Barium carbonate as a flux, a matting and crystallizing agent and combines with certain colouring oxides to produce unique colours not easily attainable by other means. Its use is somewhat controversial since some claim that it can leach from glazes into food and drink. To provide a safe means of use, BaO is often used in fritted form. In the brick, tile, earthenware and pottery industries barium carbonate is added to clays to precipitate soluble salts (calcium sulfate and magnesium sulfate) that cause efflorescence. Barium carbonate Barium carbonate (BaCO), also known as witherite, is a chemical compound used in rat poison, bricks,
Nickel silver (Shadow model); these are far rarer than traditional lacquered brass saxophones. Student-level flutes and piccolos are also made of silver-plated nickel silver, although upper-level models are likely to use sterling silver. Nickel silver produes a bright and powerful sound quality; an additional benefit is that the metal is harder and has more corrosion resistance than brass. Because of its hardness, it is the most commonly used material for woodwind keys. Most clarinets, flutes, oboes and similar wind instruments have nickel silver keys, normally silver-plated. It is used to produce the tubes (called staples) onto which oboe reeds are tied. Many