La technique de trempage («dip-coating») est un procédé rapide et efficace pour former des films minces de copolymères à blocs (CPB) d’épaisseur et de nano-morphologies variées. Très peu d’études ont toutefois porté sur le trempage des CPB supramoléculaires et/ou photosensibles. Le trempage du CPB poly(styrène-b-4-vinyl pyridine) (PS-P4VP) a premièrement été étudié avec des petites molécules (PM) d’acide 1-naphtoïque (NCOOH) et de 1-naphtol (NOH) capables de former des ponts hydrogène (ponts H) avec le bloc P4VP dans 4 solvants (tétrahydrofurane (THF), p-dioxane, toluène et chloroforme). Le ratio d’incorporation (RI) molaire PM/VP dans les films trempés augmente avec la vitesse de retrait mais sa variation dépend fortement du solvant et de la PM utilisés. Le RI et la morphologie des films minces dépendent de la possibilité (ou non) du solvant à former des ponts H avec la PM et de sa sélectivité au bloc de PS menant (ou non) à des micelles de P4VP/PM en solution dont la rigidité influence l’état cinétique du système en film mince. La dépendance en une courbe en V de l’épaisseur des films en fonction la vitesse de retrait définit deux régimes, nommés régimes capillaire et de drainage. Ces régimes influencent différemment le RI et la morphologie finale. Nous nous sommes ensuite intéressés aux complexes de PS-P4VP avec des azobenzènes (AB) photosensibles, le 4-hydroxy-4’-butyl-azobenzène (BHAB) et le 4-hydroxy-4’-cyano-azobenzène (CHAB). Ces AB peuvent non seulement former des ponts H avec le bloc P4VP mais aussi s'isomériser entre les formes trans et cis sous illumination. Les expériences avec PS-P4VP/BHAB dans le THF et le toluène ont révélé que l'irradiation pendant le trempage permet de provoquer une transition entre les morphologies sphérique et cylindrique à basses vitesses de retrait. Ces transitions sont expliquées par l’augmentation du ratio molaire BHAB/VP pris dans les films sous illumination et par le plus grand volume des isomères BHAB-cis par rapport aux BHAB-trans. L'irradiation permet également de moduler l'épaisseur des films sans égard à la présence des AB. Finalement, des solutions de PS-P4VP/CHAB et PS-P4VP/BHAB dans le THF avec un CPB de masse molaire plus élevée ont été étudiées afin de comprendre l’effet d'un temps de demi-vie plus court de l’AB et de la présence de micelles en solution. Le photocontrôle morphologique perd de son efficacité avec le CHAB car l’augmentation du RI de CHAB dans les films illuminés par rapport aux films non irradiés est moins prononcée que pour les complexes de BHAB. Le choix du PS-P4VP est également important puisque la présence de micelles dans les solutions de THF du PS-P4VP(36,5k-16k), même si elle n’influence pas les RI BHAB/VP, fige davantage la morphologie sphérique en solution par rapport à une solution non-micellaire de PS-P4VP(24k-9,5k), limitant les possibilités de transition morphologique. / Dip-coating is a rapid and efficient method for forming thin films of block copolymers (BCPs) of various thicknesses and nano-morphologies. However, very few studies focused on dip-coating of supramolecular and/or photosensitive BCPs. Dip-coating of poly(styrene-b-4-vinyl pyridine) (PS-P4VP) BCPs was first studied using the small molecules (SM), 1-naphthoic acid (NCOOH) and 1-naphthol (NOH), which can form hydrogen bonds with the P4VP block, in four different solvents [tetrahydrofuran (THF), p-dioxane, toluene and chloroform]. The uptake molar ratio, SM/VP, in the thin films generally increases with the dip-coating rate, but its variation is strongly dependent on the solvent and the PM used. More specifically, the uptake ratio as well as the morphology of the dip-coated thin films depend on the ability (or lack thereof) of the solvent to form hydrogen bonds with the SM and its selectivity towards the PS block, which leads (or does not lead) to micellar P4VP/PM solutions, where the rigidity of the micellar cores influences the kinetic state of the dried thin film. The dependence of film thickness on the dip-coating rate, which is V-shaped, defines two regimes, termed capillarity and draining. These regimes influence the uptake ratio and final morphologies differently. Subsequently, we investigated a relatively low molecular weight PS-P4VP (24k-9,5k), which does not form micellar solutions in THF, complexed