Nickel-based superalloys are particularly suitable for applications under corrosive conditions. Economic advantages can be achieved by limiting the use of materials to the surface region. Furthermore, the tribological property profile can be significantly improved by surface hardening. In the present study, the possibility of a process combination comprising a coating and a surface hardening technology was investigated. For this purpose, Inconel 718 coatings were applied to austenitic stainless steel by laser cladding. Subsequently, a thermochemical surface hardening by boriding was carried out. Scanning electron microscopic (SEM) examinations were performed to evaluate the microstructure. The phase composition was determined by means of X-ray diffraction (XRD) for the different states of the coating system. The influence of thermochemical hardening was investigated for different wear conditions. The increase in microhardness and wear resistance clearly demonstrates the utilization potential of the presented process combination.

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The processing of high-entropy alloys (HEAs) via laser metal deposition (LMD) is well known. However, it is still difficult to avoid chemical intermixing of the elements between the coating and the substrate. Therefore, the produced coatings do not have the same chemical composition as the HEA feedstock material. Single-layer CrFeCoNi and AlCrFeCoNi HEA coatings were deposited using high-speed laser metal deposition (HS-LMD). Elemental mapping confirmed a good agreement with the chemical composition of the powder feedstock material, and revealed that chemical intermixing was confined to the immediate substrate interface. The coatings are characterized by a homogeneous structure with good substrate bonding. The machining of these coatings via turning is possible. Subsequent diamond smoothing results in a strong decrease in the surface roughness. This study presents a complete manufacturing chain for the production of high-quality HS-LMD HEA coatings.