Electrodeposition of NiP composite coatings with nano and sub-micron sized SiC has been carried out to investigate the possibility of replacing hard chromium coatings. The composition and structure of the coatings were evaluated by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis, respectively. Microhardness was measured by Vickers indentation and polarization measurements were carried out to study the corrosion behavior of the coatings. The results showed that submicron particles can be codeposited with a higher content as compared to nano sized ones. However, even if a smaller amount of the nano-sized SiC particles are incorporated in the coating, the contribution to an increasing microhardness was comparable with the submicron sized particles, which can be related to the higher density of codeposited particles. SiC particles did not change the anodic polarization behavior of NiP coatings in a 3.5% NaCl solution. Finally, the effect of heat-treatment on the coatings properties at 400 °C for 1 h was studied to investigate the contribution of particles and heat-treatment on hardness and corrosion properties. It was found that the heat-treatment doubled the microhardness and changed the anodic polarization behavior of the coatings from passive to active with respect to the as-plated conditions.
In this study, electrodeposition of Ni-P composite coatings has been carried out to investigate the possibility of replacing hard chromium coatings. Therefore, electrodeposition of Ni-P based composite coating with different SiC particle size (50 nm, 100 nm and 500 nm) or B4C (500 nm) was performed. The coating's composition was evaluated by energy dispersive spectroscopy (EDS), microhardness of the coatings was measured by Vickers indentor and polarization measurements were carried out to study the corrosion behavior of the coatings. The results showed that B4C particles can codeposit in higher percent respect to SiC ones. Ceramic particles increased microhardness of Ni-P coatings to 700HV0.01. The polarization behavior of all the coatings in 3.5% NaCl was similar in as plated state proving that particles did not hindered the passive behaviour. Finally, the effect of heat-treatment (at 400 ºC for 1 hour) on the coating's properties was studied to compare the contribution of particles and heat-treatment on mechanical and corrosion properties of the coatings. Heat-treatment increased the coating's microhardness and changed the anodic polarization behavior of the coatings respect to the as plated conditions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved.
The effect of fillets formed between the base and plate fins of rheocast aluminium heatsinks on the thermal resistance of the heatsinks has been quantified by simulation. Simulation methodology, including sequential optimization has been developed in order to determine hotspot distributions where the fillets have the maximum effect. Combination of different fillet dimensions with various base thickness levels and aluminium alloys having inhomogeneous thermal conductivity have been investigated. For the studied cases, the effect of fillets on heatsink thermal resistance differs from negligible to 6%. The results would guide thermal designers on contribution of fillets to the heat transfer in multi-fin heatsinks for natural convection.
Experimental evaluation of several active anti-condensation methods for application in non-hermetic electronics enclosures was performed in harsh climatic conditions, including RH = 70% and T = 43 °C. The studied methods included blowing the air along the exposed surface, combination of blowing and air heating as well as local heating of the exposed surface in natural convection conditions. The purpose was to prevent/remove the dew on/from the exposed surface of a micro-condensation sensor. The difference between the methods was quantified in terms of time for dew removal. The power consumption aspects were discussed. A CFD based optimization methodology was developed to determine the heating profiles for the local anti-condensation PCB heater in a non-hermetic cabinet exposed to the quickly changing climatic conditions. The potential for 60% energy savings was revealed by simulation.
The paper investigates the effect of variations both in temperature cycling profile and in SAC305 solder Young's modulus in the PBGA256 package on the thermo-mechanical reliability. FE simulations quantify the effect of cycle reduction and counting techniques by introducing different temperature profiles having identical dwell- and period time characteristics. A difference of 30% in predicted accumulated creep strain energy density per cycle has been determined for the studied profiles. Under the provided modelling assumptions and simplifications, the maximum variation of the thermal fatigue life of SAC305 solder joints is within 30% as the result of experimentally determined Young's modulus variation in as-delivered packages.
