The use of suspensions in the thermal spraying process, makes it possible to apply sufficiently thin (<30 μm), metallic coatings made of nickel-chromium alloy 2.4869 (NiCr8020). High velocity oxy-fuel suspension flame spraying (HVSFS) is used to manufacture these thin metallic coatings in order to be able to effectively use them as electric panel heaters. Area heating capacities of 25 W cm -2 are possible with them and heating rates of 15 K s -1 even outperform many ceramic heating elements. In addition, it provides a flexible way to apply the heating coatings directly to the components to be heated. The use of fine powders in the micron and sub-micron ranges allows a more precise adjustment of the coating thickness, compared to conventional thermal spraying techniques, even in the thickness range below 10 μm. Therefore, an adaption to customer needs is possible regarding the electric panel heater characteristics, like electric resistance, applied voltages and current range and heating rates.

Metallic coatings can be produced easily with thermal spray and cold gas spray processes. However, when coating thicknesses below 50 μm are required for economical or technological reasons, the use of these well-established processes becomes more challenging. The company OBZ Innovation GmbH has developed spray processes that can produce metallic coatings with thicknesses of less than 20 μm. Such coatings are of interest for applications such as cold gas sprayed silver coatings with high purity and good electrical conductivity. Thinner sprayed coatings of such valuable materials have economic advantages, and the process may be competitive with commonly used thin film coating methods.

This paper presents developments in the field of induction capable coatings, mainly used for induction cookware on aluminum or copper base material, based on work by OBZ Innovation GmbH. The aim was to develop a new type of “intelligent” induction coating that influences the magnetic susceptibility depending on its temperature. This not only allows to limit the maximum reachable temperature, but also supports the uniform heat distribution over the bottom of the cookware. Thus, this new type of “intelligent” induction coating regulates such important boundary conditions, independently of undesirable or even unsafe settings of an end-user. Finally, this makes cooking easier, healthier and more durable as it prevents damaged PTFE sealings and safer by reducing the danger of fire because of overheating and burning. Additionally, such coatings can be used in further applications, whenever a passively limited or uniform heat distribution is advantageous, for example when the temperatures are too high or in general an electronic control system is for technical or economical reasons not suitable.

In order to meet the increased requirements for power electronics in the automotive sector, an effective utilization of difficult installation spaces is necessary. A new production concept to realize this 3D integration of electronic circuit boards directly on components is the combination of thermal spraying and cold gas spraying to create multilayer-coating systems consisting of conducting and insulating coatings. In this study two- and tree-dimensional demonstrators were developed, showing the flexible use of thermal spraying in mechatronics and power electronics. In contrast to past studies on this construction concept, the main focus of this study was on the optimization of the ceramic insulting coatings and bond strength of the metallization. The ceramic coatings showed a dielectric strength and electrical resistance, which was suitable for most applications. Additional post treatment improved the electrical resistance in humid conditions. Already 150 µm thick electrical insulation layers showed a breakdown voltage of more than 5 kV AC and a specific electrical resistance of 5.1011 Ω.m.

Electrically insulating coatings featuring high dielectric strength, high electrical resistance and high thermal conductivity are essential for applications in high power electronics. The capability of HVOF-sprayed coatings for high power electronic components based on 20 different powders was investigated in this study. The powders used are aluminum oxide ceramics containing additives of chromium oxide, titanium oxide and magnesium oxide. Key result of this study is that both, pure alumina (Al 2 O 3 ) and one class of spinel (Al 2 O 3 - 28MgO) meet the requirements for electrical insulation. In order to reach high resistivity, the insulation coatings should be sealed subsequently. The amount of impurities, such as Na 2 O or Fe 2 O 3 must be less than 0.1%.

This paper deals with some of the latest developments and serial production applications at OBZ innovation GMBH. With three serial production cold gas systems and one for the R&D department, obz innovation gmbh is the leading supplier of cold sprayed coatings. The development of the well-known serial production process of a sinusoidal copper coating for hybrid cars is explained. Furthermore our ferritic chromium steel induction coating and our newly developed product, an immanent temperature limiting function for safety critical reasons, will be addressed. As an example for a current field of research currently examined at obz within a public funded project will be discussed insulating ceramics for power electronics with cold sprayed circuit paths for a potential use in fields like automotive and others. Last but not least, the latest product, “obz fingerprint” and “obz sensor” coatings that can be used against plagiarism and as a sensory element are presented for the first time.

In this study, nickel and Inconel coatings were deposited on aluminum and steel substrates by cold gas spraying. Fine, standard, and coarse nickel powders and two standard Inconel (625 and 718) powders were selected as feedstock materials and sprayed at different gas pressures and temperatures. A coaxial air-cooled nozzle was used in spray trials, except for the fine Ni powder, which required a water-cooled nozzle to prevent clogging at high temperatures. Coating microstructures were examined and various properties were measured including shear strength, adhesive tensile strength, hardness, and porosity. Cross-sectional images of different coating samples are presented and discussed along with test results.

This work investigates the properties of insulating coatings deposited by HVOF and atmospheric plasma spraying and the effects of various sealants. It is shown that adhesive tensile strength depends strongly on surface roughness and that the dielectric strength of a material is normally higher in the unsealed state. In the case of a new sealant, however, the dielectric strength of HVOF sprayed alumina coatings is shown to be higher in the sealed state, which potentially opens new applications in high-performance electronics.

For the development and quality control of highly electrically conductive coatings, a device is required by which the electric conductivity can be measured. For this purpose a handheld device for measuring the electric conductivity of nonferrous metals in a nondestructive manner was tested. The measurement principle is based on an eddy current sensor which allows determining the electric conductivity within seconds. The method fulfills the demands for using it in the environment of a job shop for thermal spraying. Coatings applied with different thermal spraying methods like cold gas, HVOF, electric arc or flame spraying have been examined. Thus, it will be presented a comparison of the electric conductivity dependent on different spraying methods. Additionally, important edge conditions for spraying and measuring the conductivity of highly electrically conductive coatings like the influence of the oxygen content of the powder, the minimal coating thickness measurable with the device and the influence of the surface roughness onto the measurement were analyzed.