Volker Güther

Bio: Volker Güther is an academic researcher. The author has contributed to research in topics: Cathode & Boron. The author has an hindex of 1, co-authored 1 publications receiving 9 citations.

Cathodic-arc deposition with boron-alloyed titanium cathodes

Abstract: Titanium cathodes containing low boron concentrations were recently found to be important for (1) the reduction of droplet emission and (2) the formation of a denser structure of reactively deposited Ti–B–N hard coatings. Based on these results, detailed studies on the cathode behaviour and the Ti–B–N coating properties were performed using titanium cathodes containing 0–7.5 at% boron and cemented carbides and α-iron substrates. The cathode characteristics showed a more or less marked decrease of the arc voltage (at constant current), the cathode erosion, the evaporation-related substrate current and the critical arc current with increasing boron content. The Ti–B–N coatings deposited in a laboratory system were characterised in particular for their morphology, hardness and roughness, the latter being strongly reduced with increasing boron content. Thermal treatments (650°C) showed an increasing thermal stability with increasing boron content.

Historical developments and new trends in tribological and solid lubricant coatings.

Abstract: In recent years, several new solid lubricant and modern lubrication concepts have been developed to achieve better lubricity and longer wear life in demanding tribological applications. Most of the traditional solid lubricants were prepared in the form of metal, ceramic and polymer-matrix composites. They have been used successfully in various engineering applications. Recent progress in thin-film deposition technologies has led to the synthesis of new generations of adaptative, self-lubricating coatings with composite or multilayered architectures, by using duplex/multiplex surface treatments. These modern self-lubricating coatings progressively make their way into the commercial marketplace and meet the ever-increasing performance demands of more severe applications. The present paper reviews our recent understanding of the lubrication mechanisms of both traditional and new solid lubricants, with particular emphasis on solid lubricant methods and practices.

Solid Lubricant Coatings: Recent Developments and Future Trends

Abstract: In recent years, great strides have been made in the formulation of solid lubricant coatings for a wide range of industrial applications These coatings are now available in nano-structured and/or -composite forms to provide better performance and durability even under very severe sliding conditions By coupling these coatings with smart surface engineering strategies (such as micro-texturing and/or -patterning), researchers have achieved higher levels of performance and durability in demanding tribological applications Some of these advanced coatings are now commercially available and can meet the ever-increasing performance and durability requirements of severe tribological applications This paper will provide a historical overview of recent developments in solid lubricant coatings and will expand on the lubrication mechanisms of both traditional and new solid lubricants Special emphasis will be placed on modern practices that are aimed at enhancing the properties of these coatings and expanding their uses in practical applications

Multicomponent and multiphase hard coatings for tribological applications

Abstract: Plasma vapour deposition (PVD) processes are often used to deposit coatings and thin films in order to reduce wear and friction of tools and machine parts. These techniques especially allow the deposition of a broad spectrum of materials, particularly covering the nitrides and carbides of the transition metals and some borides and oxides as well as carbon-containing coatings like diamond, diamond-like, metal-carbon and carbon-nitrogen coatings. On the basis of the binary compounds TiN and TiC, various strategies were developed to improve or adapt the hard coatings to a specific tribological problem. This was first realized in multicomponent coatings by adding other metallic or non-metallic elements — also with graded concentrations. Further developments were focussed on the deposition of multiple-layer and multilayer coatings and most recently on nanostructured coatings where in addition to hard components also soft and lubricating materials are simultaneously deposited. The paper reviews the recent developments of tribological coatings giving examples of their structure, properties and performances.

Properties of superhard nc-TiN/a-BN and nc-TiN/a-BN/a-TiB2 nanocomposite coatings prepared by plasma induced chemical vapor deposition

Abstract: Using high frequency plasma chemical vapor deposition (P CVD) at a total pressure of several mbar with TiCl 4 , BCl 3 , N 2 and H 2 as reactants, superhard nanocomposite nc-TiN/a-BN and nc-TiN/a-BN/a-TiB 2 coatings with hardness of 40–50 GPa were reproducibly deposited and characterized in terms of their phase composition, nanostructure, thermal stability, oxidation resistance and mechanical properties. By analogy with earlier studied systems nc-M n N/a-Si 3 N 4 (M=Ti, W, V) and nc-TiN/a-Si 3 N 4 /a- and nc-TiSi 2 , the maximum hardness of the nc-TiN/a-BN and nc-TiN/a-BN/a-TiB 2 coatings was obtained at the percolation threshold when there is about one monolayer of thin continuous tissue of a-BN between the TiN nanocrystals. It was shown that the thermal stability and oxidation resistance of these coatings is fairly high but lower than that of the nc-TiN/a-Si 3 N 4 and nc-TiN/a-Si 3 N 4 /a-TiSi 2 coatings.