High purity micron and sub-micron scale nickel materials have been mass-produced by the nickel carbonyl process for many decades. The same technology is being explored for mass production of nano-scale nickel products. The paper presents an overview of nickel carbonyl technology suitable for mass production of nano-scale nickel powders with surface areas exceeding 100 m2/g, and various three-dimensional nickel based micro structures. The industrial processes are based on the homogeneous decomposition of carbonyl in the free space of a CVD reactor and on the heterogeneous decomposition of carbonyl on a variety of substrates, including polymer foams and carbon fibres.