finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

HomeFAQsBooksHelpWantedAdvertiseForum
topic 9387

I NEED DEFINITIONS ON SOME BASIC ELECTROPLATING LINGOS


(2001)

I am a student and needs some basic information or definition on the following processes:

(1) Conversion Coating

(2) Black Oxide

(3)Zinc Whiskers

What is the difference between chromate and dichromate? What is the purpose of both? Why do we use black oxide? From what I heard it does not offer an excellent corrosion protection.Why can't chrome be barrel plated.

Hey this is all I will ask from all you experts and pro for now(<;)

Thanks you,

Rishie Jhapps
- TORONTO


(2001)

Metal finishing, like any other field, has its lingo and shorthand. But sometimes a piece of lingo or shorthand only has a specific meaning within a specific context.

To a zinc plater, conversion coating means the process where chromates are applied to the zinc plated surface. To an aluminum processor, conversion coating means the process where chromates are applied to the aluminum. To a painter or powder coater, conversion coating means phosphatizing. But in general, it is a non-electrified process wherein the substrate takes part in the reaction. But, as I say, it's contextual: some people consider aluminum anodization (which is an electrolytic process) to be a conversion coating process.

Black oxide usually means an oxidation process applied to steel to give it a shiny black finish and a modicum of corrosion protection. It is performed in hot, concentrated caustic solutions containing an oxidizing agent.To circuit board platers, though, it's something totally different and involves, I believe, oxidation of the copper for better interlayer bond strength.

It is believed that metal coatings attempt to relieve internal stresses by reconstituting themselves as shoots or whiskers. This has long been a problem with tin plating. It has likewise been a known phenomena with zinc plating, but in the old days when things were bigger, zinc whiskers were not much of a problem. With miniaturization, these tiny whiskers are far bigger in proportion and are causing problems. Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2001)

I am also interested in Zinc Whiskers. I am having trouble with zinc possibly coming off of a raised floor in a computer room and bridging gaps in the power supply. This causes the power supply to fail. Is there any way to accelerate the growth of these zinc whiskers, or come up with a way to find them?

Paul Hilgeman
- Waukesha, Wisconsin, USA



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.