I believe that Cr on its own (as in chrome coating) oxidizes as Cr(III) when exposed to air, and similarly I think that it is the same for Cr as a component of stainless steel.
Is it always the case that an alloy containing chromium will oxidize as Cr(III) when exposed to air at room temperature, or are there alloys which might form Cr(VI) instead?
The situation which brings this question to mind is the case of a computer hard disk platter. In the case of a "head crash" of the hard disk, layers of the platter are ground to dust. The layers as I understand are composed of various things: Some kind of carbon polymer as an outer covering, magnetic layers of things like Co-Pt-Cr or Co-Ni-Cr (I found a source which suggests "traces of boron or tantalum" are also added to this layer), and also layers composed of things like Cr-Ti or Cr-Ni. I'm wondering whether any of these layers would cause hexavalent chromium to form.