What performance losses will silicon dioxide cause to ceramics when used as a sintering aid for ceramic ?
I would like to know the effect of different sintering aids on the properties of alumina ceramics.
The higher the aluminum oxide content in corundum ceramics, the higher its temperature resistance (maximum application temperature). On the other hand, the fewer impurities, the higher the sintering temperature of corundum ceramics and the more complex the technology for its production.
As is always the case in technology, real ceramics are always a compromise between the requirements for properties and the capabilities of the manufacturing technology. For this reason, small additions of sintering activators, usually SiO2 or Cr2O3, make it possible to reduce the cost of the production technology of corundum ceramics without significantly deteriorating its properties.
Dear friend Qiuan Sun this question is somehow related to my work. I am also working on the effect of different sintering aids on various properties of ceramics.
So, I want to refer to my recent paper where the effect of five different sintering aids on the structural and electrical properties of the ceramics are studied.
Article Study of structural and electrical properties of oxides adde...
Thank You.
1. Although glass shows a lower dielectric constant than ceramics, ceramic–glass composites are used to benefit from their superior breakdown strength (BDS). Although the BDS is improved with glass addition, the dielectric constant of the composite is reduced with the increase in the percentage of glass additive due to its lower dielectric constant.
2. Also, during sintering, the glass phase additive, due to its lower melting temperature, forms a liquid phase between the solid particles, promoting the dissolution–precipitation process for enhanced sintering activity. This contributes to the reduction of the sintering temperature, an increase in density, and a refined grain size. This excessive liquid phase formation with higher glass content could promote grain growth and increase microstructural defects such as porosity, causing the so-called “de-sintering” phenomenon, ultimately degrading the electrical properties of the system.
I hope that answers your question, Qiuan Sun .
the effects of silicon dioxide as a sintering aid are nuanced and depend on carefully managing factors like impurity levels, sintering conditions, and the specific requirements of the intended application. Achieving optimal results involves a fine-tuned approach to ensure that the advantages in densification and mechanical properties are not compromised by potential drawbacks like impurity introduction or unfavorable changes in material behavior.
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