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Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

From Wikipedia, the free encyclopedia

27 iron ← cobalt → nickel - ↑ Co ↓ Rh
General
Name, Symbol, Number	cobalt, Co, 27
Chemical series	transition metals
Group, Period, Block	9, 4, d
Appearance	metallic with gray tinge
Standard atomic weight	58.933195(5) g·mol−1
Electron configuration	[Ar] 3d7 4s2
Electrons per shell	2, 8, 15, 2
Density (near r.t.)	8.90 g·cm−3
Liquid density at m.p.	7.75 g·cm−3
Melting point	1768 K (1495 °C, 2723 °F)
Boiling point	3200 K (2927 °C, 5301 °F)
Heat of fusion	16.06 kJ·mol−1
Heat of vaporization	377 kJ·mol−1
Heat capacity	(25 °C) 24.81 J·mol−1·K−1
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K 1790 1960 2165 2423 2755 3198
Atomic properties
Crystal structure	hexagonal
Oxidation states	2, 3 (amphoteric oxide)
Electronegativity	1.88 (Pauling scale)
Ionization energies (more)	1st: 760.4 kJ·mol−1
	2nd: 1648 kJ·mol−1
	3rd: 3232 kJ·mol−1
Atomic radius	135 pm
Atomic radius (calc.)	152 pm
Covalent radius	126 pm
Miscellaneous
Magnetic ordering	ferromagnetic
Electrical resistivity	(20 °C) 62.4 nΩ·m
Thermal conductivity	(300 K) 100 W·m−1·K−1
Thermal expansion	(25 °C) 13.0 µm·m−1·K−1
Speed of sound (thin rod)	(20 °C) 4720 m/s
Young's modulus	209 GPa
Shear modulus	75 GPa
Bulk modulus	180 GPa
Poisson ratio	0.31
Mohs hardness	5.0
Vickers hardness	1043 MPa
Brinell hardness	700 MPa
CAS registry number	7440-48-4
Selected isotopes
Main article: Isotopes of cobalt iso NA half-life DM DE (MeV) DP 56Co syn 77.27 d ε 4.566 56Fe 57Co syn 271.79 d ε 0.836 57Fe 58Co syn 70.86 d ε 2.307 58Fe 59Co 100% Co is stable with 32 neutrons 60Co syn 5.2714 years β- 2.824 60Ni
References
This box: view • talk • edit

Cobalt (IPA: /ˈkəʊbɒlt/) is a hard, lustrous, silver-grey metal, a chemical element with symbol Co. It is found in various ores, and is used in the preparation of magnetic, wear-resistant, and high-strength alloys. Its compounds are used in the production of inks, paints, and varnishes.

[edit] Notable characteristics

Cobalt is a silver or grey ferromagnetic element with atomic number 27. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. It is frequently associated with nickel, and both are characteristic ingredients of meteoric iron. Mammals require small amounts of cobalt salts. Cobalt-60, an artificially produced radioactive isotope of cobalt, is an important radioactive tracer and cancer-treatment agent. Cobalt has a relative permeability two thirds that of iron. Metallic cobalt commonly presents a mixture of two crystallographic structures hcp and fcc with a transition temperature hcp→fcc of 722 K.

Common oxidation states of cobalt include +2 and +3, though +1 is also seen.

[edit] Applications

[edit] Naturally occurring cobalt uses

• Alloys, such as
  • Superalloys, for parts in gas turbine aircraft engines.
  • Corrosion- and wear-resistant alloys.
  • High speed steels.
  • Cemented carbides (also called hard metals) and diamond tools.
• Magnets and magnetic recording media.
  • Alnico magnets.
  • Samarium-cobalt magnets.
• Catalysts for the petroleum and chemical industries.
• Electroplating because of its appearance, hardness, and resistance to oxidation.
• Drying agents for paints, varnishes, and inks.
• Ground coats for porcelain enamels.
• Pigments (cobalt blue and cobalt green).

