LIGHT-ELEMENTS ANALYSIS USING HE-3 MICROBEAM

Coatings containing light elements such as carbon, nitrogen or oxygen play actually an important role in surface engineering as a means to i mprove the tribological performance. In this paper, we have studied th e wear tracks on a diamond coating after a fretting test against a Cr steel ball. The microprobe facility of the LARN has been used to deter mine light elements concentration in the wear tracks because the size of the tracks was less than 100 mu m and the transfer layer from the C r steel counterbody was not uniform. Quantitative analysis of oxygen h as been performed using the 2.392 MeV resonance of the O-16(He-3, alph a(0))O-15 reaction at 90 degrees, while carbon has been measured simul taneously with the C-12(He-3, p(1))N-14 reaction at 175 degrees. The cross sections and the Q-value of this reaction are so high that an ab sorber is not required, so we can also measure the backscattered He-3 particles in the same detector. A correlation between carbon, oxygen a nd iron has been made to investigate the possibility of interdiffusion between the diamond coating and the transferred material due to the f retting test.