RHP Technology GmbH and Co KG

Seibersdorf, Austria

RHP Technology GmbH and Co KG

Seibersdorf, Austria
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Neubauer E.,RHP Technology GmbH and Co. KG | Neubauer E.,AIT Austrian Institute of Technology | Kitzmantel M.,RHP Technology GmbH and Co. KG | Kitzmantel M.,AIT Austrian Institute of Technology | And 2 more authors.
Composites Science and Technology | Year: 2010

With a continuous improvement of the production techniques for carbon nanofibers and carbon nanotubes along with an improvement of the available qualities of the materials, these reinforcements have been introduced into polymers, ceramics and metals. While in the field of polymers first success stories have been published on carbon nanofiller reinforcements, up to now metals containing these types of nanofillers are still a topic of intensive research. Basically a similar situation were found in those days, when micron sized carbon fibers came on the market. Today many applications of carbon fiber reinforced composites are existing, while metals reinforced with conventional carbon fibers are still only found in niche applications.Several reasons can be identified, why the introduction of carbon based nanofillers (nanofibers/nanotubes) into metallic matrices is a difficult task. Nevertheless it is worthwhile to carry out systematic studies in this field due to the excellent and promising thermal, electrical, mechanical or tribological properties of the nanofillers.This paper gives an overview and summarises the activities related to carbon nanotubes and nanofibers used as a reinforcement in metallic matrix materials. The main challenges and the potential with respect to material properties will be discussed. © Elsevier Ltd.


Hell J.,Vienna University of Technology | Chirtoc M.,University of Reims Champagne Ardenne | Eisenmenger-Sittner C.,Vienna University of Technology | Hutter H.,Vienna University of Technology | And 5 more authors.
Surface and Coatings Technology | Year: 2012

In most metal matrix composites (MMCs) interfaces are decisive but hard to manipulate. Especially copper-carbon composites can exhibit excellent mechanical and thermal properties only if the Cu/C interface is modified by an optimised interlayer. Due to the excellent thermal conductivity and mechanical stability of diamond this form of carbon is preferred as reinforcement in heat sink materials (copper-diamond composite) which are often subjected to severe thermal and mechanical loads. In the present case niobium and boron interlayers of various thicknesses were deposited on diamond and vitreous carbon substrates by magnetron sputter deposition. After the coverage of all samples by a copper film, a part of the samples was subjected to heat treatment for 30. min at 800. °C under high vacuum (HV) to simulate the thermal conditions during the production of the composite material by uniaxial hot pressing.De-wetting during heat treatment leads to the formation of holes or humps in the Cu coating. This effect was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A comparison of time-of-flight secondary ion mass spectroscopy (TOF SIMS) profiles of heat treated samples with those of as deposited ones showed the influence of interdiffusion during the heating process. Diffusion behaviour and chemical composition of the interface were also studied by cross sectional transmission electron microscopy (X-TEM) investigations using focused ion beam (FIB) cut samples. The thermal contact resistance (TCR) of the interface was calculated from results obtained from modulated infrared radiometry (IR). Thin interlayers suppressed de-wetting most effectively and consequently the TCR at the Cu-diamond interface was found to decrease. Therefore they are promising candidates for optimising the Cu-diamond interface. © 2012 Elsevier B.V.


Vollnhofer W.,Vienna University of Technology | Vollnhofer W.,Aerospace and Advanced Composites GmbH | Vollnhofer W.,RHP Technology GmbH and Co. KG | Eisenmenger-Sittner C.,Vienna University of Technology | And 8 more authors.
Surface and Coatings Technology | Year: 2012

