When refractory materials are used for a long time at high temperatures, their appearance and volume remain stable and do not change (shrinkage or expansion), which is called high-temperature volume t

When refractory materials are used for a long time at high temperatures, their appearance and volume remain stable and do not change (shrinkage or expansion), which is called high-temperature volume temperature resistance. It is an important indicator for evaluating the quality of products. Zirconia ceramic

During the firing process of refractory materials, the physical and chemical changes during the process generally do not reach the equilibrium state at the firing temperature. When the product is subjected to high temperature during long-term use, some physical and chemical changes will still continue. On the other hand, during the actual firing process of products, due to various reasons, there may be products that are not fully fired. When these products are used in a kiln and subjected to high temperature, some firing changes continue to occur, resulting in changes in the volume of the products& Flash; Shrinkage or expansion, which is an irreversible change in volume, is called residual shrinkage or expansion, and is also weighed for burning shrinkage or expansion. The magnitude of the volume change after re firing indicates the high-temperature volume stability of the product.

The volume change during reburning can be expressed as volume percentage or linear percentage change:

LC=(L1-L0)Χ 100/L0

Vc=(V1-V0)Χ 100/V0

In the formula, LC&flash& Flash; Change rate of sample reburning line,%;

Vc&flash& Flash; Change rate of sample volume after re firing,%;

L0, L1&flash& Flash; Indicate the length of the sample before and after reburning, in mm;

V 0, V 1&ndash& Flash; Sequentially represent the volume of the sample before and after reburning, cm3;

According to the above two formulas, a positive value indicates expansion, and a negative value indicates contraction. When the volume change of reburning is small, it can be considered that Vc=3LC.

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