with two photosensitive azobenzene (AB) small molecules, namely 4-hydroxy-4'-butyl-azobenzene (BHAB) and 4-hydroxy-4'-cyano-azobenzene (CHAB). These ABs not only can form hydrogen bonds with the P4VP block but can also isomerize between trans and cis forms under illumination. Experiments with PS-P4VP/BHAB in THF (non-micellar) and toluene (micellar) showed that irradiation during dip-coating provokes a transition from spherical to cylindrical morphology at low dip-coating rates not observed in the dark. This transition is explained by the increase in the BHAB/VP uptake ratio under illumination and by the larger volume of the BHAB cis form relative to BHAB trans isomers. Irradiation also increases the film thickness, even without AB present, which is attributed to a heating effect. Thus, the combination of in-situ irradiation with dip-coating has been shown to be a useful and simple method for external control of photosensitive thin film patterns. Finally, THF solutions of PS-P4VP/CHAB and PS-P4VP/BHAB with the low molecular weight BCP (non-micellar) and a BCP of higher molecular weight (36,5k-16k, micellar) were investigated to understand the effect of shorter (CHAB) vs. longer (BHAB) AB half-life and the presence or not of micelles in solution. The morphological photocontrol loses some of its effectiveness with CHAB, as shown by the less pronounced increase in uptake ratio of CHAB compared to BHAB in the illuminated films relative to non-irradiated films dip-coated from THF solutions. The presence of micelles does not influence the (BHAB/VP) uptake ratio, but it slows down the morphological evolution in the drying films, as shown by the freezing in of greater spherical morphological character compared to the non-micellar solution, thereby limiting the possibilities of a morphological transition.

No description available.

Les bioverres du système quaternaire SiO2-CaO-Na2O-P2O5 obtenus par fusion doivent être coulés à 1400°C, ce qui ne permet pas la mise en forme de matériaux complexes comme par exemple des composites macroporeux en biocéramiques (HA et TCP) recouverts d’une couche uniforme de bioverre. Pour contourner cette limitation, la voie sol-gel a été utilisée dans cette étude. Le but principal a été de synthétiser par le procédé sol-gel, deux compositions quaternaires du système SiO2-CaO-Na2O-P2O5 habituellement obtenues par fusion. Il s’agit des compositions 45S5® de L.L. Hench et 47Q de C. Duée. Ces verres sont inversés, c’est à dire qu’ils contiennent plus d’éléments modificateurs (calcium et sodium) que d’éléments formateurs (silicium et phosphore). Pour la synthèse sol-gel, du TEOS (TétraEthylOrthoSilicate) et du TEP (TriEthylPhosphate) ont été utilisés pour introduire les formateurs. En utilisant des précurseurs minéraux pour le calcium et le sodium, il existe des difficultés à maintenir le gel amorphe lors de son séchage. En effet, les précurseurs minéraux sont le siège de mécanismes de dissolution-précipitation liés entre autres aux solvants choisis, à la nature et à la concentration des anions dans le milieu. L’étude s’est donc orientée vers l’utilisation d’autres précurseurs des modificateurs afin de limiter la part des anions qui contribuent au phénomène de précipitation non souhaité. Deux procédés de synthèse originaux ont été alors mis au point avec des précurseurs alcoolates, acétates et du glycérol. Avec ces procédés, la nature amorphe des composés a été confirmée et leurs caractéristiques thermiques ont été ensuite étudiées. Tous les verres sol-gel réalisés sont bioactifs. Les compositions de base, 45S5® et 47Q, ont été ensuite dopées avec de l’argent afin de doter les bioverres d’une action antibactérienne. Des cellules L132 ont été utilisées pour évaluer la toxicité des poudres des deux procédés solgel. Le procédé le moins toxique a été conservé pour la suite de l’étude. Les bioverres dopés et non dopés ont été alors déposés à la surface d’échantillons plats et macroporeux en HA et TCP par une technique de trempage-retrait. Des tests de prolifération et de formation de biofilms par Pseudomonas aeruginosa ont été réalisés sur des pastilles de TCP recouvertes et ont mis en évidence un effet toxique des dépôts contenant de l’argent. Des mesures de prolifération et de vitalité sur des cellules humaines MG63 ont été également