The paper reveals benefits of multi-disciplinary computer simulation and parametric studies in the design of silver plating process for improved coating distribution. A finite element model of direct current silver plating is experimentally validated for an Assaf panel without agitation. The model combines tertiary current distribution with Butler-Volmer electrode kinetics and computational fluid dynamics at a very low flow-rate. The effect of charge transfer coefficients on the throwing power of the process is quantified for the studied geometry, and variation of cathodic current density and exchange current density is investigated. A simpler model based on secondary current distribution is employed to quantify the effect of electrolyte conductivity on the throwing power of the process. A model combining tertiary current distribution and computational fluid dynamics has been developed and experimentally validated for simulation of complex telecom component electroplating in agitated electrolyte. The effect of current density on the process throwing power is quantified. Recommendations regarding modeling methodology and the effect of electrochemical and process parameters on the thickness distribution have been developed.
A mathematical model of an AC/DC/AC power converter with an energy storage device has been developed on the basis of a bridge-element concept, that can be employed in the design phase for power quality and conducted emission analysis of micro grids. A prototype of a 5 kW AC/DC/AC power converter is built and a mockup of electric energy trading system is realized. Measurements conducted for three operating modes emulating electric energy transfer and power consumption in trading conditions have revealed a low voltage total harmonic distortion, not exceeding 1.3% for the tested cases.
A mathematical model of a multi-phase power conversion system composed of modified bridge-elements (B-system) capable for parallel computation has been developed. Experimental validation on the example of a power system including a synchronous generator and an AC-DC rectifier has been performed. A mathematical algorithm for B-system assembly and steps to obtain mathematical model of the B-system have been developed. Integration of mathematical models of conversion system into the complete model of a multi-phase power system has been explained and evaluation of computational efficiency of parallel computation techniques for the developed model of an AC-DC-AC converter has been performed. The presented modelling method can be employed in the design phase of smart grids, for power quality and conducted emission analysis.
Prestudy of test bed for fuel cells This report investigates the potential needs and benefits of a Swedish national test bed for fuel cell and hydrogen technologies. The analysis is based on an interview study among 43 organisations within the field, as well as on inventory studies on existing test infrastructure in Sweden. The result is aggregated into a proposal that describes a test bed in terms of functionality and organisation.
The Blue Move project aims to generate an increased demand for hydrogen as a fuel and investigate the business potential of heavy machinery in the Öresund-Kattegatt- Skagerrak (ÖKS) region, contributing for renewable energy in the transport sector to increase. The use of heavy machinery generates significant carbon dioxide emissions and local air pollution. By using machines with batteries and/or fuel cells instead of combustion engines, local air pollution and climate impact from the machines can be reduced. Electrification also reduces noise and vibration problems, contributing to an improved local and working environment. Customers' requirements are changing and within the near future some clients will only buy zero-emission vehicles. For example, many municipalities have high environmental targets and aim to be climate neutral and fossil fuel-free by 2030. Setting the requirements for public procurement, municipalities and regions become very important players in the process of converting to fossil fuel-free working machines. Electrification is on the rise and the development is fast, which, in addition to the environmental benefits, allows many benefits such as increased service life and a reduced number of components. The cost and character of the service of the vehicles will also change. The choice between electrical operation with batteries or with fuel cells depends on the cost, weight and space requirement for the current energy need. When operating on fuel cells, the heavy machinery can be quickly fueled, and it has an unchanged performance from full to empty tank. The use of fuel cells is also space-saving compared with fullelectric machines since areas for charging or battery change are not required. Today there are both battery and fuel cell - electric heavy machinery available on the market. This report gives an overview of available equipment, but also prototype and demo machines. Both a continued technical development and an increased market share for emission-free vehicles are required to meet future environmental goals. In order to achieve success, it is important that customers and manufacturers meet.
Blue Move har utarbeidet en rapport som belyser 12 ulike muligheter for produksjon, industri, lagring og distribusjon av hydrogen i ØKS-regionen.
Rapporten belyser ogs viktigheten av lav elavgift for hydrogenproduksjon gjennom beregninger gjort for en nyetablert hydrogenstasjon.
Interreg-prosjektet Blue Move arbeider for å fremme økt bruk av fornybar energi som erstatning for fossile drivstoff i ØKS-regionen. Mulighetsstudien som er samlet i denne rapporten ser nærmere på hvilke produksjonsmetoder som er mest relevante, relatert til tilgjengelig fornybar kraft. Videre beskriver den hvordan hydrogenet kan anvendes utover veitransport, og på hvilken måte det kan ha betydning for veitransport at det også kommer andre anvendelsesområder.
