Will there be a nickel-free iWatch?

316L INOX has very little nickel; 2%-3%. Here is the full formula:

Fe, <0.03% C, 16-18.5% Cr, 10-14% Ni, 2-3% Mo, <2% Mn, <1% Si, <0.045% P, <0.03% S

As you can see, the largest single metallic component after Iron (Fe) is Chromium. I just did some research on Nickel allergy, and it says that watches with stainless steel backs are OK. I then looked up 316L; it's the standard steel for surgical instruments and medical implants such as hip replacements and orthopedic screws. So I think it's safe to assume that it is hypoallergenic.

See: http://www.azom.com/article.aspx?ArticleID=2382 for more details.

Lawrence, your posted link (table 1) says nickel is 10-14% (which other web sites confirm as well) and chromium is up to 18%. But you are right that clinical studies indicate no reaction with 316L steel in nickel sensitive patients (there are papers mentioned in pubmed from studies in the journal contact dermatitis that specifically studied 316L steel in 1994). I suppose it would depend on the degree of one's sensitivity to nickel though?

Seems the question really isn't how much nickel in a given steel, but how labile it is when exposed to human skin, sweat & oils. 316L apparently showed very little nickel leaching in clinical trials, and did not elicit a sensitivity reaction in,patients with known nickel sensitivity.

http://www.ncbi.nlm.nih.gov/pubmed/9330816

Oops, you are right; I read it wrong. But it is still used inside the body, for surgical instruments, and is recommended for nickel-sensitive individuals on the medical websites I checked. While I would check with an allergist, it appears to be safe. My guess is that the alloy is bonded tightly enough to prevent significant exposure.