Analysis of the fundamentals of the cell structure formation while direct freeze foaming of biocom-patible ceramic foams

点击翻译按钮获取中文摘要

Frozen foams are novel and innovative cellular structures based on a direct foaming process that can be produced from any material that can be processed by powder technology. The foam production process is influenced by a very complex interaction of various process and material parameters, which were previously chosen purely empirically and were also difficult to reproduce. For the targeted and application-oriented design of properties, it is necessary to investigate phenomena occurring during foam formation and the effect of relevant process and material parameters on the structural properties in order to derive manufacturing and quality guidelines (e.g. mechanical strength, cell/pore sizes, pore size distribution). The possible applications of such foam structures cover a very large field and range from biomedical applications (e.g. bone substitute or cell aeration material) to carriers for catalysts, biosensors or pharmaceuticals to heat and noise insulating materials. The diversity of these applications results from the range of possible starting suspensions and above all from the process parameter-dependent foam structure properties, such as the cell geometry, the cell size distribution, the proportions of open and closed cells as well as the composition of the cell webs.In the finished first phase (grant number 310892168) it was possible to achieve a deeper understanding of the principles of freeze foam structure formation by analyzing the influence of selected suspension and process parameters on relevant structural properties of biocompatible ceramic foams. On the basis of the knowledge acquired, the focus of the continuation of the project is on the targeted adjustment and tailoring of the macrostructure (homogenization of the pore size/distribution in the foam cells) and the microstructure (influencing and control of freezing structures in the web pores) to produce ceramic foams suitable for stress and application.