R.Cremer
,
D.Kurapov
,
C.Martinez
,
O.Kyrylov
,
D.Neuschütz
金属学报(英文版)
Compounds of the B-C-N system are very promising to produce superhard coatings with good tribological, chemical and thermal properties. Consequently, BCN films were prepared by plasma enhanced chemical vapor deposition (PECVD). The films were deposited from gaseous mixtures of BCl3-C2H4-N2-H2-Ar in different unipolar and bipolar pulsed glow discharges at 550G and analyzed with respect to composition, electronic structure and mechanical properties. The microstructure and composition of the BCN films were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and reflection electron en- ergy loss spectroscopy (REELS). Mechanical properties were characterized using both the traditional Vickers method and nanoindentation. The films, that were deposited using a bipolar pulsed generator, were weak and had a sponge-like structure, whereas the films prepared using an unipolar generator were well adherent, had a hardness of more than 11GPa and very high elastic recoveries of up to 80%. The elasticity properties supposedly result from the formation of a fullerene-like structure.
关键词:
boron carbonitride
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null
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null
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null
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null
R.Cremer
,
D.Neuschütz
金属学报(英文版)
The increasing complexity of modern functional materials leads to the demand of acost efficient tool for the development of new products. One possible approach to thisquestion is the adaptation of combinatorial methods to the specific requirements of ma-terials industry. These methods, originally developed for the pharmaceutical industry,have recently been applied to the screening of superconductive, magnetoresistant andphotoluminescent materials. The principle of these combinatorial approaches is thedeposition of large materials libraries in one process combined with fast methods forthe determination of the resulting properties. In this paper, the deposition and charac-terization of laterally graded materials libraries (composition spread) is presented. Thefilms have been deposited by reactive magnetron sputtering, using two or three metallictargets at a low angle to the substrate surface as well as a system of apertures. Toillustrate the advantages of combinatorial approaches for the development of advancedmaterials, the multicomponent metastable hardcoatings (Ti, Al)N and Ti-Al-Si-N arediscussed with special emphasis on the relations between structure and composition onthe one hand and the oxidation resistance of these coatings on the other. The resultsillustrate that the composition spread approach is a powerful and cost efficient tool forthe development and optimization of new multicomponent functional materials.
关键词:
combinatorial chemistry
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null
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null
,
null
O.Kyrylov
,
R.Cremer
,
D.Neuschütz
金属学报(英文版)
In the last years a variety of plasma sources have been developed for film depositionby plasma activated deposition techniques. In addition to RF- and DC-sources, pulsedplasma sources are gaining increased attention. This interest is driven by the wish ofdepositing coatings with superior properties as compared to those deposited by conven-tional techniques. One prominent example of coatings that are significantly enhancedby the usage of pulsed plasmas is alumina. Although crystalline α-alumina can be de-posited by thermal CVD at temperatures above 1000℃ for two decades, no process forthe deposition of crystalline alumina on heat sensitive substrates like tempered steelsat low temperatures is commercially available up to now. In this paper, the depositionof alumina films from gaseous mixtures of AlCls-N2-H2-Ar in a bipolar pulsed glowdischarge at about 500℃ is reported. Special attention was paid on the correlation be-tween plasma characteristics and film properties. The measurements revealed that theproperties of the resulting coatings were significantly influenced by the characteristicsof the power supply. Depending on the gas composition and the plasma parameters,alumina films with high hardness and good adhesion were deposited.
关键词:
alumina
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null
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null
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