Titannitrid als gasabgabereduzierende Schicht auf Edelstahl

TiN films were deposited on stainless steel samples using a new coating procedure, the so-called modified pulse arc process. The influence of titanium nitride films on the outgassing rate was studied and the obtained results were discussed. Measurements of the outgassing rate carried out with untreated stainless steel samples and with stainless steel samples coated with titanium nitride by DC arc process are compared with the results obtained from the samples coated with the modified pulse arc process in order to get information about the influence of the coating procedure on the outgassing rate.     

Oberflächentechnik. Korrosion,Verschleiß, Wechselwirkung zwischen Oberfläche und Grundwerkstoff

Metal finishing — corrosion, wear, interaction between surface and basic metal . The influence of the surface on the behaviour of metals by mechanical stress and chemical attack has been studied. The results described complete former publications [1]. There also are discussed the necessary fundamentals.     

Das Laufrad

Zusammenfassung Zwei gekoppelte, punktsymmetrische Sechsecke bilden eine kinematische Kette mit Laufgrad 1. Solch eine Kette sei hier ‘Quasi-Rad’ genannt, weil die zw?lf Drehgeienke sich über drei konzentrische Kreise verteilen. Das Quasi-Rad kann abgeleitet werden aus dem Wunderlichschen Zw?lfstabgetriebe, und zwar von dem Typ, der vier Antiparallelogramme enth?lt. Hintergrund für diese Umwandlung ist die Erg?nzung, die sp?terOene Bottema diesem Getriebe gegeben hat, n?mlich die Erg?nzung von Wunderlichs Getriebe mit vier die gezwungene Bewegung nicht behindernden St?ben. Eine weitere Umwandlung findet statt mittels einer partiellen Umwandlung von vier Antiparallelogrammen in vier Galloway-Ketten. Von dem daraus zu erhaltenden Quasi-Rad beschreiben einander gegenüberliegende Punkte offensichtlich Koppelkurven eines Gelenkvierecks. Dasselbe trifft zu für den Mittelpunkt des Rades bezüglich jeder der zw?lf Seiten. Diese Eigenschaften erm?glichen es dem Konstrukteur, die Abmessungen so zu ?ndern, da? die parallele Kontraktion oder Dehnung des Rades auf erwünschte Weise vorgeschrieben werden kann. Im zweiten Teil dieses Aufsatzes wird n?her eingegangen auf die m?glichst beste Geradführung des Radmittelpunktes und auf die verschiedenen Ausführungen der Speichenketten, die für den Fu?wechsel und den Antrieb des Rades n?tig sind.     

Das Niederdruckplasma

Low pressure plasmas exhibit extraordinary properties caused by the combination of short and long range interactions. As the energy is almost selectively transferred to the electrons, the thermodynamic conditions for equilibrium are severely violated. The plasma screens itself against external influences. Therefore, the realization of higly sophisticated processes in simple vacuum recipients is feasible. Plasmas are excited by coupling of waves in the rf and microwave regions. Sputtering and plasma etching are the most important technologies.     

Haftung und Grenzflächenreaktionen im Verbundsystem α-Al2O3/Ni

Adhesion and Interfacial Reactions in the αAl ₂ O ₃/ Ni Composite System. Composite models consisting of a zylindrical sapphire rod surrounded by a sintered nickel ring are used to determine the influence of small amounts of titanium or zirconium (as alloying additions in the nickel) on the adhesion and compatibility between the composite components. Poor nickel gives temporally and thermally stable-shear strength values between 50 and 70 N/mm². With nickel containing 0,05 at.-% Ti or Zr the shear strength increases to 250–280 N/mm² by using favourable sintering conditions (i. e. 1300°C, 1 h). This increase is caused by an improvement of adhesion which can be explained by the formation of strong chemical bonds. These bonds are produced by chemical reactions between the sapphire surface and the alloyed active metals Ti or Zr in the nickel. With longer sintering times, higher sintering temperatures, and/or higher active metal concentrations, these reactions cause roughening of the sapphire surface and precipitation of active metal oxide phases at the interface or in the adjacent nickel zone. Those reactions-caused alterations of the interface region are changing the shear behaviour and can lead to a decrease of shear strength. The shear strength values of such specimens dont allow conclusions of the real adhesion between the components.     

