|Great huge rings of solid chromium.|
This is a sputtering target made by the TOSOH corporation, used to deposit chromium on something by vacuum sputtering, discarded as scrap by some company in southern California, and then bought from a scrap metal yard by John Wechselberger, the source of some of my largest bulk samples of semi-exotic metals.
When I first saw them, I had grave doubts that they could be solid chromium, despite all assurances that they were. But one crack with a sledge hammer proves that they are not stainless steel with a thin layer of chromium as I had suspected: They are pure solid chromium through and through, as evidenced by the broken crystal surface, which looks nothing like steel. (And by the fact that I could break them at all: These are 3.75 pound monsters disks that would have been extremely strong if they were any kind of steel.)
I have four such disks, which I think is a tremendous lot of chromium! They are stamped "Cr-2N8", which almost certainly means 99.8% pure. Notations such as 3N5 or 5N are commonly used to mean 99.9% or 99.999% respectively. They were probably hot isostatically pressed (hipped) or sintered from chromium powder, then machined.
Source: John Wechselberger
Contributor: Theodore Gray
Acquired: 18 August, 2003