Sufficient Wetting Research Articles

Facile fabrication of porous open-cell polymer structures from sacrificial “natural templates” and composite resins

In this paper, we investigate several types of “natural or bio sourced templates” (sugar, salt, bone, coral, PLA 3D-printed scaffolds) for a the simple elaboration of macro porous thermoplastic or thermosetting polymers, especially based on resins commonly used in composites manufacturing. Open-cell, macro porous polymer foams are obtained from resin impregnation of the template. The process consists of 3 simple steps: (a) impregnation (infiltration/infusion) of the template, (b) polymerization of the resin, (c) removal of template, mainly by water. We compared several resins and showed that a low viscosity and a sufficient wettability enable fast impregnation of templates, where impregnation times are < 4 min for samples on 10 to 30 mm thicknesses. The resulting polymeric porous structure is the overall replication of the template, exhibiting mainly open pores in the range of 100 to 500 μm, and densities from 0.25 to 0.4 g cm−3. Such open foams behave as sponges and can (re) absorb liquids either polar (water), alcohols or non polar liquids such as silicon oil, which are filling the entire void volume. We proved the feasibility of an easy and fast impregnation by composite resins to provide either rigid or soft porous polymers (or ‘foams’) that can be further chemically modified. On the other side, before polymerization, the introduction of a functional additive to the reactive infusion formulation, provides homogeneously functionalized foams. Here an impact modifier is tested.

Low-Temperature Bonding of Cu Through Self-Propagating Reaction Under Various Temperatures and Pressures

Abstract Low temperature soldering has been realized to create a strong metallurgical interconnection between Cu using the self-propagating exothermic reaction by Al–Ni NanoFoil. This technique presents a great potential for electronics integration with a significantly reduced processing temperature (at least 150 °C lower than traditional techniques) and minimal thermal effects to the components. In this study, finite element analysis was performed to predict the temperature profiles across bonding interfaces, which were subsequently correlated with the formation and quality of the bonded structures. It has been revealed that, for nonequilibrium nanosized phases and defects, their formation and distribution were primarily attributed to the solid–liquid interdiffusion and rapid solidification, under the highly transient regime due to a drastic heating/cooling (105–107 °C/s). The preheating and pressure applied to the bonding structure were clearly beneficial to improve the quality of bonding. This was achieved by the thinned solder thickness and the correspondingly improved temperature profiles that enable a sufficient wetting, filling, and interfacial reactions. Through the comparative analysis of the numerical predictions and the experimental results, the solder layers must completely melt across their thickness and have a total heat over 30 K ms on the Cu to ensure robust interconnections with a shear strength of approximately 37 ± 3 MPa and dense continuous bonding interfaces.

Multilayers of poly(ethyleneimine)/poly(acrylic acid) coatings on Ti6Al4V acting as lubricated polymer-bearing interface.

To achieve an efficient lubricated interface on titanium alloy (Ti6Al4V) alloy, polyelectrolyte multilayer (PEM) polymer coatings, based on poly(ethyleneimine)/poly(acrylic acid) (PEI/PAA), were fabricated on the surface of Ti6Al4V alloy substrates using the layer-by-layer (LbL) assembly technique. Their composition and morphology were confirmed by Fourier-transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The tribological properties were investigated by a ball-on-disk rotating tribometer using deionized water, saline, and calf serum. The results exhibit that (PEI/PAA)*n coatings have the internal cross-linked network and porous structure on the surface. The surface of PEI/PAA coatings-modified Ti6Al4V shows the sufficient wettability. The polymer-bearing interface of (PEI/PAA)*10 exhibits a low friction coefficient, 0.059, for 2 hr, and represents an 88% decline compared with bare Ti6Al4V. Moreover, the wear track on the polymer-bearing interface is superlow. There is no obvious wear volume, which indicates effective wear resistance. The hydrated layer, the cross-linked network structure, and the porous structure of PEM coatings are the main factors for efficient tribological properties. The multilayer PEI/PAA coating shows the potential uses of developing the lubricated-bearing interface on Ti6Al4V alloy.

