Blue tungsten oxide for thermal insulating glass material can be added to the sintered tungsten skeleton to increase the density and thermal conductivity of the composite. So, why not understand the mechanism of adding blue tungsten oxide powder into sintered skeleton?
The migration speed of gas phase directly affects the speed of reaction and the final product morphology. The higher the reduction temperature, the faster the reaction rate and the more intense the gas phase migration. Also, the sintering and recrystallization of powder are promoted. So, the powder forms powder agglomerate. And tungsten powder particles are easily coarsened. On the contrary, it is more favorable for preparing fine tungsten powder if the reduction temperature is low, the temperature rise process is relatively gentle, the reaction speed is moderate, the gas phase migration is stable, and the water vapor generated by the reaction is easily diffused and escaped.
Under the above mechanism, the reduction process of blue tungsten oxide powder creates a new interface between tungsten powders, and this new interface contributes to the formation of the sintered neck and promotes sintering. The surface activity of tungsten powder is enhanced by repeated redox and vapor phase shifting, thereby lowering the sintering temperature of the skeleton.
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http://www.tungsten-powder.com/Blue-Tungsten-Oxide.html
