## 3 Results
In the immediate surface, increased nickel intensities could be detected, especially in the case of the 8 h bording treatment. This result is in line with the results of the XRF measurements. However, within the borided layer, the gradient between the main alloying elements diminished. Independent of the treatment time, a simultaneous but gradual increase in the relative intensities of the main alloying elements was observed, starting from a depth of about 20 \(\upmu\)m. The GDOS measurements complement the characterizations of the structure of the boride layer, which was also analyzed by SEM. The phase composition was determined by XRD measurements. The diffraction patterns of the coatings are shown in Figure 3 as a function of boriding time. In the as-clad state, the coating exhibited a single-phase microstructure consisting of the gamma (\(\gamma\)) phase with a face-centered cubic (fcc) crystal structure. Successful inert gas control in the process was confirmed by the absence of oxides on the surface. The results of the two borided samples confirmed the successful formation of a boride layer. BNi\({}_{2}\) was detected as the  
Figure 1: Microstructural SEM cross section images (BSD) of the laser-clad coating of Inconel 718 for a boriding duration of (**a**) 2 h and (**b**) 8 h.  
Figure 2: Elemental distribution within the diffusion layer of Inconel 718 laser-clad coatings measured by GDOS (**a**) 2 h (**b**) 8 h.  
main boride phase in both (2 h and 8 h) cases. FeB could be detected as an additional phase and was detectable at significantly lower intensities for both treatment durations. With increasing bording time, the intensity of the BNi\({}_{2}\) phase increased significantly, which hinted at an increase in the boride layer thickness. The characteristic peaks of FeB occurred more intensely at higher angles for 8 h of treatment, indicating a high depth of detection. A successful formation of a precipitation layer was possible by diffusion enrichment with boron. To investigate the influence of the treatment condition on the resulting properties, surface hardness measurements have been conducted. The results are summarized in Table 5. For both treatment regimes, the resulting hardness exceeded 1600 HV0.001 and was significantly higher than the reference hardness of Inconel 718 with 377 HV0.001. Although a higher average microhardness was determined for a longer duration of the thermochemical treatment, no clear trend can be derived due to the high standard deviation. The main reason for this was structural defects within the precipitation layer. The wear behavior was investigated using ball-on-disk and reciprocating ball-on-plane tests. The results are summarized in Figure 4. Compared to the untreated condition, bording significantly improved the wear resistance under both wear conditions. In the ball-on-disk test, the borided coating offered almost full protection under the test conditions used for sliding wear. Significant improvements could also be seen in the reciprocating wear test. The maximum wear depth of the borided coating was in the range of the thickness of the boride layer. Figure 3: Diffractograms of Inconel 718 coating in as-clad and borided state. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Untreated** & **Borid Layer 2 h** & **Borid Layer 8 h** \\ \hline
377 \(\pm\) 35 & 1628 \(\pm\) 352 & 1708 \(\pm\) 375 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Surface microhardness HV 0.001 of borided Inconel 718 laser-clad coatings.