Cobalt blue glass

• Lithium ion battery electrodes.
• Steel-belted radial tires.
• Purification of histidine-tagged fusion proteins in biotechnology applications.

[edit] Radioisotopes of Cobalt

Naturally occurring cobalt is composed of 1 stable isotope, ⁵⁹Co. 22 radioisotopes have been characterized with the most stable being ⁶⁰Co with a half-life of 5.2714 years, ⁵⁷Co with a half-life of 271.79 days, ⁵⁶Co with a half-life of 77.27 days, and ⁵⁸Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are less than 18 hours and the majority of these have half-lives that are less than 1 second. This element also has 4 meta states, all of which have half-lives less than 15 minutes.

The isotopes of cobalt range in atomic weight from 50 u (⁵⁰Co) to 73 u (⁷³Co). The primary decay mode for isotopes with atomic mass unit values less than that of the most abundant stable isotope, ⁵⁹Co, is electron capture and the primary mode of decay for those of greater than 59 atomic mass units is beta decay. The primary decay products before ⁵⁹Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes.

[edit] Use of Cobalt radioisotopes in medicine

Cobalt-60 (Co-60 or ⁶⁰Co) is a radioactive metal that is used in radiotherapy. It produces two gamma rays with energies of 1.17 MeV and 1.33 MeV. The ⁶⁰Co source is about 2 cm in diameter and as a result produces a geometric penumbra, making the edge of the radiation field fuzzy. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection. The ⁶⁰Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common. Cobalt with alloying additions of chromium and molybdenum is widely used as a bio-medical implant material.

Cobalt-57 (Co-57 or ⁵⁷Co) is a radioactive metal that is used in medical tests; it is used as a radiolabel for vitamin B-12 uptake. It is useful for the Schilling's test.^[2]

[edit] Industrial uses for radioactive isotopes

Cobalt-60 (Co-60 or ⁶⁰Co) is useful as a gamma ray source because it can be produced—in predictable quantity, and high activity—by simply exposing natural cobalt to neutrons in a reactor for a given time. It is used for

• sterilization of medical supplies, and medical waste;
• radiation treatment of foods for sterilization (cold pasteurization);
• industrial radiography (e.g., weld integrity radiographs);
• density measurements (e.g., concrete density measurements); and
• tank fill height switches.

[edit] History

Cobalt compounds have been used for centuries to impart a rich blue color to glass, glazes, and ceramics. Cobalt has been detected in Egyptian sculpture and Persian jewelry from the third millennium BC, in the ruins of Pompeii (destroyed AD 79), and in China dating from the Tang dynasty (AD 618–907) and the Ming dynasty (AD 1368–1644)^[3]. Cobalt glass ingots have been recovered from shipwrecks dating to the time of the Minoans^{[citation needed]}.

Swedish chemist Georg Brandt (1694–1768) is credited with isolating cobalt sometime between 1730 and 1737. He was able to show that cobalt was the source of the blue color in glass, which previously had been attributed to the bismuth found with cobalt.

During the 19th century, cobalt blue was produced at the Norwegian Blaafarveværket (70-80% of world production), led by the Prussian industrialist Benjamin Wegner.

In 1938, John Livingood and Glenn Seaborg discovered cobalt-60.

The word cobalt is derived from the German kobalt, from kobold meaning "goblin", a term used for the ore of cobalt by miners. The first attempts at smelting the cobalt ores to produce cobalt metal failed, yielding cobalt(II) oxide instead; not only that, but because of cobalt's curious affinity for arsenic, the primary ores of cobalt always contain arsenic, and upon smelting the arsenic oxidized into the highly toxic As₄O₆, which was breathed in by workers.

[edit] Biological role

Cobalt in small amounts is essential to many living organisms, including humans. Having 0.13 to 0.30 mg/kg of cobalt in soils markedly improves the health of grazing animals. Cobalt is a central component of the vitamin cobalamin, or vitamin B-12.