Densified W[sbnd]Cu composite fabricated via laser additive manufacturing

Tungsten-Copper (WCu) composites are promising materials for electrical and thermal applications. However, their fabrication remains limited using conventional techniques, such as powder metallurgy, which are not suitable for manufacturing densified complex WCu components. In this work, laser additive manufacturing (LAM) technology was introduced for fabricating W-25 wt%Cu composites. A densified WCu composite, free of apparent cracks and pores, is successfully synthesized using optimum process parameters of laser power 2000 W and laser scan speed 360 mm/min in an Ar atmosphere with less than 10 ppm O. The densification of WCu composites is owing to the sufficient wetting of solid W particles by the molten liquid Cu and the surface smoothing of the W particles. The good wetting of the solid W particles by the liquid Cu is due to the low oxygen content and the combined effect of increased capillary force and reduced friction force. The W grains are rounded, indicating some solution-reprecipitation of sharp particle edges originating from the increase in solubility from curvature effects.

A semi-analytical model research of liquid collar shape and coalescence in pore throat during snap-off

When a wetting fluid is being displaced by a non-wetting gas in a capillary tube, a thin film of the wetting fluid is often left on the tube walls. To snap off the non-wetting gas, sufficient wetting fluid has to be collected in the pore throat, which will form a liquid lens that across the throat like a bridge, and a smaller gas bubble can be generated by snap-off. A number of researches have been conducted to study the phenomenon of snap-off both theoretically and experimentally. However, some dynamic characteristics of snap-off still remain unclear. In this work, a geometric model of pore throat and liquid collar formed in it was established, and multiple data sets of liquid collar shape were calculated. Following the principle that an interface system has a tendency of reducing its surface area, an evolvement path of liquid collar shape was concluded from the contour maps of calculation outcomes. Then a model of liquid flowing in film was derived, and the flow rate of liquid flowing from film into collar was calculated. Finally, the coalescence time of liquid collar calculated by model is almost the same with the measured time by experiment, and the film thickness utilized in model calculation is within a reasonable range of the experiment result, which proves a considerable reasonability and precision of the model. The liquid collar model in this work provides a new idea and reference for studying the morphological and dynamic characteristics of liquid collar in pore throat during snap-off.

Exploring the influences of Li2O/SiO2 ratio on Li2O – Al2O3 – SiO2 – B2O3 – BaO glass-ceramic bonds for vitrified cBN abrasives

Abstract Li2O–Al2O3–SiO2–B2O3–BaO glass-ceramic bonds for vitrified cBN abrasives with various Li2O/SiO2 ratio were prepared by the traditional melt-quenching method. The structure of parent glass was identified by X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FTIR). The reduction in the Li2O/SiO2 ratio increased the connectivity of the glassy network, resulting in a decrease of the crystallization ability for the parent glasses. Besides, a comprehensive understanding of measured and calculated coefficient of thermal expansion (CTE) for glass-ceramic bonds demonstrated that the simultaneous presence of a higher content of LiAlSi2O6 and LiAlSi3O8 along with the absence of SiO2 precipitation were believed to contribute largely to the lower CTE of glass-ceramic bonds. Lastly, the highest bending strength of cBN composites (100.53 MPa) relied on the sufficient wetting of B3 glass-ceramic bonds (Li2O/SiO2 = 0.11) on cBN and the close CTE between them when composites were sintered at 860 °C for 2 h, indicating B3 is a kind of suitable and promising glass-ceramic bonds for cBN abrasives.

高强混凝土内养护的研究进展

高强高性能混凝土在各类建筑工程中被广泛地应用。但由于高性能混凝土水胶比较低、胶凝材料用量较大，其早期的自收缩较为严重，从而产生微裂纹进而开裂，严重影响其力学性能和耐久性。而内养护技术依靠预吸水材料释放水分维持混凝土内部充分湿润，可以有效地减少自收缩，保障混凝土的力学性能和耐久性。本文从内养护剂的作用机理、内养护剂的种类、不同内养护剂的作用效果对比以及内养护剂的工程应用等方面总结了近年来高强混凝土内养护的研究进展。 High-performance concrete is widely applied to all kinds of building and construction projects. Due to the low water to binder ratio and large amount of cenmentitious materials, the autogenous shrinkage of high-performance concrete is significantly severe, thus resulting in microcracks and even cracking. So the mechanical properties and durability of concrete are seriously impacted. The internal curing technology relies on the pre-absorbent materials to release moisture to maintain sufficient internal wetting of the concrete, which can effectively reduce the autogenous shrinkage and ensure the mechanical properties and durability of the concrete. This paper has summarized the research progress in internal-curing of high strength concrete in recent years from the aspects of the working mechanism of the internal curing reagents, the types of the internal curing reagents, comparison of the effect of different internal curing reagents and the engineering application of the internal curing reagents.

