The common materials in our daily lives are those that undergo thermal expansion and contraction, but aluminum silicate ceramic fiber materials exhibit thermal shrinkage properties, which are deeply rooted in their unique physical and chemical structures.
Firstly, from a physical perspective, aluminum silicate ceramic fibers undergo intensified molecular and atomic activity at high temperatures, leading to changes in the microstructure of the fibers. This change may manifest as a reduction in internal pores of fibers, collapse of pipeline structures, and overall volume shrinkage of fibers. Especially when fibers are subjected to continuous thermal loads, their internal stress state gradually adjusts, leading to more significant shrinkage phenomena.
Secondly, from a chemical perspective, aluminum silicate ceramic fibers may undergo a series of complex chemical reactions at high temperatures, such as crystallization, grain growth, and crystal transformation. These processes not only alter the crystal structure of the fibers, but may also lead to a redistribution of chemical components within the fibers, thereby affecting their dimensional stability. Especially during the transition of fibers from amorphous to crystalline state, the phenomenon of thermal shrinkage is particularly evident, accompanied by volume shrinkage and morphological changes.
In addition, impurity elements such as Na2O, K2O, etc. in aluminum silicate ceramic fibers are prone to evaporation at high temperatures, which not only leads to defects inside the fibers, but also exacerbates the friction and bonding between fibers, thereby further promoting the occurrence of thermal shrinkage. Meanwhile, the release of thermal stress in fibers at high temperatures is also one of the important factors leading to shrinkage. During the heating process, due to the gradual release of internal stress, the fiber shape tends to become more compact, exhibiting thermal shrinkage characteristics.
In summary, the thermal shrinkage properties of aluminum silicate ceramic fiber materials are determined by the complex changes in their internal physical and chemical structures at high temperatures. This property requires special attention in the application of materials to ensure their dimensional stability and performance in high-temperature environments. Therefore, when selecting aluminum silicate ceramic fiber materials, it is necessary to fully consider their thermal shrinkage characteristics and take corresponding measures to control and compensate for them.
