Electroless copper flash on zincate

A. Sorry, Peter, I've personally never heard of that. But an alkaline electroless nickel strike prior to the electrolytic nickel plating should work fine.

Sorry, Peter, I thought that when I said I've personally never heard of a process, I was implying that I can't answer questions about it :-)

I suspect that it will not work, because I suspect that zinc is not catalytic to electroless copper but, again, I don't know that for a fact.

Where and why would you need cyanide? What alternate cyanide-bearing process did you have in mind? If you're simply trying to eliminate cyanide in your shop, what is wrong with the alkaline electroless nickel strike which I previously suggested and which eliminates the need for cyanide by eliminating the use of cyanide copper?
Do you need copper on the parts for some reason? What are the parts, what are you trying to do? We ask that you please post details of your situation because it is so hard to productively reply to abstract questions where 90% of the situation is held in reserve, such that any answer requires endless ifs-ands-&-buts and usually leads to lost motion anyway :-)

A. Nickel Glycolate Strike

There, now in a few weeks, this letter should be picked up by finishing.com search engine, so I can find it when I need it.

Guide ASTM B253 Standard Guide for Preparation of Aluminum Alloys for Electroplating

Copyright 2001 AMERICAN SOCIETY FOR TESTING AND MATERIALS, West Conshohocken, PA. All rights reserved.

1. Scope

1.1 This guide covers cleaning and conditioning treatments used before metal deposition (Section 5), and immersion deposit/strike procedures (Section 6) that enhance the adhesion of metals that are subsequently applied to aluminum products by electrodeposition or by autocatalytic chemical reduction.

1.2 The following immersion deposit/strike procedures are covered:

1.2.1 Zinc immersion with optional copper strike (6.3).

1.2.2 Zinc immersion with neutral nickel strike (6.4).

1.2.3 Zinc immersion with acetate-buffered, nickel glycolate strike (6.5).

1.2.4 Zinc immersion with acid or alkaline electroless nickel strike.

1.2.5 Tin immersion with bronze strike (6.6). etc, etc.

A. Pete: Your concern seems to be about cyanides. What I don't understand is why do you want to have copper between aluminum and nickel. As Tom stated, there are several ways to prepare aluminum for electronickel plating that don't use cyanide in any form. I would go for a zincate followed by EN, then an acid nickel strike to activate EN, then straight to your conventional electrolytic nickel bath. Let us know about your outcome ... and good luck.