Ceramic stains

Stannic oxide, SnC>2, is a white powder, insoluble in acids and alkalis. It is an excellent glaze opacifier, a component of pink, yellow and maroon ceramic stains and of dielectric and refractory bodies. 

Table 5.9-14. Colorants for Enamels and Ceramics (Stains and Oxides) (Selection).

Zirconium-Iron Pink. A ceramic stain suitable for the colouring of a variety of glazes maturing at 1220-1280°C. This firing range is greater than that permissible with chrome-tin pink or with chrome-alumina pink. 

Zirconium oxide is used in the production of ceramic colors or stains for ceramic tile and sanitary wares. Zirconia and siHca are fired together to form zircon in the presence of small amounts of other elements which are trapped in the zircon lattice to form colors such as tin—vanadium yellow, praseodymium—zircon yellow [68187-15-5] vanadium—zircon blue [12067-91 -3] iron—zircon pink [68412-79-3] indium—vanadium orange (105—108). 

The high-temperature stability of SiC-based ceramics is well-known, and therefore its composite materials have been investigated for application to high-tem-perature structural materials [19-21]. However, well-known SiC-based fibers and matrix-materials stained with alkali salt are easily oxidized at high temperatures in air [22]. This would be a serious problem when these materials are used near the ocean or in a combustion gas containing alkali elements. In particular, a silicon carbide fiber containing boron (a well-known sintering aid for SiC) over 1 wt% was extensively oxidized under the above condition. In this... 

Abrasive cleaners arc used lo remove soils and stains from hard surfaces that are durable lo the scouring action. Such surfaces include stainless steel and porcelain plumbing fixtures, metal and ceramic cooking utensils, and various stone, metal, and ceramic building surfaces. Typically, these products consist of a very high level of abrasive (commonly silica flour) with moderate to low levels of a dry chlorine bleach (KDCC or chlorinaled trisodium phosphate) and low levels of surfactant (LAS) and builder (STP) for wetting action and improved stain removal... 

Ceramic (high temp stain-resistant) crucible, clay triangle... 

In traditional areas such as ceramic tiles, praseodymium oxide in a zirconium silicate matrix is used as a yellow stain. Cerium oxide is used as an opacifier or to give esthetic effects in the glaze. Other pigment colours, such as orange with yttrium oxide and light purple with neodymium oxide can be prepared. The compositions of these pigments are given in Table 12.19. 

The polycondensate of Fomblin and 3-(trimethoxysilyl)propyl amine prepared by Moore [3] was used to provide resistance to water, oil, and stain repellency to a substrate or fabric. De Dominicis [4] used mono and difunctional perfluoropolyether phosphates and amidosilane derivatives as antistaining agents for ceramic materials. 

Two additional hydrofluoric acid methods have been reported (1,2), and are similar to that described above. The method of Hughes et al. has also been the subject of two comparative studies relevant to the analysis of ceramics (2,31). Techniques that retain silicon have been discussed (1,2) and involve either fusion with lithium metaborate [or sodium carbonate (2)] or high pressure dissolution in a PTFE bomb. An alternative high pressure method, developed by Price and Whiteside (32), was evaluated in the course of this investigation but was found to be unreliable for stained glass of medieval composition in many experiments dissolution was incomplete. Attempts to modify the procedure by varying the prescribed dissolution parameters produced insufficiently consistent results although superior conditions were established (Table I). 

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