Let's Galvanize at Home

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Electrogalvanizing is a process in which a layer of zinc is bonded to steel in order to protect against corrosion. The process involves electroplating, running a current of electricity through a saline/zinc solution with a zinc anode and steel conductor. Zinc electroplating maintains a dominant position among other electroplating process options, based upon electroplated tonnage per annum. According to the International Zinc Association, more than 5 million tons are used yearly for both Hot Dip Galvanizing and Electroplating.The Plating of Zinc was developed at the beginning of the 20th century. At that time, the electrolyte was cyanide based. A significant innovation occurred in the 1960's with the introduction of the first acid chloride based electrolyte.The 1980's saw a return to alkaline electrolytes, only this time, without the use of cyanide. Compared to hot dip galvanizing, electroplated zinc offers these significant advantages:

Lower thickness deposits to achieve comparable performance Broader conversion coating availability for increased performance and color optionsBrighter, more aesthetically appealing, deposits

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Step 1: Ways to Galvanize

The corrosion protection afforded by the electrodeposited zinc layer is primarily due to the anodic potential dissolution of zinc versus iron (the substrate in most cases). Zinc acts as a sacrificial anode for protecting the iron (steel). While steel is close to ESCE= -400 mV (the potential refers to the standard Saturated calomel electrode (SCE), depending on the alloy composition, electroplated zinc is much more anodic with ESCE= -980 mV. Steel is preserved from corrosion by cathodic protection. Conversion coatings (hexavalent chromium (CrVI) or trivalent chromium (CrIII) depending upon OEM requirements) are applied to drastically enhance the corrosion protection by building an additional inhibiting layer of Chromium and Zinc hydroxides. These oxide films range in thickness from 10 nm for the thinnest blue/clear passivates to 4 µm for the thickest black chromates.
Additionally, electroplated zinc articles may receive a topcoat to further enhance corrosion protection and friction performance.The modern electrolytes are both alkaline and acidic:

This is not harder than it looks.we are going to electroplate steel using zinc sulfate.But you can use zinc hydroxide or zinc chloride.

Step 2: Supplies for Galvanizing

1. Safety Wear

2. Metal Object To Be Plated (Must be Steel)

3. A Power Supply (3v-6v)

4. Zinc Sulfate/Zinc Hydroxide/Zinc Chloride

5. Water

6. A Beaker (Glass Or Plastic Object Can Be Used Instead)

7. Zinc Metal (Can Be Found Inside Zn-C Batteries)

8. Sand Paper (120)

9. A Tissue Paper

10. Wires

11. Self Confidence and a Clean Workplace

Step 3: Making an Electrolyte

If you don't have zinc sulfate or zinc chloride.Here is a way to make it.

Zn+H2SO4=ZnSO4+H2 (It means that if you add zinc to sulfuric acid you will get zinc sulfate and hydrogen gas)

Zn+CuSO4(Aq)=ZnSO4+Cu (It means that if you add zinc to copper sulfate solution you will get copper and zinc sulfate)

Zn+NaOH=ZnOH+H2 (It means that if you add zinc metal into sodium hydroxide solution you will get zinc hydroxide and hydrogen gas)

Step 4: Prepare for the Plating

Dissolve a teaspoon of Zinc salt in about 100ml of water

Now place the metal to be plated and the zinc metal in the beaker.And don't let them touch each other.

Connect wires to the electrodes

now,connect the negative side of your power supply to the metal to be plated

Connect the positive side to the Zinc metal.Please make sure your metal and the zinc metal is clean and if not sand it with a sandpaper.Cleaning is highly recommend for a high quality plating.Also sand it after plating to.Do not use 120 for that!!! use a 360 it is good!

Step 5: Let It Go!

You can see some soapy form is forming,it's normal.Keep this for about 15 minutes and get it out.

And wipe the metal object with a tissue and again let it plate.

You have to do this for about 5 times for a perfect plating.

Step 6: Dry Your Object

When you finished plating,slowly wash it and let it dry for some hours.Your object will be ash color if you done it right.Please wash the beaker and dispose the chemicals properly.

Thanks for Reading

Comment and request for new science instructables! i will do them for you.

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11 Discussions

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__Rational__

Question 2 months ago on Step 4

Hu, you mention Zinc Sulphate in previous point and suddenly introduces water and zink salt? Where did the electrolyte dissappear to, and where did the salt suddenly come from?

I am a newcomer so maybe I am just a bit to new to understand if the salt is the same as the electrolyte.

If it is the same, then I would like to know how much H2SO4 and how much zink is needed to create 100 gram equal of salt? My guess would be to calculate using molar mass, from secondary school chemistry, .. ???

how concentrated should the H2SO4 be? Like battery acid?

Thanks for such a well written article!!!

Sincerely
David

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Landy007

Question 1 year ago on Step 2

Hi, just wondering if zinc oxide would work for electrolyte? Thank you for your time.

1 answer
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john henryLandy007

Answer 3 months ago

zinc oxide and water alone would be a bad electrolyte.

you can also use vinegar and magnesium sulfate (unscented Epson salt) as an electrolyte and its cheap.
but its not as good as zinc sulfate.

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john henry

3 months ago

I was trying to figure out how to make this and was about to use hydrocloric acid and copper sulfate to get sulfuric acid and copper chloride then add zinc to the sulfuric acid.
but this is much easier. already had everything to do it either way.

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Zn+NaOH=ZnOH+H2

I tried, there is just no reaction at all

besides you talked about zinc chloride which is way easier to make by mixing zinc and hydrocloridricc acid

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SHOE0007

2 years ago

I have recently ordered through e-bay 99.8% zinc powder and I will place it in either potassium hydroxide or sodium hydroxide. Probably potassium hydroxide since it is a stronger base.

Then I will add heat and convert copper pipes into fake silver with electrolysis.

Finally the solution will be rinsed off (to get rid of the lye) and the metal will be steamed again to convert it into Bronze-gold.

I have also ordered graphite rods so that they will not react as much. I tend to do this with chromium as well.

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mpetković1

2 years ago

When you add zinc metal to sodium hydroxide you get sodium zincate.

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gmccusker

3 years ago

Very "to the point" and informative. I've plated with tin before using electrolyte I bought and tried making my own without much success. would the idea of making tin sulphate apply here too? a while back I got a book on making it using stannus sulphate, both sulphuric and hydrochloric acid (not sure why both) and some form of floride (cant remember exactly) but it didnt work so well. I just want to make something simple and small scale this time around. Any info you could share would be wonderful ^.^

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SHOE0007

3 years ago

You know that maybe you should consider plating with cobalt (cobalt chloride) and other salts. That is what I am trying to do to make my own biofuel cell.

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australianoz

3 years ago on Step 6

Thanx for the instructo, very detailed. I've done this loads of times before to de-rust and plate using copper or zinc. Your detail of process and chemical solutions add to the pleasure of reading. Great Job