The Main Role of Borax, Urea, Sodium Nitrite, Etc.
Most of the enamel additives used for enamel slurry mixing are electrolytes that are easily soluble in water, and are used as saturated solutions. Today we will introduce the role of common enamel additives such as borax, urea, sodium nitrite, and magnesium sulfate in the enamel slurry, which is convenient for enamel factories to apply in the actual operation process.
Magnesium Sulfate (MgSO4•7H2O): Retaining agent for ground coat, titanium enamel and color enamel. Excessive amount will reduce the staying effect, and will cause the porcelain surface to be rough and reduce the adhesion.
Barium chloride (BaCl2•2H2O): The retention agent of antimony enamel, titanium enamel and colored enamel, it is difficult to handle if the excessive consistency is large, but it is forbidden to use bright red and cadmium yellow.
Potassium carbonate (K2CO3): Titanium enamel retention agent, excessive amount will cause piping watermarks, yellowing, and serious boiling.
Sodium carbonate (Na2CO3): Solve the pitting of the ground coat layer, the bullet points and small black spots of the surface enamel layer, and excessive amount will cause the enamel slurry to stay poorly.
Potassium Chloride (KCL): A retention agent for titanium enamel, excessive amount will cause piping watermarks, yellowing, and serious boiling.
Sodium Chloride (NaCl): Used for surface enamel, it can increase the strength of powder blank, and excessive amount will affect the gloss of porcelain surface.
Borax (Na2B4O7•10H2O): Solve the pitting defect of the ground coat layer, and excessive amount will easily cause boiling or shrinkage.
Urea (NH) 2CO: Increase the strength of the enamel powder blank, and solve the defects such as powder lines, black lines of piping watermarks, and black spots. Excessive amount will reduce the physical and chemical properties of enamel products (gloss, acid resistance, heat resistance, impact resistance) and cause boiling defects, so red enamel paste should not be used.
Sodium nitrite (NaNO2): Solve the yellow rust spots caused by poor drying of the ground coat powder. Excessive amount can easily cause piping watermarks, blistering or boiling.
Potassium chlorate (KClO3): Solve the boiling point of the titanium enamel layer. Excessive amount will reduce the luster and cause the edge watermark to boil. The enamel products with red edge enamel should be added less to avoid darkening the edge enamel color.
Sodium chlorate (NaClO3): The effect is the same as that of potassium chlorate.