Rare earth metals, also known as rare earth elements, is the general term for scandium, yttrium and lanthanide 17 elements in group III of the periodic table, commonly expressed by R or RE. Rare earth metals have a luster between silver and iron, and it has highly chemically reactive. The content of impurities has a great influence on their properties, so the physical properties are often significantly different. Most rare earth metals are paramagnetic, and gadolinium is more ferromagnetic than iron at 0 ° C. Terbium, dysprosium, holmium and erbium also exhibit ferromagnetism at low temperatures. The low melting point of lanthanum and cerium and the high vapor pressure of samarium, europium and ytterbium show great differences in the physical properties of rare earth metals. Samarium, europium, and gadolinium have a larger thermal neutron absorption cross section than cadmium and boron, which are widely used as control materials for nuclear reactors. Rare earth metals have plasticity, and samarium and ytterbium are the best. Except ytterbium, yttrium group rare earths have higher hardness than cerium group rare earths.
Main Usage:
1. Rare earth metals and alloys play a deoxidation and desulphurization role in steelmaking, which can reduce the content of both to less than 0.001%, change the shape of inclusions, refine grains, so as to improve the processing performance of steel, improve strength, toughness, corrosion resistance and oxidation resistance.
2. Used in the manufacture of nodular cast iron, high-strength gray cast iron and vermicular cast iron, which can change the form of graphite in cast iron, improve the casting process, and improve the mechanical properties of cast iron (alloy steel, cast iron).
3. Adding rare earth metals to bronze and brass smelting can improve the strength, elongation, heat resistance and electrical conductivity of the alloy. The high temperature strength can be improved by adding 1 ~ 1.5% rare earth metal to the cast aluminum-silicon alloy. Adding rare earth metal to aluminum alloy wire can improve the tensile strength and corrosion resistance.
4. Rare earth metal and transition metal composite oxide catalysts are used for gas purification to convert carbon monoxide and hydrocarbons into carbon dioxide and water.
Post time: Jan-26-2024