• Materials for Ceramics

Zinc Oxide Raw

Alternate Names: Zinc 88, Zinc 90

Notes

Raw zinc oxide has not been calcined so it has some LOI on firing.

Related Information

Frits instead of raw zinc, lithium, barium, strontium

Raw material sources of zinc, lithium, barium, strontium have issues (e.g. precipitates in glaze slurries, toxicity, high drying shrinkage and carbon burnoff that affect laydown and fired surface defects like pinholes, blisters, orange peeling, crystallization). Yet the oxides that these materials supply to the glaze melt - ZnO, Li₂O, BaO and SrO, can be sourced from frits which melt much better and remove most of the problems. Consider examples made by Fusion:
-Frit F-493 has 11% Li₂O
-F-403 has 35% BaO
-F-581 has 39% SrO
-FZ-16 has 15% ZnO
These frits source other oxides but such are common in most glazes and glaze calculation can be used to retain the overall chemistry. Although these are expensive, the benefits are game changers. But there is a problem: Potters can't get these. Therefore they have difficulty creating the dazzling visual effects of many commercial glazes.

Raw and calcined zinc oxides in a crystalline glaze

Zinc oxide calcined (left) and raw (right) in typical crystalline glaze base (G2902B has 25% zinc) on typical cone 6 white stoneware body. This has been normally cooled to prevent crystal development. The melting pattern is identical. Note how badly these are crazed, this is common since crystalline glazes are normally high in sodium.

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