Potential of quasi-inverted pyramid with both efficient light trapping and sufficient wettability for ultrathin c-Si/PEDOT:PSS hybrid solar cells

In this paper, a simple and cost-effective wet chemical method is presented to form quasi-inverted pyramids (QIP) on ultrathin c-Si for efficient light trapping and sufficient wettability. The QIP is fabricated by a well-known two-step Ag assisted chemical etching method followed by a post nanostructure rebuilding (NSR) process. The variation of [Ag+] realizes the modulation of QIP size from sub-micro scale to micro scale. The comparable average absorptance value of 50µm c-Si with double-sided QIP fabricated under 0.5mM [Ag+] (QIP-50) to that of 182µm c-Si with double-sided conventional micro-scale pyramid in the spectral range of 300 – 1100nm demonstrates an over 3.6-fold reduction in material usage. In comparison with nanopores-structured light-trapping configuration, the QIP-50 possesses much smaller specific surface area of ~2.39, which alleviates the surface recombination losses. After wet oxidation treatment, the water contact angle (WCA) of QIP-50 (35.73°) can achieve a comparable value to that of wet oxidized polished wafer (33.30°), demonstrating sufficient wettability of the QIP for high efficiency ultrathin c-Si/PEDOT:PSS hybrid solar cells. The finding of QIP with both efficient light trapping and superior wettability provides a new opportunity to improve the performance of ultrathin c-Si/PEDOT:PSS hybrid solar cells with a simple process at low cost.

Method of stir casting of Aluminum metal matrix Composites: A review

Among the variety of manufacturing processes available for discontinuous metal matrix composites, stir casting is generally accepted as a particularly promising route, currently practiced commercially. Its advantages lie in its simplicity, flexibility and applicability to large quantity production with cost advantage. The major problem of this process is to obtain sufficient wetting of particle by liquid metal and to get a homogenous dispersion of the particulates. The present review is on the method employed in stir casting such as, how the base metal is melted, at what temperature and state it is to be maintained, what conditions the particulates are added and how the stirring time and stirring speed affect the final composite material. The effect of stirrer design and feeding mechanism has also been discussed. The variation in the type of mixing the particulates into the metal matrix has also been dealt with in the paper. In the introductory part the stir casting methodology with a diagram has been laid out to give an overview of the overall process of casting of metal matrix composites. The limitations of the process are also listed in the paper.

Surface study of sintered alumina substrates using solution‐processed ZnO nanorods as a microscopic wettability indicator

Wettability and its distribution are crucial factors that indicate the surface conditions of substrates. We report a surface study of sintered alumina substrates using solution‐processed ZnO nanorods as a microscopic wettability indicator. The alumina substrates comprising of micrometer‐sized sintered grains were treated separately with ultraviolet/ozone (dry process) or ozone water (wet process), and their surface conditions were characterized by conventional surface analysis methods, such as water contact angle, X‐ray photoelectron spectroscopy and grazing angle attenuated total reflection Fourier transform infrared spectroscopy. The results showed that the alumina substrates treated with ultraviolet/ozone and ozone water had distinct clean surfaces compared to those without treatments, but no significant differences were noted between these two ozone‐based treatments. Then, as a wettability‐sensitive deposition technique, Pd‐catalyzed chemical deposition of ZnO nanorods was performed on the alumina substrates, which involved dip coating of Pd nanoparticles on the substrates in aqueous solutions, followed by the chemical solution growth of ZnO. Vertically aligned ZnO nanorods of ~85 nm in diameter were densely formed along a rough surface of the substrates. Morphological uniformity of the nanorods varied depending on the treatment condition; local surfaces with sufficient wettability provided uniform nanorods but those with insufficient wettability gave irregular nanorods, making the visualization of the microscopic surface wettability possible. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Essential Role of Viscosity of SWCNT Inks in Homogeneous Conducting Film Formation

