As a high-performance material, alumina substrate has been widely used in electronics, aerospace and new energy fields. The preparation process involves many complicated processes, in which casting and drying process are the key links to ensure the quality of the substrate. In this article, the effects of raw material formula, casting film thickness and sintering process parameters on the properties of alumina ceramic substrate were investigated, and the drying process after casting and its mechanism on the quality of the substrate were analyzed.
Raw material formula and casting film thickness control:
The final thickness and thickness uniformity of alumina ceramic substrate are directly affected by the precise ratio of raw material formulation and the appropriate thickness of cast film strip. A reasonable ratio of raw materials helps to form a stable casting slurry, and the choice of film thickness determines the initial shape of the green strip, which jointly determines the basic quality of the substrate.
Influence of sintering process parameters:
Debonding sintering is a key step in substrate preparation, and its process parameters such as temperature and time directly affect the appearance quality and surface roughness of the substrate. Optimizing these parameters can significantly improve the overall performance of the substrate, such as increasing strength and reducing porosity.
Importance of drying process and phased implementation:
Due to the high viscosity properties of the cast slurry, the drying process is the key to ensure the strength and complete stripping of the green strip. During the drying process, the production and release of the internal stress of the green sheet and the imbalance of the specific gravity caused by the volatilization of the solvent require the formulation of an accurate drying process. The constant speed drying stage aims to quickly evaporate the liquid phase film on the surface, while the reduced speed drying stage focuses on the slow diffusion of the internal solvent to ensure drying uniformity and avoid defects such as cracking and warping.
Specific analysis of drying process:
In the drying process of green strip, because the evaporation rate of liquid film on the surface is much higher than the diffusion rate of solvent inside, it needs to be carried out in stages. In the constant drying stage, the drying rate is constant, which matches the evaporation rate of the surface solvent, and the surface liquid phase film is mainly removed. When the surface drying is completed, it enters the reduced speed drying stage, and the drying rate is gradually reduced to adapt to the rate of internal solvent diffusion to the surface, ensuring the uniformity and stability of the drying process.
In summary, the preparation process of alumina ceramic substrate requires strict control of raw material formula, cast film thickness and desviscosification sintering process parameters. As a key step, the accurate implementation of drying process is crucial to ensure the thickness uniformity, appearance quality and surface roughness of the substrate and other engineering application indicators. By implementing constant speed and reduced speed drying in different stages, the stress change inside the green sheet can be effectively controlled, and the drying defects can be avoided, which provides a strong guarantee for the preparation of high-performance alumina ceramic substrate. In the future, with the continuous progress of material science and preparation technology, the preparation process of alumina ceramic substrate will be more refined and intelligent, providing a more high-quality material basis for applications in various fields.
