- Email: [email protected]
3922. Trapping of deuterium implanted into stainless steel at low temperature. (USA)
Classified abstracts 3 9 2 2 - 3 9 9 6 Classified abstracts on this page 3 9 2 2 - 3 9 2 9
Editor's note
The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
I. G e n e r a l v a c u u m s c i e n c e and engineering 11. GASES A N D SOLIDS 11 3922. Trapping of deuterium implanted into stainless steel at low temperature. (USA) Stainless steel 316 specimens have been implanted with deuterium ions at 7 keV up to doses of 2 x l0 ta D/cm 2 at --120°C. Trapped quantities and depth profiles of the implanted atoms have been determined using the 3He (d,p) 4He nuclear reaction, using both the product particles for making the analyses. Up to doses of 5 × 10 Iv D/cm 2 the implanted deuterons were retained within the analyzing zone, but at higher fluences the amounts retained no longer increased linearly with the bombardment dose. Deuterium to metal atom ratios of nearly 1 : 1 were observed. The density of retained deuterium was not a function of holding time at --120°C, but upon warming, the loss of deterium could be measured. At roughly --50°C the rate of loss was a maximum, and by +40°C only a few percent of the original amount of deuterium remained. (Germany) C J Altstetter et al, J Vac Sci Technol, 15 (2), 1978, 706-709. 11 3923. Effect of primary ion energy and surface chemistry on the secondary ion yields in low-energy SIMS experiments. (USA) The chemisorption of oxygen on W(100) and Mo(100) single-crystal surfaces was studied using a static mode SIMS technique at primary ion energies ranging from 150 eV to 2 keV. The following secondary ion yields O - , W O z - and M o O z - were found to be sensitive to the changes in the chemisorbed oxygen layer at different stages of chemisorption. Significant enhancement in the sensitivity of the O - yield to the chemisorption process was observed when the energy of the Ne + primary ion energy was below 500 eV. M L Yu, J Vac Sci Technol, 15 (2), 1978, 668-671. 11 3924. Ion nitriding of steels. (USA) This paper deals with the 'ion-nitriding' method of nitriding various grades of steels in a laboratory model furnace. Four different grades of steels such as AISI 4140, Nitralloy 135 Mod, high-speed steel M2 and stainless steel 304 were ion nitrided at different temperatures with cycle times ranging from 1 to 36 h in a gaseous mixture of nitrogen and hydrogen under a total pressure of 7 torr (9.1 × 103 Pa). Results obtained with 4140 steel show that ion nitriding at 950°F is much faster than conventional gaseous nitriding. At a given temperature of ion nitriding, case depth s treatment time follows a parabolic law for all four grades of steels. Current theoretical and experimental evidence has been used to explain different nitriding rates observed for various steels. Finally results of ion nitriding performed at 750°F have been presented to show the versatility of this process. P C Jindal, J Vac Sci Technol, 15 (2), 1978, 313-317. 11 3925. Quasisimultaneoas SIMS, AES and XPS investigations of the oxidation of Mo, Ti and Co in the monolayer range. (USA) The oxidation of Mo, Ti and Co at oxygen exposures up to several hundred Langmuirs has been investigated by combination of static SIMS, 'static' AES (i.e. direct counting of the N(E) spectrum at low primary electron current) and XPS. The proportionally of the O(ls) and O(KLL) signals allows one to establish a coverage scale in the submonolayer range. For Mo and Ti, saturation of the Auger and O(ls) signals is reached after 4 and 9 L, respectively. The beginning surface oxidation is indicated by the successive appearance of the compound secondary ions MeO, ± at about 2-20 L. For Ti, the indepth growth of the 'oxide' is indicated at exposures above 8 L by the chemical shift of the Ti 2p levels, whereas for Mo no shift of the
Mo(3d) levels is present up to 1000 L. Co behaves similarly to Ti, except for the higher oxygen doses needed for saturation and an additional phase at 0 -- 5 L, which is characterized by enhanced Co +, CoO + and O - emission, a break in the O(1 s) vs exposure curve and an initial O(ls) level with different binding energy. (Germany). A Benninghaven et ul, J Vac Sci Technol, 15 (2) 1978, 506-509. 11 3926. Surface resonances and the oxidation of single-crystal aluminum (USA) Valence-band photoemission spectra have been studied on singlecrystal aluminum faces using polarized sychrotron radiation. New intrinsic and oxygen-related extrinsic surface resonance features are observed within 5 eV of the Fermi level. These surface resonances arc correlated with oxygen uptake on the (100), (I I0) and (l I I) faces as observed in both valence and core-level spectroscopy. Considerable face dependence to the oxidation is shown. Although aluminum is a free-electron-like metal, its surface behaviour on single-crystal faces shows effects due to localized charge. R Z Bachrach et al, J Vac Sci Technol, 15 (2), 1978, 488-493. 