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Yep, the most common grades of stainless steel you're likely to encounter are chromium and nickel alloys of carbon steel, with the common marine / surgical grad

Yep, the most common grades of stainless steel you're likely to encounter are chromium and nickel alloys of carbon steel, with the common marine / surgical grade 316 stainless containing between two and three percent molybdenum for added corrosion resistance. And yep, they're corrosion resistant because the chromium instantly forms an oxide layer that protects the underlying metal. Stainless steels are expensive partly because they're difficult to work with, generally having poorer machinability than regular carbon steels, and tend to work harden more rapidly too.

Maursault 5y ago
Sure, stainless steel resists corrosion, but it is a pretty bad electrical conductor, especially compared Cu, Au, or Ag. (I'm not disagreeing with you, this is for the benefit of GP.)
- thaumasiotes 5y ago
  What about aluminum? I looked up a table of electrical resistivity: resistivity $/kg Cu 1.7e-8 10.3 Au 2.4e-8 63600 Ag 1.6e-8 827 Fe 1.0e-7 ? (cheap) Al 2.8e-8 3.23 But I don't know how important any of these numbers are. The table suggests that iron is about 6 times more resistive than copper or silver and 4 times more resistive than gold. Gold itself looks about 50% worse than copper while being more than six thousand times as expensive, so for gold to be used, resistance to corrosion must be important. Silver is the best metal listed in the table, and slightly better than copper, so I assume the cost difference explains why we have lots and lots of copper wiring and not so much silver wiring. Aluminum is a bit (17%) worse than gold for resistivity, but aluminum is cheap. Why use gold? I can imagine a few reasons: - This table gives values at 20 centigrade, but things change at a more relevant temperature. - There's some kind of important threshold around 2.5e-8 ohm-meters, so that gold is on the right side of usability and aluminum just misses it. - Aluminum's corrosion resistance is different in nature from gold's, and the difference matters. Are any of those true?
  - Maursault 5y ago
    > for gold to be used, resistance to corrosion must be important. from google, copy pasta: "Gold plating is the deposit of a thin layer of gold metal on a substrate, typically in the 0.25 – 5 micron range (0.00001”-0.0002”)." Not a lot of gold is used in plating the business ends of an RCA cable or TRS connector. Al, yes, more copy pasta: "Aluminum has a very high affinity to oxygen. When a new aluminum surface is exposed in the presence of air or any other oxidizing agent, it quickly develops a thin, hard film of aluminum oxide (or hydrated oxide in non-stagnant water). This aluminum oxidation is precisely what makes aluminum so corrosion-resistant." But I doubt the thin, hard film of aluminum oxide conducts as well as gold. Nope.[1] [1] https://hypertextbook.com/facts/2006/EuniceHuang.shtml https://hypertextbook.com/facts/2006/EuniceHuang.shtml

Maursault 5y ago

Sure, stainless steel resists corrosion, but it is a pretty bad electrical conductor, especially compared Cu, Au, or Ag. (I'm not disagreeing with you, this is for the benefit of GP.)

thaumasiotes 5y ago
What about aluminum? I looked up a table of electrical resistivity: resistivity $/kg Cu 1.7e-8 10.3 Au 2.4e-8 63600 Ag 1.6e-8 827 Fe 1.0e-7 ? (cheap) Al 2.8e-8 3.23 But I don't know how important any of these numbers are. The table suggests that iron is about 6 times more resistive than copper or silver and 4 times more resistive than gold. Gold itself looks about 50% worse than copper while being more than six thousand times as expensive, so for gold to be used, resistance to corrosion must be important. Silver is the best metal listed in the table, and slightly better than copper, so I assume the cost difference explains why we have lots and lots of copper wiring and not so much silver wiring. Aluminum is a bit (17%) worse than gold for resistivity, but aluminum is cheap. Why use gold? I can imagine a few reasons: - This table gives values at 20 centigrade, but things change at a more relevant temperature. - There's some kind of important threshold around 2.5e-8 ohm-meters, so that gold is on the right side of usability and aluminum just misses it. - Aluminum's corrosion resistance is different in nature from gold's, and the difference matters. Are any of those true?
- Maursault 5y ago
  > for gold to be used, resistance to corrosion must be important. from google, copy pasta: "Gold plating is the deposit of a thin layer of gold metal on a substrate, typically in the 0.25 – 5 micron range (0.00001”-0.0002”)." Not a lot of gold is used in plating the business ends of an RCA cable or TRS connector. Al, yes, more copy pasta: "Aluminum has a very high affinity to oxygen. When a new aluminum surface is exposed in the presence of air or any other oxidizing agent, it quickly develops a thin, hard film of aluminum oxide (or hydrated oxide in non-stagnant water). This aluminum oxidation is precisely what makes aluminum so corrosion-resistant." But I doubt the thin, hard film of aluminum oxide conducts as well as gold. Nope.[1] [1] https://hypertextbook.com/facts/2006/EuniceHuang.shtml https://hypertextbook.com/facts/2006/EuniceHuang.shtml