What are the electrodes that will corrode least when making sodium chlorate?

First, I read that gold is less corrosive than platinum, but platinum is used commercially although it's more expensive. Why is this? Also on the chart I looked at, it showed graphite being less corrosive than both gold and platinum, but when I've seen pure graphite use it creates a black sludge. Is this simply the graphite breaking down because it's so soft or is it actually being oxidized and corroding. If it is breaking down could that be fixed with a good binder? Also a lot of people seem to like stainless steel so how does that compare to carbon, gold, platinum, and graphite. I know that it creates a little bit of a toxic chemical but I'm not that worried about that because I'm only saving the chlorate. Finally, how does lead dioxide figure in compared to carbon, gold, platinum, graphite, and stainless. Thank you in advance.