On the Use of MÖssbauer Nuclei as Probes of Radiation Induced Effects at Interfaces

ABSTRACTConversion electron M6ssbauer spectroscopy was used as a means of investigating radiation induced changes at thin film interfaces. 25 Å thick layers of 57Fe were evaporated onto substrates of Si,SiO2 and A12O3 andcovered with 150 Å 56Fe. Samples were then subjected to ion irradiation with 20 MeV C14+ to doses ranging from 1012 to 2x 1014 ions/cm2 and subsequently annealed in vacuum at 450 ºC. Mössbauer spectra were recorded before and after each step. The analysis revealed chemical alterations, induced by the ion bombardment, indicative of film-substrate bond formation and reconstruction of residual surface hydrocarbons. The results are interpreted in view of accompanying enhancements in thin film adhesion.

Compared Nitrogen Implantations of Various Alloyed Steels

ABSTRACTNitrogen implantations in pure iron and various stE-els are investigated using nuclear reaction analysis, Conversion Electron M6ssbauer Spectroscopy and Grazing angle X-ray Diffraction. The present work sums up all the significant results although it does not constitue a systematic study. It describes the influence of the chemical composition and the structure effect of the matrix as well as those of the implantation time. The N-martensite, ε-nitride and ε-carbonitride phases are principally identified. The fraction of iron bound with nitrogen is evaluated in the different steels. The strong influence of the small chromium amounts inside the matrix upon the nitride formation is underlined. A preferential orientation of these phases is shown. SIMS experiments are presented in particular to determine the carbon distribution in the first surface layers.