Wear-resistant coatings with in-situ and ex-situ carbides by laser cladding

• Applicant: Professor Dr.-Ing. Uwe Glatzel
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials ; Coating and Surface Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559986830

Using ex-situ tungsten carbides and in-situ titanium carbides offers great synergistic potential for laser powder clad wear protection coatings. For a maximized wear protection effect, in-depth knowledge of the complex cause-effect relationships of material, process, and resulting coating properties is necessary. The objective of this research project is to analyze the complex microstructures of particle-reinforced laser powder cladding of nickel-based wear protection coatings in correlation to the resulting mechanical and tribological coating properties. Stainless steel 1.4301 plates are used as a substrate, as these have similar thermal expansion properties to the Ni-based coating and are also comparatively inexpensive. After parameter optimization, the effectiveness of coating with combined carbide application is examined to determine whether it is synergistic for achievable wear protection. First, suitable spherical powders with fused tungsten carbides are prepared and characterized by vacuum gas spraying of flux-cored wires. Laser powder cladding is used to apply particle-reinforced coatings containing additional titanium carbides. Crucial material and process parameters are identified and adjusted by a parameter study of the coating and microanalysis of the initial materials, atomized powders, and applied wear protection coatings. After the respective metallographic preparation, the microstructures are detected by scanning electron microscopy, and the element distributions are evaluated by energy-dispersive X-ray spectroscopy. The homogeneous, well-bonded particle distribution of as fine-dispersed, spherical carbides as possible is an essential prerequisite for optimized wear protection. Chemical compositions are investigated through micro-X-ray fluorescence analysis and formed phases by X-ray diffraction analysis. The bonding and dissolution behavior of the combined carbides and interactions between the coating constituents are determined. Mechanical behavior is evaluated by Martens hardness, and pin-on-disc tribometer tests verify the wear protection performance. The experimental work is complemented by modeling the diffusion processes at the interface of carbides and matrix. Overall, the results from this research project will contribute to the optimized development of particle-reinforced wear protection coatings by utilizing combined ex-situ and in-situ carbides. Regardless of the industry, improved wear protection coatings offer higher operational reliability, longer service life, and efficient material use, contributing significantly to the overall systems' quality and sustainability.

• DFG Programme: Research Grants