Gadolinium is a silver-white metal, ductile, with a melting point of 1313°C, a boiling point of 3273°C, and a density of 7.901g/m3. Gadolinium is magnetic at room temperature. Gadolinium is relatively stable in dry air and loses luster in humid air; gadolinium has the highest thermal neutron capture surface, which can be used as reactor control material and protective material; magnetic refrigeration with gadolinium salt can obtain ultra-low temperature close to absolute zero.
Can react slowly with water; dissolve in acid to form corresponding salt.
Gadolinium reacts slowly with water; dissolves in acid to form the corresponding salt.
Element use: commonly used as a material for absorbing neutrons in atomic reactors. Also used in microwave technology, phosphors for color TVs.
Darkened in moist air. Soluble in acid, insoluble in water. The oxide is white powder. Salts are colorless. It has special properties such as good superconductivity, high magnetic moment and room temperature Curie point. Gadolinium has the following isotopes: 152Gd, 154Gd~158Gd, 160Gd.
Application fieldAn important property of gadolinium is that each of the seven orbitals has one electron, the largest number of unpaired electrons in the rare earth element. The magnetic moment that depends on this unpaired electron is the largest, and it is expected that this characteristic can be effectively utilized.
medical field:
In medical applications, the complex of gadolinium-diethylenediaminepentaacetic acid (DTPA) can be used as an MRI (magnetic resonance imaging diagnosis) image shading adjuster just like the X-ray contrast agent barium. That is to say, the water around gadolinium is affected by the magnetic field moment of the gadolinium nucleus, showing that it is different from the water that is not affected, and using the control screen is helpful for the diagnosis of the disease.
Industrial field: The well-known industrial technology called magnetic freezing is to use magnetic field to generate heat when it becomes a magnet, and to remove the heat-absorbing property of magnetic field when the magnetic disappears for cooling. Small and efficient refrigerators can be made.
In the magnetic bubble memory device, gadolinium-potassium-garnet is used as the media substance. Magnetic bubble memory is to add a magnetic field in the vertical direction of the material to make it into a cylindrical magnetic field, strengthen the magnetic field, and soon produce the phenomenon that the magnetic field disappears. Information can be stored using magnetic bubble memory devices, which are generally used for information collection.
Other uses of gadolinium are in optical fibers and optical discs, along with terbium and dysprosium. Optical magnetic recording is to use light to replace the magnetic reading magnetization and non-magnetization, which has the characteristics of high density and rewritable recording.
In the field of nuclear energy: in the atomic energy industry, the isotopes of europium and gadolinium are used as control rods and neutron absorbers for light water reactors and fast breeder reactors.
The use of gadolinium is the strong reaction of all elements to thermal neutrons. In addition to the control of atomic reactors, it can also absorb invisible neutrons with gadolinium and make them emit light, as a fluorescent agent for photosensitive X-ray film. use.
specific purpose
Its main uses are:
(1) Its water-soluble paramagnetic complex can improve the nuclear magnetic resonance (NMR) imaging signal of the human body in medicine.
(2) Its sulfur oxides can be used as matrix grids for oscilloscope tubes and X-ray fluorescent screens with special brightness.
(3) Gadolinium in gadolinium gallium garnet is an ideal monolithic substrate for bubble memory memory.
(4) It can be used as a solid-state magnetic refrigeration medium without the limitation of Camot cycle.
(5) It is used as an inhibitor to control the chain reaction level of nuclear power plants to ensure the safety of nuclear reactions.
(6) Used as an additive for samarium cobalt magnets to ensure that the performance does not change with temperature.
In addition, gadolinium oxide is used together with lanthanum to contribute to changes in the vitrified region and to improve the thermal stability of the glass. Gadolinium oxide can also be used to make capacitors and X-ray intensifying screens. In the world, efforts are being made to develop the application of gadolinium and its alloys in magnetic refrigeration, and breakthroughs have been made. At room temperature, a magnetic refrigerator using superconducting magnets, metal gadolinium or its alloys as the refrigeration medium has come out.