Ceramic colours

The firing colour was discussed in the paragraph on coarse ceramics. Colours are measured quite often in the plastics industry, but I have not be able to find out if the method applied there is also applied in the ceramics industry. It is certain,however, that colours are measured visually in the brick industry, i.e. colour charts are used as reference... 

J. F. Verrill and F. Malkin, Thermochromic Behavior of the Ceramic Colour Standard, paper presented at the AIC Silver Jubilee Meeting, Princeton, NJ, June 23-24,1992. 

In the final stage of manufacture, domestic porcelain is finished by various decorative techniques. The most frequent is colouring with so-called ceramic colours which are applied onto the glaze and fired at 600 — 850 C. The under-glaze colours are used less often. Ceramic colours are mixtures of colouring substances (e.g. CoO. ... 

Coloured glazes contain colouring agents either dissolved in frit or ceramic colourants are added as heterogeneous insoluble ingredients to the mill. Ceramic colourants are mostly synthetic minerals and their mixtures. Glazes also make pos-... 

Aubergine Purple. A ceramic colour, containing Mn, introduced in the 18th century, when it was used for underglaze decoration. 

Brunner s Yellow. An antimony yellow recipe given by K. Brunner in 1837 1 part tartar emetic, 2 parts lead nitrate, 4 parts NaCl. The mixture is calcined and then washed free from soluble salts prior to its use as a ceramic colour. 

Cadmium Sulphide. CdS sp. gr. 4.8 m.p. 1750 C. A constituent of some ruby-coloured glass, of some yellow enamels, and of Cd-Se red ceramic colours which can be fired at temperatures up to about 850°C. Sintered CdS can be used as a photoconductive ceramic. 

Cadmium Sulphoselenide. CdSjc CdSe. A ceramic pigment, the basis of a range of yellow, orange and red ceramic colours. See cadmium selenide ... 

Canton Blue. A violet-blue ceramic colour made by the addition of barium... 

Celeste Blue. A ceramic colour made by softening the normal cobalt blue by the addition of zinc oxide. 

Chrome-Alumina Pink. A ceramic colour consisting principally of CrjOj, AI2O3 and ZnO when used as a glaze stain, the glaze should contain ZnO and little, if any, CaO. It is recommended that, for use under-glaze, the glaze should be leadless. The colour depends on diffusion of Cr into the insoluble AI2O3 lattice and is normally stable up to 1300 C. 

Sometimes used as a source of COBALT OXIDES (q.v.) in ceramic colours. 

Coral Red. A ceramic colour. One form of coral red consists of basic lead chromate this compound is unstable and the decorating fire must be at a low temperature. 

Dresden Green. A ceramic colour for use up to about 1100°C. It consists of (%) CoO, 24 CrjOj, 52 ZnO, 24. Dressing. The process of removing, from the face of an abrasive wheel, those grains that have become dulled during use. 

Enamel Colour. A ceramic colour for the on-glaze decoration of pottery. Enamel Firing. In the British pottery industry this term is synonymous with DECORATING FIRING (q.V.)... 

Encapsulated Colours. Ceramic colours in which the chromophore (q.v.) is physically trapped or encapsulated in the crystal matrix, not forming a part of the crystal lattice itself (cf. lattice colours). The pink cadmium sulphoselenide inclusion pigments (Degussa, Br. Pat. 1403470,1975) were of this type, with the pigment trapped in the ZIRCON (q.v.) lattice. Later developments have led to means to... 

Flux. A substance that, even in small quantities, lowers the fusion point of material in which it is naturally present (e.g. alkalis in clays) or of material to which it has been added (e.g. borax added to glazes). The term is also used for the prepared low-melting glasses that are added to ceramic colours to fuse them to the ware on which they are being used as decoration. 

Jar Mill. A small ball mill (q.v.), the revolving cylinder being a vitreous ceramic jar such mills are used in the grinding of small batches of ceramic colours and vitreous enamels. 

Lattice Brick. A hollow building brick, or block, in which the cells form a pattern of open lozenges such bricks are claimed to have a high heat-insulating value because of the extended path of any heat flow through the solid material. Lattice Colour. Ceramic colours in which the CHROMOPHORE (q.v.) or colouring atom forms part of the crystal lattice. 

Lithography (UK) Decalcomania (USA). A method used for the decoration of pottery by means of transfers. A special paper is used but the ceramic colours cannot be printed directly and the actual printing is done in varnish and the colour then dusted on. The Litho or Decal (to use the common contractions of these words) is placed... 

Naples Yellow. See lead antimonate. Napoleon Green. A ceramic colour that can be fired-on at temperatures up to 1000 C. It consists of (%) CoO, 30 Ct203. 45 hydrated AI2O3,15 ZnO, 10. Nasicon. The compound Na3Zr2PSi20i2 is a superionic conductor with application as a solid electrolyte. 

Pannetier s Reds. Brilliant on-glaze ceramic colours, based on iron oxide, developed in the early 19th century by Pannetier in Paris. 

Paris Green. A ceramic colour suitable for firing up to about 1050°C and consisting of (%) Cr203,25 CoO, 4 ZnO, 8 whiting, 12 borax, 8 flint, 43. Paris White. See whiting. 

Peach Bloom. A glaze effect on pottery produced by the Chinese and characterized by its soft pink colour with patches of deeper red. It is achieved by the addition of copper oxide to a high-alkali glaze but requires very careful control of the kiln atmosphere the bloom results from incipient devitrification of the glaze surface. Peacock Blue. A ceramic colour made from a batch such as 33% Cobalt oxide, 7% standard black (q.v.), 45% China Stone, 15% Flint. 

Rinman s Green. A colouring material consisting of a solid solution of CoO in ZnO it finds limited use as a ceramic colour. (S. Rinman, Kong. Vet. Akad. Handl, p. 163,1780.)... 

Sacrificial Red. Old Chinese name for the ceramic colours known as ROUGE FLAMBfi and SANG DE BOEUF (q.v.). 

Sodium Antimouate. Na2O.Sb2O5.y2 H2O An opacifier for dry-process enamel frits for cast-iron enamel-ware and for some acid-resistant frits for sheet steel enamels. It is also a source of antimony for yellow ceramic colours. Sodium Carboxymethylcellulose. See carboxymethylcellulose. 

Sphene (or Titanite). CaO.SiO2.TiO2 m.p. 1386°C. This mineral has been found in the ceramic colour known as CHROME-TIN PINK (q.V.). 

Standard Black. A ceramic colour a quoted composition is 30 parts C02O3 56 parts Fc203, 48 parts Cr203, 8 parts NiO and 31 parts AI2O3. 

Titanium Oxides. The common oxide is Ti02 m.p. approx. 1850 C. Used as an opacifier, particularly in vitreous enamels, and as a constituent of some ceramic colours. Titania and titanate electroceramics, for use in the radiofrequency field, are based on this oxide and its compounds. Titania occurs in three crystalline forms anatase, BROOKiTE and rutile (see under each mineral name). Ti20, TiO, Ti203 and Ti305 also exist. 

Uranium Oxides. The important oxides of uranium are UO2, U3O8 and UO3. The dioxide (m.p. 2880 C theoretical density 10.%) is used as n nuclear fuel element. Uranium oxide has been used to produce red and yellow glazes and ceramic colours. 

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