Metallic glazes

Although heavy metal glazes are prohibited in commercial manufacture of ceramics in many countries, there are still reports of lead and other toxic heavy metals showing up in dishes imported from countries without similar controls or in ceramic items made by individuals who do not take the appropriate precautions. Because the glaze seems permanent and impervious to water and ordinary foods, it might seem that such materials would not be a hazard, but acidic solutions can extract significant amounts of the heavy metals and result in chronic low-level lead poisoning. 

Daton, J. Minerals, Metals, Glazing and Man Harrap London, 1978 pp. 

Balsam of sulphur 5114 A boiled mixture of sulphur and oltva oil used asa medicine and as an ingredient in a metallic glaze ... 

As cyhndrical resistors cermet or metal glaze resistors are mostly used for high-resistance values and high voltages. The available resistance range is 100 kfi to 100 MS2. The standard TCR is 200 ppm/K but a TCR better than 25 ppm/°C is possible. The stability is good and the current noise acceptable for such high values. 

Variable film resistors are made with carbon composition films, usually on a paper laminate substrate, or with metal glaze films on a ceramic substrate. It is complicated to trim these resistive elements. Therefore, the tolerance on the resistance of film variable resistors is usually high, in the order of 20%. For most applications, however, this is no problem. 

Metal glaze films are very stable, and their TCR can be much better than carbon composition. Besides being used in professional equipment they are also used in consumer electronics where conductive carbon films are not good enough, such as high-voltage trimmers in television sets. For specific applications, variable resistors may be combined with fixed resistors in a network. 

The noise energy depends on the n umber of charge carriers in the resistive element. Resistors with many charge carriers have a low current noise level. Therefore, wire wound resistors are extremely good in this respect. For film resistors, metal films are better than carbon films and metal glaze. Carbon composition resistors have an extremely high noise level. Within one type, low values are better than high ones and big... 

Polished metal packings and poor wetting surfaces (some plastics, glazed porcelain, etc.)... 

Semimetal that occurs as a tin-type, brittle form and as a yellow, unstable, nonmetallic form. Its main use is in alloys to harden other metals. Without the addition of antimony, lead would have remained the "softy" of the Periodic Table. But with antimony, lead ruled the print world and later found use in the production of rechargeable batteries. It can be found in older ceramic glazing (yellow orange). Everyday encounters antimony sulfide in match heads and red rubber, antimony oxide is used as a flame retardant. Pure antimony is starting to become of interest in the electronics sector. 

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