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About TungstenTungsten, (or Wolfram as it is known in many parts of the world) is an extremely hard and very dense gray to white metallic element extracted from wolframite, scheelite and other minerals. Tungsten has the highest melting point, lowest coefficient of expansion and lowest vapor pressure of any metal. It is also corrosion resistant and does not break down or decompose. Due to its unique attributes tungsten has few, if any, replacements in a majority of its industrial applications.HARDNESS
- Second only to diamond (tungsten carbide)
- Industrial applications - high speed cutting tools, heavy machinery, specialty alloys
HEAT RESISTANCE - Highest melting point and lowest coefficient of expansion of all metals
- Industrial applications - jet turbine engines, light bulb filaments
DENSITY - Greater than lead and uranium
- Industrial applications - sporting goods (golf clubs, tennis racquets, darts), ballast
ENVIRONMENTALLY BENIGN - Does not break down or decompose
- Industrial applications - sports fishing weights, shotgun shot, new applications being developed as an alternative to lead
About MolybdenumReferences:
Molybdenum (from the Greek meaning "lead-like"), is a chemical element with the symbol Mo and atomic number 42. It has the sixth highest melting point of any element, and for this reason it is often used in high-strength steel alloys. Molybdenum is found in trace amounts in plants and animals, although excess molybdenum can be toxic in some animals. Molybdenum was discovered in 1778 by Carl Wilhelm Scheele and first isolated in 1781 by Peter Jacob Hjelm.Characteristics:
Molybdenum is a transition metal with an electronegativity of 1.8 on the Pauling scale and an atomic mass of 95.9 g/mole. It does not react with oxygen or water at room temperature. At elevated temperatures, molybdenum trioxide is formed in the reaction 2Mo + 3O2 -> 2MoO3.
In its pure metal form, molybdenum is silvery white and very hard, though it is somewhat more ductile than tungsten. It has a melting point of 2623°C, and only tantalum, osmium, rhenium and tungsten have higher melting points. Molybdenum burns only at temperatures above 600°C. It also has the lowest heating expansion of any commercially used metal.Applications:
The ability of molybdenum to withstand extreme temperatures without significantly expanding or softening make it useful in applications that involve intense heat, including aircraft parts, electrical contacts, industrial motors, and filaments. Molybdenum is also used in alloys for its high corrosion resistance and weldability. Most high-strength steel alloys are .25% to 8% molybdenum. Despite being used in such small portions, more than 43×106kg of molybdenum is used as an alloying agent each year in stainless steels, tool steels, cast irons, and high temperature superalloys.
Because of its lower density and more stable price, molybdenum is implemented in the place of tungsten. Molybdenum can be implemented both as an alloying agent and as a flame-resistant coating for other metals. Although its melting point is 2623 °C, molybdenum rapidly oxidizes at temperatures above 760 °C, making it better-suited for use in vacuum environments.
Molybdenum disulphide (MoS2) is used as a lubricant and an agent. It forms strong films on metallic surfaces, and is highly resistant to both extreme temperatures and high pressure. Sodium molybdate is a bright orange pigment used with ceramics and plastics. Molybdenum trioxide (MoO3) is used as an adhesive between enamels and metals. Molybdenum powder is used as a fertilizer for some plants, such as cauliflower.
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