Preparation of fine nickel powders via reduction of
nickel hydrazine complex precursors
(1. Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China;
2. Department of Materials Science and Engineering, Missouri University of Science and Technology,
223 McNutt Hall, Rolla, MO 65409, USA)
2. Department of Materials Science and Engineering, Missouri University of Science and Technology,
223 McNutt Hall, Rolla, MO 65409, USA)
Abstract: Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.
Key words: multilayer ceramic capacitors; chemical reduction; nickel hydrazine complex; nickel powders; precursor