Newly developed inorganic single-wall carbon nanotube (SWCNT) inks of the Zn/Al complex and colloidal silica give a quite homogeneous SWCNT film on the polyethylene terephthalate (PET) substrate by the bar-coating method, whereas the surfactant-based SWCNT inks of sodium dodecyl sulfonate (SDS) and sodium dodecyl benzene sulfonate (SDBS) cannot give a homogeneous film. The key properties of SWCNT inks were studied for the production of homogeneous SWCNT films. The contact angle and surface tension of the inorganic dispersant-based SWCNT inks were 70° and 72 mN m(-1), respectively, being close to those of water (71.5° and 71 mN m(-1)). The viscosity was significantly higher than that of water (0.90 mPa·s), consequently, providing sufficient wettability, spreadability, and slow drying of the ink on the substrate, leading to homogeneous film formation. On the other hand, the surfactant dispersant-aided SWCNT inks have the contact angle and surface tension twice lower than the inorganic dispersant-based SWCNT inks, guaranteeing better wettability and spreadability than the inorganic dispersant-based inks. However, the small viscosity close to that of water induces a heterogeneous flow of SWCNT ink on rapid drying, leading to inhomogeneous film formation.

A High-Flux Polysulfide Blocking Membrane Fabricated By Shear Alignment of Discotic Nematic Liquid Crystals of Graphene Oxide on Sulfur Cathode

With consistent technological advances, demands for batteries with considerably higher specific energy than current Lithium ion devices are apparent. As an extremely promising alternative to Li-ion, the electrochemistry of Lithium-Sulfur (Li-S) has received strong attention due to its theoretical specific capacity of 1675 mAh g-1 and theoretical specific energy of 2500 Wh kg-1. Turning the principle of the Li-S concept into practice though faces a number of key challenges. Among these challenges, the continuous crossover of highly soluble polysulfides – the electrode active material from the cathode through the separator to the lithium anode and vice versa - is primarily responsible for rapid capacity fading of Li-S cells.[ 1 ] Accordingly, the focus of the research effort in this area has been devoted to the retention of sulfur and its reduction products on the cathode side of the battery. These studies have produced some striking improvements in both the sulfur cathode durability and the role that the separator plays in a Li-S battery.[ 2 , 3 ] The separator is a critical component in liquid electrolyte energy storage devices. Sitting between the positive and negative electrode to prevent physical contact between them, the membrane should show sufficient wettability, porosity, chemical, mechanical, thermal and dimensional stability while demonstrating high permeability and high flux. However, for electrochemical systems where redox-active species are dissolved or dispersed in the electrolyte, such as redox flow batteries, fuel cells, and Li-S batteries, permselectivity is also a crucial property. Little attention has been paid to the usage of permselective membranes in the Li-S cells while tremendous efforts have been devoted to the structure and composition of the cathode. A few recent articles have explored the use of permselective membrane separator in mitigating the issue of migration of polysulfides.[ 3 , 4 ] Despite partial success with retention of polysulfides, the presence of such permselective membranes results in a natural decrease in the ion flux across the membrane. This may potentially hinder the industrial use of permselective membranes in Li-S battery where the rate capability is already an issue due to the slow kinetics of the reactions. Accordingly it is highly desirable to achieve an ion-selective transport and mitigate the consequences of polysulfides whilst enabling unimpeded transport of ions. In here we report, for the first time, the integration of a high-selectivity, high-flux GO membrane directly supported onto the sulfur electrode in a Li-S battery. This simple approach dramatically resolves the issue of dissolution of electrode material in battery electrolyte and delivers properties close to those required for a practical rechargeable battery. Our shear-aligned GO membrane which is directly coated onto the electrode, is uniquely composed of well-ordered stacks of the graphene sheets in the membrane plane and we unambiguously demonstrate that its integration in the Li-S battery hardly interferes with free ionic flow in the device. For example, alongside with excellent capacity retention arising from the inherent surface charge of the GO, the highly ordered structure of the thin (~ 0.75 µm) membrane enables the cells to deliver unprecedented high initial discharge capacities of 1616, 1400 and 1170 mAh g-1 at 0.2 C, 0.5 C and 1 C rates, respectively. The remarkable rate capability results reported in this work provides a reliable foundation to challenge the long-held belief that integrating permselective membranes in electrochemical energy storage devises suffering from electrode instability issues, although critical for capacity retention are not suitable for power characteristics. [1] M. Barghamadi, A. S. Best, A. I. Bhatt, A. F. Hollenkamp, M. Musameh, R. J. Rees, T. Rüther, Energy & Environmental Science 2014. [2] J. Song, M. L. Gordin, T. Xu, S. Chen, Z. Yu, H. Sohn, J. Lu, Y. Ren, Y. Duan, D. Wang, Angewandte Chemie 2015. [3] J.-Q. Huang, T.-Z. Zhuang, Q. Zhang, H.-J. Peng, C.-M. Chen, F. Wei, ACS nano 2015, 9, 3002. [4] C. Li, A. L. Ward, S. E. Doris, T. A. Pascal, D. Prendergast, B. A. Helms, Nano letters 2015, 15, 5724.

