The aim of this investigation is to show that it is possible to inject powder into a wire arc spray process as an alternative to using cored wire to produce particle-reinforced coatings. The equipment, materials, and procedures used are described in the paper along with the microstructure and properties of the coatings obtained. By changing the feedrate of CrC particles injected into a stream of chromium steel droplets, particle-reinforced graded layers were produced by wire arc spraying on the fly without having to stop the process.

The introduction of new wire arc spraying equipment with chopped power supplies offers many possibilities to improve the wire arc spraying process. These power sources provide higher process stability even at reduced voltages. On the one hand conventional applications can be enhanced and on the other hand new processes can be developed. Due to the high process stability the introduction of additional particles into the atomizing gas stream is possible. This can be applied to produce coatings with a high wear resistance as well as a high surface roughness. A combined technology of particle injection and the productive wire arc spraying process enables the economic production of innovative functional surfaces. In the last years ITSC, the injection of corundum particles had been presented. In this paper further strategies for inserting particles into the gas stream and experimental results are shown for iron based coatings. For the reinforcement different carbides were injected into the atomizing gas stream.

Nowadays wire arc spraying of chromium steel has gained an important market share for corrosion and wear protection applications. In order to optimize the process parameters and to evaluate the effect of the spray parameters DoE based experiments have been carried out as well. In this paper, the effects of the process parameters of spray current, voltage and atomizing gas pressure on the particle jet properties of mean particle velocity and mean particle temperature as well as plume width are presented. To monitor these values the AccuraSpray system was used. The properties of the coatings with regard to morphology, composition and phase formation are included as well. These investigations are part of the development of new power supplies and the enhancement of spray parameter range. As a result of these experiments the spray parameters can be adjusted according to the requirements of the chromium steel coatings.

The precondition of a cost efficient wire arc spraying process is an ideal process setup according to the wire material. Modern power supplies are equipped with electronic control circuits to ensure stable arc conditions at the wire tips. This is necessary for high quality wire arc sprayed coatings. The key factors to achieve this are the arc energy and fluid mechanics as well. By the use of a PID controller to maintain set spray parameters, it is possible to reduce the spray voltage down to 15 V for zinc as feedstock material. Furthermore temperature dependent parameter fluctuations can be compensated with the electronic controller, while working at maximum capacity with one hundred percent duty cycle. The paper discusses the influence of a new power supply with regard to the process stability and the enhancement of former power supply based process limitation as well as the operator guidance.

A method for the production of particle reinforced coatings by wire arc spraying will be presented in this paper. This technology is based on twin-wire electric arc spraying (TWEA) process. Here, additional particles were injected into the atomizing gas stream and sprayed in a non molten state along with wire feedstock material onto the substrate. According to the reinforcing particles, the process can be applied to produce coatings with a high wear resistance as well as a high surface roughness. In a wide range of applications, these coating characteristics are required. Due to economic constraints, coatings of large surfaces have to be done in short times at low costs. Based on wire arc spraying, the thermal spray process with the highest deposition performance, the mentioned industry requirements can be fulfilled.

This paper describes an arc spraying process developed for the production of metalized film capacitors. It discusses the role of metal spraying in capacitor manufacturing, the basics of thermal spraying, and the function of various components in a wire arc spraying system. It also reviews the production steps typically used for capacitor end spray. Paper includes a German-language abstract.