réalisées et ont permis d’observer également un effet toxique. Cet effet n’est pas souhaitable dans ce cas car il affecte la biocompatibilité de l’implant. Il devrait cependant être confirmé par d’autres tests réalisés avec d’autres lignées cellulaires. / Bioglasses of quaternary system SiO2-Na2O-CaO-P2O5 obtained by melting are cast at 1400 ° C, which does not allow the shape of complex materials, for example macroporous bioceramics composites (HA and TCP) coated with an uniform layer of bioglass. To overcome this limitation, the sol-gel process has been used in this study. The aim has been to synthesize by sol-gel process, two quaternary compositions usually obtained by melting in the SiO2- CaO-Na2O-P2O5 system. These are two compositions: 45S5® of L.L. Hench and 47Q made by C. Duée. These glasses are reversed, ie they contain more modifiers elements (calcium and sodium) as formers elements (silicon and phosphorus). For the sol-gel synthesis, TEOS (TetraEthylOrthoSilicate) and TEP (TriEthylPhosphate) have been used to introduce the formers. When minerals precursors are used for calcium and sodium, there are difficulties to maintain amorphous the gel during its drying. Indeed, minerals precursors have some dissolution-precipitation mechanisms linked to the selected solvents and the nature and concentration of anions in the medium. The use of other modifiers precursors has been made in the study to limit the proportion of anions contributing to the undesired precipitation phenomenon. Two original synthesis methods have been developed with alkoxide precursors, acetates and glycerol. With these processes, the amorphous nature of the compounds has been confirmed and their thermal characteristics have been studied. All sol-gel glasses are bioactives. The compositions, 45S5® and 47Q, have been doped with silver to add an antibacterial action to the bioglasses. L132 cells have been used to test the toxicity on the powders of the two sol-gel processes. The least toxic process is has been retained for the other tests. Doped and undoped bioglasses have been coated on the surface of flat and macroporous samples of HA and TCP by a dip-coating technique. Proliferation tests and biofilms formation by Pseudomonas aeruginosa have been made on coated TCP and show toxic effects of silver. Proliferation and vitality tests have been also made on MG63 human cells and have allowed to observe a toxic effect. This effect is not suitable in this case because it affects the biocompatibility of the implant. It would, however, be confirmed by other tests with other cell lines.

The most commonly known macro scale probing devices are simply comprised of metallic leads used for measuring electrical signals. On the other hand, micromachined probing devices are realized using microfabrication techniques and are capable of providing very fine, micro/nano scale interaction with matter; along with a broad range of applications made possible by incorporating MEMS sensing and actuation techniques. Micromachined probes consist of a well-defined tip structure that determines the interaction space, and a transduction mechanism that could be used for sensing a change, imparting external stimuli or manipulating matter. Several micromachined probes intended for biological and nanotechnology applications were fabricated, characterized and tested. Probes were developed under two major categories. The first category consists of Micro Electromagnetic Probes for biological applications such as single cell, particle, droplet manipulation and neuron stimulation applications; whereas the second category targets novel Scanning Probe topologies suitable for direct nanopatterning, variable resolution scanning probe/dip-pen nanolithography, and biomechanics applications. The functionality and versatility of micromachined probes for a broad range of micro and nanotechnology applications is successfully demonstrated throughout the five different probes/applications that were studied. It is believed that, the unique advantages of precise positioning capability, confinement of interaction as determined by the probe tip geometry, and special sensor/actuator mechanisms incorporated through MEMS technologies will render micromachined probes as indispensable tools for microsystems and nanotechnology studies.