Thermal cycling tests have been performed for a range of electronic components intended for avionic applications, assembled with SAC305, SN100C and SnPbAg solder alloys. Two temperatureprofiles have been used, the first ranging between -20 °C and +80 °C (TC1), and the second between -55 °C and +125 °C (TC2). High level of detail is provided for the solder alloy composition and the component package dimensions, and statistical analysis, partially supported by FE modeling, is reported. The test results confirm the feasibility of SAC305 as a replacement for SnPbAg under relatively benign thermomechanical loads. Furthermore, the test results serve as a starting point for estimation of damage accumulation in a critical solder joint in field conditions, with increased accuracy by avoiding data reduction. A computationally efficient method that was earlier introduced by the authors and tested on relatively mild temperature environments has been significantly improved to become applicable on extended temperature range, and it has been applied to a PBGA256 component with SAC305 solder in TC1 conditions. The method, which utilizes interpolated response surfaces generated by finite element modeling, extends the range of techniques that can be employed in the design phase to predict thermal fatigue of solder joints under field temperatureconditions.
Purpose-The purpose of this paper is to introduce a novel computational method to evaluate damage accumulation in a solder joint of an electronic package, when exposed to operating temperature environment. A procedure to implement the method is suggested, and a discussion of the method and its possible applications is provided in the paper. Design/methodology/approach- Methodologically, interpolated response surfaces based on specially designed finite element (FE) simulation runs, are employed to compute a damage metric at regular time intervals of an operating temperature profile. The developed method has been evaluated on a finite-element model of a lead-free PBGA256 package, and accumulated creep strain energy density has been chosen as damage metric. Findings-The method has proven to be two orders of magnitude more computationally efficient compared to FE simulation. A general agreement within 3 percent has been found between the results predicted with the new method, and FE simulations when tested on a number of temperature profiles from an avionic application. The solder joint temperature ranges between +25 and +75 °C. Practical implications-The method can be implemented as part of reliability assessment of electronic packages in the design phase. Originality/value-The method enables increased accuracy in thermal fatigue life prediction of solder joints. Combined with other failure mechanisms, it may contribute to the accuracy of reliability assessment of electronic packages.
RF power amplifier demonstrators containing each one GaN-on-SiC, HEMT, CHZ015AQEG, from UMS in SMD quad-flat no-leads package (QFN) were subjected to thermal cycles (TC) and power cycles (PC) followed by electrical, thermal and structural evaluation. Two types of solders i.e. Sn63Pb36Ag2 and lead-free SnAgCu (SAC305) and two types of TIM materials (NanoTIM and TgonTM 805) for PCB attachment to liquid cold plate were tested for thermomechanical reliability. Changes in electrical performance of the devices namely reduction of the current saturation value, threshold voltage shift, increase of the leakage current and degradation of the HF performance were observed as a result of an accumulated current stress during PC. No significant changes in the investigated solder or TIM materials were observed.
RF power amplifier demonstrators containing each one GaN-on- SiC, HEMT, CHZ015A-QEG, from UMS in SMD quad-flat noleads package (QFN) were subjected to thermal cycles (TC) and power cycles (PC) and evaluated electrically, thermally and structurally. Two types of lead-free solders (Sn63Pb36Ag2 and SnAgCu (SAC305)) and two types of TIM materials (NanoTIM and TgonTM 805) for PCB attachment to liquid cold plate were tested for thermo-mechanical reliability. Changes in electrical performance of the devices namely reduction of the current saturation value, threshold voltage shift, increase of the leakage current and degradation of the HF performance were observed as a result of an accumulated current stress during PC. No significant changes in the investigated solder or TIM materials were observed.
The RF power amplifier demonstrators containing each one GaN-on-SiC, HEMT, CHZ015A-QEG, from UMSin SMD quad-flat no-leads package (QFN) were subjected to thermal cycles (TC) and power cycles (PC) andevaluated electrically, thermally and structurally. Two types of solders, Sn63Pb36Ag2 and lead-free SnAgCu(SAC305), and two types of TIM materials, NanoTIM and TgonTM 805, for PCB attachment to the liquid cold platewere tested for thermo-mechanical reliability. Changes in the electrical performance of the devices, namely thereduction of the current saturation value, threshold voltage shift, increase of the leakage current and degradation ofthe HF performance were observed as a result of an accumulated current stress during PC. No significant changes inthe investigated solder or TIM materials were observed.