Copper Plating of Knife Blade with No Electricity

You must have removed the chromium and/or nickel plate, and revealed the copper coating underneath...

http://www.verneschromeplating.com/chrome-plating.html

The blade was not chrome plated.It is solid stainless steel.The copper came off after working it on a stone.No copper plating on this blade, or it would have revealed itself in prior sharpening.

Then it was probably just stained from the chemicals....some sort of reaction....

You have a cathode and copper ions available to migrate onto the knife blade.

Or, is it an anode?

Don't remember.

It's chemistry 101.

It's galvanic something or other.

Can you duplicate it consistently? May have a new plating process here.

The post is led. the blade is stainless. Wet crud is a salty electrolyte.

As soon as the blade metal touches the post in the crud: Instantaneous classical electrodeposition.

Need to know if the post clamps on your batteries are made of lead or copper (bronze)

The post clamps are stainless steel studs with ss nuts.The cable terminals are copper.

These are golf cart batteries, and have bolts instead of clamps like automotive batteries have.

The battery posts,as normal,are lead.

The cables were removed,both ends,while cleaning.

No contact with battery when cleaning.

You've made an assumption and stated it as fact, but your later remarks don't match, so i have a question and hypothesis for you.

Lead (Pb) terminals and SS cable terminations but you describe initially "copper-laden crud" on the terminals. where did that come from? Is it really copper? Is the cable end exposed allowing copper corrosion on the batteries? (probably)

Whatever it is, the residue has reacted with the knife blade and as previously stated there has been a galvanic depositionof copper and some other metalic portion has migrated from your knife blade alloy into the crud layer.

The reaction is "chemical" in nature (yes at microscopic level it is electrical interaction) and quite normal. Such action can also cause localised pitting (not acid etch) especially where larger grains of such materials are concentrated. you may have neutralised the acids, but still had a reactive salt solution present. During the scraping process, you also had lead, SS, your knife blade, the blade sheath/springs/rivets etc all potentially involved in a damp environment. Galvanic transfer!

Allow me to elaborate:

The batteries have lead posts that have screw terminals, consisting of an imbedded ss threaded stud,and a ss nut.The cables, 750 MCM, are copper,with copper ring terminals factory crimped onto the copper wire.The ring terminals once had a tin plating, but it has been eaten away by the acid.The green crud,("copper laden",by my own description,because copper usually corrodes to a greenish color). The copper evidently is from corrosion of the copper terminal and wire.

If you have never seen the batteries on a golf cart it is hard to visualize what I am talking about,they are a deep cycle battery, similar to a marine battery.

THANKS! Just what I needed.

I didn't deserve that Good Answer....even though I work with this stuff every day, it could be alchemy as far as I know. There is some sort of galvanic thing going on within its own solution is all I know.

I remember doing an experiment a long time ago in chemistry. Put a nail in a copper salt solution (copper sulphate or chloride). The iron dissolves and the copper plates out as iron ions replace the copper ions in the solution.

#1: you mention pitting on your ferromagnetic steel blade

#2: you mention copper deposits

Here is the answer: Electrolyte is present, copper salts are present, moisture is present, ferromagnetic steel is always anodic with respect to copper metal, therefore, some of the steel leaves as ferrous ion, whilst copper is deposted on larger cathodic areas of the steel. This kind of steel generally corroded at mild pH with localized anodes and larger cathodic areas. Thus you could easily see large areas of the blade where copper deposited.

I'm still trying to figure out how you were able to attain guru status but good for you

All it takes is perseverance.

As should be obvious, it takes no special intelligence to attain the exalted status of Guru.

After all, I are one!

I admit it was a wisecrack remark.....I actually have no idea what the parameters are to gain the status nor do I care

Guru is simply anybody who has posted 500 times, or more.

What you didn't read the FAQ's? No? That puts you in the supermajority.

of course I didn't. my VCR HAS BEEN FLASHING "1200, 1200" SINCE 1980 I'm lazy

"I'm Lazy" Your tag line says otherwise.
So, that means that the vacuum fluorescent display in your VCR has flashed an incredible 1,040,688,000 times, so far.