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Bismuth Trioxide (Bi2O3)
 

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Specification

Assay (as Bi2O3) 99.9% minimum
Loss on Drying 0.1% maximum
Chloride (Cl) 10 ppm maximum
Sulfate (SO4) 10 ppm maximum
Potassium (K) 15 ppm maximum
Aluminum (Al) 10 ppm maximum
Iron (Fe) 5 ppm maximum
Calcium (Ca) 10 ppm maximum
Copper (Cu) 5 ppm maximum
Magnesium (Mg) 5 ppm maximum
Arsenic (As) 5 ppm maximum
Lead (Pb) 10 ppm maximum
Silicon (Si) 30 ppm maximum
Sodium (Na) 30 ppm maximum
Antimony (Sb) 50 ppm maximum
Cadmium (Cd) 10 ppm maximum
Nickel (Ni) 5 ppm maximum
Tin (Sn) 20 ppm maximum
Manganese (Mn) 10 ppm maximum
Average particle size, at d50 <3 microns
Check for impurities via ICP  

Historical Background

Bismuth was probably used as a beauty care product during antiquity. Also, traces of bismuth can be found in Greek and Roman coins.

In the late middle ages and early renaissance, Europeans started using bismuth in paints, or in alloys for dishes, trays, and containers for the preservation of wine. Since it enhanced castability and wear resistance of type-print, Bismuth brought a definite improvement to the emerging art of printing. (Around the same time, a knife was forged in Machu Picchu that contained 18% bismuth--suggesting parallel metalworking development in the New World).

In the following centuries, bismuth's properties continued to be little understood, but with the Age of Reason came increasing scientific investigation, and increasing understanding of the metal and its derivatives. Bismuth is fairly unique among the heavy metals, as it is considered safe, non-carcinogenic and non-toxic.

(For lots more on bismuth, try the Bismuth Institute:
http://www.bismuth.be.)

Bismuth Trioxide

Two significant crystalline forms of bismuth trioxide are known. The first is monoclinic and is stable between 25 and 710 degrees centigrade. It is pale yellow, a solid with a density of about 9.32 grams per cubic centimeter. Above 710 degrees, the material takes on its second form, which is pseudocubic, bright yellow to deep orange with a density of 9.04 grams per cubic centimeter. This latter form is prepared by introducing oxygen at 800 degrees, melts at 820 degrees and is stable to about 1750 degrees. Impurities are sometimes introduced, in the cubic form, as silicon is retained.

Bismuth trioxide can be prepared in one of several ways. Oxygenation of bismuth metal at 750 to 800 degrees; thermal decomposition of other compounds containing bismuth; and precipitation of a hydrated oxide in a bismuth salt solution.

Bismuth trioxide is insoluble in water. It dissolves in acids to form salts. It can form any number of different oxides when combined with oxides of calcium, cadmium, lead, barium and other elements.

Inclusions of bismuth trioxide lower the processing temperature of ceramics from a typical 1400°C to around 1000°C. Aside from easier handling and energy savings, the lower temperatures allow the use of cheaper components. Typical of the world of electronics, the range of applications continues to grow, pointing to uses in ceramics, electronics and "warm" superconductors.

If you believe you have a use for bismuth trioxide, contact us. We will be happy to discuss and help you implement your application.

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