Surface smoothness is an important characteristic of ceramic glazes as it influences chemical resistivity, glossiness
and stainability of glazes. Surface crystallinity of zirconia-based and titania-based glazes (as two common
opaque glazes), calcium-zinc based matte glaze and also two transparent glazes with different compositions
were studied in thiswork. Degree of surface crystallinity measured by stereologicalmethods using scanning electron
microscopy (SEM) images showed that transparent glaze has the minimum degree of crystallinity (2.1%)
and the maximum amount (25.4%) was obtained for matte glaze. In addition, X-ray diffraction (XRD) was used
to characterize the glaze mineralogy. Optical surface profiler showed that the smoothest surface belongs to titania-
based opaque glaze (Ra = 0.0157 μm) and transparent glaze (Ra = 0.0168 μm). In contrast, the roughest
glaze surface corresponded to the matte glaze (Ra = 0.2772 μm). The results suggest that surface roughness is
influenced by crystallinity of surface, but degree of surface crystallinity is not the only parameter that can influence
the surface roughness. The most important factor is the morphology of the crystals grow and their protrusion
from the surface.
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