Chromium plating pollution source reduction by plasma source ion implantation

There is growing concern over the environmental and workers' health issues due to the chemical baths and rinse water used in the hard chromium plating process. In this regard the significant hardening response of chromium to nitrogen ion implantation can be environmentally beneficial from the standpoint of decreasing the thickness and the frequency of application of chromium plating. In this paper the results of a study of nitrogen ion implantation of chrome-plated test flats using the non-line-of-sight plasma source ion implantation (PSII) process are discussed. Auger electron spectroscopy (AES) showed the implanted layer thickness to be about 2000 Å. Electron spectroscopy for chemical analysis (ESCA) indicated the formation of chromium nitride phase in the implanted layer. The wear resistance improves after implantation owing to both surface hardening and a decrease in coefficient of friction. Corrosion resistance in saline solution improved moderately after PSII treatment.