Das Vakuumsystem der TOSKA-Spulentestanlage

Plasma confinement in fusion reactors requires large magnetic fields which are generated by superconducting solenoids. The coils of the future reactor ITER have a size of some 18 m × 10 m. Their construction is a technical challenge: the body of the coil suffers from large mechanical forces, originating from the magnetic field, as well as substantial thermal stress resulting from the cooling to 4.2 K. Nevertheless, the coils are required to be absolutely vacuum tight since no loss of the refrigerant helium is permissible. In the Research Center Karlsruhe (FZK) prototype coils are tested in operation under high vacuum conditions. The test chamber has a volume of 170 m³. It is pumped by an oil diffusion pump with a nominal pumping speed of 16 000 l/s. As fore and roughing pumps, a combination of Roots and rotating vane pump are employed. The available effective pumping speed of the oil diffusion pump has been measured by two different procedures: via the resulting equilibrium pressure in case of an injected stationary gas flow, and via the time-dependent decrease of pressure during pump-down. The measurements give an effective pumping speed of some 2 000 l/s. The main reason for the small pumping speed (as compared to the nominal value) is the small conductances of the inserted vacuum components and baffles. When the heating power of the oil diffusion pump is reduced to one half, the pumping speed decreases only slightly, whereas the maximum throughput decreases to one third.     

Das Zeitstandverhalten von Feinblei

The creep behaviour of sheet lead . The exact dimensioning of building components subject to deformation through creep is becoming an increasingly important factor in modern engineering. A search of the literature for the mechanical properties of sheet lead shows that differing statements are made on the mechanical behaviour of lead (1–3). Above all, it is repeatedly found that the strength properties over long periods are derived from short-term trials and that characteristic values such a expansion rate and creep rate are given, which have been determined from such trails. In order that definite information can be given on the strength properties of lead and its alloys used for technical purposes, genuine creep trails over long periods are necessary.     

Das Vakuumsystem der GSI-Beschleunigeranlage

An overview on the synchrotron and the storage ring is given. Some of the most important components are described. Vacuum pumping and measurement are shown as well as bakeout system and controls. The report closes with a summary of the first operational results.     

Das Strahlrohrvakuumsystem des HERA-Protonenringes

The beam pipe vacuum system of the HERA proton ring has a length of 6.3 km. During operation of the superconducting magnets the beam pipe is at the temperature of liquid helium over about 5.5 km. There are no detectable leaks within this critical section. The operational pressure is below 10^?12 mbar. The round beam tubes with length up to 10 m are coated with copper of good electrical conductivity from the inside. The remaining 800 m of the system are at ambient temperature. The chambers have different complicated cross sections produced with high precision. Inspite of limited space in certain areas, bakeout up to 300°C is possible in situ.     

Das Ultra-Hochvakuumsystem bei DESY 1. Teil: Das Vakuum der Elektronen-Beschleuniger

The beam pipes of HERA and DORIS, of the pre-accelerators, and the transport lines are more than 13 km long ultra-high vacuum system. For the first time the vaccum chambers of the HERA electron storage ring are made out of a copper-tin alloy. Therefore new production and brazing techniques had to be applied. In a 15 m long special furnace two channels were brazed at the left and right side of the actual chamber, one channel is for the water cooling, the other one houses the integrated sputter ion pumps. More than 1400 beam pipes up to 12 m long were produced at DESY using mainly eutectic silver-copper brazing alloy. The connections are flexible compensators made out of stainless steel. With specially developed r.f. shielded “Schott valves” the 6336 m long beam pipe is subdivided in 41 autonomous vacuum sections. The leak detection in the underground ring tunnel is done with portable magnetic helium mass spectrometers. During the operation of HERA the vacuum is continually observed and remotely controlled in the central accelerator control room.     

