Simulation-supported design of brazing tape architectures for the build-up brazing of wear-resistant coatings

• Applicants: Professorin Dr.-Ing. Kirsten Bobzin; Professor Dr.-Ing. Christoph Broeckmann
• Subject Area: Coating and Surface Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560886376

Every year, wear causes high energy losses, CO2 emissions and direct costs in an amount of billions. Effective wear protection is therefore a key to sustainability, emission reduction and resource savings. An efficient and established technology for the production of wear-resistant coatings, for example for turbines, compressors or in mining, is brazing by means of brazing tapes. In this simple coating process, up to s = 4 mm thick composite layers of hard material particles and a metal matrix can be applied to the component surface to be protected. However, the micro- and macroscopic residual stresses that occur and are still not adequately researched, as well as the differences in properties between the base material and the coating, which can sometimes lead to failure of the coating or the component, are problematic. For this reason, the use of this process is limited to materials with low coefficients of thermal expansion, such as ferritic steels. In addition to this technical motivation, research into buildup brazing is motivated by a possible substitution of cobalt-bonded WC carbides due to increasing toxicological concerns and also with regard to a reduced use of the strategically important metals tungsten and cobalt. The aim of the research project is to develop an effective numerical model for calculating the macroscopic and microscopic residual stresses, the design of brazed wear protection coatings based on this model and also the verification of the model using real brazed wear protection coatings. In a first step, the thermal behavior of the wear-resistant coating and the base material with regard to thermal expansion and phase transitions, as well as material properties such as young’s modulus and hardness as a function of temperature, will be determined for numerical modeling. In a second step, reference coatings will be brazed onto ferritic base material and characterized in detail with regard to properties and, in particular, residual stresses. Based on this work, a micromechanical model can be established in a further step, which will be used to design and manufacture new wear-resistant coatings with reduced residual stresses and changes in properties. In a final step, these new designed coatings will be applied to steel with a high coefficient of thermal expansion and subsequently investigated in detail with regard to properties and residual stresses in order to validate the developed micromechanical model.

• DFG Programme: Research Grants