Inhomogeneity of CoCrW powder products manufactured by SLM technology

The article deals with selective laser melting process using CoCrW powder. Our aim was to identify the influence of product position on the building platform and the re-use of powder on roughness, hardness, porosity and corrosion properties of materials, made under uniform process parameters. Roughness was tested with a stylus profilometer, corrosion resistance by electrochemical impedance spectroscopy and linear polarization. Porosity was assessed by image analysis on metallographic sections taken in two mutually perpendicular directions. The same metallographic sections were used to measure microhardness. The results confirmed a statistically significant dependence of the surface roughness with the position on the platform as well as with the recycling of the powder used. The corrosion resistance of the materials was excellent. Increased porosity values and lower hardness occurred in the middle of the building platform. The reason for the variation of the properties within the building platform can be seen in the unequal laser input energy in the individual positions of the plate.