11 3927. Electronic orbitais of Se bonded to Ni(100). (USA) New angle-integrated UPS spectra are presented at different angles of light incidence for NeI radiation on Ni(100)c(2x2)Se. These spectra show that a Se-derived orbital lies in the energy range of the Ni d band as suggested by Fisher. The corresponding INS spectrum is also given and discussed. It is shown that the present Ni sample produces a two-domain c(2 × 5)Se structure at one-quarter monolayer as opposed to the p(2 × 4)Se structure observed on earlier samples. F Froitzheim and H D Hagstrum, J Vac Sci Technol, 15 (2), 1978, 485-487. 11 3928. Purposeful modification by gas adsorption of atomically clean iron surfaces at room temperature and characterization by 21.2 eV photoemission. (USA) We have previously explored purposeful exposure of an atomically clean surface to controlled environments as a technique for obtaining surfaces with desired properties. The incorporation of nitrogen into atomically clear iron is an example of beneficial clean surface modification and results in enhancement of resistance to corrosion at room temperature in dry and moist air, relative to initially air exposed samples. The in situ 21.2 eV photoelectron spectroscopy, using a windowed discharge lamp and residual gas analysis were performed on clear iron and iron in the course of N= and HzO exposures as well as Nz-O2 and N2-HzO sequential exposures. These room-temperature UPS adsorption studies, which covered pressures from 5 × I0 -a to 0.5 tort indicate the following: dissociative adsorption of N2 and H20; molecular HzO adsorption at pressures greater than 0.05 torr; the dissociative adsorption of oxygen on nitrogen-treated surfaces (as on untreated surfaces); and a complex reaction between preadsorbed nitrogen and water vapour. The in situ adsorption results are consistent with spin orbital electronegativity concepts together with electronic structure calculations in the self consistent field-X,, approximation. The Fe-N=-H20 study is consistent with a proposed model in which the inhibition of molecular water vapour adsorption on nitrogen-treated iron is responsible for the resistance to corrosion noted. C Russo and R Kapiow, J Vac Sci Technol, 15 (2), 1978, 479-484. 11 3929. Determination of adsorbate bond geometry using photoemission. (USA) It has been known for some time that angle-resolved photocmission can give in principle a great deal of information about the valence states of adsorbed species. Recently this technique has been used to determine the orientation of CO on Ni, and Cu and N O on Ni. The 193
Editor's note
The label immediately following the title of each item denotes country or origin of publication, and that at the end of each abstract indicates country of origin of work (where known).
I. G e n e r a l v a c u u m s c i e n c e and engineering 11. GASES A N D SOLIDS 11 3922. Trapping of deuterium implanted into stainless steel at low temperature. (USA) Stainless steel 316 specimens have been implanted with deuterium ions at 7 keV up to doses of 2 x l0 ta D/cm 2 at --120°C. Trapped quantities and depth profiles of the implanted atoms have been determined using the 3He (d,p) 4He nuclear reaction, using both the product particles for making the analyses. Up to doses of 5 × 10 Iv D/cm 2 the implanted deuterons were retained within the analyzing zone, but at higher fluences the amounts retained no longer increased linearly with the bombardment dose. Deuterium to metal atom ratios of nearly 1 : 1 were observed. The density of retained deuterium was not a function of holding time at --120°C, but upon warming, the loss of deterium could be measured. At roughly --50°C the rate of loss was a maximum, and by +40°C only a few percent of the original amount of deuterium remained. (Germany) C J Altstetter et al, J Vac Sci Technol, 15 (2), 1978, 706-709. 11 3923. Effect of primary ion energy and surface chemistry on the secondary ion yields in low-energy SIMS experiments. (USA) The chemisorption of oxygen on W(100) and Mo(100) single-crystal surfaces was studied using a static mode SIMS technique at primary ion energies ranging from 150 eV to 2 keV. The following secondary ion yields O - , W O z - and M o O z - were found to be sensitive to the changes in the chemisorbed oxygen layer at different stages of chemisorption. Significant enhancement in the sensitivity of the O - yield to the chemisorption process was observed when the energy of the Ne + primary ion energy was below 500 eV. M L Yu, J Vac Sci Technol, 15 (2), 1978, 668-671. 11 3924. Ion nitriding of steels. (USA) This paper deals with the 'ion-nitriding' method of nitriding various grades of steels in a laboratory model furnace. Four different grades of steels such as AISI 4140, Nitralloy 135 Mod, high-speed steel M2 and stainless steel 304 were ion nitrided at different temperatures with cycle times ranging from 1 to 36 h in a gaseous mixture of nitrogen and hydrogen under a total pressure of 7 torr (9.1 × 103 Pa). Results obtained with 4140 steel show that ion nitriding at 950°F is much faster than conventional gaseous nitriding. At a given temperature of ion nitriding, case depth s treatment time follows a parabolic law for all four grades of steels. Current theoretical and experimental evidence has been used to explain different nitriding rates observed for various steels. Finally results of ion nitriding performed at 750°F have been presented to show the versatility of this process. P C Jindal, J Vac Sci Technol, 15 (2), 1978, 313-317. 