Die Filtration unter aggressiven Einsatzbedingungen, z.B. Einsatz in korrosiven Medien, Abgasfiltration, stellt besondere Anforderungen an das Filtermaterial. Sogenanntes "Liquid Phase Sintered Silicon Carbide" (LPS-SiC) erfüllt die Anforderungen sehr gut. Deshalb bestand das Ziel der Arbeit besteht darin, erstmals aus LPS-SiC asymmetrische keramische Membranen (grobporöses Substrat mit dünner, feinporiger Membran) herzustellen. Als Additivsystem fanden Yttriumoxid und Aluminiumoxid Verwendung. Es wurde Siliciumcarbid der Körnung F1200 auf Substrat der Körnung F500 abgeschieden. Dem Herstellungsverfahren kommt für die Qualität der Membran eine große Bedeutung zu. Daher wurden in dieser Arbeit folgende Beschichtungsmethoden untersucht, um die optimale Methode zu identifizieren: Tauchbeschichtung, elektrophoretische Abscheidung, Druckfiltration und Einsatz von Transfertapes (Transfertapes: Mischung aus Polyacrylatkleber und Pulver). Im Mittelpunkt stand dabei die Druckfiltration. Hierfür wurde eine neue Apparatur konzipiert und aufgebaut. Für die schlickerbasierten Methoden wurde ein wässriges System entwickelt, bei dem auf den Einsatz von organischen Hilfsstoffen verzichtet werden konnte. Die elektrostatische Stabilisierung konnte durch gezieltes Anlösen von Yttriumoxid, Ausfällen von feinskaligem Yttriumhydroxid und Belegung des Siliciumcarbids mit dem Yttriumhydroxid erreicht werden. Die Elektrophorese führte zu keinen befriedigenden Ergebnissen aufgrund des undefinierten spezifischen Widerstandes des Substrats (siehe Dissertation Jan Ihle, Bergakademie Freiberg 2004). Die Druckfiltration erwies sich als das geeignetste Verfahren. Mit ihr konnten ohne Einschränkungen hochwertige Membranen erzeugt werden. Druck und Zeit sind bei gegebenen Feststoffgehalt frei wählbar. Der Druck wurde zwischen 2*10E4 und 1*10E5 Pa variiert. Höherer Druck führte zu feineren Porengrößen (mittlere und maximale Porengröße). Mit der Druckfiltration konnten Membranen ohne makroskopische Defekte erzeugt werden. Sie führte im Vergleich aller Verfahren zu der geringsten Rauhtiefe der Membranen. Die Tauchbeschichtung ließ sich in diesem System nur über den Feststoffgehalt steuern. Membranen aus der Tauchbeschichtung wiesen makroskopische Fehler (große oberflächliche Poren) auf. Die Methode führte hinsichtlich Porengrößen und Rauhtiefe zu den schlechtesten Werten. Die Transfertape-Methode als neuartiger Ansatz erwies sich für das LPS-SiC System als noch nicht ausgereift. Das direkte Bekleben der Substrate war möglich. Hinsichtlich der Membrandicke sind aber Grenzen bei ca. 50 µm gesetzt. Darüber hinaus reißen die Membranen. Es wurden Schwankungen in der Entbinder- und Sinterschwindung verzeichnet. Weiterhin werden große Hohlräume im Substrat nicht von den Transfertapes abgeformt. Beide Effekte erhöhen die Spannungen beim Sintern, so dass bei geringeren Schichtdicken Risse entstehen. / Silicon Carbide (SiC) fulfills many requirements, e.g. a high robustness in terms of corrosion, which makes it a suitable Material for ceramic membranes. The aim of this work was to produce ceramic membranes out of porous liquid phase sintered Silicon Carbide (LPS-SiC). As additives Alumina and Yttria were used. The SiC based on commercial abrasive powders F1200 (Membrane) and F500 (Substrate). Different techniques of membrane formation were applied in order to find the optimum processing procedure: Dip Coating, Electrophoretic Deposition (EPD), Pressure Filtration and the usage of so called Transfer Tapes, a blend of Polyacrylate and ceramic powders). For the slip based methods a water based system was developed without the need of organic additives. A pure electrostatic stabilization was facilitated by solving Yttria with Hydrochloride Acid and precipitation, resulting in the coverage of the SiC particles with finely dispersed Yttria. The EPD was not successful due to a undefined specific resistance of the substrate. The pressure filtration turned out to be the best, most versatile method, leading to defect free membranes with the lowest measured surface roughness. The pressure ranged between 2*10E4 and 1*10E5 Pa. Higher pressure lead to finer pores. The Dip Coating was controlled only by the solids content. Membranes by Dip Coating showed macroscopic defects. As a new concept for ceramic membrane fabrication the Transfer Tapes needed further investigation. The direct gluing on the substrate was possible. The thickness of the membrane was limited to 50 microns in order to keep free of cracks. The Transfer Tapes exhibited pronounced fluctuations in the debinding and sintering shrinkage, leading to increased tension during sintering. Furthermore cavities, (e.g. big pores) were bridged. Both effects lead to increased tension during sintering.

Aqueous solutions were studied using photoelectron and Auger spectroscopy, based on synchrotron radiation and a liquid micro-jet setup. By varying the photon energy in photoelectron spectra, we depth profiled an aqueous tetrabutylammonium iodide (TBAI) solution. Assuming uniform angular emission from the core levels, we found that the TBA+ ions were oriented at the surface with the hydrophobic butyl arms sticking into the liquid. We investigated the association between ions and their neighbors in aqueous solutions by studying the electronic decay after core ionization. The (2p)−1 decay of solvated K+ and Ca2+ ions was studied. The main features in the investigated decay spectra corresponded to two-hole final states localized on the ions. The spectra also showed additional features, related to delocalized two-hole final states with vacancies on a cation and a neighboring water molecule. These two processes compete, and by comparing relative intensities and using the known rate for the localized decay, we determined the time-scale for the delocalized process for the two ions. We compared to delocalized electronic decay processes in Na+, Mg2+, and Al3+, and found that they were slower in K+ and Ca2+, due to different internal decay mechanisms of the ions, as well as external differences in the ion-solute distances and interactions. In the O 1s Auger spectra of aqueous metal halide solutions, we observed features related to delocalized two-hole final states with vacancies on a water molecule and a neighboring solvated anion. The relative intensity of these feature indicated that the strength of the interaction between the halide ions and water correlated with ionic size. The delocalized decay was also used to investigate contact ion pair formation in high concentrated potassium halide solutions, but no concrete evidence of contact ion pairs was observed. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 726

This Ph.D. thesis deals with problems about voltage dips and short voltage interruptions, generally named as voltage events, which origin in power supply networks and have a negative influence for all connected electric appliances. In this thesis single phase appliances are considered. These problems closely relate with area of electromagnetic compatibility which solve all questions about correct operation of different types of electric appliances during electromagnetic disturbances impact. Voltage events are ones of the many types of electromagnetic disturbances. The connection between disturbance sources and sensitive electric appliances is created by power supply lines. The immunity of electric appliances to voltage dips and short interruptions is currently tested via voltage dips with strictly defined parameters which are intended by class of electromagnetic environment in which the usage of electric appliance is recommended. During immunity tests the rectangular shape of voltage dips is preferred. The main descriptive parameters of testing voltage events are the residual voltage and the event time duration. But voltage dips and short interruptions defined by this way do not closely relate with parameters of real voltage dips and interruptions occurred in public supply system where parameters of voltage dips are variable. Moreover in the power supply system there are many of others voltage parameters which can have a significant influence to immunity level of connected electric appliances. This Ph.D. thesis also deals with finding more voltage event parameters. Although the voltage events occurrence in the power supply system is not limited and voltage events are considered only as informative voltage parameter it is important to monitor voltage events occurrence. The monitoring device has to be able to operate for ling time period and it has to detect parameters of voltage events with adequate accuracy. The accuracy of detected event parameters and the detection delay depends on the detection algorithm characteristics. That is why the part of this thesis relates with a comparison of several detection algorithms and their abilities to correct detection of voltage event parameters. The main purpose of this thesis is the proposal of connection between classification of voltage dips and short interruptions occurred in power supply system with the classification of electric appliances immunity to these voltage events. On the base of many of provided electric appliances immunity tests and also on the base of long time period voltage events monitoring the special compatibility levels are proposed in this thesis. The observation of proposed compatibility levels will bring the increasing level of reliable operation of all connected electric appliances.

This critical review summarizes recent developments in the fabrication of patterned polymer brushes. As top-down lithography reaches the length scale of a single macromolecule, the combination with the bottom-up synthesis of polymer brushes by surface-initiated polymerization becomes one main avenue to design new materials for nanotechnology. Recent developments in surface-initiated polymerizations are highlighted along with diverse strategies to create patterned polymer brushes on all length scales based on irradiation (photo- and interference lithography, electron-beam lithography), mechanical contact (scanning probe lithography, soft lithography, nanoimprinting lithography) and on surface forces (capillary force lithography, colloidal lithography, Langmuir–Blodgett lithography) (116 references). / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Die Filtration unter aggressiven Einsatzbedingungen, z.B. Einsatz in korrosiven Medien, Abgasfiltration, stellt besondere Anforderungen an das Filtermaterial. Sogenanntes "Liquid Phase Sintered Silicon Carbide" (LPS-SiC) erfüllt die Anforderungen sehr gut. Deshalb bestand das Ziel der Arbeit besteht darin, erstmals aus LPS-SiC asymmetrische keramische Membranen (grobporöses Substrat mit dünner, feinporiger Membran) herzustellen. Als Additivsystem fanden Yttriumoxid und Aluminiumoxid Verwendung. Es wurde Siliciumcarbid der Körnung F1200 auf Substrat der Körnung F500 abgeschieden. Dem Herstellungsverfahren kommt für die Qualität der Membran eine große Bedeutung zu. Daher wurden in dieser Arbeit folgende Beschichtungsmethoden untersucht, um die optimale Methode zu identifizieren: Tauchbeschichtung, elektrophoretische Abscheidung, Druckfiltration und Einsatz von Transfertapes (Transfertapes: Mischung aus Polyacrylatkleber und Pulver). Im Mittelpunkt stand dabei die Druckfiltration. Hierfür wurde eine neue Apparatur konzipiert und aufgebaut. Für die schlickerbasierten Methoden wurde ein wässriges System entwickelt, bei dem auf den Einsatz von organischen Hilfsstoffen verzichtet werden konnte. Die elektrostatische Stabilisierung konnte durch gezieltes Anlösen von Yttriumoxid, Ausfällen von feinskaligem Yttriumhydroxid und Belegung des Siliciumcarbids mit dem Yttriumhydroxid erreicht werden. Die Elektrophorese führte zu keinen befriedigenden Ergebnissen aufgrund des undefinierten spezifischen Widerstandes des Substrats (siehe Dissertation Jan Ihle, Bergakademie Freiberg 2004). Die Druckfiltration erwies sich als das geeignetste Verfahren. Mit ihr konnten ohne Einschränkungen hochwertige Membranen erzeugt werden. Druck und Zeit sind bei gegebenen Feststoffgehalt frei wählbar. Der Druck wurde zwischen 2*10E4 und 1*10E5 Pa variiert. Höherer Druck führte zu feineren Porengrößen (mittlere und maximale Porengröße). Mit der Druckfiltration konnten Membranen ohne makroskopische Defekte erzeugt werden. Sie führte im Vergleich aller Verfahren zu der geringsten Rauhtiefe der Membranen. Die Tauchbeschichtung ließ sich in diesem System nur über den Feststoffgehalt steuern. Membranen aus der Tauchbeschichtung wiesen makroskopische Fehler (große oberflächliche Poren) auf. Die Methode führte hinsichtlich Porengrößen und Rauhtiefe zu den schlechtesten Werten. Die Transfertape-Methode als neuartiger Ansatz erwies sich für das LPS-SiC System als noch nicht ausgereift. Das direkte Bekleben der Substrate war möglich. Hinsichtlich der Membrandicke sind aber Grenzen bei ca. 50 µm gesetzt. Darüber hinaus reißen die Membranen. Es wurden Schwankungen in der Entbinder- und Sinterschwindung verzeichnet. Weiterhin werden große Hohlräume im Substrat nicht von den Transfertapes abgeformt. Beide Effekte erhöhen die Spannungen beim Sintern, so dass bei geringeren Schichtdicken Risse entstehen. / Silicon Carbide (SiC) fulfills many requirements, e.g. a high robustness in terms of corrosion, which makes it a suitable Material for ceramic membranes. The aim of this work was to produce ceramic membranes out of porous liquid phase sintered Silicon Carbide (LPS-SiC). As additives Alumina and Yttria were used. The SiC based on commercial abrasive powders F1200 (Membrane) and F500 (Substrate). Different techniques of membrane formation were applied in order to find the optimum processing procedure: Dip Coating, Electrophoretic Deposition (EPD), Pressure Filtration and the usage of so called Transfer Tapes, a blend of Polyacrylate and ceramic powders). For the slip based methods a water based system was developed without the need of organic additives. A pure electrostatic stabilization was facilitated by solving Yttria with Hydrochloride Acid and precipitation, resulting in the coverage of the SiC particles with finely dispersed Yttria. The EPD was not successful due to a undefined specific resistance of the substrate. The pressure filtration turned out to be the best, most versatile method, leading to defect free membranes with the lowest measured surface roughness. The pressure ranged between 2*10E4 and 1*10E5 Pa. Higher pressure lead to finer pores. The Dip Coating was controlled only by the solids content. Membranes by Dip Coating showed macroscopic defects. As a new concept for ceramic membrane fabrication the Transfer Tapes needed further investigation. The direct gluing on the substrate was possible. The thickness of the membrane was limited to 50 microns in order to keep free of cracks. The Transfer Tapes exhibited pronounced fluctuations in the debinding and sintering shrinkage, leading to increased tension during sintering. Furthermore cavities, (e.g. big pores) were bridged. Both effects lead to increased tension during sintering.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Eutectic (63% tin-37% lead) or near-eutectic (40% tin-60% lead) tin-lead solder is widely used for creating electrical interconnections between the printed wiring board (PWB) and the components mounted on the board surface. For components mounted directly on the PWB mounting pads, that is, surface mounted components, the tin-lead solder also constitutes the mechanical interconnection. Eutectic solder has a melting point of 183°C (361°F). It is important to realize that its homologous temperature, defined as the temperature in degrees Kelvin over its melting point temperature (T(m)), also in degrees Kelvin, is defined as T/T(m). At room temperature (25°C = 298K), eutectic solder's homologous temperature is 0.65. It is widely acknowledged that materials having a homologous temperature ≥ 0.5 are readily subject to creep, and the solder joints of printed wiring assemblies are routinely exposed to temperatures above room temperature. Hence, solder joints tend to be subject to both thermal fatigue and creep. This can lead to premature failures during service conditions. The geometry, that is, the lead configuration, of the joints can also affect failure. Various geometries are better suited to withstand failure than others. The purpose of this paper is to explore solder joint failures of dual in-line (DIP) integrated circuit components, leadless ceramic chip carriers (LCCCs), and gull wing and J-lead surface mount components mounted on PWBs.