For some reason, if you rub iron oxide or lodestone (both very crumbly, dark, mineral-like materials) into soft, unhardened steel, their particles actually get stuck into the surface of the steel (that is, darkening it). My question is, how does this work? How come iron oxide and lodestone can get stuck, and how come other materials (like silicone carbide, for example) do not?My second question is, are there any materials that can get stuck into steel, that is also blue in color, and how would I best obtain it?
If you look at the surface of untreated steel even with a low power microscope you will see a surface that is far from smooth, there are pits and occlusions dotting the surface. Steel is not polished when you see it this way so the only treatment to the surface was the extrusion process or forming done on it by the presses. Iron oxide has a very small particle size and when pulverized into a powder it can easily fill the pits and voids in the steel surface coloring it.
the coloured metals that u often see are anodised, which means that their surface has reacted with air to form a protective, porous oxide coating. because it is so porous, highly-concentrated dyes can be injected into them to colour them.