11 3925. Quasisimultaneoas SIMS, AES and XPS investigations of the oxidation of Mo, Ti and Co in the monolayer range. (USA) The oxidation of Mo, Ti and Co at oxygen exposures up to several hundred Langmuirs has been investigated by combination of static SIMS, 'static' AES (i.e. direct counting of the N(E) spectrum at low primary electron current) and XPS. The proportionally of the O(ls) and O(KLL) signals allows one to establish a coverage scale in the submonolayer range. For Mo and Ti, saturation of the Auger and O(ls) signals is reached after 4 and 9 L, respectively. The beginning surface oxidation is indicated by the successive appearance of the compound secondary ions MeO, ± at about 2-20 L. For Ti, the indepth growth of the 'oxide' is indicated at exposures above 8 L by the chemical shift of the Ti 2p levels, whereas for Mo no shift of the
Mo(3d) levels is present up to 1000 L. Co behaves similarly to Ti, except for the higher oxygen doses needed for saturation and an additional phase at 0 -- 5 L, which is characterized by enhanced Co +, CoO + and O - emission, a break in the O(1 s) vs exposure curve and an initial O(ls) level with different binding energy. (Germany). A Benninghaven et ul, J Vac Sci Technol, 15 (2) 1978, 506-509. 11 3926. Surface resonances and the oxidation of single-crystal aluminum (USA) Valence-band photoemission spectra have been studied on singlecrystal aluminum faces using polarized sychrotron radiation. New intrinsic and oxygen-related extrinsic surface resonance features are observed within 5 eV of the Fermi level. These surface resonances arc correlated with oxygen uptake on the (100), (I I0) and (l I I) faces as observed in both valence and core-level spectroscopy. Considerable face dependence to the oxidation is shown. Although aluminum is a free-electron-like metal, its surface behaviour on single-crystal faces shows effects due to localized charge. R Z Bachrach et al, J Vac Sci Technol, 15 (2), 1978, 488-493. 11 3927. Electronic orbitais of Se bonded to Ni(100). (USA) New angle-integrated UPS spectra are presented at different angles of light incidence for NeI radiation on Ni(100)c(2x2)Se. These spectra show that a Se-derived orbital lies in the energy range of the Ni d band as suggested by Fisher. The corresponding INS spectrum is also given and discussed. It is shown that the present Ni sample produces a two-domain c(2 × 5)Se structure at one-quarter monolayer as opposed to the p(2 × 4)Se structure observed on earlier samples. F Froitzheim and H D Hagstrum, J Vac Sci Technol, 15 (2), 1978, 485-487. 11 3928. Purposeful modification by gas adsorption of atomically clean iron surfaces at room temperature and characterization by 21.2 eV photoemission. (USA) We have previously explored purposeful exposure of an atomically clean surface to controlled environments as a technique for obtaining surfaces with desired properties. The incorporation of nitrogen into atomically clear iron is an example of beneficial clean surface modification and results in enhancement of resistance to corrosion at room temperature in dry and moist air, relative to initially air exposed samples. The in situ 21.2 eV photoelectron spectroscopy, using a windowed discharge lamp and residual gas analysis were performed on clear iron and iron in the course of N= and HzO exposures as well as Nz-O2 and N2-HzO sequential exposures. These room-temperature UPS adsorption studies, which covered pressures from 5 × I0 -a to 0.5 tort indicate the following: dissociative adsorption of N2 and H20; molecular HzO adsorption at pressures greater than 0.05 torr; the dissociative adsorption of oxygen on nitrogen-treated surfaces (as on untreated surfaces); and a complex reaction between preadsorbed nitrogen and water vapour. The in situ adsorption results are consistent with spin orbital electronegativity concepts together with electronic structure calculations in the self consistent field-X,, approximation. The Fe-N=-H20 study is consistent with a proposed model in which the inhibition of molecular water vapour adsorption on nitrogen-treated iron is responsible for the resistance to corrosion noted. C Russo and R Kapiow, J Vac Sci Technol, 15 (2), 1978, 479-484. 11 3929. Determination of adsorbate bond geometry using photoemission. (USA) It has been known for some time that angle-resolved photocmission can give in principle a great deal of information about the valence states of adsorbed species. Recently this technique has been used to determine the orientation of CO on Ni, and Cu and N O on Ni. The 193