Hardness and Tribological Effects of Ion Implantation on Electroplated Chromium

Abstract

AbstractThe effects of ion implantation on two types of electroplated chromium were studied. Both hard chromium and low contraction chromium were plated onto samples of AISI 4340 grade steel and subsequently implanted with N2+ or Ar+ at ion energies of 150 keV and 75 keV, respectively. The dose was varied from 9.4 x 1015 to 3.1 x 1018 atoms/cm2 and the implantation was conducted at both room temperature and 500 °C. The properties of the resulting surface layers were characterized using secondary ion mass spectrometry and Knoop microhardness. The dry sliding wear and friction behavior was also compared between implanted and unimplanted layers. An increase in hardness was observed for both types of electroplated chromium. The wear rate and friction coefficient were reduced in the nitrogen implanted samples. At the intermediate doses tested, the elevated temperature condition provided improved wear and friction properties compared to the room temperature condition.