The electrochemical characterisation of graphite felts

With the increasing demand for advanced energy storage, redox flow batteries (RFBs) are a rapidly growing market and research area. Carbon fibre based materials like graphite felts (GFs) are commonly used in RFBs as electrodes due to their electrochemical activity, high permeability for liquids, high surface area and relatively low cost. Previous characterisation of GFs has involved flow systems, which can be complicated to replicate and expensive. Using pre-treatment techniques to ensure sufficient wetting, GFs can be used effectively in quiescent electrochemistry. By combining the experimental voltammograms with digital simulations, key properties such as capacitance, electrode kinetics, average pore size and electrochemical surface area can be determined. This allows for the rapid and low cost examination of multiple GFs and pre-treatment methods, providing a useful tool for RFB development. In addition, the GF electrodes used in the study show promising limit of detection values, with initial experiments suggesting these electrodes may have applications in electroanalysis.

Feasibility of non-invasive detection of engineered nanoparticles in food mimicking matrices by Optical Coherence Tomography

The study was dedicated towards the detection of Engineered Nanoparticles (ENPs) by means of Optical Coherence Tomography (OCT). Polymeric films were produced to mimic complex food matrices whereas gold nanorods (AuNRs) were embedded to act as ENPs. The straightforward coating application resulted in a sufficient film wetting, adhesion and homogenous AuNR distribution. Compared to food samples, these films are simpler and better defined. Such artefacts are therefore promising candidate materials for quality assurance and regulatory matters. The OCT investigations revealed a dependency of the measured signal intensity on the AuNR concentration in the film. The limit of detection for the setup and material was estimated to be −8dB. This value corresponds to a ppm nanoparticle concentration being well below the concentration used in food additive applications. Thus, the findings indicate the potential of OCT to screen food/feed products for a number of ENPs.

Ultrasonic-Assisted Thermocompression Bonding Method of Solder Anisotropic Conductive Film Joints for Reliable Camera Module Packaging

In this paper, to improve the reliability of anisotropic conductive film (ACF) joints in the camera module packaging without any mechanical damages, ultrasonic-assisted thermocompression (TC) bonding was investigated using solder ACFs. This technology uses small lateral-direction ultrasonic vibration during the TC ACF bonding to break solder oxide layers for sufficient solder wetting on the electrodes at ACF joints. Bonded solder ACF joints were investigated in terms of solder ACF joint morphology, resistance, adhesion strengths, and reliabilities. In addition, the stability of camera module components after bonding process was also observed. Ultrasonic-assisted TC bonded solder ACF joints showed excellent solder wetting compared with conventional TC bonded solder ACF joints due to broken solder oxide layers by applied ultrasonic vibration. The Au contents diffused from electroless nickel immersion gold-finished Cu pads to solders was about 12 atomic% in the ultrasonic-assisted TC bonding. The Au contents were three times higher than that of the solders in the conventional TC bonding. In the ultrasonic-assisted TC bonding, ultrasonic amplitude was optimized. At the optimized amplitude, solders were well wetted and showed no mechanical damages of camera module components. Adhesion strength of ultrasonic-assisted TC bonded solder ACF joints was almost the same as that of TC bonded ACF joints due to fully cured resins in these samples. During the unbiased autoclave test (121 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> , 2 atm, 100%RH), ultrasonic-assisted TC bonded ACF joints showed no open-circuit failure compared with conventional TC bonded Ni ACF joints due to metallurgical alloy joints between solder balls and electrodes by sufficient solder wetting. These results prove that ultrasonic-assisted TC bonding using solder ACFs can be applied for highly reliable ACF assembly in the camera module packaging without any mechanical damages.

Smart cure cycle to improve tensile load capability of the adhesively bonded joint

Generally, the thermal residual stress which is generated during the curing process of an adhesive significantly decreases the tensile load capability of adhesively bonded joints. In this work, a smart cure cycle with abrupt cooling and postcuring at room temperature was devised to eliminate thermal residual stress and to produce sufficient interfacial wetting. For monitoring and controlling the curing reaction, dielectrometry was used, where the dissipation factor of the adhesive joint was measured. These results showed that the tensile load capability of the adhesively bonded joint fabricated by the smart cure cycle was greatly enhanced because the thermal residual stress was reduced, and sufficient interfacial wetting between the adhesive and adherend was achieved.

