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Highly luminescent MOF coatings were grown on nanostructured alumina membranes via melt, electride and CVD approaches.

Additive manufacturing of casting cores and molds is state of the art in industrial application today. However, improving the properties of chemically bonded casting cores regarding temperature stability, bending strength, and surface quality is still a major challenge. The process of slurry-based 3D printing allows the fabrication of dense structures and therefore sinterable casting cores. This paper presents a study of the slurry-based fabrication of ceramic layer compounds focusing on the drying process and the achievable properties in slurry-based 3D printing of casting cores. This study aims at contributing to a better understanding of the interrelations between the drying conditions in the 3D printing process and the properties of sintered specimens relating thereto. The drying intensity influenced by an IR heater as well as the drying periods are varied for layer thicknesses of 50, 75, and 100 µm. Within this study, a process window applicable for 3D printing of sinterable casting cores is identified and further indications are given for optimization potentials. At layer heights of 75 µm, bending strengths between ~8 and 11 MPa as well as densities of around 50% of the theoretical density were achieved. Since the mean roughness depth Rz is determined to be <30 µm in plane, an application of slurry-based 3D printing in investment casting is conceivable.

Slurry-based 3D printing allows ceramic green bodies to be fabricated at high packing densities. In contrast to powder-based binder jetting, full densification of printed parts can be achieved in a subsequent sintering step as fine particles dispersed in a suspension are cast and compacted. Slurry-based 3D printing is thus expected to overcome the application limits of the powder-based alternative in metal casting in terms of unfavorable properties like high surface roughness, low density and low mechanical strength. To ensure stress-free drying and therefore high qualities of the compounds made in layers, it is crucial to fabricate single layers with a high level of homogeneity. This paper presents a CFD model based on the open-source simulation environment OpenFOAM to predict the resulting homogeneity of a cast slurry layer with defined parameter sets or coater geometries using the Volume-Of-Fluid method. Moreover, a novel method of spatial reconstruction is proposed to evaluate the surface quality of layers on a minimised computional demand. By comparing the results of the simulation with the real macroscopic behaviour determined in experiments, the approach is found to be a useful tool for suggesting suitable parameters and coater geometries for processing slurries. A precise reconstruction of the outline of the coating area with different process parameters and an approximate prediction of the effect on surface roughness was achieved.