Nickel Etching Economics

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