Different directions characterize the advances being made in thermal spraying today. On the one hand, spray processes are becoming colder, on the other hand, high-performance systems are being designed which enable a higher powder throughput, thus making production faster and more efficient. The current spectrum of substrate materials is much broader and even more versatile, as can be seen with new materials which prevent thermal stresses from arising during the production process. More and more applications require the use of special cooling methods to increase the cooling efficiency and, in turn, optimize the process. An ongoing objective of the gas industry is to offer the user hardware which not only exploits all the advantages of CO 2 , for example, but which is also suited to new applications.

This work assesses various ways of improving the corrosion protection and service life of thermally sprayed coatings used in offshore structures. Test results show that improvement is possible even in the case of Zn-Al15 spray coatings and, that in some cases, coating thickness can be reduced without loss of corrosion protection. Test samples were prepared by arc and cold-gas spraying and some of the coatings were sealed. The protective characteristics of the various coating systems were evaluated in a 25-week cyclic aging test as defined in ISO 20340. The results are compared based on the degree of blistering, rusting, and corrosion penetration at the scratch as well as adhesion to the substrate.

The basic idea when using common plasma gases for arc spraying with their varying levels of energy was first of all to achieve higher system efficiency and to produce coatings with fewer oxides. The differentiation between the open arc process and plasma spraying is the advantage using active gases with a much higher energy level, for example using fuel gases to influence the process characteristics and to get high end coatings. As these results from this work in arc spraying show, the increased need for research into this technology at the moment is definitely of importance. The main market of arc spraying can be found in the area of corrosion protection, the technology’s growth stems from those areas which are interested in manufacturing high-quality coatings with substantially more cost-effective wire. In order to broaden the range of thermal spray applications, we have endeavored to investigate the issue of the right gas mix for arc spraying. In doing so, it was concluded that, by using wire as the spray material, this cost-effective process can often be used as an equally viable alternative to other methods. The optimization of costs and tailoring of coating properties to suit specific applications are just some of these influencing variables.