Vitrification in the context of "Vitreous enamel"

Stoneware is a broad class of pottery fired at a relatively high temperature, to be impervious to water. A modern definition is a vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire clay. This definition excludes stone vessels that are carved from a solid chunk of stone. End applications of stoneware include tableware and decorative ware such as vases.

Stoneware is fired at between about 1,100 °C (2,010 °F) to 1,300 °C (2,370 °F). Historically, reaching such temperatures was a long-lasting challenge, and temperatures somewhat below these were used for a long time.

Porcelain (/ˈpɔːrs(ə)lɪn/), also called china, is a ceramic material made by heating raw materials, generally including kaolinite, in a kiln to temperatures between 1,200 and 1,400 °C (2,200 and 2,600 °F). The greater strength and translucence of porcelain, relative to other types of pottery, arise mainly from vitrification and the formation of the mineral mullite within the body at these high temperatures. End applications include tableware, decorative ware such as figurines, and products in technology and industry such as electrical insulators and laboratory ware.

The manufacturing process used for porcelain is similar to that used for earthenware and stoneware, the two other main types of pottery, although it can be more challenging to produce. It has usually been regarded as the most prestigious type of pottery due to its delicacy, strength, and high degree of whiteness. It is frequently both glazed and decorated.

Earthenware is glazed or unglazed nonvitreous pottery that has normally been fired below 1,200 °C (2,190 °F). Basic earthenware, often called terracotta, absorbs liquids such as water. However, earthenware can be made impervious to liquids by coating it with a ceramic glaze, and such a process is used for the great majority of modern domestic earthenware. The main other important types of pottery are porcelain, bone china, and stoneware, all fired at high enough temperatures to vitrify. End applications include tableware and decorative ware such as figurines.

Earthenware comprises "most building bricks, nearly all European pottery up to the seventeenth century, most of the wares of Egypt, Persia and the near East; Greek, Roman and Mediterranean, and some of the Chinese; and the fine earthenware which forms the greater part of our tableware today" ("today" being 1962). Pit fired earthenware dates back to as early as 29,000–25,000 BC, and for millennia, only earthenware pottery was made, with stoneware gradually developing some 5,000 years ago, but then apparently disappearing for a few thousand years. Outside East Asia, porcelain was manufactured at any scale only from the 18th century AD, and then initially as an expensive luxury.

Terracotta, also known as terra cotta or terra-cotta (Italian: [ˌtɛrraˈkɔtta]; lit. 'baked earth'; from Latin terra cocta 'cooked earth'), is a clay-based non-vitreous ceramic fired at relatively low temperatures. It is therefore a term used for earthenware objects of certain types, as set out below.

Usage and definitions of the term vary, such as:

Bone china is a type of vitreous, translucent pottery, the raw materials for which include bone ash, feldspathic material and kaolin. It has been defined as "ware with a translucent body" containing a minimum of 30% of phosphate derived from calcined animal bone or calcium phosphate. Bone china is amongst the strongest of whiteware ceramics, and is known for its high levels of whiteness and translucency. Its high strength allows it to be produced in thinner cross-sections than other types of whiteware. Like stoneware, it is vitrified, but is translucent due to differing mineral properties.

In the mid-18th century, English potters had not succeeded in making hard-paste porcelain (as made in East Asia and Meissen porcelain), but found bone ash a useful addition to their soft-paste porcelain mixtures. This became standard at the Bow porcelain factory in London (operating from around 1747), and spread to some other English factories. The modern product was developed by the Staffordshire potter Josiah Spode in the early 1790s. Spode included kaolin, so his formula, sometimes called "Staffordshire bone-porcelain", was effectively hard-paste, but stronger, and versions were adopted by all the major English factories by around 1815.

Egyptian faience is a sintered-quartz ceramic material from Ancient Egypt. The sintering process "covered [the material] with a true vitreous coating" as the quartz underwent vitrification, creating a bright lustre of various colours "usually in a transparent blue or green isotropic glass". Its name in the Ancient Egyptian language was tjehenet, and modern archeological terms for it include sintered quartz, glazed frit, and glazed composition. Tjehenet is distinct from the crystalline pigment Egyptian blue, for which it has sometimes incorrectly been used as a synonym.

It is not faience in the usual sense of tin-glazed pottery, and is different from the enormous range of clay-based Ancient Egyptian pottery, from which utilitarian vessels were made. It is similar to later Islamic stonepaste (or "fritware") from the Middle East, although that generally includes more clay.

The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. An amorphous solid that exhibits a glass transition is called a glass. The reverse transition, achieved by supercooling a viscous liquid into the glass state, is called vitrification.

The glass-transition temperature T_g of a material characterizes the range of temperatures over which this glass transition occurs (as an experimental definition, typically marked as 100 s of relaxation time). It is always lower than the melting temperature, T_m, of the crystalline state of the material, if one exists, because the glass is a higher energy state (or enthalpy at constant pressure) than the corresponding crystal.