Flow Characteristics of Enamel Slurry
Enamel slurry belongs to the category of mud, so from a broad sense, it is not a Newtonian liquid. In most cases, mud is a colloidal system, that is, one phase is very fine, and the distribution is embedded in the other phase. The medium can be solid, liquid or gas. The colloid is not in a state of thermal equilibrium. One of its most important properties is that their inner surface is much larger than their outer surface. The solid particles are distributed in the liquid. The system in is called a suspension.
According to the different particle sizes in the solid state, one can distinguish between coarse particle distribution, colloidal particle distribution and molecular state distribution. The transition between them is variable and there is no exact quantitative definition. If in a colloidal system, the solids are filled with liquid and the distance between the solids is less than their average diameter, the system will solidify and the liquid suspension will become one. The viscosity of the enamel frit (enamel slurry) slurry mainly depends on the speed gradient, flow process and pressure. In the aqueous liquid system, the temperature only plays an auxiliary role, which is generally defined by room temperature, and is different from oil. Emulsification, in this latter case, the oil temperature has a very large influence on its rheological properties.
Enamel slurry is an internal viscous liquid in a certain flow range, plus thixotropy. They are mainly composed of enamel frit , water, clay, quartz, colored oxides, and retention agents, which affect the grinding of dry powder enamel layer.
There are certain requirements for the fluidity of the enamel slurry. The enamel slurry is required to have a certain viscosity, but it cannot be stopped, and has good enamelling operability. The enamel slurry must be evenly distributed on the enamel body during the conveying process. , The enamel-coated wet enamel layer should not flow, and the dried dry powder porcelain layer should not be cracked, and has a certain strength, and can withstand transportation to the firing key without being damaged.
The above requirements do not exclude the requirements of other physical properties. Physical properties such as density and fluidity must be guaranteed by exact data and are within the allowable range.