**Investigation of the Foam Development Stages by Non-Destructive Testing Technology Using the Freeze Foaming Process**

**Johanna Maier 1,\*, Thomas Behnisch 1, Vinzenz Geske 1, Matthias Ahlhelm 2, David Werner 2, Tassilo Moritz 2, Alexander Michaelis 2 and Maik Gude 1**


Received: 12 November 2018; Accepted: 4 December 2018; Published: 6 December 2018

**Abstract:** With a novel Freeze Foaming method, it is possible to manufacture porous cellular components whose structure and composition also enables them for application as artificial bones, among others. To tune the foam properties to our needs, we have to understand the principles of the foaming process and how the relevant process parameters and the foam's structure are linked. Using in situ analysis methods, like X-ray microcomputed tomography (μCT), the foam structure and its development can be observed and correlated to its properties. For this purpose, a device was designed at the Institute of Lightweight Engineering and Polymer Technology (ILK). Due to varying suspension temperature and the rate of pressure decrease it was possible to analyze the foam's developmental stages for the first time. After successfully identifying the mechanism of foam creation and cell structure formation, process routes for tailored foams can be developed in future.

**Keywords:** Freeze Foaming; in situ computed tomography; non-destructive testing; bioceramics
