A New Hafnium-Beryllium System Prioduced by Ion Implantation and Annealing Techniques
- PDF / 287,819 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 44 Downloads / 136 Views
A NEW HAFNIt4-BERYLLIUM SYSTEM PRIODUCED BY ION IMPLANTATION AND ANNEALING TECH•NIQUES J.C. SOARES*, A.A. MELO*, M.F. DA SILVA**, E.J. ALVES**, K.FREITAG***, AND R. VIANDEN*** *Centro de Ffsica Nuclear da Universidade de Lisboa, Lisboa, Portugal; **Laborat6rio Nacional de Engenharia e Tecnologia Industrial, Sacavem, Portugal; ***University of Bonn, F.R. Germany. ABSTRACT Low and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation These of beryllium commercial foils and single crystals. samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling A new metastable system has been discovered in techniques. implanted hafnium dose low a in TDPAC-measurements 0 Channeling 500 C. at annealed foil beryllium measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from The the previous position occupied after implantation. the with connected is system this of formation layer under the redistribution of oxygen in a thin This effect does not take place precisely at the surface. same temperature in foils and in single crystals. INTROUCION
Implanting atoms in a solid by bombardment with energetic ions (in the keV to MeV range)
results normally in the creation of defects due to the
energy loss by nuclear collisions. The high concentration of lattice defects in the region where the implanted ion comes to rest, the annealing behaviour of these defects and the diffusion coefficient of foreign atoms in a lattice are the most responsible parameters for the formation of a stable or metastable solid solution using the ion implantation technology. The use of nuclear techniques to study these solid solutions might be quite appropriate because they give complementary information about the same system. These and RBS combined with the like hyperfine interactions techniques, ion channeling, have shown quite interesting results in recent years. In particular it has been successfully applied to the study of ions implanted in beryllium metal [1,2]. It has been shown [1] that the implantation of beryllium single crystals with hafnium ions produces an interstitial solid solution where the hafnium ions occupy displaced tetrahedral sites in the beryllium lattice. The same results are obtained using beryllium commercial foils but in this case the samples must be annealed at 200 °C after the implantation [3]. In the present work the stability of the hafnium-beryllium system formed by ion implantation has been systematically investigated as a function of the annealing temperature in the range betwen 300 and 600 9C. The information of depth profiles of the implants and lattice location
Mat. Res.
Soc. Symp. Proc. Vol.
27 (1984) OElsevier Science Publishing Co.,
Inc.
188
Quadrupole precession of l81Ta Fig.l temperature using an Hf implanted foil.
100 t(ns)
80
60
40
20
0
in
Be
measured
at
room
A22G22(t)
0
20
4.0
6
Data Loading...
