Canadian Patent Application No.: CA 2307036
A closed loop, carbon monoxide self-contained preferably continuous process and apparatus for the production of nickel or nickel coated objects by nickel vapour deposition (NVD), comprising placing an object (34) to be treated with nickel carbonyl in a deposition chamber (28); feeding a gaseous mixture of nickel carbonyl and carbon monoxide to the chamber; producing the nickel or nickel coated object and a nickel carbonyl-depleted gaseous mixture; removing nickel carbonyl from the nickel carbonyl-depleted gaseous mixture in a primary (40) and subsequent secondary (48, 50) condensation unit and, preferably, a tertiary condensation unit to produce an essentially nickel carbonyl-free gas.
The secondary and tertiary (72, 74) condensation units operably freeze out and subsequently thaw nickel carbonyl and most preferably each comprises a pair of units linked in parallel arrangement operative in alternating, alternate freeze-thaw modes. Carbon monoxide-containing gas is recycled to a nickel carbonyl reactor (86).