Moisture is often regarded as one of the main reasons for poor processability of powders using Laser-powder bed fusion (L-PBF) processes. To determine the influence of moisture on the spreadability, a superalloy powder IN718 commonly used for L‑PBF processes has been conditioned in two different states: once in the as-received and dry condition and once in a moist condition obtained by storing the powder for four weeks in an atmosphere containing a relative humidity of 75%. Using a self-built spreading tester and a subsequent analysis method specially developed for testing the spreadability of a powder, the differently conditioned IN718 powder batches have been investigated regarding the surface roughness and flatness of the powder layers. Additionally, the formation of empty spots between the powder particles in the top layer has been studied.

In Laser Beam Powder Bed Fusion (LB-PBF) technologies, spreading of powder layers as dense and as fully covered as possible is of crucial importance for a good processability of powders. Poorly covered layers or layers with undesirable features in it, such as elongated, powderless craters in the direction of spreading, might result in defective printed parts. The reason for this could be either poor powder quality or a poorly adjusted build job. To investigate the surface coverage of a single spread powder layer, a new method was developed using the Spreading Tester. With this, two powder grades differing mostly in their particle shape were used to investigate the impact of powder shape on the surface coverage.

One of the major drawbacks of a solid oxide fuel cell (SOFC) is the longtime stability. In order to have mechanical stability, the cell can be supported by a so-called porous metal support. These metal supports are usually manufactured by tape casting. This work, in contrast, is focused on processing these supports by different powder metallurgical techniques such as the press-and sinter route, gravity sintering or metal injection moulding. For some samples a shrinkage of 15% could be obtained as defined by the shrinkage of the ceramic functional layers (in case of desired ''co-sintering an interval of 15-20% is preferable). The most promising manufacturing routes were found to be gravity sintering (about 50% porosity) and MIM (20-28% porosity): in both cases the pores are homogeneously distributed, and only slight agglomeration of pores can be seen.

In recent years, the interest in additive manufacturing technologies has increased significantly, most of them using powders as feedstock material. It is therefore essential to check the quality of the powder before processing in order to ensure the same quality of the printed components at all times. This kind of quality assurance of a powder should be carried out independently of the additive manufacturing technology used. Since there is a lack of standards in this field, various powder analysis methods are available, with which, in principle, the same characteristics can often be measured, at least nominally. To verify the validity of these methods, three different nickel-based powders used for additive manufacturing were examined in the present study using standard methods (apparent density, tap density, Hall flow rate, optical microscopy, scanning electron microscopy) and advanced characterization methods (dynamic image analysis, x-ray microcomputed tomography, adsorption measurement by Brunauer–Emmett–Teller method). A special focus has been given on particle size distribution, particle shape, specific surface area, and internal porosity. The results of these measurements were statistically compared. This study therefore provides an insight into the advantages and disadvantages of various optical characterization techniques.

Currently there is considerable interest in understanding and quantifying the powder characteristics that affect the quality of the top spread powder layer for processes such as powder bed fusion and binder jetting. For this purpose, a new testing device has been developed in order to assess several aspects of this top spread powder layer. Using different measurement procedures, the roughness of the top layer, the surface coverage of a single spread powder layer and the powder bed density of an entire spreading experiment can be determined. Since the tester is freely programmable, the individual process steps of spreading a single powder layer can also be varied. Using these methods, the influence of different process parameters such as e.g. the spreading velocity or the distance between the blade and the building platform, which is also referred to as gap size in general, on the quality of the top or only a single spread layer and on the powder bed packing density can be examined. This study presents the new test device as well as the corresponding measurement procedures mentioned, the reproducibility of the results, which, depending on the measurement method and the measured parameter, range between 0.24 and 4.81%, and the influence of the spreading strategy, which defines the chronological order of the single steps during spreading.