IPMD 14th Edition 2010-2011, 10 pages, 7181 words

Author: Dr Oleg Neikov, Institute for Problems of Material Science, Kiev, Ukraine

The following review highlights the main methods used for production of copper, aluminium, titanium and nickel powder, including key powder properties. The review updates that written by Professor Oleg Neikov from the Institute for Problems of Materials Science in Kiev, Ukraine and published in the 12th Edition International Powder Metallurgy Directory.

The relationship of non-ferrous powder to ferrous powder shipments in tonnage terms is about one to four. However, in market value terms aluminium, silver and zinc are all close to the value of iron powders [1, 2] Whilst the bulk of ferrous powders are produced by water atomisation of liquid steel, the methods used to produce the various non-ferrous powders are numerous. For example, non-ferrous powders are produced by mechanical, chemical and electrochemical methods. The comminution of solid metals and alloys is done by milling in impact mills, ball, vibration and edge-runner mills, attritors and jet mills. The dispersion of melts includes granulation, atomisation and mechanical separation.

General chemical methods comprise the precipitation from a gaseous phase, carbonyl and reduction methods. The electrochemical methods include electrolysis and cementation.

The present review focuses on production and properties of copper and copper alloy powders, aluminium, nickel and titanium powders produced by various widely used and also new advanced methods. Atomisation is the most common method that allows the production of powders over a wide range of compositions and in a wide variety of powder particle sizes from the few microns to a few mm. Chemical and electrolytic methods are widely used for producing high-purity and fine powders. One of the basic methods for the production of nanopowders is extraction from gaseous phase. The disintegration (milling) of solid non-ferrous metals has significant limitation due to the ductility of most of them. Nevertheless, milling in high-energy apparatus such as attritors finds many applications for mechanical alloying of powders.

Atomisation

Because of the simplicity of the breakup of a liquid stream into fine droplets, atomisation has become the prevailing production method for many non-ferrous metals and their alloys. Currently, the worldwide atomisation capacity for non-ferrous metal powders amounts 106 metric tons/year [2]. Atomisation also allows the manufacture of new types of rapidly solidified powders attaining properties not achievable by traditional metallurgy. The general types of atomisation processes include.....

Further sections of this article include:

• Atomisation
  - Gas atomisation
  - Water atomisation
• Nanopowders
• Copper and copper alloy powders
  - Oxidation-reduction process
  - Electrolytic processes
  - Atomised copper powders
• Copper alloys
• Ultrafine copper powders
• Aluminium and aluminium alloy powders
• Titanium powder
  - Chemical reduction process
  - Hydride/dehydride process
  - Electrode-Oxidation (EDO) process,
  - Armstrong Process
  - Gas atomisation process
  - Plasma-rotating electrode process (
  - Plasma atomisation process
  - Plasma Meting Induction Guiding Gas Atomisation (PIGA)
• Nickel and nickel alloy powders
  - Carbonyl processes
  - Hydrometallurgical processing
  - Atomisation
  - Electrolytic method
  - Mechanical alloying

Figures and Tables:

Fig. 1 Free-fall atomiser type with binary water cone configuration [4]

Fig. 2 Schematic of close-coupled atomiser type (gas atomisation only).

Fig. 3 Principle of the internal mixing nozzle

Fig. 4 Pressure-swirl hybrid prefilming atomiser [6]

Fig. 5 ‘ANVAL Atomiser 1’ designed for producing large tonnages of alloy powders (Courtesy ANVAL)

Fig. 6 Schematic of microlayered material deposition on gas turbine blades [8]

Fig. 7 Material evaporation process following by condensation: (a), from one source; (b), from two sources [12]

Fig. 8 Installation UE-204 of the E.O.Paton Electric Welding Institute International centre for electron beam technologies used for electron beam evaporation and following physical vapour deposition in vacuum and the manufacture of various materials & components (Courtesy Prof B.A.Movchan)

Fig. 9 Model CGS 16 fluidised bed jet mill (Courtesy NETZSCH-Feinmahltechnik, Germany)

Fig. 10 SEM micrograph (at different magnifications) of Nanotech (Korea) commercially manufactured WC-10 wt%Co nanopowder produced by spray drying of liquid sources, subsequent hydrogen reduction and carburisation [16]

Fig. 11 Electrolytic cell for copper powder production.

Fig. 12 Production plant for electrolytic precipitation of copper (Courtesy Ecka Granules, Germany)

Fig. 13 Electrolytic copper powder particles are dendritic in shape giving high specific surface area and green strength

Fig. 14 Ultrafine MicroTronic 100 copper powder produced by the wet chemical precipitation method

Fig. 15 (left), Ultrafine copper powder 110 produced by wet process; (right), ultrafine Cu 1200YP grade powder (Courtesy Mitsui Mining, Japan)

Fig. 16 Liquid metal flow at the tip of a confined nozzle during atomisation process

Fig. 17 Schematic illustrating the developed water atomisation technology for aluminium alloy powders

Fig. 18 Ultimate tensile strength ranges of the aluminium alloys made from water atomised powders

Fig. 19 SEM micrographs: (left), Ti sponge fines made by sodium thermic process [34]; (centre), Ti-6Al-4V powder made by the plasma rotating electrode process [34]; (right), Ti powder made by plasma atomisation process [Ref 38]

Fig. 20 Scanning electron micrograph of typical acicular shape “heavy” powder produced by carbonyl decomposition

Fig. 21 Scanning electron micrograph of linked particle nickel powder type produced by carbonyl decomposition

Fig. 22 Vale Inco’s Type 123 nickel powder (Courtesy Vale Inco, USA)

Fig. 23 Scanning electron micrograph at lower (a) and higher (b) magnifications of quasi cubic shape powder Norilsk Nickel type UT3 for PM application (Courtesy Norilsk Nickel, Russia)  

Table 1 Properties of typical commercial grades of copper powders produced by oxide reduction, electrolytic process and atomisation

Table 2 Properties of typical commercial grades of copper alloy powders

Table 3 Properties of typical commercial atomised aluminium powders

Table 4 Typical chemical analysis and technological characteristics of chemical reduction process titanium sponge fines and sintered Ti-6Al-4V produced from these fines and Al-V master alloy powders