[edit] Occurrence

Cobalt ore

Cobalt output in 2005

Cobalt is not found as a native metal but generally found in the form of ores. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite.

In 2005, the Democratic Republic of the Congo was the top producer of cobalt with almost 40% world share followed by Canada, Zambia, Russia, Brazil and Cuba, reports the British Geological Survey.

see also Category:Cobalt minerals

[edit] Compounds

There is a wide variety of cobalt compounds. The +2 and +3 oxidation states are most prevalent, however cobalt(I) complexes are also fairly common. Cobalt(II) salts form the red-pink [Co(OH₂)₆]²⁺ complex in aqueous solution. Adding excess chloride will also change the colour from pink to blue, due to the formation of [CoCl₄]^2-. Cobalt oxides are antiferromagnetic at low temperature: CoO (Neel temperature 291 K) and Co₃O₄ (Neel temperature: 40 K), which is analogous to magnetite (Fe₃O₄), with a mixture of +2 and +3 oxidation states. The oxide Co₂O₃ is probably unstable; it has never been synthesized. Other than Co₃O₄ and the brown fluoride CoF₃ (which is instantly hydrolyzed in water), all compounds containing cobalt in the +3 oxidation state are stabilized by complex ion formation.

see also Category:Cobalt compounds

[edit] Precautions

Powdered cobalt in metal form is a fire hazard.

Cobalt compounds should be handled with care due to cobalt's slight toxicity.

⁶⁰Co is a high-energy gamma ray emitter. Acute high-dose exposures to the gamma emissions, such as can occur when irradiation equipment is inadvertently diverted into scrap, can cause severe burns and death. Extended esposures increase the risk of morbidity or mortality from cancer.^[4]

Nuclear weapon designs could intentionally incorporate ⁵⁹Co, some of which which would be activated in a nuclear explosion to produce ⁶⁰Co. The ⁶⁰Co, dispersed as nuclear fallout, creates what is sometimes called a dirty bomb or cobalt bomb, once predicted by physicist Leó Szilárd as being capable of wiping out all life on earth.

[edit] References & notes

• Los Alamos National Laboratory: Cobalt

1. ^ Nuclides and Isotopes: Chart of the Nuclides, 16th Edition, by Edward Baum, Harold Knox, and Thomas Miller; Knolls Atomic Power Laboratory; 2002
2. ^ JPNM Physics Isotopes
3. ^ Encyclopedia Britannica Online.
4. ^ The Juarez accident

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

Από τη Βικιπαίδεια, την ελεύθερη εγκυκλοπαίδεια

Το χημικό στοιχείο Κοβάλτιο είναι ένα μέταλλο με ατομικό αριθμό 27 και ατομικό βάρος 58,9332 . Έχει θερμοκρασία τήξης 1495 C° και θερμοκρασία βρασμού 2870 C°. Το σύμβολό του είναι Co.

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

Fra Wikipedia, den frie encyklopædi

27 – ↑ Co ↓ Rh

Udseende Gråligt, sølvskinnende metal Generelt Navn(e): Kobolt Kemisk symbol: Co Atomnummer: 27 Atommasse: 58.933195(5) g/mol Grundstofserie: Overgangsmetal Gruppe: 9 Periode: 4 Blok: d Elektronkonfiguration: [Ar] 3d7 4s2 Elektroner i hver skal: 2, 8, 15, 2 Kovalent radius: 126 pm Kemiske egenskaber Oxidationstrin: 2, 3 (amfoterisk oxid) Elektronegativitet: 1,88 (Paulings skala) Fysiske egenskaber Tilstandsform: Fast Krystalstruktur: Hexagonal Massefylde: 8,90 g/cm3 Massefylde på væskeform: 7,75 g/cm3 Smeltepunkt: 1495 °C Kogepunkt: 2927 °C Smeltevarme: 16,06 kJ/mol Fordampningsvarme: 277 kJ/mol Varmeledningsevne: (300 K) 100 W·m–1K–1 Varmeudvidelseskoeff.: 13,0 μm/(m·K) Elektrisk resistivitet: (20°C) 62,4 nΩ·m Magnetiske egenskaber: Ferromagnetisk Mekaniske egenskaber Youngs modul: 209 GPa Forskydningsmodul: 75 GPa Kompressibilitetsmodul: 180 GPa Poissons forhold: 0,31 Hårdhed (Mohs' skala): 5,0 Hårdhed (Vickers): 1043 MPa Hårdhed (Brinell): 700 MPa

