###### Abstract  
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.  
Inconel 718; IN718; laser cladding; laser-clad; boriding; boronizing; hardening; wear Science]Article  
B. of Laser-Clad Inconel 718 Coatings for Enhanced Wear Resistance]B.M.L. [PERSON], M.G., [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], M.  
case of nickel-based alloys. A process combination consisting of a coating step, as well as surface layer hardening, can provide economic advantages, especially in comparison to monolithic component design. Such a process combination is currently unexplored in the case of laser-clad, nickel-based superalloys.  
However, a series of studies on the thermochemical surface hardening of coating systems have proven the fundamental feasibility of this process combination. Initial investigations were carried out on high-velocity oxy-fuel (HVOF) and plasma-sprayed AISI 316L coating systems [32; 33]. Further investigations on the surface hardening of cold gas sprayed coatings confirmed the results [34; 35]. By carburizing, nitriding, and nitrocarburizing at low process temperatures, the formation of an expanded austenitic phase could be achieved. This has led to a significant increase in wear resistance [32; 33; 34; 35; 36; 37; 38]. Investigations on plasma nitriding of austenitic layers produced by direct laser metal deposition and laser powder-bed fusion could also confirm the improvement potential [39; 40]. First investigations on the thermochemical surface hardening of powder feedstock materials for coating processes were carried out [41]. In addition to the methods for interstitial surface hardening, various possibilities of precipitation hardening by nitriding were also considered [38]. In comparison to solid solution hardening, a different diffusion behavior was demonstrated. First investigations showed the suitability of a powder-pack boriding treatment for improving the wear resistance of thermally sprayed coating systems [42; 43]. Laser cladding causes a higher thermal load on the substrate material compared to thermal spraying. Nevertheless, laser-clad coatings are characterized by a higher corrosion resistance due to their compact structure.  
In the present study, the concept of a process combination consisting of a coating step by laser cladding and subsequent surface hardening by boriding was investigated using the alloy Inconel 718. The conducted feasibility study clearly showed the potential of such a process combination.