Molybdenum Metal & Molybdenum Alloys

Molybdenum metal is usually produced by powder metallurgy techniques in which Mo powder is hydrostratically compacted and sintered at about 2100°C. Hot working is done in the 870-1260°C range. Moly forms a volatile oxide when heated in air above about 600°C and therefore high temperature applications are limited to non-oxidizing or vacuum environments.

Molybdenum alloys have excellent strength and mechanical stability at high temperatures (up to 1900°C). Their high ductility and toughness provide a greater tolerance for imperfections and brittle fracture than ceramics.

Molybdenum Alloys

The unique properties of molybdenum alloys are utilised in many applications:

-High temperature heating elements, radiation shields, extrusions, forging dies, etc;

-Rotating X-ray anodes used in clinical diagnostics;

- Glass melting furnace electrodes and components that are resistant to molten glass;

-Heat sinks with thermal expansivity matching silicon for semiconductor chip mounts;

- Sputtered layers, only Ångstroms (10-7 mm) thick, for gates and interconnects on integrated circuit chips;

- Sprayed coatings on automotive piston rings and machine components to reduce friction and improve wear.

Molybdenum Electrodes

For specialised applications, Mo is alloyed with many other metals:

Mo-tungsten alloys are noted for exceptional resistance to molten zinc;

Mo is clad with copper to provide low expansion and high conductivity electronic circuit boards;

Mo-25% rhenium alloys are used for rocket engine components and liquid metal heat exchangers which must be ductile at room temperature.

Brief Introduction To Molybdenum Electrode

Molybdenum (Mo) is commonly used as back contacts for Cu(In,Ga)Se2(CIGS) thin film solar cells because it has the good electrical properties of an ohmic contactand is an inert, mechanically durable substrate duringthe absorber film growth. In general, Mo is deposited bydc sputtering onto soda-lime glass substrates. The elec-trical and the mechanical properties of sputtered refrac-tory metal films are known to vary with the working gaspressure . 

CIGS thin film growth occurs at tempera-tures > 500  and at these temperatures, the thermallyinduced extrinsic stresses in the glass-Mo structure maycause bending or mechanical distortion of substrate .During the formation of CIGS films, Na ions diffuse fromthe soda-lime glass substrate through the Mo back con-tact into the absorber layer. The diffusion of Na into theabsorber film depends on the deposition conditions of theMo back contact .

Molybdenum Electrodes

Molybdenum films were deposited on soda-lime glass substrates by using DC magnetron sputtering. Their structural and morphological properties and their electrical resistivities were analyzed with respect to the working gas (Ar) pressure. The electrical resistivity of the Mo films monotonically increased as the gas pressure was increased. The films showed a (110) preferred orientation,regardless of the working gas pressure. The surface morphology of the films changed from an elon-gated grain structure at lower working pressures to a porous nodular shape at higher pressures.The surface roughness of the films increased with the working gas pressure. Secondary ion mass spectrometry data showed that Na diffusion from the soda lime glass substrate through the Moback contact was high, for the film sputtered at 5 mTorr. Cu(InGa)Se2 solar cells fabricated on Mofilms sputtered at 5 mTorr showed the best conversion efficiencies.

Molybdenum Disc

Molybdenum Disc Characteristics:


They have smooth and clean surface, their flat roughness is down to Ra 1.6.
They have good conductions, small linear expansion coefficient and good heat-resistance.

Specifications:
Diameter Range:  7 ~ 100mm    
Thickness Range:  0.8 ~ 4.0mm.
Square Piece:  4 ~ 25mm2          

Molybdenum Disc

Thickness:  0.5 ~ 1.5mm
Parameters:
Density:  10.15g/cm3    Resistivity:  Less than 6.26 × 10-6Ωcm.
Linear Expansion Coefficient:  4.0 × 10-6K-1 ~ 6.4 × 10-6K-1.

Molybdenum Disc Applications:
Be made to the thyristor silicon parts and its electric parts supporting base material..

Molybdenum Pollution

The average contents of molybdenum is 1.3 PPM, in the earth crust。Fossil fuels containing molybdenum in natural water body is in very low concentrations, and molybdenum in sea water of the average concentration is 14 micrograms/l.

Molybdenum

But due to the Human activities widely used molybdenum and burning of molybdenum content fuel , so increase the molybdenum in the environment circulation.

What is more Weathering make the molybdenum released from the rock. Molybdenum distribution are not regularly, thus cause some areas lack of molybdenum and appear "water and soil disease".