Verglaster

Verglaster is a term used in materials science and crafts to describe the surface layer produced by vitrification or glazing that has a glass-like, non-porous texture. The word is encountered in English-language specialist texts and in some ceramic and architectural contexts.

Origins and usage: The term derives from verglasen, a German verb meaning to glaze over. In English, verglaster may denote either the surface coat itself or the substance bearing the coating, depending on the context and author.

Formation and properties: A verglaster layer is formed by applying a vitreous glaze to a substrate and firing or cooling to promote a glassy phase. The resulting layer is typically hard and chemically durable, with very low porosity and a high-gloss finish. Depending on glaze composition and firing profile, it can be transparent, translucent, or opaque. The interface between substrate and glaze is influenced by thermal expansion compatibility and bonding quality.

Applications: In ceramics, verglaster coatings reduce porosity and add color and luster on stoneware and porcelain. In architecture, glazed surfaces in tiles and façades may be described as verglasted. In metalworking and decorative arts, verglasted coatings can provide wear resistance, corrosion protection, or a distinctive reflective appearance.

Variants and terminology: Some writers use verglaster interchangeably with glazed or vitrified surfaces, though others reserve the term for coatings produced by specific glaze systems or vitrification protocols. Related concepts include glaze, vitrification, glass-ceramics, and surface coatings.