Kobolt (opkaldt efter bjergtrolden Cobold, som ifølge den folkelige overtro i Tyskland spillede bjergmændene et puds, når udsmeltning af malm slog fejl) er det 27. grundstof i det periodiske system, og har det kemiske symbol Co: Under normale temperatur- og trykforhold optræder dette overgangsmetal som et gråt og sølvskinnende metal, der er hårdere end stål, men samtidig også skrøbeligt og "sprødt".

[redigér] Kemiske egenskaber

Kobolt "opfører" sig i kemisk henseende omtrent som jern og nikkel; det angribes ikke af atmosfærisk luft. I kemiske forbindelser optræder kobolt almindeligvis med oxidationstrin +2 og +3, og ved sjældnere lejligheder med oxidationstrin +1.

Glas farvet med kobolt

[redigér] Tekniske anvendelser

Allerede for 4000 år siden blev koboltholdige mineraler brugt som blåt farvestof i Ægypten. Metallisk kobolt bruges i legeringer, f.eks. hurtigstål, hvor de medvirker til at gøre materialet slidstærkt og korrosionsbestandigt, eller tilføjer magnetiske egenskaber, der bruges i magneter (alnico) og magnetiske medier som magnetbånd og disketter.

Kobolts modstandsdygtighed overfor korrosion udnyttes ved at galvanisere andre metaller med det. Kobolt bruges også til elektroder i batterier, som katalysator for en række industrielle kemiske processer, og det indgår i stoffer der hjælper maling, lak m.v. med at tørre.

Den radioaktive isotop kobolt-60 udsender gammastråling: Denne stråling bruges til radioterapi, til at sterilisere ting, der ikke tåler høje temperaturer, og til at opdage strukturelle skader indvendigt i metalemner.

[redigér] Historie

Kobolt er i århundreder blevet brugt til at give glas, glasur og keramik en intens blå farve i mange forskellige kulturer verden over. Opdagelsen af kobolt som et grundstof blev gjort af den svenske kemiker Georg Brandt engang i perioden fra 1730 til 1737: Han fandt ud af, at kobolt var kilden til den blå farve i glas, og ikke som man troede dengang, bismuth, der ofte findes sammen med kobolt.

Op igennem det 19. århundrede stod Blaafarveværket i Norge for 70 til 80 procent af verdensproduktionen.

[redigér] Forekomst og udvinding

Kobolt findes ikke i "fri", metallisk form i naturen, men i form af forskellige malme, primært koboltit, erytrit, glaucodot og skutterudit. Koboltforekomster er ofte "blandet op" med andre metallers malme, og af den grund udvindes kobolt typisk som et biprodukt fra udvindingen af kobber og nikkel.

Det meste kobolt udvindes i den Demokratiske Republik Congo, Folkerepublikken Kina, Zambia, Rusland og Australien, men også Finland, Aserbajdsjan og Kazakhstan råder over forekomster. Og i Ontario i Canada findes byen Cobalt (det engelske navn for kobolt), hvor kobolt udvindes som et biprodukt fra sølv-udvinding.

Sammen med nikkel indgår kobolt i det jern, man finder i meteoroider.