It is known that quasicrystals show interesting material properties like a reduced surface energy, low adhesion and a low coefficient of friction. One quasicrystal which is an equilibrium phase and which is of special interest due to the low cost of the constituents is Al 59Cu 25.5Fe 12.4B 3. AlCuFeB coatings were deposited on different substrates by magnetron sputtering. All targets used were produced at the RHP-Technology GmbH by uniaxial hot pressing, using different powders. The targets show ceramic behavior like low electrical and thermal conductivity as well as high brittleness, which is probably due to the developed quasicrystalline phase. For deposition, the following parameters were varied: deposition power, working gas pressure, post annealing parameters. The deposited coatings were analyzed by high resolution scanning electron microscope (HRSEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The targets suffer from crack formation which results in statistical deviations in the coating composition and a systematic dependence of the coating composition on the working gas pressure and deposition power. It could be shown that a quasicrystalline AlCuFeB phase develops if the chemical composition is close enough to the nominal Al 59Cu 25.5Fe 12.4B 3 composition and if appropriate post annealing parameters are chosen. © 2011 Elsevier B.V.


Neubauer E.,RHP Technology GmbH and Co KG | Kitzmantel M.,RHP Technology GmbH and Co KG | Wilfinger T.,RHP Technology GmbH and Co KG | Kladler G.,RHP Technology GmbH and Co KG
Euro PM 2014 Congress and Exhibition, Proceedings | Year: 2014

Direct hot pressing as well as Spark Plasma Sintering are rapid densification methods which allow a fast compaction of powders. Here cycle times are typically in the range of minutes to hours. By using a Rapid Sinter Pressing (RSP) process the densification of powders can be done in seconds. By using fast processing in combination with a compaction pressure of up to 150 MPa (which is 3-5 times higher compared to standard hot pressing) it is possible to have a certain control on microstructure as well as a control on reactions between the different constituents which are used. The first part of this paper shows the successful use of the rapid sinter pressing technology for densification of pure titanium. A binary metal combination of Ti-Al was studied with focus on the effect of rapid processing on microstructure, hardness as well as functional properties such as thermal conductivity.


Neubauer E.,RHP Technology GmbH and Co KG | Garcia L.,Sandvik AB | Kladler G.,RHP Technology GmbH and Co KG | Kitzmantel M.,RHP Technology GmbH and Co KG
International Powder Metallurgy Congress and Exhibition, Euro PM 2013 | Year: 2013

There is a continuous trend in powder technology towards using rapid hot consolidation techniques for the fast manufacturing of materials. Compared to standard pressing/sintering techniques which are successfully used for the production of high volume parts for automotive applications, high performance materials such as composite materials require hot pressing or hot isostatic pressing techniques. These methods are rather long in cycle time. For the manufacturing of small parts within the past years a technology called RSP - Rapid Sinter Pressing was introduced. The method of rapid sinter pressing is basically consisting of a permanently heated pressing die (up to 950°C) in which a pre- compacted part is automatically inserted and consolidated under mechanical pressure up to 100 - 300 MPa in around 10 -60 seconds. Additional benefits of this approach are the possibility to bi-layer or sandwich structures as well as functionally gradient layers. Examples on results will be given for different materials such as pure copper, W-Cu and Mo-Cu.


Bolzoni L.,Charles III University of Madrid | Ruiz-Navas E.M.,Charles III University of Madrid | Neubauer E.,RHP Technology GmbH and Co. KG | Gordo E.,Charles III University of Madrid
Journal of the Mechanical Behavior of Biomedical Materials | Year: 2012

Hot-pressing is a powder metallurgy process where loose powder is loaded into a mould, usually of graphite, and sintered by the simultaneous application of high temperature and pressure. In this study elemental titanium and Ti-6Al-7Nb alloy powders are hot-pressed under different conditions in order to study the influence of the processing parameters on the microstructure and mechanical properties. The samples are characterised in terms of relative density, microstructure, XRD, percentage of interstitials, three-point bending test and hardness. Relative densities as high as 99% are obtained, the oxygen and carbon content remains almost constant but nitrogen percentage increases. This is due to the interaction with the BN coated mould and leads to the formation of a reacted layer in the surface, composed by different titanium compounds, which greatly affect the mechanical properties. Nevertheless, the removal of this reacted layer leads to an important improvement of the ductility, especially for elemental titanium. © 2012 Elsevier Ltd.


