Barium ferrite these species include BaFeO, BaFeO, and BaFeO. A one-step hydrothermal process can be used to form crystals of barium ferrite, by mixing barium chloride, ferrous chloride, potassium nitrate, and sodium hydroxide with a hydroxide to chloride concentration ratio of 2:1. Nanoparticles are prepared from ferric nitrate, barium chloride, sodium citrate, and sodium hydroxide. The typical preparation, however, is by calcining barium carbonate with iron(III) oxide: Barium ferrite has been considered for long term data storage. The material has proven to be resistant to a number of different environmental stresses, including humidity and corrosion. Because ferrites are already oxidized it can
Brass instrument Traditionally the instruments are normally made of brass, polished and then lacquered to prevent corrosion. Some higher quality and higher cost instruments use gold or silver plating to prevent corrosion. Alternatives to brass include other alloys containing significant amounts of copper or silver. These alloys are biostatic due to the oligodynamic effect, and thus suppress growth of molds, fungi or bacteria. Brass instruments constructed from stainless steel or aluminium have good sound quality but are rapidly colonized by microorganisms and become unpleasant to play. Most higher quality instruments are designed to prevent or reduce galvanic corrosion between any steel in