Production Techniques and Physical and Technological Properties of Nickel Powders (Review)

The paper presents a comprehensive analysis of leading trends in nickel powder production techniques. The physical and technological properties of nickel powders are systematized according to chemical composition, average size and morphology of particles and their agglomerates, specific surface area, and apparent density. These data will be useful to potential consumers for the optimal design of functional properties of nickel powder products. The review compares industrial and modern techniques, focusing on their key advantages and disadvantages. The development of new process methods and techniques, such as reduction of nickel oxides with hydrogen in fluidized bed reactors and rotary furnaces, is demonstrated. Various methods for synthesizing nanosized nickel powders for special applications, being at the laboratory research stage, are considered. These methods include deposition and thermal decomposition from solutions using various precursors, synthesis under microwave radiation, laser ablation, plasma chemical synthesis, green synthesis, etc. The properties of powders produced by the reduction of nickel precursors with hydrazine, alkali metal borohydrides, polyols, urotropine, polystyrene, etc. are analyzed. Environmetal and human health concerns related to nickel powder production methods are briefly discussed. Carbonyl, electrolytic, and hydrometallurgical methods allow the production of nickel powders in large quantities but involve high energy consumption and production toxicity. Wet chemistry methods for producing nanosized nickel powders use various toxic chemical reagents, potentially causing environmental issues when implemented industrially. Hydrogen reduction of nickel oxide, as an environmentally friendly method, offers unconditional advantages, including reduced greenhouse gas emissions and zero solvent waste.