Nickel powders are produced by electrochemical precipitation from aqueous solutions of metal salts, followed by drying and heat treatment in a reducing environment, in accordance with the requirements of the technical specifications:
- ТУ 1793-001-07622839-2002, mark ПНЭ-1, ПНЭ-1 «Lux»;
- ТУ 1793-005-07622839-2003, mark А-2;
- ТУ 1793-007-07622839-2004, mark АЭ-II-БТ
They are used in powder metallurgy, as a binder based on nickel, for corrosion-resistant or non-magnetic grades of hard alloys, in the production of magnets, batteries, filter elements, electrical contacts, special coatings, dyes, catalysts, welding electrodes, composite adhesives, ferrites, and when creating wear-resistant coatings on aircraft engine parts.
Nickel electrodes made of the finest powders are also used in fuel cells. Here, the catalytic properties of nickel and its compounds are of particular importance. Nickel is an excellent catalyst for complex processes occurring in chemical sources of current.
Investigations of the morphology and crystal-chemical characteristics of nickel powders, demonstrated by the Institute of Solid State Chemistry of the Ural Branch of the RAS using X-ray diffraction and scanning electron microscopy (SЭМ) on electron microscopes JEOL JSM 6390 LA и Zeiss NEON 40, showed that electrolytic nickel powders are nanostructured.
SЭМ images of electrolytic nickel powder show a coral-like dendritic structure of intergrown powder particles.
With an increase of 10 thousand times, it can be seen that the intergrown particles 2-3 μm long and 0.5 to 1.0 μm thick are placed like needles on spruce branches 10-15 μm in length.
A more detailed SEM study of the powder, with an increase of 50,000 times, showed the presence of a multitude of particles with dimensions of 100 nm.
|Type of powder||The average particle diameter (dsp) / median of the distribution (dm), μm *||Mass fraction of particles (%), indicated particle sizes μm **||Bulk density, ρн, g/cm³|
|A-2||(19,6±4,0)/(17,5±)||90÷93 7||7÷10||-||1,4 ÷ 1,6|
*Definitely by sedimentation method
**Specifically, the methods of sieve analysis
|Ni, not less than,% of mass||Content of elements, not more than% mass|