A Review of Freeze Casting: Preparation Process, Modified Methods, and Development Tendency

Abstract: Fabricating materials with nacre-like structure have received considerable attention as it shows an excellent combination of mechanical strength and toughness. A considerable number of researchers have reported the preparation method of bionic structure, such as layer-by-layer assembly, vacuum filtration, coextrusion assembly, electrophoresis deposition, water-evaporation-induced assembly, 3D printing, and freeze casting. Compared with other techniques, freeze casting, known as ice templating, is an environmentally friendly, prolongable, and potential method, so it has been rapidly developing and widely researched in recent decades. In this review, the front six methods with their benefits and limitations are briefly introduced. Then, the freeze casting technique with the preparation process and modified technique is emphatically analyzed. Finally, the future tendencies of materials application and technique application are discussed. Freeze casting consists of suspension preparation, solidification, sublimation, and post-treatment processes. The mechanism and influence of parameters during suspension preparation and solidification processes are principally discussed. It must be pointed out that the performance and structure of samples are closely related to the model and external force. Besides, the adjustable process parameters of freezing casting are a strong guarantee of obtaining the target product. The purpose of this review is to promote freeze casting workers to understand the influence of parameters and enlighten them in new experimental designs.