The initial oxide state of powder is essential to the robust additive manufacturing of metal components using powder bed fusion processes. However, the variation of the powder surface oxide composition as a function of the atomizing medium is not clear. This work summarizes a detailed surface characterization of three 316L powders, produced using water atomization (WA), vacuum melting inert gas atomization (VIGA), and nitrogen atomization (GA). X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy analyses were combined to characterize the surface state of the powders. The results showed that the surface oxides consisted of a thin (~4 nm) iron oxide (Fe ₂ O ₃ ) layer with particulate oxide phases rich in Cr, Mn, and Si, with a varying composition. XPS analysis combined with depth‐profiling showed that the VIGA powder had the lowest surface coverage of particulate compounds, followed by the GA powder, whereas the WA powder had the largest fraction of particulate surface oxides. The composition of the oxides was evaluated based on the XPS analysis of the oxide standards. Effects of Ar sputtering on the peak positions of the oxide standards were evaluated with the aim of providing an accurate analysis of the oxide characteristics at different etch depths.

High power diode laser with coaxial powder injection was used to deposit single tracks of cobalt alloy on to a carbon steel plate in order to study dilution. Two different methods to evaluate dilution are proposed and validated: dilution results to be proportional to the average percent or iron present in the clad. To study the correlations between dilution and processing parameters, clads were produced in different processing conditions. Dilution is correlated with the specific energy, and equation to estimate the average iron contamination of the clads was found. ‘Trial and error’ method was applied to improve this estimation. A statistically better prediction of the iron contamination is obtained when the combined parameter P^2.5/F⁴ is used. Dilution influences clad microstructure and thus hardness of the final coating, which decreases on increasing dilution. Phase distribution is also affected by dilution, Fe and C contamination stabilises α-fcc phase.

High power diode laser with coaxial powder injection was used to deposit single tracks of cobalt alloys with tungsten carbides on to a carbon steel plate in order to study carbide dissolution in the metallic matrix. Two kinds of cobalt alloy powders (Stellite 12 and Stellite 21) having different content of tungsten and carbon were used. Processing parameters were changed to obtain different cladding conditions, and effect of substrate preheating was evaluated too. Carbides dissolution, measured with image analysis and EDXS analysis, increases with the increase in the laser power. A low carbon and the absence of tungsten in the matrix powder promote carbides dissolution. Substrate preheating also leads to a higher dissolution. Matrix microhardness of the Stellite 21 increases with the increase in carbides dissolution, while matrix microhardness of the Stellite 12 does not change. Hardness of the coatings is slightly influenced by the dissolution phenomena.