Crystalline SiC films are of technological interest because of potential applications in optoelectronics, in high-temperature semiconducting devices, as a fusion first-wall material (coated onto steel), and as a material with high wear resistance (again coated onto steel). Much of the usefulness of crystalline SiC is preserved in the amorphous state, a-SiC. Many investigations have been directed towards the study of the structure and mechanical properties of this kind of amorphous film; nevertheless, little is known about bombardment-induced chemical and compositional changes. Here we present an overview of observations and interpretations relevant to bombardment-induced structural and compositional changes in SiC and other carbides. Particular emphasis is placed on N+-implantation, which leads to SiC(x)N(y) compounds with C being gradually substituted with N. It is shown that N-implantation strongly enhances the a-SiC-stainless steel adhesion by promoting the formation of new chemical bonds at the ceramic-metal interface. By examining data from the literature, we find more or less clear evidence for a number of radiation-induced transport processes. These include (a) Gibbsian segregation, (b) vaporization, (c) long-range forces such as that provided by unbalanced charges, (d) defect-induced transport, and (c) preferential loss of C from the surface. These phenomena help to explain composition changes variously at or beneath the surface of SiC. When low to medium energy hydrogen collides with a carbide surface both chemical and transport-related processes occur. In the future generation of fusion reactors very high levels of tritium could be present in either a trapped or mobile form in walls and other internal parts. Thus tritium permeation even through thick wall materials may present problems. The permeation of hydrogen through a-SiC films is discussed showing that it can be strongly affected by surface changes.
Scheda prodotto non validato
I dati visualizzati non sono stati ancora sottoposti a validazione formale da parte dello Staff di IRIS, ma sono stati ugualmente trasmessi al Sito Docente Cineca (Loginmiur).
|Titolo:||Chemical and compositional changes induced by ion-implantation in sic and resulting hydrogen permeation properties|
|Autori:||Miotello, Antonio; R., Kelly; L., Laidani|
|Titolo del periodico:||SURFACE & COATINGS TECHNOLOGY|
|Anno di pubblicazione:||1994|
|Numero e parte del fascicolo:||n. 1-3|
|Codice identificativo Scopus:||2-s2.0-0028466051|
|Codice identificativo ISI:||WOS:A1994NX76000009|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/S0257-8972(94)80008-1|
|Appare nelle tipologie:||03.1 Articolo su rivista (Journal article)|