Reticulated polymer foam templates are characterized by sharp-edged triangular struts. They transfer this attribute to open-celled structures based on them, for instance, in the case of ceramic and metal foams prepared by the well-known and industrially established replica technique. One characteristic element of these kind of foams is the hollow, triangular strut core left by the polymeric template after its decomposition during the heat treatment step. Moreover, the triangular strut shape can also be found in metal foams prepared by investment casting. In both examples, the mechanical strength of the resulting foam structure will be affected by the sharp-edged strut shape of the template, either by stress concentration or by the low portion of strut material per volume of the foam.
On that account, different approaches to fill the hollow strut core of replica foams or increase the strut thickness of the template in case of the investment casting, have been reported in the literature.
In this lecture, an alternative slurry-based technology for adjusting the strut thickness will be presented. This approach allows to adjust the strut thickness in a wide range and can be used for the preparation of replica foams as well as the creation of compact ceramic bodies consisting of a well-defined network of pore channels. The influence of the modification of the triangular cross-section to a more circular one, on the coating behaviour and the later mechanical properties of ceramic replica foams, will be discussed briefly. Also, as an alternative example of moulds for investment casting, the preparation of zeolite-based bricks for a thermochemical storage approach will be shown.