Analytical Sciences

Non-destructive Rapid Analysis Discriminating between Chromium(VI) and Chromium(III) Oxides in Electrical and Electronic Equipment Using Raman Spectroscopy

Sonoko KIKUCHI,*¹ Kazuteru KAWAUCHI,*² Masaru KUROSAWA,*³ Hisashi HONJHO,*³ and Teruo YAGISHITA*⁴

*1 Analysis Division, Fujitsu Analysis Laboratory Ltd., 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki 211-8588, Japan
*2 Application & Research Center, JEOL Ltd., 1-2 Musashino 3-chome, Akishima, Tokyo 196-8558, Japan
*3 Technical Laboratory, Analysis Center Co., Ltd., 3-4-9 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan
*4 Nanotechnology Business Creation Initiative, 24 Kandanishikicho, 3-chome, Chiyoda-ku, Tokyo 101-0054, Japan

The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were detected in films at around 1000 and 500 cm^-1, while chromium(III) compounds generated no bands in the region between 2000 and 200 cm^-1. The analysis took about 1 min, whereas the usual diphenylcarbazide-colorimetric method for analyzing chromium(VI) compounds takes about 10 h.

J-STAGE: View this article in J-STAGE