Powder production

Uniquely compared to other powder suppliers, LPW Technology offers powder manufactured by several different methods. Each process has distinct advantages and disadvantages. The common processes are explained below. However, for specific enquires, including information on our range of pre-blended Tungsten Carbide containing Cobalt and Nickel matrix powders, please contact us directly.

Methods of Powder production

Gas atomisation

The most common method of powder production. Elemental feedstock is melted under an air or inert gas blanket, or under vacuum. The chamber is then backfilled with gas to force molten alloy through a nozzle where high velocity air, N, He or Ar gas impinges onto the flowing melt and breaks it up. Powder is mostly spherical, with some asymmetric particles and satellites present. A satellite is when a smaller particle sticks to a larger one during solidification. Heat sizes range from 5kg to 3000kg. Size ranges from 0 to 500 micron. Yield within 20-150 micron range varies from 10 to 50% of total. Mostly used for Ni, Co and Fe alloys, also available for Ti and Al alloys.

gas-atomised

Water atomisation

Similar to gas atomisation but water is employed as the atomising medium. Used mostly for unreactive materials such as steels, it produces irregular shaped particles.

Plasma atomisation

A relatively new technique that produces high quality and extremely spherical powder. Wire feedstock is fed into a plasma torch that with the aid of gases atomised the powder. Size ranges from 0 – 200 micron. Limited to alloys that can be formed into a wire feedstock.

plasma-atomised

EIGA (Electrode Induction melting Gas Atomisation)

Works with all alloys but is most economic with reactive alloys like Ti. Feedstock, in the form of bar, is rotated and melted by an induction coil. A film of molten metal flows downwards into a gas stream for atomisation. Therefore, material does not come in contact with either crucible or electrode during process. Powder size is 0 to 500 micron and morphology is similar to gas atomised. Process is cheap, clean, good for small batches and produces small diameter powder.

 

eiga

 

PREP (Plasma Rotating Electrode Process)

Similar to EIGA process but the rotating feedstock bar is melted when it comes into contact with a plasma. Powders are extremely spherical but yields are limited below 100 micron, so price can be very high.

Centrifugal atomisation

A simple process that is not in wide-spread use. A good compromise between Gas Atomised and Plasma Atomisation. Generates powder that is more spherical and has lower entrapped gas porosity than Gas Atomisation but not to the quality of Plasma Atomisation or PREP. However, is cheaper than both PREP and Plasma Atomisation. Best suited to larger batch sizes of less reactive low melting temperature alloys, but can also make Nickel superalloys.

Plasma Spheroidisation

LPW Technology uses high energy plasma to produce highly spherical and dense metallic powders. LPW’s system uses plasma to transform agglomerated powders produced by spray drying or sintering techniques, or angular powders produced by conventional crushing methods, into spherical powder. Powder is gravity fed from the top and it is sprayed through the plasma by using various nozzle types depending on specific powder characteristics. Individual powder particles are completely melted and solidify in a spherical shape. Plasma treated powder is fully dense and highly spherical. Surface contamination is also significantly reduced through the vaporisation of impurities.

At LPW we have a high level of expertise in Additive Manufacturing (AM) and a long experience of working with leading companies within the aerospace, biomedical, and automotive industries. We utilise this knowledge and the capabilities of plasma technology to produce highly spherical and low contamination powders:

  • High melting temperature refractory metals such as Ta, W, Nb, and Mo
  • Customer specific metallic and ceramic compositions
  • Improve flowability and reduce contamination levels of standard products produced by gas or water atomisation
  • Reconditioning of metallic powders that have been used several times within an AM machine. Powder purity, morphology, and surface contamination change during use, especially Oxygen, Nitrogen, and Hydrogen

plasmaatomisation

Technical library

Information about the standard Additive Manufacturing powders provided by LPW Technology.

Case studies

Research undertaken into how powders and machine parameters can affect final build and environmental effects on powder composition.

Brochures

Our brochures provide an overview of Additive Manufacturing powders and services from LPW Technology, download them here.

Research & development

Details of the pioneering programmes of collaborative research LPW Technology is working on with partner organisations.