[redigér] Kobolt i biologien

Pattedyr har brug for små mængder af kobolt-holdige salte i deres føde; omking 0,2 mikrogram kobolt om dagen. Blandt andet indgår kobolt i B12-vitamin.

For meget kobolt i kosten (20–30 μg pr. dag) giver anledning til hudsygdomme og forgiftingssymptomer i organerne. Da man i Canada brugte kobolt til at stabilisere skummet på øl, steg dødeligheden blandt ihærdige øl-drikkere af, hvad der blev kaldt for "canadisk øldrikker-hjerte"; hjertets muskulatur var blevet svækket af store doser kobolt. Siden er man gået helt bort fra at bruge kobolt i ølproduktionen.

[redigér] Isotoper af kobolt

Naturligt forekommende kobolt består af én stabil isotop, kobolt-59 — dertil kendes 22 radioaktive isotoper, hvoraf kobolt-60 har den længste halveringstid med 5,2714 år. De øvrige isotoper har halveringstider fra ca. 9 måneder og nedefter.

Kobolt-59 kan omdannes til det stærkt radioaktive kobolt-60, når det bombarderes med neutroner: Den såkaldte koboltbombe er et atomvåben, som er designet til at udvikle store mængder kobolt-60 og dermed forøge strålingen fra det radioaktive nedfald.

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

U Cobaltu (simbulu Co) hè u 27imu elementu chimicu. A so massa atomica hè 58,9332 g/mol è a so densità hè 8,89 g/cm3 . U Cobaltu hè statu scupertu in u 1735 da Brandt.

[edit] Riferimenti

• Listinu di l'elementi chimichi annantu à a wikipedia in talianu è in francese

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

ferro - cobalt - níquel CO Rh Ir
General
Nom, símbol, nombre	cobalt, Co, 27
Sèrie química	metall de transició
Grup, període, bloc	9 , 4 , d
Densitat, duresa Mohs	8900 kg/m3, 5.0
Aparença	metàl·lic amb tint gris
Propietats atòmiques
Pes atòmic	58,933200 uma
Radi mitjà†	135 pm
Radi atòmic calculat	152 pm
Radi covalent	126 pm
Radi de Van der Waals	Sense dades pm
Configuració electrònica	[Ar]3d74s2
Estats d'oxidació (Òxid)	2,3 (amfòter)
Estructura cristal·lina	Hexagonal
Propietats físiques
Estat de la matèria	Sòlid (ferromagnètic)
Punt de fusió	1768 K
Punt d'ebullició	3200 K
Entalpia de vaporització	376,5 kJ/mol
Entalpia de fusió	16,19 kJ/mol
Pressió de vapor	175 Pa a 1768 K
Velocitat del so	4720 m/s a 293,15 K
Informació diversa
Electronegativitat	1,88 (Pauling)
Calor específica	420 J/(kg*K)
Conductivitat elèctrica	17,2 106 m-1·ohm-1
Conductivitat tèrmica	100 W/(m*K)
1er potencial d'ionització	760,4 kJ/mol
2on potencial d'ionització	1648 kJ/mol
3er potencial d'ionització	3232 kJ/mol
4t potencial d'ionització	4950 kJ/mol
Isòtops més estables
iso. AN Període de semidesintegració CD ED MeV PD 56Co Sintètic 77,27 dies ε 4,566 56Fe 57Co Sintètic 271,79 dies e 0,836 57Fe 58Co Sintètic 70,86 d e 2,307 58Fe 59Co 100% Co és estable amb 32 neutrons 60Co Sintètic 5,2714 anys β- 2,824 60Ni
Valors en el SI d'unitats i en CNPT (0º C i 1 atm), excepte quan s'indica el contrari.

El cobalt és un element químic de nombre atòmic 27 i símbol Co situat en el grup 9 de la taula periòdica dels elements.

