60 Years of Open‐Celled Ceramics Based on Replica Technique: Applications, Obstacles, and Opportunities

Open‐celled ceramics look back on a remarkable history of development and innovation spanning around 60 years. Starting with the first patents to produce ceramic foams in the 1960s, the Schwartzwalder process became established industrially for manufacturing molten metal filters. Since then, a wide range of potential applications for these specific structured materials has been identified and discussed in the literature, such as porous burners, direct heaters, structured catalyst supports, filters, bone substitute materials, energy absorbers, preforms, and lightweight or acoustic construction components. For such high‐performance applications, ceramic foams require high quality in terms of purity, mechanical strength, high temperature, and chemical resistance or structural design. On this account, production technologies and material variety of ceramic foams have developed rapidly over the past few decades, and there are numerous applications in the industrial sector. This article gives an overview of the current state of development of open‐celled ceramic foams for various applications. Based on selected examples, it is demonstrated for which applications an industrial implementation is successfully realized and why some applications will never get beyond the proof‐of‐concept stage in research.