Ceramic chemistry studies the relationship between the physical properties of fired ceramics and

ceramic glaze Ceramic glaze is an impervious layer or coating of a vitreous substance which has been fused to a pottery body through firing. Glaze can serve to color, decorate or waterproof an item. Glazing renders earthenware vessels suitable for holding ...

s and their chemistry. Although ceramic technicians have long understood many of these relationships, the advent of computer software to automate the conversion from batch to formula and analysis has brought this science within the reach of many more people. Physical properties of glazes in fired products (like

thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

, index of refraction, color and melting temperature or range) are directly (but not solely) related to the chemistry. Properties of glass melts like

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

and surface tension are also principally products of chemistry. Technicians in the ceramic tableware, artware, sanitaryware,

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...

fiberglass Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...

, bottle glass, optical and related industries all use this science. In ceramic chemistry, fired glazes are viewed as composed of oxides (examples are SiO₂, Al₂O₃, B₂O₃, Na₂O, K₂O, CaO, Li₂O, MgO, ZnO, MnO, Fe₂O₃, CoO). Each oxide is known to contribute specific properties to the fired glass. Many materials suppliers publish chemical analyses of their products that cite percentages of these oxides as well as volatile components (components that burn away during firing giving off gases and fumes such as H₂O, CO₂, SO₃). For example, in traditional ceramics here are some examples of what the application of ceramic chemistry can accomplish. * Fix

glaze defects Glaze defects are any flaws in the surface quality of a ceramic glaze, its physical structure or its interaction with the body. Body/glaze interaction problems Glaze defects can be as a result of the incompatibility of the body and the selected ...

crazing Crazing is the phenomenon that produces a network of fine cracks on the surface of a material, for example in a glaze layer. Crazing frequently precedes fracture in some glassy thermoplastic polymers. As it only takes place under tensile stress, ...

, blistering, pin-holing, settling, clouding, leaching, crawling, marking, scratching, powdering * Substitute

frit A frit is a ceramic composition that has been fused, quenched, and granulated. Frits form an important part of the batches used in compounding enamels and ceramic glazes; the purpose of this pre-fusion is to render any soluble and/or toxic compo ...

s, incorporate better, cheaper materials, or replace no-longer-available ones * Adjust glaze melting temperature, gloss, surface character and color (in ceramics color is a matter of chemistry) * Identify weaknesses (e.g. proximity to volatile firing zones, use of unreliable materials) in glazes to avoid problems * Creating and optimizing base glazes to work with difficult colors or stains and for special effects dependent on opacification, crystallization or variegation * Create glazes from scratch and use native materials in the highest possible percentage In ceramic bodies the physical properties of the final fired product are often more related to the firing curve, the physical properties (e.g. particle size and shape, decomposition history) of the ingredient materials and the mineralogy and interaction between the different particle types.

References

Ceramic chemistry - H. H. Stephenson - Google Books
{{DEFAULTSORT:Ceramic Chemistry Pottery Inorganic chemistry