NICKEL RELEASE FROM NICKEL-PLATED METALS AND STAINLESS-STEELS

Nickel release from nickel-plated metals often induces allergic contac t dermatitis, but, for nickel-containing stainless steels, the effect is not well-known. In this paper, AISI 304, 316L, 303 and 430 type sta inless steels, nickel and nickel-plated materials were investigated. 4 tests were performed: patch tests, leaching experiments, dimethylglyo xime (DMG) spot tests and electrochemical tests. Patch tests showed th at 96% of the patients were intolerant to Ni-plated samples, and 14% t o a high-sulfur stainless steel (303), while nickel-containing stainle ss steels with a low sulfur content elicited no reactions. Leaching ex periments confirmed the patch tests: in acidic artificial sweat, Ni-pl ated samples released about 100 mu g/cm(2)/week of nickel, while low-s ulfur stainless steels released less than 0.03 mu g/cm(2)/week of nick el, and AISI 303 about 1.5 mu g/cm(2)/week. Attention is drawn to the irrelevance of the DMG spot test, which reveals Ni present in the meta l bulk but not its dissolution rate. Electrochemical experiments showe d that 304 and 316 grades remain passive in the environments tested, w hile Ni-plated steels and AISI 303 can suffer significant cation disso lution. Thus, Ni-containing 304 and 316 steels should not induce conta ct dermatitis, while 303 should be avoided. A reliable nitric acid spo t test is proposed to distinguish this grade from other stainless stee ls.