Fall 1992
Nickel Etching Economics
This paper effectivelx extends earlier work on ~tchant
regeneration systems, regeneration being the process by
which “spent” elehanl is oxidized back to a reusable form in order
10 maintain a consistent etch rate and product quality in the etch
bath. In these two papers the etching of iron with ferric chloride
was considered as a model for an economical and technical
assessment of various etchant regeneration techniques and
various conclusions were drawn as to the effectiveness of the
different techniques according to the volume of metal etched per
annum, Apart from maintaining etchant quality, regeneration was
cited as a means to reduce the problems and costs associated with
the correct waste disposal procedures required by legislation and
also as a means of reducing downtime spent on emptying.
cleaning and refilling etching machines.
Although iron/ferric chloride was the most logical model to
start with in order to explain the principles. iron is rarely etched in
industry unless alloyed with other elements. However, other
metals and alloys complicate the model, especially where the
contamination through build-up of by-products is unacceptable. This paper extends the chloride system. Two nickelalloys,
Invar (36% Ni and the balance predominantly Fe) and 42alloy
(42% Ni, balance Fe) are considered in particular. The
economical and technical aspects of etchant regeneralion are
discussed together with the possibility of metal recovery.
Dr. David Allen and Heather J.A. White, Cranfield Institute of Technology