[edita] Característiques principals

El cobalt és un metall dur, ferromagnètic, de color blanc blavós. La seva temperatura de Curie és de 1388 K. Normalment es troba junt amb níquel, i ambdós solen formar part dels meteorits de ferro. És un element químic essencial per als mamífers en petites quantitats. El Co-60, un radioisòtop de cobalt, és un important traçador i agent en el tractament del càncer.

El cobalt metàl·lic està comunament constituït d'una mescla de dos formes al·lotròpiques amb estructures cristal·lines hexagonal i cúbica centrada en les cares sent la temperatura de transició entre ambdós de 722 K.

Presenta estats d'oxidació baixos. Els compostos en els que el cobalt té un estat d'oxidació de +4 són poc comuns. L'estat d'oxidació +2 és molt freqüent, així com el +3. També hi ha complexos importants amb l'estat d'oxidació +1.

[edita] Aplicacions

• Aliatges entre les que cal assenyalar superaliatges usades en turbines de gas d'aviació, aliatges resistents a la corrosió, acers ràpids, i carburs cementats i eines de diamant.
• Imans (AlNiCo) i cintes magnètiques.
• Catàlisi del petroli i indústria química.
• Recobriments metàl·lics per deposició electrolítica pel seu aspecte, duresa i resistència a l'oxidació.
• Assecant per a pintures, vernissos i tintes.
• Recobriment base d'esmalts vitrificats.
• Pigments (cobalt blau i cobalt verd).
• Elèctrodes de bateries elèctriques
• Cables d'acer de pneumàtics.
• L'Isòtop Co-60 s'usa com a font de radiació gamma en radioteràpia, esterilització d'aliments (pasteurització freda) i radiografia industrial per al control de qualitat de metalls (detecció de clavills).

[edita] Rol biològic

El cobalt en petites quantitats és essencial per a nombrosos organismes, inclosos els humans. La presència de quantitats entre 0,13 i 0,30 ppm en el sòl millora ostensiblement la salut dels animals de pasturatge. El cobalt és un component central de la vitamina B12 (cianocobalamina).

[edita] Història

Material de vidre acolorit amb cobalt

L'element va ser descobert per George Brandt. La data del descobriment varia en les diverses fonts entre 1730 i 1737. Brandt va ser capaç de demostrar que el cobalt era el responsable del color blau del vidre que prèviament s'atribuïa al bismut.

El seu nom prové del alemany kobalt o kobold, esperit maligne, anomenat així pels miners per la seua toxicitat i els problemes que ocasionava ja que igual que el níquel contaminava i degradava els elements que es desitjava extraure.

Durant el segle XIX, entre el 70 i 80% de la producció mundial de cobalt s'obtenia en la fàbrica noruega Blaafarveværket de l'industrial prussià Benjamin Wegner.

El 1938 John Livingood i Glenn Seaborg van descobrir el cobalt-60. La primera màquina de radioteràpia, bomba de cobalt, construïda al Canadà per un equip liderat per Ivan Smith i Roy Errington es va utilitzar en un pacient el 27 d'octubre de 1951; l'equip es troba actualment exposat en el Saskatoon Càncer Centre, a la ciutat de Saskatoon (Saskatchewan).

[edita] Abundància i obtenció

Mena de Cobalt

El metall no es troba en estat natiu, sinó en diversos minerals, raó per la qual s'extrau usualment junt amb altres productes, especialment com a subproducte del níquel i el coure. Les principals menes de cobalt són la cobaltita, eritrina, cobaltocalcita i skuterudita.

Els majors productors de cobalt són la Xina, Zàmbia, Rússia i Austràlia.

[edita] Compostos

A causa dels diversos estats d'oxidació que presenta, hi ha un abundant nombre de compostos de cobalt. Els òxids CoO (temperatura de Neel 291 K) i Co₃O₄ (temperatura de Neel 40 K) són ambdós antiferromagnètics a baixa temperatura.

