Observations
  • Home
  • Observations
  • Trendcasting
  • Odds 'n Ends
  • Science/Technology/Experiments
  • Mental Health

Autocatalytic deposition of copper

9/1/2011

2 Comments

 
Picture
Autocatalytic  deposition of a metal in ionic solution is sometimes called electroless plating. In this case we will be plating copper onto an iron surface without any electricity. The process has been around for a long time and has many interesting applications. In this experiment we will use 1/4 cup of distilled white vinegar, and 1 teaspoon of regular salt and dissolve with stirring. The salt is added to the vinegar (5% Acetic acid) to provide more of an electrical carrier. (More conductive). Old pennies that have reacted with the air over time form copper oxide on the surface. Copper without the oxide is bright and shiny. If you place about 10 old dull pennies in the vinegar, the oxide will be removed and the pennies will be bright. The copper from the copper oxide that has been removed is now in ionic form, not as the metal. This makes it chemically available to plate out on iron.

Picture
Leave the pennies in the solution for about 5 minutes then remove and rinse. Note: If you leave a couple of the pennies wet with the solution, they will form a green "patina" in about an hour, which is an accelerated form of copper oxide. Place an iron nail or other piece of iron in the solution for about 30 minutes. You will see the copper actually plating out on the surface of the iron. Shiny screws, nuts, and washers fail to work as they are bright and have been coated with zinc (galvanized) to prevent rust. So, you really need plain iron.
Picture
This experiment is a fairly simple demonstration of electroless plating. But, the process used in industry is much more complicated and involves a lot of "secret" protected chemistry. It is used extensively for plastics which are not conductive at all. They are "seeded" with a conductive chemical and then copper plated with a strike coat. This is just enough to make them conductive and can then be plated with other metals such as chrome or nickle. Enjoy...
Upcoming posts: Ultrasonic cavitation, Cold cathode lighting, and a really cheap Digital counter.

2 Comments
Erik
10/8/2016 06:29:48 pm

Would you expect that wiping the ionic copper solution over a bare, ungalvanized steel surface would achieve a noticeable effect? Perhaps with multiple coats? Do you think using a stronger acid, like H2SO4, would enhance the effect?

I ask because I'm making a large steel sculpture and would like to use this technique to protect the metal, and also for artistic effect.

Reply
Ken
10/9/2016 04:33:30 pm

Hi Erik,
I have some doubts about how well the copper will form with just short contact such as applying with rubbing or spray although it may be worth a try. But, the resulting copper coating is really a strike coat and is only about 1 micron thick and may not stand up well with abrasion. Electroplating is as simple and will perhaps work better if the size of the object is not too large. Hope that this comment is helpful, Ken.

Reply



Leave a Reply.

    Author

    The author has an eclectic background in chemistry, electronics, writing, mental health, and community action...Ken

    Archives

    June 2021
    March 2020
    September 2019
    August 2018
    August 2017
    March 2017
    December 2016
    November 2016
    October 2016
    August 2016
    April 2016
    December 2015
    September 2015
    May 2015
    March 2015
    February 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    December 2013
    November 2013
    October 2013
    August 2013
    July 2013
    June 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013
    December 2012
    November 2012
    October 2012
    September 2012
    August 2012
    July 2012
    June 2012
    May 2012
    April 2012
    March 2012
    February 2012
    January 2012
    December 2011
    November 2011
    October 2011
    September 2011
    August 2011
    July 2011
    June 2011
    May 2011

    RSS Feed

    Categories

    All
    Acid And Bases
    Amateur Scientist
    Anodizing Aluminum
    Anthocyanin Indicator
    Ant Orientation
    Artificial Intelligence
    Bar And Cr Code
    Cable Tie
    Carbon Dioxide Fun
    Catalase And H2o2
    Chemical Art
    Cold Cathode
    Color Hot Glue Sticks
    Common Chemicals
    Copper Plating
    Cyanotype/Blueprint
    Dot Com
    Electroluminescence
    Epoxy Art
    Experiments
    Hydrogels
    Infrared Photography Basics
    Magnetic Money
    Old Textbooks
    Photograms
    Science
    Static Electricity Detector
    Technology
    Yogurt