Laser-Mig Hybrid Welding Of Aluminium To Steel — Effect Of Process Parameters On Joint Properties

Laser MIG hybrid welding was recently suggested as a feasible process for joining of aluminium to steel for both structural as well as tailored blank applications. To promote an understanding of the process and the effect of process parameters on joint properties, laser MIG hybrid welding experiments were performed to join aluminium alloy AA6016 to DC05 zinc-coated steel sheets, in the thickness range of 1 mm, in a butt joint configuration. Among the process parameters varied were laser power, MIG arc power, wire feed rate, welding speed and arc position relative to the abutting edges. By metallographic cross-sections and tensile tests, the effect of these process parameters on joint properties such as wetting length, intermetallic phase layer thickness and tensile strength could be elucidated. Based on these results, a process parameter envelope resulting in adequate and reproducible joint properties (sound weld bead, sufficient and regular wetting, thin intermetallic phase layer, tensile strength exceeding 180 MPa) was established. Within this parameter envelope, corrosion behaviour was rated not critical, and forming behaviour showed promising results.

Dissimilar Metal Joining of Steel to Aluminum Using the Arc Heat Source

Car manufactures have been asked to avoid the unnecessary waste of energy and reduce pollution. Replacing steel with lightweight materials on car bodies is considered as one method to reduce the vehicle weight to achieve these requirements. Therefore, in this study, we selected a modified metal inert gas welding-brazing process to join aluminum to zinc coated steel on the lap geometry. The main purpose of this research was to reveal the relationship between weldability and various process parameters such as Zn coated thickness, kind of coated treatment type, filler wire type and welding condition. Metallurgical observations and mechanical testes were carried out to evaluate the weld quality. Based on these results, we could find that the weldability of dissimilar materials were depend on sufficient and regular wetting by heat input and gap condition. The tensile-shear test results, all the fracture occurred in the HAZ of aluminum and the strength was up to 70% of base metal of aluminum. However zinc coated thickness in the range of 10㎛ to 30㎛ was no related with welded strength. Also we could find that silicon content of filler wire is very important to minimize the thickness of intermetallic compound layer. Silicon might be disturbed to the growth intermetallic compounds.

NCP (Non Conductive Paste) for Narrow Gap Flip Chip Package and TSV Package

Pre-applied process followed by mounting chip and underfill at the same time is considered as promising underfill process for coming finer pitch and narrower gap flip chip package with Cu pillar and also TSV package with micro bumps. On the other hand, conventional mass reflow could introduce too much stress on low-k chip with advanced node. Pre-applied underfill process can reduce stress on low-k chip by dispersing stress into underfill material at the connection with thermal compression bonding process. One of the challenges of thermal compression bonding process with NCP is trapping material and poor connection at the bonding area. Creeping and voiding are other challenges for NCP. This presentation reports material design of a new NCP, features, and reliability results. Our newly developed NCP material was dispensed smoothly, and didn't cause creeping up on the backside of the chip. While low thixotropic NCP tends to create voids because of easier NCP spreading out when chip is mounted, this NCP material showed good performance in terms of voiding because of high thixotropic index, less spreading out even under heating condition (&amp;lt;80degC) and reduced out gas in this material. We explored appropriate fluxing material inside NCP, optimized filler size and distribution, viscosity, thixotropic index and curing behavior to avoid trapping issue. Cross-section of bonding area showed sufficient solder wetting and this NCP material had excellent connectivity. In addition, this NCP material can be processed in a very short time. The TV underfilled by this NCP material was subjected to reliability tests, and passed 5x reflow test (JEDEC standard preconditioning Level 3), 1000 cycles of temperature cycle test (−55degC to 125degC), and 200 hours of biased HAST test (135degC/85%RH/1.3V).

Effect of Processing Paramters on Metal Matrix Composites: Stir Casting Process

Conventional stir casting process has been employed for producing discontinuous particle reinforced metal matrix composites for decades. The major problem of this process is to obtain sufficient wetting of particle by liquid metal and to get a homogenous dispersion of the ceramic particles. In the present study, aluminium metal matrix composites were fabricated by different processing temperatures with different holding time to understand the influence of process parameters on the distribution of particle in the matrix and the resultant mechanical properties. The distribution is examined by microstructure analysis, hardness distribution and density distribution.