Strong ceramic foams from polyurethane templates

The most conventional manufacturing route for ceramic foams with open cells consists of coating reticulated polyurethane foams. The resulting material has well defined cell size, but suffers from low mechanical strength owing to the presence of hollow struts. As a result, the performance and utilisation of ceramic foams manufactured by this method are limited in certain applications. One solution to overcoming this inherent disadvantage is to use a stronger ceramic coating material and to ameliorate the wetting of the polyurethane template. Such a material is reaction bonded Al2O3 (RBAO), which has high mechanical strength as a result of its fine grain structure, with less or even without glassy phases at the grain boundaries. The present work demonstrates the feasibility of producing strong ceramic foams by using a reaction bonded modified replica technique starting from polyurethane templates varying in both composition and cell size distribution.