The behaviour of a triode plasma-assisted chemical vapour deposition (PACVD) system was studied with a newly developed simulation program based upon a one-dimensional particle (cloud in cell) model. ...The simulations were performed with argon as process gas to focus on the behaviour of the system without having to deal with complicated plasma chemistry. The simulations show that it is possible to control the production (and transport) of reactive species and the ion bombardment independently using the freedom to choose the total pressure, the r.f. amplitude and the d.c. voltage. In combination with these simulations a number of experiments were done where TiN was deposited on molybdenum substrates. The surface topology of these coatings, as analysed with atomic force microscopy, changes with increasing pressure from ‘egg’-like to columnar.
Six diamond coatings were produced by microwave plasma‐assisted chemical vapour deposition (MW PACVD) on polished SiC substrates. Process gas pressure and process gas composition were varied ...systematically, resulting in different coating morphologies, roughnesses and grain sizes.
Friction and wear were investigated for unlubricated vibrating contact conditions in air at room temperature. Tribological tests on diamond coatings were performed in a ball‐on‐disc configuration, with steel balls (100Cr6) and alumina balls acting as counterbodies. For comparison of the tribological performance of the diamond coatings, standard tests were performed with a stroke of 200 μn, a load of 10 N, and a frequency of 20 Hz. The effect of relative humidity (RH) was investigated by testing in dry (3% RH), in normal (50% RH), and in moist air (100% RH), respectively To investigate running‐in effects and wear propagation, the test duration (104, 105, and 1.2·106 sliding cycles) was varied.
For steel/diamond pairings, high wear at the steel ball and high friction were measured, influenced by roughness and grain size of the diamond coating and by relative humidity. For Al2O3 against diamond, a pronounced running‐in of friction and wear was found. High friction and high wear at the beginning of each test are followed by a stationary phase with extremely low friction coefficients (⩽ 0.05) and with wear rates below the limit of resolution. This running‐in depends on grain size and roughness of the coating, on relative humidity, as well as on the operational parameters. Surface analysis using SEM, EDX, LRS and AFM was conducted, to investigate tribologically induced surface changes.
Hard DLC coatings combine unique mechanical, chemical, and electrical properties. The possibility to produce them at very low temperatures, compared to those of conventional hard coatings, makes them ...an excellent choice for wear parts being coated without loss in hardness. The lifetime of cutting tools, not necessarily coated at low temperatures, can significantly be improved by using hard DLC coatings in machining. Sophisticated industrial coating technology capable of combining PVD-sputtering and PACVD can be provided for that. Steadily increasing demands for the performance of wear parts and cutting tools in connection with the versatility of these technologies will lead to an increasing market and further diversification.
Amorphous hydrogenated carbon (a-C:H) films were prepared by plasma enhanced chemical vapor deposition (PECVD) using methane. The optical properties of a-C:H films were investigated by reflectance ...and transmittance spectrometry in the visible and near-infrared regions. The dependence of refractive index, optical gap, and absorption coefficient are examined as a function of plasma power.
Provider: - Institution: - Data provided by Europeana Collections- Dresden, Technische Universität Dresden, Diss., 2012- All metadata published by Europeana are available free of restriction under ...the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
