The son of light among rare earth metals – scandium

Scandium is a chemical element with the element symbol Sc and atomic number 21. The element is a soft, silver-white transition metal that is often mixed with gadolinium, erbium, etc. The output is very small, and its content in the earth’s crust is about 0.0005%.

1. The mystery of scandium element

The melting point of scandium is 1541 ℃, the boiling point is 2836 ℃, and the density is 2.985 g/cm³. Scandium is a light, silver-white metal that is also very reactive chemically and can react with hot water to generate hydrogen. Therefore, the metal scandium you see in the picture is sealed in a bottle and protected with argon gas. Otherwise, the scandium will quickly form a dark yellow or gray oxide layer and lose its shiny metallic luster.

2. Main uses of scandium

The uses of scandium (as the main working substance, not for doping) are concentrated in very bright directions, and it is not an exaggeration to call it the son of light.

1). Scandium sodium lamp can be used to bring light to thousands of households. This is a metal halide electric light source: the bulb is filled with sodium iodide and scandium iodide, and scandium and sodium foil are added at the same time. During high-voltage discharge, scandium ions and sodium ions respectively emit light with their characteristic emission wavelengths. The spectral lines of sodium are two famous yellow rays at 589.0 and 589.6nm, while the spectral lines of scandium are a series of near-ultraviolet and blue light emissions from 361.3 to 424.7nm. Because they are complementary colors, the overall light color produced is white light. It is precisely because the scandium sodium lamp has the characteristics of high luminous efficiency, good light color, energy saving, long service life and strong fog-breaking ability that it can be widely used in television cameras and squares, stadiums, and road lighting, and is called the third generation. light source. In China, this kind of lamp is gradually promoted as a new technology, but in some developed countries, this kind of lamp has been widely used as early as the early 1980s.

2). Solar photovoltaic cells can collect the light scattered on the ground and turn it into electricity that drives human society. Scandium is the best barrier metal in metal-insulator-semiconductor silicon photovoltaic cells and solar cells

3). Gamma ray source, this magic weapon can emit great light by itself, but this kind of light cannot be received by our naked eyes. It is a high-energy photon flow. What we usually extract from minerals is 45Sc, which is the only natural isotope of scandium. Each 45Sc nucleus has 21 protons and 24 neutrons. If we put scandium in a nuclear reactor and let it absorb neutron radiation, just like putting a monkey in Taishang Laojun's alchemy furnace for 7,749 days, 46Sc with one more neutron in the nucleus will be born. 46Sc, an artificial radioactive isotope, can be used as a gamma ray source or tracer atom, and can also be used for radiotherapy of malignant tumors. There are countless uses such as yttrium-gallium-scandium garnet lasers, scandium fluoride glass infrared optical fibers, and scandium-coated cathode ray tubes in television sets. It seems that scandium is destined to be bright.

3、 Common compounds of scandium

1). Terbium scandate (TbScO3) crystal - has good lattice matching with perovskite structure superconductors, and is an excellent ferroelectric thin film substrate material

2). Aluminum scandium alloy - First, it is a high-performance aluminum alloy. There are several ways to improve the performance of aluminum alloys. Among them, microalloying and strengthening and toughening have been the forefront of high-performance aluminum alloy research in the past 20 years. In shipbuilding, aerospace The application prospects in high-tech sectors such as industry, rocket missiles, and nuclear energy are very broad.

3). Scandium oxide - Scandium oxide has excellent physical and chemical properties, so it has a wide range of applications in the field of materials science. First, scandium oxide can be used as an additive in ceramic materials, which can improve the hardness, strength and wear resistance of ceramics, making them more durable. In addition, scandium oxide can also be used to prepare high-temperature superconductor materials. These materials exhibit good electrical conductivity at low temperatures and have great application potential.