What is a good quality quartz ceramic? And what are its advantages?

Quartz ceramics is an essential consumable for jewelry casting, what is a good quality quartz ceramic? And what are its advantages? Yihui brand quartz series uses selected fused silica as the main raw material, mainly used for melting platinum, gold and other high temperature alloys. Its main ingredient silica content of not less than 99.99%, room temperature compressive strength ≥ 70MPa, high strength and high thermal shock resistance.

Fused silica is produced by melting natural high-purity silica in an electric furnace at temperatures above 1760°C, followed by rapid cooling. This process transforms the crystalline silica into an amorphous glass melt. The low coefficient of thermal expansion of fused silica helps to prevent cracking and deformation of the shell during the dewaxing and baking process, and helps to ensure the dimensional stability of the casting. The high transparency of fused quartz at high temperature can transfer heat through radiation, making its thermal conductivity exceed that of aluminosilicate shells. And make the casting cooling faster, easier to get sound casting.

 

Advantages

(1) The price of fused quartz is cheaper than zircon, plus the density is much lower than zircon, so replacing zircon with fused quartz can reduce the cost of shell making.

(2) The raw material of fused quartz is selected and then remelted by electric arc, and square quartz is removed, so there are few impurities and high purity. So the stability of coating slurry has never been a problem. It has been proved that the stability of fused silica-silica sol coating can usually be more than 1 year.

(3) High temperature crystallization, low temperature phase change, so that the casting surface is easy to clean up.

Use and maintenance of quartz crucibles

The main chemical composition of quartz crucible is silicon dioxide, which does not act with other acids except hydrofluoric acid, and is easy to act with caustic alkali and alkali metal carbonates. It is very stable to heat and can be heated directly on the flame. However, like glassware, it is easily broken and should be used with special care. In addition, quartz crucible can be used with potassium bisulfate (sodium), sodium thiosulfate (dried at 212 degrees Celsius), etc. as melting agent, and the melting temperature should not exceed 800 degrees Celsius.