LuckPr provide high pure rare earth borides CeB6 LaB6 PrB6 NdB6 SmB6 EuB6 YbB6
LuckPr producing rare earth borides CeB6 LaB6 PrB6 NdB6 SmB6 EuB6 YbB6 ,
Cerium Boride, also called Cerium Hexaboride or CeB6, is a refractory ceramic material. The principal use of cerium hexaboride is a coating of hot cathodes, or hot cathodes made of cerium hexaboride crystals. It usually operates at temperature of 1450 °C. Cerium hexaboride, like lanthanum hexaboride, slowly evaporates during the cathode operation. In conditions where CeB6 cathodes are operated under 1850 K, CeB6 should maintain its optimum shape longer and therefore last longer. While the process is about 30% slower than with lanthanum boride, the cerium boride deposits are reported to be more difficult to remove.
Lanthanum Boride, also called Lanthanum Hexaboride or LaB6, is an inorganic chemical and refractory ceramic material. It has a high melting point of 2210 °C and is insoluble in water and hydrochloric acid. It is extremely hard, with a Mohs hardness of 9.5. It has a low work function and one of the highest electron emissivities known, and is stable in vacuum. Stoichiometric samples are colored intense purple-violet, while boron-rich ones (above LaB6.07) are blue. Ion bombardment changes its color from purple to emerald green. LaB6 is a superconductor with a relatively low transition temperature of 0.45 K.
Praseodymium Boride, also called Praseodymium Hexaboride, is one of the rare earth borides, the molecular formula is PrB6. The rare-earth hexaborides have the cubic CaB6 structure , with rare-earth ions lying on a simple cubic lattice enclosing an octahedral B6 cage. Praseodymium hexaboride PrB6 and neodymium hexaboride NdB6 are also antiferromagnetic metals in which the magnetic properties are treated as being governed by localized magnetic moments of rare earth ions that interact with each other through conduction electrons (the Ruderman–Kittel–Kasuya–Yosida mechanism). praseodymium hexaboride is believed to have a higher emission constant, and a lower volatility and congruent vaporization, which give rise to a lower operation temperature and longer service life comparing with conventional cathodic emission materials.
The structure of neodymium hexaboride (NdB6) is an example of this latter complex three-dimensional structural type, in which B6 octahedra are arranged in a body-centered cubic lattice with the octahedra linked to the apices of other octahedra in all six directions, giving a rigid yet relatively open structure. The strong multicenter, covalent bonding of these boron polyhedra is believed to impart the observed high stability, hardness, and high melting points to most of the boride materials. While it is not possible to account for the boride structures in simple bonding terms, it is generally believed that the metal center donates electrons to the boron units in the boron-rich compounds, such as NdB6. In the case of NdB6 , the closo-boron octahedra require 14 valence electrons (2n+2), of which 12 are provided by the boron atoms. If the neodymium then provides two electrons to the cage, one ‘free’ valence electron should remain per metal center, making the material an excellent conductor. This analysis is consistent with Hall-effect, solid-state 11 B NMR and conductivity measurements on these materials.
Samarium Boride, also called Samarium Hexaboride, is one of the rare earth borides, the molecular formula is SmB6. SmB6 is an intermediate-valence compound where samarium is present both as Sm2+ and Sm3+ ions at the ratio 3:7. It belongs to a class of Kondo insulators. At temperatures above 50 K its properties are typical of a Kondo metal, with metallic electrical conductivity characterized by strong electron scattering, whereas at low temperatures, it behaves as a non-magnetic insulator with a narrow band gap of about 4–14 meV. The cooling-induced metal-insulator transition in SmB6 is accompanied by a sharp increase in thermal conductivity, peaking at about 15 K. The reason for this increase is that electrons do not contribute to thermal conductivity at low temperatures, which is instead dominated by phonons. The decrease in electron concentration reduced the rate of electron-phonon scattering.
Samarium Boride, also called Samarium Hexaboride, is one of the rare earth borides, the molecular formula is SmB6.
Europium Boride, also called Europium Hexaboride, is one of the rare earth borides, the molecular formula is EuB6. Its rigid crystal structure comprises cubical arrangements of metal atoms in a web of covalently bonded boron atoms. The unit cell can be described as a cube with boron octahedra occupying eight corners of the cube with a metal atom at the bodycenter position. The metallicity of EuB6 depends on the valence of the metal atom in EuB6. For a bivalent metal, EuB6 behave as non-metallic, and for trivalent metals, EuB6 show metallic property since the third electron of the metal goes to the conduction band contributing to the electrical property of EuB6. The valence electrons of boron are spread over five bonds creating electron vacancy. For each unit cell of EuB6, this situation produces two-hole states for every B6 group where each metal atom provides two electrons to fill the holes. These characteristics together with the strong bonds between the boron atoms in the crystal structure framework produce EuB6 that have electro-magnetic properties with high thermal stabilities.
Gadolinium Boride, also called Gadolinium Hexaboride, is one of the rare earth borides, the molecular formula is GdB6. In the metallic compound GdB6, gadolinium shows a very unusual magnetic behavior. GdB6 crystallizes in a cubic CaB6-type structure and orders antiferromagnetically at TN=16 K. While no crystal field splitting is expected for the Gd3+ ground state, earlier studies showed deviations from the Curie-Weiss law of magnetic susceptibility far above TN and a Schottky anomaly at 30 K in the specific heat measure-ments. The existence of short-range ordering above TN to explain the anomalous magnetic behavior in GdB6 Recent studies of the electrical resistivity and magnetic torque reveal the existence of a second magnetic transition around 10 K in zero magnetic field and a more complicated magnetic field-versus-temperature phase diagram.
Ytterbium Boride Powder, also called Ytterbium Hexaboride, is one of the rare earth borides, the molecular formula is YbB6. Ytterbium hexaboride is black crystalline powder. Among all REB6, YbB6 is especially attractive for its relatively low density, high mechanical strength, and high melting point characteristics. The crystalline form of YbB6 has cubic Pm-3m space group symmetry like most of the rare-earth hexaborides (REB6), resembling the crystal structure of CsCl. Rare-earth ion and octahedral B6 occupy Cs site and Cl site respectively, and the octahedral B6 cluster links to each other by strong covalent bonds providing high hardness characteristics.
YbB6 is traditionally synthesized through mechano-chemical processes, high temperature sintering methods, vacuum calcination, and combustion synthesis.