Baca L.,Aerospace and Advanced Composites GmbH | LenceS Z.,Slovak Academy of Sciences | Jogl C.,Aerospace and Advanced Composites GmbH | Neubauer E.,RHP Technology GmbH and Co. KG | And 3 more authors.
Journal of the European Ceramic Society | Year: 2012

Cermets containing TiB 2 and single or mixed metals were produced by conventional hot-pressing technique at 2100°C for 1h. Nickel, tantalum and their mixtures were used as alloying substances to enhance the density of TiB 2 composites. The influence of metal addition on the microstructure and tribological properties were investigated. The addition of Ta powder greatly refined the microstructure of sintered samples. Similarly, the mixture of Ni and Ta metals hindered the grain growth of TiB 2 particles during the hot-pressing while the samples were sintered up to 98% of theoretical density. The wear behaviour of the composites was assessed by ball on disk tests. The wear rate against alumina counterbody varied in the range of (5.9-21.2)×10 -6mm 3/Nm. The friction coefficient was not affected significantly by the alloying substances and only slightly increased from 0.58 for pure TiB 2 to 0.67 for samples with Ta addition. © 2011 Elsevier Ltd.


Chlup Z.,Academy of Sciences of the Czech Republic | Baca T.,Aerospace and Advanced Composites GmbH | Halasova M.,Academy of Sciences of the Czech Republic | Neubauer E.,RHP Technology GmbH and Co. KG | And 3 more authors.
Journal of the European Ceramic Society | Year: 2015

Titanium diboride (TiB2) doped with Ni and Ta was prepared by both the standard and the rapid hot-pressing method. The obvious limitations of the pure TiB2 ceramics to be fully densified are the low inter-diffusion rates, exaggerated grain growth at temperatures exceeding 2000°C, and micro-cracks produced after sintering causing high brittleness. There is only limited number of approaches how to improve the fracture resistance together with sinterability. The method used in this work is based on doping of the basic microstructure by nickel and tantalum metals with the aim to prepare composite systems with high density and enhanced fracture resistance. The positive influence of both dopants on the microstructure and fracture behaviour was demonstrated by means of microstructure, mechanical properties and fractographic analysis. This new approach, where the careful selection of metallic dopants is needed, led to the refinement of microstructure resulting in the increase of flexural strength above the level of 700MPa and fracture toughness of 6.0MPam1/2. © 2015 Elsevier Ltd.


Neubauer E.,RHP Technology GmbH and Co. KG | Kapaun W.,RHP Technology GmbH and Co. KG | Kladler G.,RHP Technology GmbH and Co. KG | Windisch H.F.,RHP Technology GmbH and Co. KG | Angerer P.,RHP Technology GmbH and Co. KG
Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2011 | Year: 2011

Within the past years direct hot pressing came up as a method for the rapid consolidation of materials. Especially when starting from powders in a submicron size the densification speed is very important to keep the microstructure at a fine level in order take advantage of better properties. Within this work pure W (different powders) and W-Ti (different Ti content) were consolidated by two different hot pressing methods. While conventional hot pressing is characterised by a rather slow process (>8 hours) the rapid heated hot pressing is finished in less than 1 hour. The microstructure of samples prepared at different temperatures/pressing conditions is compared by SEM analysis.


Falk Windisch H.,RHP Technology GmbH and Co. KG | Kapaun W.,RHP Technology GmbH and Co. KG | Kladler G.,RHP Technology GmbH and Co. KG | Kitzmantel M.,RHP Technology GmbH and Co. KG | Neubauer E.,RHP Technology GmbH and Co. KG
Proceedings of the Euro International Powder Metallurgy Congress and Exhibition, Euro PM 2011 | Year: 2011

A dense Ti-Al (50/50 at%) composite material with low amount of Ti-Al phases was consolidated using inductive hot pressing. Influence upon density and microstructure was investigated using different Tipowder and hot pressing cycles. Using induction heated hot pressing technique very short hot pressing cycles were compared to much longer hot pressing cycles like conventional resistance heated hot pressing technique. The results show that using rapid hot-pressing and a Ti-powder with rather large grain size dense Ti-Al composite could be consolidated containing a limited amount of Ti- Al phases.

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