Abstract: Sacrificial lost casting cores of green or fired ceramic, which include at least one tension spring as a metallic reinforcing element, wherein at least one end of this reinforcing element lies near one of the surfaces of the casting core or extends therethrough, and wherein the melting point of all metallic reinforcing elements lie above the melting point of the casting metal, as well as processes for production of such casting cores, including the steps of preparing a principal mold, seating therein at least one reinforcing element, filling the principal mold with ceramic slip, drying the slip for formation of a green ceramic and releasing the casting core from the principal mold. The principal mold is preferably lined with a flexible internal mold or liner. The reinforcing element in the form a tension spring can be used following casting for breaking up the ceramic casting core.

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: Sacrificial lost casting cores of green or fired ceramic, which include at least one tension spring as a metallic reinforcing element, wherein at least one end of this reinforcing element lies near one of the surfaces of the casting core or extends therethrough, and wherein the melting point of all metallic reinforcing elements lie above the melting point of the casting metal, as well as processes for production of such casting cores, including the steps of preparing a principal mold, seating therein at least one reinforcing element, filling the principal mold with ceramic slip, drying the slip for formation of a green ceramic and releasing the casting core from the principal mold. The principal mold is preferably lined with a flexible internal mold or liner. The reinforcing element in the form a tension spring can be used following casting for breaking up the ceramic casting core.