Das Big Data Game

This article looks at how games and play contribute to the big data-driven production of knowledge in High-Energy Physics, with a particular focus on the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), where the author has been conducting anthropological fieldwork since 2014. The ludic (playful) aspect of knowledge production is analyzed here in three different dimensions: the Symbolic, the Ontological, and the Epistemic. The first one points towards CERN as place where a cosmological game of probability is played with the help of Monte-Carlo simulations. The second one can be seen in the agonistic infrastructures of competing experimental collaborations. The third dimension unfolds in ludic platforms, such as online Challenges and citizen science games, which contribute to the development of machine learning algorithms, whose function is necessary in order to process the huge amount of data gathered from experimental events. Following Clifford Geertz, CERN itself is characterized as a site of deep play, a concept that contributes to understanding wider social and cultural orders through the analysis of ludic collective phenomena. The article also engages with Peter Galison’s idea of the trading zone, proposing to comprehend it in the age of big data as a Playground. Thus the author hopes to contribute to a wider discussion in the historiographical and social study of science and technology, as well as in cultural anthropology, by recognizing the ludic in science as a central element of understanding collaborative knowledge production.     

Das Zeitstandverhalten von Hartblei

The creep properties of hard lead The exact dimensioning of structural elements which are susceptible to creep deformation is acquiring increasing technical importance. A search through the literature (1, 2, 3, 4) for the mechanical properties of hard lead alloys reveals hardly any data on the creep behaviour of these materials. Genuine creep tests extending over prolonged periods are required in order to obtain definitive data on the strength properties of lead and its common engineering alloys. The following discussion reports on the results of creep tests lasting up to 80 000 hours on five types of hard lead.     

Das Langzeitverhalten von Metallklebverbindungen

The Long Term Behaviour of Metal bonds Important results fort he prediction of the long term strength of metal bonds are available by measuring the glue-line deformation of mechanical loaded shear-specimens under artifical humid climate. The maximum load is 50% of the shear strength, the testing time needed is 1000 h. It is sufficient to measure the glue line deformation on one point of the overlap-length because differences in other deformation along the glue line are equalized by the plastic deformation capacity of the adhesives.     

Das Vakuumschulen‐Zertifikat

Certification of Vacuum Trainings This article describes the certification process for quality assurance of vacuum trainings by the German Vacuum Society (DVG). This quality certification was established in 2014. The first certification has been completed, another is ongoing. The certification ensures all participants a certain level of teaching and learning content in both theoretical and practical parts of the trainings. The applicants are assessed by a team of auditors named by the DVG. The procedure also includes discussion about possible improvements. The spectrum of training courses that can be certified covers general vacuum trainings and special training like leak detection, coating technologies, or mass spectrometry. For further information please contact Dr. Michael Wahl, Tel. +49 631 205‐73‐3333, E‐Mail wahl@ifo.uni‐kl.de     

Das Karlsruhe Tritium Neutrino Experiment

The Karlsruhe Tritium Neutrino Experiment — The Word's Most Accurate Scale Scale The mass of the neutrino is one of the big open questions in particle physics, astrophysics and cosmology. The Karlsruhe TRItium Neutrino (KATRIN) experiment aims to measure the neutrino mass with a sensitivity of 200 meV/c². This corresponds to an improvement by a factor of 10 compared to predecessor experiments. In order to achieve this improvement, the KATRIN experiment needs to solve technical challenges from various technical fields such as high voltage, cryogenics or vacuum technology. A considerable challenge is the operation of a large spectrometer with a volume of 1240 m³ in a pressure regime of 10^?11 mbar.     

Das Diffusionsschweißen von Titanlegierungen

Diffusion Bonding of Titanium Alloys. Diffusion bonding is a 4 stage process involving surface deformation atomic bonding interface diffusion and grain growth. These processes can proceed in the above order or more or less simultaneously. The effect of production parameters and material properties on the basic mechanisms is investigated. Several diffusion bonding techniques for industrial applications have been developed and are discussed in detail. Experience with the diffusion bonding of titanium alloys has shown that base material properties may be obtained in the weld zone. Actual parts fabricated by diffusion bonding sometimes show higher strength than made without welding. Some of the difficulties associated with diffusion bonding are presented. The economical and technical advantages of the diffusion bonding process are shown by reference to typical applications where this technique can be successfully applied.