Quartz box bowl,also known as quartz crucible,is commonly referred to as box bowl by northerners and crucible by southerners.Quartz box bowls have many advantages,such as high purity,strong temperature resistance,large size but high precision,good insulation performance,energy saving,and relatively stable quality.Due to its porous,multiphase,and heterogeneous structure,it is required to be able to be repeatedly used under alternating thermal load conditions,and therefore should possess the following properties.
1、High refractoriness and load softening temperature
Due to the fact that the quartz box bowl carries blanks during kiln loading and bears a certain load at high temperatures,especially the lower part of the bowl column,which bears a greater load.Therefore,it should have high fire resistance and load softening temperature to ensure smooth firing of the product.If the fire resistance is low,especially when the softening temperature under high temperature load is lower than the firing temperature of the product,deformation(bending wall,sinking bottom)will occur,and even cause the collapse of the bowl column.
2、Good thermal stability
During the firing process,quartz bowls must repeatedly withstand rapid changes in high temperature and cooling.If there is no resistance to rapid temperature changes,it is easy to crack,resulting in a decrease in usage and defects such as slag falling onto the product.
3、Good thermal conductivity
During the process of firing the product inside,the heat is first transferred to the quartz bowl,and then to the product.Therefore,it is required to have good thermal conductivity to ensure uniform heating and cooling of the product,thereby improving the thermal efficiency of the kiln and shortening the firing cycle.
4、High mechanical strength
During use,it is necessary to repeatedly transport and load the products,especially after high-temperature firing,where there are often sticky joints between bowls.When exiting the kiln,a wooden mallet should be used to strike and separate them.Therefore,it is required to have high mechanical strength.
5、Reduced shrinkage during re burning
The volume shrinkage that occurs again due to the increase in sintering degree as the frequency of use of the quartz bowl increases is called re firing shrinkage.If shrinkage occurs every time it is re burned,it will cause its shape to mutate,its regularity to decrease,and even lead to instability and collapse accidents.Therefore,it is required that its re burning shrinkage be as small as possible.
In order to improve the firing quality of the product,increase the frequency of use of the quartz box bowl,and reduce production costs,the above requirements must be fully considered when selecting the formula and designer shape,as well as determining the manufacturing process,to ensure that the manufactured quartz box bowl has good performance.

Editor: Brianna