposition of braze filler coatings is investigated. Different light weight alloy substrates, i.e. aluminum AA1050, AA3005, AA5754 and AA7022, magnesium AZ91 and titanium TiAl6V4, are used. Filler coating materials depend on the substrate melting temperature. So for aluminum alloys Al12Si and zinc based fillers, for AZ91 pure zinc and for Ti6Al4V different Cu-Ni blends are applied. CGS process parameters are varied with regard to process gas (nitrogen) temperature and pressure, powder feed rate and spray distance. Correlation to process characteristics and economical aspects are given. The usability of the produced filler coatings is shown by different optimized brazing/soldering processes. In case of aluminum braze joints a full metallographical investigation is carried out by optical and scanning electron microscopy as well as EDXS analyses. The gathered results are compared with those of conventional filler material addition, i.e. wire, roll plating and foil.