- First Name
- Sep 29, 2021
- Reaction score
- Tucson, Az
- 2020 Tesla Model S
Surely Tesla has a few chemical engineers or materials scientists. After all they are making batteries. Much has been written about cathodic protection (underground pipelines/tanks) and sacrificial anodes (water heaters). Bolt a few ounces of magnesium to "all the right places." The magnesium will corrode before the aluminum. Inspect annually. Replace as needed.The 6,000-ton die-casting machine currently being used for Model Y/3 is using aluminum for its casting.
My concern, hopefully, yours too, the 8,000-ton die-casting machine schedule to be used for the Cybertruck is also using aluminum for its castings.
The main concern is, aluminum and stainless steel parts will be assembled together.
You shouldn't use Stainless Steel and Aluminum Together - it causes Galvanic Corrosion.
(Galvanic corrosion is the transfer of electrons from one material (anode) to another (cathode).
- Anode – material that is positively charged, electrons leave this material
- Cathode – material that is negatively charged, electrons enter this material
- Electrolyte – liquid that aids in the process of electron transfer
- Corrosion/corrode – Destroy or weaken metal gradually
Galvanic corrosion occurs when two materials (an anode and a cathode) come into contact with each other and an electrolyte. Electrolytes can be environmental factors such as humidity or rainwater. When these factors come into play, electron transfer will begin to occur. Depending on the level of resistance in an electrolyte, this transfer can happen much faster. This is why saltwater, an electrolyte with very low resistance, is a common factor when considering what product to use. Due to this, it is incredibly important to consider what material you are going to use in an environment. When working with a marine, saltwater environment, you even need to consider the type of stainless steel you are using.
There are multiple kinds of rust that can occur during the oxidization process.
How Can Galvanic Corrosion be stopped?
There are a few steps you can take if you MUST use these materials together.
Just an FYI, for the engineers/production staff, to perform during the manufacture of this product.
- Add an insulator between the two materials so they no longer connect. Without that connection, the transfer of electrons cannot occur. Well Nuts are a commonly used fastener to help separate materials that can suffer from galvanic corrosion.
- Use materials with the same potential. Metals with the same corrosion resistance are typically ok to use together.
- If you are in a situation where only one of the materials will come into contact with an electrolyte then the transfer of electrons will not occur.
- If there is a coating on the cathode it can prevent the transfer through increased resistance.
- Consider your environment before installing. Choose materials that will work for your environment.
- Coat or paint your assembly (completely) so that the electrolyte cannot make contact with the materials
- Use neoprene EPDM or bonding washers as a barrier in between the metals.