Introduction to the preparation process of rolled film ceramics

Sheet forming also belongs to plastic forming. The prepared billet is mixed with a certain amount of organic plasticizer to make it plastic. Plasticizers are prepared from adhesives, plasticizers, solvents, defoamers, etc. Adhesives are required to have sufficient adhesive force, good film-forming properties (good ductility and toughness), and have the characteristics of less ash after burning and non-toxicity. The role of the plasticizer is to insert between the segments of the polymer compound, weaken the attraction between each other, and prevent the adhesive from elastic shrinkage and rupture after being deformed by force, thereby improving the plasticity of the blank. The main function of the solvent is to dissolve the binder and plasticizer. Commonly used adhesives, plasticizers and solvents for film forming are listed in Tables 4-6. According to practical experience, the quality requirements of polyvinyl alcohol when used as a rolling film adhesive are: ① The degree of polymerization is between 1400-1500 (if the polymerization is too large, the elasticity of the rolled film is too large; if the polymerization is too small, the rolling The film produced has poor plasticity and high brittleness); ② the degree of alcoholysis is between 80% and 90%; ③ the alkali content should be appropriate (too high alkali content will reduce the degree of polymerization of polyvinyl alcohol). Typical formulations of plasticizers for rolling films are shown in Table 4-7. The prepared rolling film slurry is placed between two rollers for rolling, and the required thickness is achieved after several times of rolling by adjusting the distance between the rollers. Figure 4-10 shows the schematic diagram of the rolling film forming principle. The rolled billets also need to be punched into the required billets. During roll forming, the billet is only rolled in the thickness and advancing direction, and the force in the width direction is small. Therefore, the billet and the binder will inevitably be aligned. During drying and sintering, the transverse shrinkage is large, deformation and cracking are prone to occur, and the properties of the green body will also be anisotropic. Roll-film forming is suitable for the production of flake products below 1mm, but for ultra-thin sheets with thickness less than 0.08mm, roll-film forming is difficult to roll and the quality is not easy to control. Roll-film forming is suitable for the production of flake products below 1mm, but for ultra-thin sheets with thickness less than 0.08mm, roll-film forming is difficult to roll and the quality is not easy to control. Using the method of rolling film forming, YSZ electrolyte sheet, PTCR ceramic sheet, ZnO-glass varistor and so on have been prepared.