Abstract: A shaped ceramic abrasive grain, in particular based on alpha-Al2O3, includes two substantially parallel base surfaces with a polygonal base shape, said surfaces being connected by means of at least one stand surface, which is arranged substantially perpendicularly to the base surfaces, in order to position the abrasive grain on an abrasive article underlay. The abrasive grain has at least one cutting element which is arranged substantially opposite the at least one stand surface, wherein the cutting element includes at least one facet which is oriented obliquely to the base surfaces. The disclosure additionally relates to an abrasive article with abrasive grain and to a method for producing such abrasive grain.

Abstract: The manufacture and use of sacrificial molds for metal casting, in particular for sacrificial molds of green ceramic. For production of the ceramic cast mold one frequently resorts to slip-casting in which the shaping of the mold is brought about by casting of liquid slip into the original mold. Bubbles or blisters frequently occur in this casting, which in the later mold lead to not tolerable surface and joint faults of the mold. This can only partially be counteracted by employment of so-called boosting and careful pouring. It is thus the task of the invention to provide a process for production of mold cores of slip ceramic for metal casting, in which the problem of bubbles or blisters is at least reduced. The invention is solved by using a porous original mold. This provides the advantage, that enclosed or trapped air bubbles or blisters can escape through the pores of the original mold, while the slip on the basis of its surface tension cannot penetrate into the pores.

Abstract: The invention concerns the production of frangible ceramic mold cores for metallic casting, their production and use. In general, by the conventional debindering of the green ceramic, a substantial mechanical weakening of the cast mold occurs. Thus is particularly true in the case of awkward component geometry, such that a destruction of fine structures or freely projecting mold parts can occur during casting. It is thus the task of the invention to provide a geometrically complex mold core of slip-ceramic for metal casting, which exhibits a sufficiently high structural stability, in order to survive removal from pre-molds, as well as to survive metal casting without damage, and which thereafter can be removed in simple manner from the cast part. The task is solved in that the mold core includes ceramic microparticles, as well as a stable outer skin in which the microparticles are joined with each other by sintered nanoparticles.

Abstract: Components build up of layers can be produced by means of the so-called three dimensional printing process from plaster or cement powder. It is the task of the present invention to provide another component build up in layers and a process for production thereof, which component exhibits at least comparable strength and at most the same manufacturing cost. The task is solved thereby, that the component is a reaction product of a particulate material and an aqueous liquid, wherein the component includes a number of layers of the reaction product, and wherein the particulate material contains plaster-free cement.