The influence of process gas composition on characteristics of laser cladding processes is studied in detail at the example of a 60 HRC nickel based self fluxing alloy powder. Typically pure nitrogen, argon or helium are used as process gases in laser cladding processes. Besides mixtures of these gases also addition of hydrogen, carbon dioxide and oxygen are applied studying their influence on thermal emission, weld penetration depth and homogeneity, powder usage and crack formation. Use of identical composition of carrier gas and laser process gas is compared to use of different carrier and laser process gases. Oxygen addition increases thermal emission, but does not result in increased weld penetration depth or crack formation tendency. Thereby homogeneity of weld penetration is improved in comparison to use of pure argon. Also, maximum hardness of claddings is achieved when adding oxygen.

Advances in thermal spraying are occurring in two general directions. On the one hand, spray processes are becoming colder, facilitating the production of oxide-free coatings in air atmospheres. On the other hand, new systems are being developed that enable higher powder throughput, thus making production faster and more efficient. In order to lock in these time-saving advantages, more and more applications are using CO 2 as a cooling medium to increase cooling efficiency and optimize spraying processes. This paper provides an overview of the use of CO 2 and its suitability for new applications.

Long-term experience in handling and using individual thermal spray processes has led to the development of gas supply systems which guarantee a smooth operation at the highest level. Concrete examples will help to demonstrate the benefits and advantages such systems can offer the thermal spray user.

Not least because of the multitude of the possibilities which this process has to offer, has thermal spraying established itself in an extremely wide range of industrial sectors. In quest of new applications, special attention is frequently paid to the properties of individual systems. However, the trumps of the process can only be played out in combination with all the components as a whole. In industry nowadays, it is often the costs alone which are hotly disputed, and especially so when it comes to industrial gases. Yet precisely here infinite opportunities present themselves to positively influence the process. Starting with the optimization of costs, followed by the lifetime of the systems, through the variety of coating properties which can be tailored to the application, the influencing variables are endless. Investigations into this potential are already in full swing. Powder manufacturers are testing the many possibilities in their laboratories and have put their heads together with the R&D departments of hardware and gas suppliers in an effort to continually broaden the coating spectrum.

Spurred on by the initial success of cold spray applications, a wide range of industrial sectors have since shown a tremendous interest in the youngest of the thermal spray processes. The forerunner, oxide-free copper coatings, paved the way for a variety of materials to be successfully sprayed at the Linde Technology Centre in Munich. At the same time, the hardware for cold spraying also underwent rapid development. This now means that new materials can be processed with the highest efficiency and quality possible, using lower-cost nitrogen rather than helium which is decidedly more expensive.

The trend in thermal spraying is more and more towards a globally uniform level of high-grade spray coatings. It is therefore extremely important that auxiliaries such as spray materials or industrial gases undergo precise examination in order to exactly define their influence. Based on their application, these auxiliary materials can always be supplied at the required purity level. In order to guarantee such high levels, the gas industry invests a great deal in analysis and supply concepts which ensure this purity from the tank or cylinder through to the point of delivery. A further point is of particular significance in today’s business world. With ever-increasing raw material prices, it is absolutely essential that spray processes are optimized to the maximum. This is not only made possible by selecting the right system, but also by choosing the right gas and gas mixture.

With lightning speed, the thermal spray process cold spraying established itself as a viable coating technology. Due to such properties as dense, oxide-free coatings, a multitude of new applications now present themselves which, up to now, were not feasible using traditional processes. With the targeted and process-oriented groundwork of the competence group and the manufacturer of cold spray equipment, together with a gas company the equipment engineering for cold spraying has reached an extremely high technological level, facilitating an efficient operation with a tremendous process reliability. This work has, of course, involved extensive long-term testing of such components as the nozzle and gas heater. In the same way, by successfully adapting spray materials, cold spray coatings can now be applied in many new fields and technologies. Practical solutions are already available in the automotive and electronics industries. The constant encounter with new applications for which cold spraying can provide solutions, demonstrates that a new era of thermal spraying in all branches of industry has begun.

The high technical level of thermal spraying is based on four segments: available know-how, equipment and installations, spray materials, and industrial gases. This article discusses the application of industrial gases used in thermal spraying. It describes the processes involved in the production, provision, and storage of industrial gases as well as their properties. In addition, the article also discusses the influence of quality on the individual fuel gases used in thermal spraying.