What changes will occur in alumina ceramics at high temperatures

Aluminum oxide ceramics are high-temperature resistant ceramic materials, and the commonly used sintering temperature of aluminum oxide ceramics in the market is around 1750 degrees Celsius, with a usage temperature between 1200 degrees Celsius and 1250 degrees Celsius. When the actual use temperature of alumina ceramics is too high and they work at high temperatures for a long time, the following situations will occur.

1、 Creep of alumina ceramics

Because the components of alumina ceramics are subjected to external forces at high temperatures, plastic changes occur slowly and continuously over time. This phenomenon can be called creep. The creep of alumina ceramic components is actually closely related to stress and temperature. When stress increases or temperature rises, the creep speed also accelerates.

2、 Graphitization and spheroidization of alumina ceramics

Due to the low strength of alumina ceramic graphite, which mainly appears in the form of flakes, it can lead to a significant decrease in material strength and an increase in brittleness. Therefore, we call it graphitization; Similarly, at high temperatures, the components of alumina ceramics contain a large amount of cementite inside, resulting in the formation of coarse-grained cementite and direct inclusion in ferrite. The most important thing is that the cementite gradually transforms from flakes to spheres, which is why we call it spheroidization.

3、 Performance of alumina ceramics after thermal fatigue

If the components of alumina ceramics are subjected to alternating cold and hot work for a long time, the material's own errors will change due to thermal stress, gradually leading to small cracks and ultimately cracking. Therefore, when working under large temperature fluctuations, it is necessary to consider thermal fatigue of the components of alumina ceramics.

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