Do you know the difference between ceramic fiber blanket containing zirconium and chromium?

Both zirconium-containing ceramic fiber blankets and chromium-containing ceramic fiber blankets belong to the addition of high-temperature oxide (ZrO2, Cr2O3) to the aluminum silicate synthetic powder, which is conducive to increasing the viscosity of the glass phase and can effectively resist glassy aluminum silicate The crystallization and grain growth of the fiber at high temperatures can delay the sintering effect at the fiber interlaced contact, thereby improving the fiber's ability to resist high temperature shrinkage and the fiber's use temperature. However, no matter in terms of production technical difficulty or performance, zirconia-containing ceramic fiber blankets are better than chromium-containing ceramic fiber blankets.

 

The main differences between zirconium-containing ceramic fiber blankets and chromium-containing ceramic fiber blankets are as follows:

 1. Low eutectic melting point and melting temperature of zirconium-containing fiber raw materials, low energy consumption, ZrO2 content in the fiber is generally 15% -17%, higher up to 24%, easy fiber formation, slender fiber, high strength. However, chromium-containing synthetic materials have no eutectic melting point, and the content of Cr2O3 in the fiber should not exceed 5%. The lower melting temperature of the raw materials during the production of chromium-containing aluminum silicate fibers is about 1800 ° C, which makes it difficult to melt the raw materials, the power consumption is large, and the fiber formation is difficult. Large, short and fine fibers produced and poor fiber strength.

Second, the chromium-containing ceramic fiber blanket has a large shrinkage of the heating wire during use, and high-temperature volume stability is poor. At the same time, Cr2O3 in the fiber is volatile at high temperatures, which produces a hexavalent chromium compound, such as CrO3, which causes carcinogenesis, causing environmental pollution. Endanger human health. The use of zirconium-containing fibers is excellent, and the use of zirconium-containing ceramic fiber blankets at classification temperatures is far superior to chromium-containing ceramic fiber blankets. ZrO2 added to the fibers has good high-temperature stability and can be used at high temperatures without generating Issues such as volatility and environmental pollution.

 

Under the same temperature conditions, the thermal insulation effect of chromium-containing fiber blanket and zirconium-containing fiber blanket is basically the same. Below 1400 ° C, the linear shrinkage of chromium-containing fiber blankets is greater than that of zirconium-containing fiber blankets.

 

The application technology of ceramic fiber blanket stipulates that all types of fibers should be used below their classification temperature. Therefore, under the condition of long-term use temperature, the high-temperature volume stability (evaluated by the linear shrinkage index) of the zirconium-containing fiber blanket is better than that of the chromium-containing fiber blanket.