Glaze (metallurgy), a layer of compacted sintered oxide formed on some metals:
Compacted oxide layer glaze describes the often shiny, wear-protective layer of oxide formed when two metals (or a metal and ceramic) are slid against each other at high temperature in an oxygen-containing atmosphere. The layer forms on either or both of the surfaces in contact and can protect against wear.
Glaze (painting technique), a layer of paint, thinned with a medium, so as to become somewhat transparent
- A glaze is a thin transparent or semi-transparent layer on a painting which modifies the appearance of the underlying paint layer. Glazes can change the chroma, value, hue and texture of a surface. Glazes consist of a great amount of binding medium in relation to a very small amount of pigment. Drying time will depend on the amount and type of paint medium used in the glaze. The medium, base, or vehicle is the mixture to which the dry pigment is added. Different media can increase or decrease the rate at which oil paints dry.
Often, because a paint is too opaque, painters will add special media or a lot of medium to the paint to make them more transparent for the purposes of glazing. While these media are usually liquids, there are solid and semi-solid media used in the making of paints as well. For example, many classical oil painters have also been known to use ground glass and semi-solid resins to increase the translucency of their paint.
Ceramic glaze, a vitreous coating to a ceramic material whose primary purposes are decoration or protection
Ceramic glaze is an impervious layer or coating of a vitreous substance which has been fused to a ceramic body through firing. Glaze can serve to color, decorate or waterproof an item. Glazing renders earthenware vessels suitable for holding liquids, sealing the inherent porosity of unglazed biscuit earthenware. It also gives a tougher surface. Glaze is also used on stoneware and porcelain. In addition to their functionality, glazes can form a variety of surface finishes, including degrees of glossy or matte finish and color. Glazes may also enhance the underlying design or texture either unmodified or inscribed, carved or painted.
Most pottery produced in recent centuries has been glazed. Tiles are almost always glazed, and modern architectural terracotta is very often glazed. Glazed brick is also common. Domestic sanitary ware is invariably glazed, as are many ceramics used in industry, for example ceramic insulators for overhead power lines.
The most important groups of traditional glazes, named after their main ceramic fluxing agent, are:
- Lead-glazed earthenware, is shiny and transparent after firing, which only needs about 800 °C (1,470 °F). Used for about 2,000 years around the Mediterranean, in Europe and China. Includes sancai and Victorian majolica.
- Tin-glazed pottery, which coats the ware with an opaque white glaze. Known in the Ancient Near East and then important in Islamic pottery, from which it passed to Europe. Includes faience, maiolica, majolica and Delftware.
- Salt-glazed ware, mostly European stoneware. It uses ordinary salt.
- Ash glaze, important in East Asia, simply made from wood or plant ash, which contains potash and lime.
- Feldspathic glazes of porcelain.
Modern materials technology has invented new vitreous glazes that do not fall into these traditional categories.