[edita] Isòtops

El cobalt natural només té un isòtop estable, el Co-59. S'han caracteritzat 22 radioisòtops sent els més estables el Co-60, el Co-57 i el Co-56 amb períodes de semidesintegració de 5,2714 anys, 271,79 dies i 70,86 dies respectivament. En els altres isòtops radioactius són inferiors a 18 hores i la majoria menors d'1 segon. El cobalt presenta a més quatre metaestats, tots ells amb períodes de semidesintegració menors de 15 minuts.

La massa atòmica dels isòtops del cobalt oscil·la entre 50 uma (Co-50) i 73 uma (Co-73). Els isòtops més lleugers que l'estable (Co-59) es desintegren principalment per captura electrònica originant isòtops de ferro, mentres que els més pesats que l'isòtop estable es desintegren per emissió beta donant lloc a isòtops de níquel.

El cobalt-60 s'usa en radioteràpia en substitució del radi pel seu menor preu. Produeix dos rajos gamma amb energies d'1,17 MeV i 1,33 MeV i al ser la font emprada d'uns dos centímetres de radi provoca l'aparició de zones de penombra dispersant la radiació entorn de la direcció de radiació. El metall tendeix a produir una pols molt fina que dificulta la protecció enfront de la radiació. La font de Co-60 té una vida útil d'aproximadament 5 anys, però superat aquest temps continua sent molt radioactiu, per la qual cosa aquestes fonts han perdut, en certa manera, la seva popularitat a occident.

[edita] Precaucions

El cobalt metàl·lic en pols finament dividit és inflamable. Els compostos de cobalt en general han de manipular-se amb precaució per la lleugera toxicitat del metall.

El Co-60 és radioactiu i l'exposició a la seva radiació pot provocar càncer. La ingestió de Co-60 comporta l'acumulació d'alguna quantitat en els teixits, quantitat que s'elimina molt lentament. En una eventual confrontació nuclear, l'emissió de neutrons convertiria el ferro en Co-60 multiplicant els efectes de la radiació després de l'explosió i prolongant en el temps els efectes de la contaminació radioactiva; amb aquest propòsit es dissenyen algunes armes nuclears denominades bombes brutes (de l'anglès dirty bomb). En absència de guerra nuclear, el risc prové de la inadequada manipulació o manteniment de les unitats de radioteràpia.

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.

27 Желязо ← Кобалт → Никел - ↑ Co ↓ Родий
Химическа серия	метал
Група, Период, Блок	8Б, 4,
Външен вид	синьо-сив метал
Свойства на атома
Атомна маса	58,9332 u
Атомен радиус (calc)	135 (152) pm
Ковалентен радиус	126 pm
Радиус на ван дер Ваалс	... pm
Електронна конфигурация	[Ar]3d74s2
e- на енергийно ниво	2, 8, 15, 2
Оксидационни състояния (Оксид)	амфотерни оксиди (2, 3)
Кристална структура	хексагонална
Физични свойства
Агрегатно състояние	твърдо
Плътност	8,9 kg/m³
Температура на топене	1768 K (1495 °C)
Температура на кипене	3200 K (2927 °C)
Моларен обем	6,67*10-3 m³/mol
Специфична топлина на топене	16,19 kJ/mol
Специфична топлина на изпарение	376,5 kJ/mol
Налягане на парата	1000 Pa при 2423 K
Скорост на звука	4720 m/s при 293,15 K
Други
Електроотрицателност	1,88 (скала на Паулинг)
Специфичен топлинен капацитет	420 J/(kg·K)
Специфична електропроводимост	17,2*106 S/m
Топлопроводимост	100 W/(m·K)
Йонизационен потенциал	kJ/mol
Периодична система на елементите

Кобалт- химичен елемент с атомен номер 27. Той е твърд, блестящ сиво-син метал.

[редактиране] История

В 15 век в Саксония сред богатите на сребро руди често са откривани блестящи, като стомана, бели или сиви кристали, от които не се е удавало да се стопи метал; техните примеси в сребърните или медните руди пречела на изливането на тези метали. Най-вероятно, това са били съдържащи арсен кобалтови минерали - кобалтин CoAsS, или сулфиди на кобалта.

