1) Rust removal through electrolysis

Electrolysis is a process in which there is an exchange between atoms due to oxidation (loss of electron) and reduction (gain of electron) from an external power source.

If we put two conducting posts into a body of water, connect one post to the positive terminal of a battery and the other post to the negative terminal, electrolysis will occur. At the negative terminal (cathode), electrons are supplied, given to the surrounding water, reducing it. Subsequently, at the positive terminal (anode) electrons are taken from the surrounding water, oxidixing it. This process turns our body of once "pure" water H₂O into a mixture of liquid water, hydrogen gas, and oxygen gas:

H₂O -> H₂O + H₂ + O₂

Rust is a combination of iron (Fe) and oxygen (O) in the form Fe₂O₃. To remove rust from an object we simply need to make the object our cathode by connecting it to the negaive terminal of our power source. Now, by supplying electrons to the rust we can separate iron and oxygen through reduction:

2Fe₂O₃ -> 4 Fe²⁺ + 3O₂^2-

The separated oxygen gas is now free to combine with the hydrogen gas to once again form water, leaving you with your original iron object.

Fe₂O₃ + 3H₂ = 2Fe²⁺ + 3H₂O

Notice that the recalimed iron is still slightly charged meaning that it is prone to rusting again in the future. To solve this we can coat the blade metal less susceptible to corrosion like aluminium, nickel, zinc, or copper.

2) Electroplating to prevent future rusting

Electroplating a type electrolysis in which we take coat an object (substrate) in a thin layer of metal. This is done by connecting the plating material to a battery's anode (+) and the substrate to the battery's cathode (-). By supplying a constant voltage negatively charged and positively charged ions (anions and cations) transfer to the anode and cathode respectively, evenly coating the desired part.

For this project I used electroplating to coat the blade in a layer of nickel.