Rare earth metal (rare earth me tals), also known as a rare earth element, is a general term for a group â…¢B periodic table scandium, yttrium, lanthanides 17 elements, commonly represented by R or RE. Their names and chemical symbols are é’ª (Sc), é’‡ (Y), 镧 (La), 铈 (Ce), 镨 (Pr), é’• (Nd), é’· (Pm), é’ (Sm), é“• (Eu ), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu). Their atomic numbers are 21 (Sc), 39 (Y), 57 (La) to 71 (Lu).
The term rare earth is the name left over from history. Rare earth elements were discovered from the end of the 18th century. At that time, solid oxides that were insoluble in water were often referred to as soil. Rare earths are generally separated by oxides and are rare, hence the name rare earth. Generally, lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, lanthanum are called rare earth or lanthanum rare earth; lanthanum, cerium, lanthanum, cerium According to the similarity and difference of the physicochemical properties of rare earth elements, in addition to strontium (some of which are classified as sparse elements), they are divided into three groups, namely, light rare earth groups are 镧, 铈, 镨, 钕, 钷; The medium rare earth group is lanthanum, cerium, lanthanum, cerium and lanthanum;
The discovery of these rare earth elements, which was separated from the Finnish J. Gadolin in 1794 and the American Marinsky in 1947, lasted for more than 150 years. Most of these rare earth elements were discovered by some mineralogists, chemists, and metallurgists in Europe. The cockroaches were obtained by ion exchange of Americans Mariinsky, LEGlendenin, and CDCoryell, obtained from rare earth elements of uranium fission products. Promethium past that does not exist in nature, until 1965, a Finnish phosphate plant found traces of promethium in dealing with apatite.
Most rare earth metals exhibit paramagnetism.钆 is more ferromagnetic than iron at 0 °C. Niobium, tantalum, niobium and tantalum also exhibit ferromagnetism at low temperatures. The low melting point of niobium and tantalum and the high vapor pressure of niobium, tantalum and niobium show great differences in the physical properties of rare earth metals. The thermal neutron absorption cross sections of lanthanum, cerium and lanthanum are larger than those of cadmium and boron which are widely used in nuclear reactor control materials. Rare earth metals have plasticity, with lanthanum and cerium being the best. In addition to bismuth, the lanthanum group has higher hardness than the lanthanum group.
Rare earth metals has been widely used in electronic, petrochemical, metallurgy, machinery, energy, light industry, environmental protection, agriculture and so on. Application of rare earth to produce fluorescent materials, rare earth metal hydride battery materials, electric light source materials, permanent magnet materials, hydrogen storage materials, catalytic materials, precision ceramic materials, laser materials, superconducting materials, magnetostrictive materials, magnetic refrigeration materials, Magneto-optical storage materials, optical fiber materials, and the like.
China has abundant rare earth mineral resources and excellent ore-forming conditions. It is uniquely endowed with abundant proven reserves, which provides a solid foundation for the development of China's rare earth industry.
A rare metal generally refers to a group of chemical elements consisting of seven elements of gallium (Ga), indium (In), thallium (Tl), germanium (Ge), selenium (Se), tellurium (Te), and thorium (Re). But others will rubidium, hafnium, scandium, vanadium and cadmium included. These seven elements have been discovered since the discovery of 碲 in 1782 until 1925. This group of elements is called a rare metal, because they are similar in physical and chemical properties, and they are grouped into one group. Second, they are difficult to form because they are often present in the same minerals. a separate independent exploitation value of scattered metal deposit (asbestos County, Sichuan Province recently found impose a tellurium-based deposit bismuth tellurium); three is their lower average content in the crust, in a few dispersed state of the associated other minerals In the middle, it can only be comprehensively recovered and comprehensively utilized in the selection of metallurgical deposits.
Sparse metals have an extremely important use and are an important part of contemporary high-tech new materials. A series of compound semiconductors, electro-optical materials, special alloys, new functional materials and organometallic compounds composed of rare metals and non-ferrous metals require the use of rare metals with unique properties. Although the amount is not large, it is crucial, and it is not necessary. Therefore, it is widely used in contemporary communication technology, electronic computers, aerospace development, medical and health, photosensitive materials, photovoltaic materials, energy materials and catalyst materials. China's rare metal minerals are rich, providing better resource conditions for the development of the rare metals industry.
Common Nails,Roofing Nails,Polished Common Nails,Galvanized Nails,Steel Nails
Roof nail
Cement nail
Length |
Diameter |
|
Inches |
mm |
BWG |
0.5" |
12.7 |
20/19/18 |
0.75" |
19 |
19/18/17 |
1" |
25.4 |
17/16/15/14 |
1.25" |
31.7 |
16/15/14 |
1.5" |
38 |
15/14/13 |
1.75" |
44.4 |
14/13 |
2" |
50.8 |
14/13/12/11/10 |
2.5" |
63.5 |
13/12/11/10 |
3" |
76.2 |
12/11/10/9/8 |
3.5" |
88.9 |
11/10/9/8 |
4" |
101.6 |
9/8 |
4.5" |
114.3 |
8/7 |
5" |
127 |
7/6 |
6" |
152.4 |
6/5 |
7" |
177.8 |
5/4 |
Big Head Nails
Product Description
Materials: Low Carbon Steel Wire(non-surface treatment), Galvanized Low Carbon Steel Wire,
Diameter: 5.0mm 5.2mm
Length: 150mm 200mm 250mm 300mm
Packing: packed with black spacers as a set, 10sets/bag, 50sets/bag
Usage: fasteners for artificial turf, weed barrier fabric, non-woven fabrics
The common nails is suitable for hard and soft wood, bamboo pieces, or plastic, wall foundry, repairing Furniture, packaging etc.Widely used in construction, decoration,and renovation. The common nails are made from carbon steel Q195, Q215 or Q235. The common nails can be polished , electro galvanized and hot dipped galvanized finished.
Common Nails,Roofing Nails,Polished Common Nails,Galvanized Nails,Steel Nails
Anping Sanxing Wire Mesh Factory , https://www.anpingsanxingwiremesh.com