摘要:

A review is given of the principal mechanisms contributing to atomic mixing produced by ion beams at initially well-defined interfaces between solid phases. Their relative importance is discussed in the light of available experimental evidence, and a critical survey is given of current mathematical models. The case of a thin interior implant layer is included. Those aspects of surface sputtering of direct relevance to the construction of the mixing equations are examined.

ISSN:0033-7579    

DOI:10.1080/00337578608206092

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Depth-selective surface Mössbauer analyses and scratch tests were performed for iron films on various substrates before and after proton bombardment. The results show that the adhesion behaviour is related to contaminants and mechanical stresses at the interface.

ISSN:0033-7579    

DOI:10.1080/00337578608206093

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A bilayer system composed of an Al 610 Å film evaporated onto a KCl single crystal and a pure KCl single crystal were both implanted with 300 keV209Bi+. The Bi depth distribution agrees with the Monte-Carlo simulation predictions in both systems. Diffusion of Bi in the Al film and in the KCl substrate of the Al/KCl system, as well as in the pure KCl crystal, is studied as a function of isochronal annealing. For low temperatures up to 200°C we observe enhanced diffusion of Bi in all systems. At higher temperatures (up to 500°C) a regular diffusion governs the depth profiles.

ISSN:0033-7579    

DOI:10.1080/00337578608206094

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Radiation enhanced adhesion of metallic thin films to insulating substrates has received considerable recent interest. However, the effect of ionizing radiation on the adhesion of insulating thin films to insulating substrates has not been investigated. We report on tests to determine whether or not adhesion of ZnS films to an SiO2substrate is improved by irradiation with low energy electrons or high energy Cl6+ions. A positive adhesion increase upon irradiation amounting to a factor of five improvement over unirradiated samples, has been found.

ISSN:0033-7579    

DOI:10.1080/00337578608206095

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Charged particle irradiation of glasses introduces network damage and alters the chemical composition. Compositional modifications are due to internal electric field formation and/or to sputtering processes, connected to different stopping power regimes (electronic or nuclear).

ISSN:0033-7579    

DOI:10.1080/00337578608206096

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Complex alkali-borosilicate glasses are being studied, and used, as media for radioactive waste encapsulation. The effects of radiation from α-decay processes on the physical properties of such glasses is of interest. The energy deposited in the glass by such decay processes can be simulated by ion implantation. We have examined the effects of ion implantation (He, Ar, Xe) on (1 -x)M2O.xB2/3.3SiO2, (M = Na, K;x= 0, 0.2, 0.4, 0.6, 0.8) glass, through measurements of induced stress (due to changes in volume ΔV/V) in the implanted glasses fabricated in the form of thin cantilever beams. These measurements show, as general features, (1) an initial expansion, over a fluence range governed by the alkali content, followed by compaction; (2) the maximum stress in the compaction regime is greatest for lowest alkali levels; and (3) the stress data scale with energy into electronic processes for the various ions and for all the glasses. These data suggest that the interstital alkali plays an important role in the radiation-induced dilatation of the glasses, i.e. the void volume occupied by alkali ions prevents compaction when bond breaking occurs and instead allows relaxation (ΔV/Vpositive). This process is competitive to the compaction (ΔV/Vnegative) which can occur following bond-breaking in alkali-free portions of the glass. The lowering of maximum stress levels with increased alkali is expected (softer glass, lower melting point, etc.). The scaling of dilatation/stress with electronic deposition rather than energy into collisional processes suggests that the ∼ 5 MeV α-particle in radioactive waste decay processes may contribute significantly to the radiation damage accrued in the glass encapsulant.

ISSN:0033-7579    

DOI:10.1080/00337578608206097

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337578608206098

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Irradiation with 200 keV electrons induced amorphism in natural beryl and cordierite, at fluences of ∼ 1026e/m2, a factor of ≈ 10 times that required to produce a similar effect in quartz. After dehydration of the beryl and cordierite by heating at 1050°C, the fluence required to induce amorphism was increased to ∼ 1027e/m2. The electron fluence required to produce amorphism in both materials decreased with decreasing electron energy, as expected if solid-phase radiolysis is responsible. CsAlSi5O12, prepared by dry-firing ceramic techniques, was rendered amorphous at a fluence of 3 × 1024e/m2(E= 200 keV). However, there was little apparent dependence of the electron fluence required to produce amorphism on electron energy over the 50–200 keV range, and Cs+migration may play a critical role in the crystalline ← amorphous transformation. A natural sphene was unaffected structurally by irradiation to a fluence of 2 × 1027e/m2(E= 200 keV). The data are consistent with established theories that open structures are prone to radiation-induced amorphism and that impurity electron- or hole-trapping centres augment the solid-phase radiolysis of silicates.

ISSN:0033-7579    

DOI:10.1080/00337578608206099

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Ar+bombardment in silica alumina lime glasses shows a high electronic density carbon photopeak (B.E. 281.7 eV) related to glass composition and elaboration process (melting temperature). For Na-bearing glass the photopeak of O☆with an excess negative charge has been identified (chemical shift between O0and O☆being 2.3 eV) and the effect of Na+mobility due to ion etching is given.

ISSN:0033-7579    

DOI:10.1080/00337578608206100

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Three crystalline ceramic materials, which occur as host phases for the long-lived actinides in many nuclear waste formulations, were doped with Cm-244, and the effects of self-radiation damage from alpha decay on microstructure and physical properties were investigated. The irradiation-induced micro- structure consists of individual amorphous tracks from both the alpha-recoil particles and the spontaneous fission fragments. The overlap of the tracks at higher doses leads to a completely amorphous state at a cumulative dose of 1.3–2.3 × 1025alpha decays/m3. This radiation-induced amorphization process results in a stored energy of ∼ 128 J/g, 5–10% swelling, factor of 10–50 increase in leachability, and an increase in fracture toughness.

ISSN:0033-7579    

DOI:10.1080/00337578608206101

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor