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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

SnBi pájecí pasta a vliv reaktivních nanočástic / SnBi Solder Paste and Influence of Reactive Nanoparticles

Rychlý, Ivo January 2018 (has links)
This work deals with effects of nanoparticles, mainly copper and silver, on properities of lead-free solder pastes. It describes basic tests done on solder pastes according to IPC-TM-650 standards. In practical section this work focuses on the preparation of Sn-Bi solder paste and the measuring of viscosity. After that different concentrations of silver copper alloy nanoparticles are added to the SnBi solder paste. These solder pastes are tested by the IPC standarts and mechanical and resistive tests are done on printed circuit boards where the effects of mixed in nanoparticles are observed.
252

Defektoskopie s využitím RTG / X-ray Defectoscopy

Velím, Michael January 2019 (has links)
This diploma thesis deals with a defect detection with X-rays in the manufacturing procedure in the electrotechnical field. The work summarises the knowledge about technical possibilities of an X-ray device Cougar of YXlon company. Part of the work is focusing on scanning in 2D, 3D visualization and automatic analysis. The thesis describes inspection methods of a connector connection, the quality of a soldered joint and an encapsulated product.
253

Termomechanická spolehlivost montáže mikroelektronických a elektronických modulů / Modern Assembly for Microelectronic and Electronic Modules

Janík, Pavel January 2010 (has links)
Project is focused on describe modern assembly of microelectronic and electronic modules in electronic devices. Sense of the project is analyse reliability and inadequacies electronic devices assembled by modern technogies. Inadequacies modern technologies are impulse for design, implementation and testing new our way of assembly microelectronic modules. Main kind of materials which are used in this project are ceramics Al2O3 and printed circuit board FR4.
254

Analýza změn v pájených spojích vzniklých vlivem stárnutí / Analysis of solder joint changes caused by aging

Paško, Martin January 2011 (has links)
These thesis deals with electromigration in solder joint. In theoretical part are described lead-free solders, surface finish, formation of solder joint, intermetallic compounds a electromigration. In practical part is investigated a effect of electromigration on growth intermetallic compounds in solder jsoint.
255

Termomechanické namáhání bezolovnatého pájeného spoje / Thermomechanical Stress of Lead Free Solder Joint

Libich, Jiří January 2011 (has links)
This diploma thesis deals with the reliability of lead-free solder joints at a different interconnection structures. The first goal is to design the test cases shape BGA (FC) for testing the strength of lead-free solder joints at shear test in link with design of measuring method to detection shear strength during isothermal aging of lead-free solder joints. Following this shear stressing is investigating influence material and process compatibility, ie. pads finishing, material of solder and integrate of temperature (this mean thermal energy supplied during soldering) to lead-free solder joint strength.
256

Vliv inertní atmosféry na smáčení povrchu u bezolovnatého pájení / Influence of Inert Atmosphere on Surface Wetting in Lead Free Soldering

Nestrojil, Michal January 2014 (has links)
This master´s thesis dealing with study of influence of inert atmosphere on the wettability of soldered surfaces. The theoretical part is discussed the issue of the soldering, solder joint, oxidation, and inert atmosphere. The glass cover with internal inert gas preheating for the wetting balance testing was prepared in the practical part. With this adjustment were realised tests, in which was examined the effect of the inert gases on the wettability of different materials combination. Further experiments were focused on plasma surface cleaning as possible flux substitution. The evaluation of these experiments were discussed in the end of this master´s thesis. Some of topics were designed for further experiments.
257

Roztékavost bezolovnatých pájek na keramických substrátech / Wetting of lead-free solders on ceramic substrates

Lipavský, Lubomír January 2014 (has links)
This master's thesis deals with issue of lead-free soldering in protective atmosphere with focus on wetting test. Theorethical part is focused on the types of lead-free solders, wettability tests performed on solder joints, different types of soldering or comparison of influence of the base material in regards to the wetting of the solder. The goal of practical part is testing and comparison of spreadability of selected lead-free solder on two conductive surfaces with different concentration of oxygen in protective nitrogen atmosphere. Testing has been performed on ceramic substrate which differs this method from others, performed on organic substrate. For an over-melted solder, the crystal-growth on surface in regards to protective atmosphere concentration is shown.
258

Návrh technologie výroby výstelky labyrintové ucpávky / Technology design of labyrinth packing lining production

Katolický, Jiří January 2008 (has links)
The diploma work is focused to evaluation of contemporary state of sealing system solution of high speed turbine engines in the world and, newly suggesting nontraditional design of labyrinth sealing lining for turbine side of small turbojet engine, including the production technology, technical-economic classification and experimental verification.
259

Propojovací technologie pro 3D elektronické a mikroelektronické konstrukce / Interconnection Technologies for 3D Electronic and Microelectronic Constructions

Nicák, Michal January 2016 (has links)
The doctoral thesis is focused on research on application possibilities of soldered interconnection structures especially for the use with innovative 3D structures assembled using the LTCC ceramic materials, PVD deposited and galvanically modified pads, solid core solder balls. It consists of several main parts. Introduction is followed by theoretical survey of current situation and technologies. Thesis continues with introduction of main goals and with summary of successively performed experiments and their results. End of the work belongs to summary of results and gained knowledge.
260

Nouvelles brasures sans plomb : conception des dispositifs d'essai, fabrication des échantillons et caractérisation / New Lead-Free Solders : testing Device Development, Specimen Fabrication, and Characterization

Tao, Quang Bang 06 December 2016 (has links)
De nos jours, une des stratégies pour améliorer les propriétés des brasures sans plomb est d'introduire en petites quantités certains éléments d'alliage. Dans notre étude, deux nouveaux types de brasures, dénommés Innolot et SAC-Bi et dont l'utilisation dans diverses applications électroniques augmente, sont caractérisées. En particulier, l'effet des éléments Ni, Sb et Bi sur les propriétés mécaniques est analysé. L'étude vise également à évaluer l'influence des facteurs de sollicitation, du vieillissement en température sur la réponse des matériaux et leurs évolutions microstructurales. A cet effet, une machine permettant de réaliser des essais de micro-traction sur éprouvettes miniatures a été conçue et fabriquée. Les sollicitations qu'elle permet d'appliquer sont multiples (traction, cisaillement et cyclage) et des conditions en température et en vitesse de déformation peuvent être imposées lors de l'essai. La fabrication des éprouvettes nécessaires aux essais a également été entreprise dans cette étude afin d'avoir un matériau similaire à celui issu du process industriel et de disposer d'une géométrie adaptée au type de caractérisation souhaitée (éprouvettes massives, à simple recouvrement, etc.).Après ces étapes préparatoires, des tests ont été réalisés sous sollicitations de traction, cisaillement, fluage et fatigue en faisant varier les conditions d'essais. Le premier objectif a été l'identification du comportement des brasures, y compris en prenant en compte l'effet du vieillissement. Ces données ont permis ensuite de réaliser des simulations thermo-mécaniques sur les matériaux utilisés sous forme de joints de brasure dans un module de puissance sous cyclage thermique. Les analyses de microstructure (SEM/EDS et EPMA) faites par la suite ont montré le rôle des éléments d'alliage (Ni, Sb et Bi) sur les performances mécaniques des brasures en termes de résistance, limite élastique et rigidité. Le rôle des facteurs d'essai, comme la température, la vitesse de sollicitation et la durée de vieillissement, a également été mis en évidence au niveau des propriétés obtenues et des changements dans la microstructure. Il a été établi que l'élément Sb permet de favoriser le durcissement par écrouissage des brasures, tandis que l'ajout des éléments Ni et Bi permettent un raffinement de la microstructure. Les essais ont aussi permis d'identifier les 9 paramètres de la loi d'Anand par une procédure numérique s'appuyant sur les données de traction et de cisaillement, permettant ainsi de réaliser des simulations par éléments finis. Ces dernières suggèrent un meilleur comportement à la fatigue pour la brasure Innolot qui bénéficie est effets favorables des additifs. / Nowadays, one of the strategies to improve the reliability of lead-free solder joints is to add minor alloying elements to solders. In this study, new lead-free solders, namely InnoLot and SAC387-Bi, which have begun to come into use in the electronic packaging, were considered to study the effect of Ni, Sb and Bi, as well as that of the testing conditions and isothermal aging, on the mechanical properties and microstructure evolution. A new micro-tensile machine are designed and fabricated, which can do tensile, compressive and cyclic tests with variation of speeds and temperatures, for testing miniature joint and bulk specimens. Additionally, the procedure to fabricate appropriate lap-shear joint and bulk specimens are described in this research. The tests, including shear, tensile, creep and fatigue tests, were conducted by micro-tensile and Instron machine at different test conditions. The first study is to characterize, experimentally, the mechanical behaviors and life time of solder joints submitted to isothermal aging and mechanical tests. The second goal of the project is to perform thermo-mechanical simulations of IGBT under thermal cycling. The experimental results indicate that, with addition of Ni, Sb and Bi in to SAC solder, the stress levels (UTS, yield stress) are improved. Moreover, testing conditions, such as temperature, strain rate, amplitude, aging time, may have substantial effects on the mechanical behavior and the microstructure features of the solder alloys. The enhanced strength and life time of the solders is attribute to the solid hardening effects of Sb in the Sn matrix and the refinement of the microstructure with the addition of Ni and Bi. The nine Anand material parameters are identified by using the data from shear and tensile tests. And then, the obtained values were utilized to analyze the stress-strain response of an IGBT under thermal cycling. The results of simulations represent that the response to thermal cycling of the new solders is better than the reference solder, suggesting that additions of minor elements can enhance the fatigue life of the solder joints. Finally, the SEM/EDS and EPMA analysis of as-cast, as-reflowed as well as fractured specimens were done to observe the effects of these above factors on the microstructure of the solder alloys.

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