Time for a Science Lesson. There will be a Test

Time for a Science Lesson.

Just kidding! There won’t be a Test.

I’m guessing not many GMG Readers would be able to pass.

 

 

RUST!

 

From WIKIPEDIA;

“Oxidation of iron metal

When iron is in contact with water and oxygen, or other strong oxidants and/or acids, it rusts. If salt is present as, for example, in salt water, it tends to rust more quickly, as a result of the electro-chemical reactions. Iron metal is relatively unaffected by pure water or by dry oxygen. As with other metals, like aluminium, a tightly adhering oxide coating, a passivation layer, protects the bulk iron from further oxidation. Thus, the conversion of the passivating iron oxide layer to rust results from the combined action of two agents, usually oxygen and water. Other degrading solutions are sulfur dioxide in water and carbon dioxide in water. Under these corrosive conditions, iron hydroxide species are formed. Unlike iron oxides, the hydroxides do not adhere to the bulk metal. As they form and flake off from the surface, fresh iron is exposed, and the corrosion process continues until all of the iron is either consumed or all of the oxygen, water, carbon dioxide, or sulfur dioxide in the system are removed or consumed.[2]

Oxidation of iron metal

When iron is in contact with water and oxygen, or other strong oxidants and/or acids, it rusts. If salt is present as, for example, in salt water, it tends to rust more quickly, as a result of the electro-chemical reactions. Iron metal is relatively unaffected by pure water or by dry oxygen. As with other metals, like aluminium, a tightly adhering oxide coating, a passivation layer, protects the bulk iron from further oxidation. Thus, the conversion of the passivating iron oxide layer to rust results from the combined action of two agents, usually oxygen and water. Other degrading solutions are sulfur dioxide in water and carbon dioxide in water. Under these corrosive conditions, iron hydroxide species are formed. Unlike iron oxides, the hydroxides do not adhere to the bulk metal. As they form and flake off from the surface, fresh iron is exposed, and the corrosion process continues until all of the iron is either consumed or all of the oxygen, water, carbon dioxide, or sulfur dioxide in the system are removed or consumed.[2]

7 thoughts on “Time for a Science Lesson. There will be a Test

    1. Swimdad, “An important approach to rust prevention entails galvanization, which typically consists of an application, on the object to be protected, of a layer of zinc by either hot-dip galvanizing or electroplating. Zinc is traditionally used because it is cheap, adheres well to steel and provides a cathodic protection to the steel surface in case of damage of the Zinc layer. In more corrosive environments (such as salt water) cadmium is preferred. Galvanization often fails at seams, holes, and joints, where the coating is pierced. In these cases the coating provides cathodic protection to metal, where it acts as a galvanic anode rusting in preference. More modern coatings add aluminium to the coating as zinc-alume, aluminium will migrate to cover scratches and thus provide protection for longer. These approaches rely on the aluminium and zinc oxides protecting the once-scratched surface rather than oxidizing as a sacrificial anode. In some cases, very aggressive environments or long design life, both zinc and a coating are applied to provide corrosion protection.” GOT IT? GOOD!

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    2. Rubber Duck says the zinc block that is placed in most boats in saltwater exposed under the water line is the sacrificial zinc. It acts as the anode to the boat, sort of like the whole boat is a battery and the zinc is the negatively charged end. Zinc does a far better job at this than the steel in the engine nearby so virtually all of the rusting attacks the zinc. It discharge the electrons from the boat just the way you do when you touch a doorknob in the winter.

      This way the zinc dissolves away and can be easily replaced and the lower unit of the engine is rust free.

      Rubber Duck fun fact in a molecular biology lab: When hooking up an electrophoreses slab gel, load sample on left and gel runs to the right. Attach the red lead to the right saying “red on right returning” and you never screw up.

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  1. Gee, I’m getting a lot of lesons today. Yahoo!!! Oh Oh, don’t tell me that Rubber Duckie is bored with the marriage already that there is time to dive into this stuff. Oh, I know Homie is out looking for food…LOL…So there is plenty of time for Rubber Duckie to dive into anything.

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