[редактиране] Произход на името

Наименованието на химичния елемент произлиза от немската дума „Kobold“ — „дух“, „джудже“.

При нагряване на съдържащи арсен кобалтови минерали се отделя отровен газ - арсенов оксид. Рудата, съдържаща тези минерали, получава от миньорите името на духа Коболд. Древните норвежци са приписвали отравянето при леене на сребро на номерата на този зъл дух. Вероятно, името на този дух е с един корен с гръцкото „кобалос“ — „дим“. С тази дума гърците наричали още и лъжците.

През 1735 година шведският минералог Георг Бранд успява да отдели от такъв минерал неизвестен до тогава метал, който той назовава кобалт. Той открива, че именно съединенията на кобалта оцветяват стъклото в син цвят.

[редактиране] Добив

Кобалтът е относително рядък метал. В най-голяма степен кобалт съдъжат никеловите руди.

Първо рудата се обогатява и се получава концентрат, който се обработва със сярна киселина или амоняк за извличане на метала.

[редактиране] Приложение

Основно кобалтът се изразходва за получаване на сплави, тъй като повишава температурната устойчивост на стоманата. Той също така участва в някои твърдостопяеми сплави за изработването на режещи инструменти.

Особено важни са магнитните сплави на основа на кобалта, от които се изработват ламели за трансформатори и електрически двигатели.

Използването на кобалт при производството на стъкло го оцветяват в синьо.

Кобалтът се използва и за пигмент в някои бои.

[редактиране] Физични свойства

Кобалтът е твърд метал, съществуващ в две модификации. В диапазона на температурите от стайна до 427 °C устойчива α-модификация. В диапазона от 427 °C до температурата на топене (1495 °C) устойчива β-модификация. Кобалтът е феромагнетик, точка на Кюри - 1121 °C.

Тънкият слой окис му придават жълтеникав оттенък.

BW Bewise Inc. Willy Chen willy@tool-tool.com bw@tool-tool.com www.tool-tool.com skype:willy_chen_bw mobile:0937-618-190 Head &Administration Office No.13,Shiang Shang 2nd St., West Chiu Taichung,Taiwan 40356 TEL:+886 4 24710048 / FAX:+886 4 2471 4839 N.Branch 5F,No.460,Fu Shin North Rd.,Taipei,Taiwan S.Branch No.24,Sec.1,Chia Pu East Rd.,Taipao City,Chiayi Hsien,Taiwan

Welcome to BW tool world! We are an experienced tool maker specialized in cutting tools. We focus on what you need and endeavor to research the best cutter to satisfy users’ demand. Our customers involve wide range of industries, like mold & die, aerospace, electronic, machinery, etc. We are professional expert in cutting field. We would like to solve every problem from you. Please feel free to contact us, its our pleasure to serve for you. BW product including: cutting tool、aerospace tool .HSS Cutting tool、Carbide end mills、Carbide cutting tool、NAS Cutting tool、Carbide end mill、Aerospace cutting tool、Carbide drill、High speed steel、Milling cutter、Core drill、Tapered end mills、Metric end mills、Miniature end mills、Pilot reamer、Electronics cutter、Step drill、Metal cutting saw、Double margin drill、Gun barrel、Angle milling cutter、Carbide burrs、Carbide tipped cutter、Chamfering tool、IC card engraving cutter、Side cutter、NAS tool、DIN tool、Special tool、Metal slitting saws、Shell end mills、Side and face milling cutters、Side chip clearance saws、Long end mills、Stub roughing end mills、Dovetail milling cutters、Carbide slot drills、Carbide torus cutters、Angel carbide end mills、Carbide torus cutters、Carbide ball-nosed slot drills、Mould cutter、Tool manufacturer.