Lighting industry
Interestingly, the use of scandium (as the main working material, not for doping) is focused on the bright direction, so it is not too much to call it the Son of Light.
The first magic weapon of scandium is called scandium sodium lamp, which 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 of their characteristic emission wavelengths. The spectral lines of sodium are 589.0 and 589.6 nm, two famous yellow lights, while the spectral lines of scandium are 361.3~424.7 nm, a series of near ultraviolet and blue light emissions. Because they complement each other, the overall light color generated is white light. It is precisely because scandium sodium lamp has the characteristics of high luminous efficiency, good light color, power saving, long service life and strong fog breaking ability that it can be widely used in television camera and square, stadium and road lighting, and is called the third generation light source. In China, this kind of lamp is gradually promoted as a new technology, while in some developed countries, this kind of lamp was widely used as early as the early 1980s.
The second magic weapon of scandium is solar photovoltaic cells, which can collect the light scattered on the ground and turn it into electricity to promote human society. Scandium is the best barrier metal in metal insulator semiconductor silicon photocells and solar cells.
His third magic weapon is called γ Ray source, this magic weapon can shine bright by itself, but this kind of light can not be received by the naked eye, it is high-energy photon flow. We usually extract 45Sc from minerals, which is the only natural isotope of scandium. Each 45Sc nucleus contains 21 protons and 24 neutrons. If we put scandium in the nuclear reactor as if we put monkeys in the alchemy furnace of Supreme Lord Lao Tzu for seventy-seven forty-nine days and let them absorb neutron radiation, 46Sc of one more neutron in the atomic nucleus will be born. 46Sc, an artificial radioisotope, can be used as γ Radiation sources or tracer atoms can also be used for radiotherapy of malignant tumors. There are also applications like yttrium gallium scandium garnet laser, scandium fluoride glass infrared optical fiber, and scandium coated cathode ray tube on television. It seems that scandium was born with light.
Alloy industry
Scandium in the form of simple substance has been widely used in the doping of aluminum alloys. As long as a few thousandths of scandium is added to aluminum, a new Al3Sc phase will be formed, which will play a role in modifying the aluminum alloy and make the structure and properties of the alloy change significantly. The addition of 0.2%~0.4% Sc (which is really the same as the proportion of home cooking salt, just a little) can increase the recrystallization temperature of the alloy by 150~200 ℃, and significantly improve the high temperature strength, structural stability, welding performance and corrosion resistance, and can avoid the embrittlement phenomenon that is easy to occur during long-term work at high temperatures. High strength and high toughness aluminum alloy, new high-strength corrosion-resistant weldable aluminum alloy, new high-temperature aluminum alloy, high-strength neutron irradiation resistant aluminum alloy, etc., have very attractive development prospects in aerospace, aviation, ships, nuclear reactors, light vehicles and high-speed trains.
Scandium is also an excellent modifier of iron. A small amount of Scandium can significantly improve the strength and hardness of cast iron. In addition, scandium can also be used as an additive for high-temperature tungsten and chromium alloys. Of course, in addition to making wedding clothes for others, because scandium has a high melting point and its density is close to that of aluminum, it is also used in high melting point light alloys such as scandium titanium alloy and scandium magnesium alloy. But because of the high price, it is generally only used in high-end manufacturing industries such as space shuttles and rockets.
ceramic material
Scandium, a simple substance, is generally used in alloys, and scandium oxides play an important role in ceramic materials. For example, tetragonal zirconia ceramic materials, which can be used as electrode materials for solid oxide fuel cells, have a very special property. The conductivity of this electrolyte will increase with the increase of temperature and oxygen concentration in the environment. However, the crystal structure of this ceramic material itself cannot exist stably and has no industrial value; In order to maintain the original properties, some materials that can fix this structure must be doped into it. The addition of 6~10% scandium oxide is like a concrete structure, so that zirconia can be stabilized on a square lattice.
There are also engineering ceramic materials like silicon nitride with high strength and high temperature resistance as densifier and stabilizer.
Scandium oxide, as a densifier, can form a refractory phase Sc2Si2O7 at the edge of fine particles, thus reducing the high-temperature deformation of engineering ceramics. Compared with other oxides, Scandium oxide can better improve the high-temperature mechanical properties of silicon nitride.
Catalytic chemistry
In chemical engineering, scandium is often used as a catalyst. Sc2O3 can be used for dehydration and deoxidation of ethanol or isopropanol, decomposition of acetic acid, and production of ethylene from CO and H2. Pt Al catalyst containing Sc2O3 is an important catalyst for heavy oil purification and refining process in petrochemical industry. In catalytic cracking of cumene, for example, the activity of Sc-Y zeolite catalyst is 1000 times higher than that of aluminum silicate catalyst; Compared with some traditional catalysts, the development prospect of scandium catalyst will be very bright.
Nuclear energy industry
Adding a small amount of Sc2O3 to UO2 in nuclear fuel of high temperature reactor can avoid lattice transformation, volume increase and cracks due to conversion of UO2 to U3O8.
fuel cell
Similarly, adding 2.5%~25% scandium into the nickel alkali battery will increase the service life.
Agricultural breeding
In agriculture, the seeds of corn, beet, pea, wheat, sunflower and others can be treated with scandium sulfate (the concentration is generally 10-3~10-8mol/L, different plants will be different), and the actual effect of promoting germination has been achieved. After 8 hours, the dry weight of roots and buds increased by 37% and 78% respectively compared with seedlings, but the mechanism is still under study.
