This research proposes an experimental methodology towards visually observing high strain rate polymer deformation characteristics at scales relevant to cold spray particle impacts. Macro-scale (~ 3 mm) polymer impact testing via a light gas gun has shown evidence of cold spray indicative features at certain (material, particle/substrate temperature, velocity, etc.) conditions.

Raising demands in industry lead to the request of different and better paper quality. New paper types like e.g., liquid food packaging (lfp) will replace former solutions like Tetrapak, magazine papers will be produced much cheaper on different machine designs. Since certain paper properties like roughness, printability, … still remain or step up in quality level. One machine component influencing the paper properties strongly is the calender with its extremely hard, coated roll surfaces. The hard metal coating on the calender rolls can determine the later paper quality significantly. The current work describes investigations on certain WC based HVOF coatings, which later will be in contact with the paper under high temperatures, extremely high load, and steam environment. Coating design from carbide particle size, metal matrix and other factors like apparent density and sintering grade were studied under real life influences. The various coating versions were compared in a slurry test using the same fines as added in the paper production process for increasing brightness and tear strength. Interesting results are discussed on technical, but also economical basis.

In this paper, the authors use computational tools to simulate thermal and mechanical processes involved in plasma spraying that lead to crack formation and delamination. The substrate-coating system is represented by a metal strip (120 x 20 x 2 mm) and a ceramic layer with a thickness of 0.06 mm. The transient heat transport problem and stress-deformation state of the 3D sample is solved via stress relaxation due to plastic deformation and distributed displacements or cracking. Paper includes a German-language abstract.

In the case of thermal insulation layers, chipping is often observed at the end of the blade, where the curve radii are very small. This failure is likely to be caused by tensile stresses perpendicular to the interface and by compressive circumferential stresses in convexly curved layers. A finite element method was used to calculate the stresses that build up during a heat cycle. The system examined consisted of a cylindrical substrate, an adhesive layer, and the APS thermal insulation layer. The viscoelastic properties of the materials were taken into account, which lead to stress relaxation of the samples, which is often determined by experiment. Creep data and modulus of elasticity of the thermal insulation layers show a large range of variation. This paper shows the influence of these broad variations on the development of the state of stress in the thermal insulation layers during a single thermal cycle. Paper includes a German-language abstract.