The high-temperature operating requirements and the issues in the packaging process of wide-bandgap power semiconductors have positioned pressureless sinter-bonding using Ag nanoparticle paste as the most promising die-attach technology. However, und...
In this paper, the microstructure of Ag nano paste joint was investigated in pressure-less sintering conditions, and the influence of the microstructure on the joint’s reliability was studied. Firstly, silver nanoparticles (Ag NPs) were synthes...
Sintered silver (Ag) die-attach has attracted much attention in power systems with high power density and high operating temperature. In this paper, we proposed a novel surface modification method for Ag nanoparticles with organic amines as a coating...
A previously pyrometallurgical process, developed to obtain a Pb-Ag alloy and a slag rich in sulfur from the recycling of a mixture of industrial wastes of jarosite and lead paste, was thermodynamically assessed at 1200 °C. The industrial jarosit...
This paper studied the microstructure and mechanical properties of sintered Ag-Cu joints and semi-sintered Ag-Cu joints under tensile and shearing actions. By a comparative analysis of the differences in sintered Ag layer microstructure characteristi...
Rapid developments in wide-bandgap semiconductors have led to the demand for interconnection materials that can withstand harsh conditions. In this study, novel Ag composite pastes were developed with the assistance of metal organic decomposition (MO...
Sintered silver paste is widely used as the die-attachment material for power semiconductors. However, sintered silver joints encounter problems, such as severe coarsening of sintered pores and oxidation issues, in harsh high-temperature environments...
This study focused on the flexible Ag/AgCl biomedical electrode fabricated by screen printing. It systematically investigated the influence of the Ag/AgCl paste on its performance. By adjusting the type of silver powder and the mass ratio of Ag to Ag...
With the development of microelectronics products with high density and high power, it is urgent to improve the electrical and thermal conductivity of electronic paste to achieve the new requirements of packaging materials. In this work, a new synthe...
This study investigated mineral admixtures that are often utilized as replacements for cement in high-performance concrete with a view to enhancing their durability and workability. The properties of concrete are closely related to the structure of i...
With the rapid development of microelectronics packaging technology, the demand for high-performance packaging materials has further increased. This paper developed novel epoxy-containing Sn-3.0Ag-0.5Cu (SAC305-ER) composite solder pastes, and the ef...
A novel bonding process using Ag agglomerates paste prepared by Ag2O reduction has been proposed, which solved the problem of Cu substrate oxidation in the conventional Ag2O sintering process for Cu–Cu bonding. By applying the Ag agglomerate paste to...
The effects of uncontrolled storage and curing temperature on the early-age mechanical behavior of cement are under-investigated issues, and the few available studies in the literature analyze their influence mainly from a chemical-physical point of...
To preserve the structural integrity of power semiconductor devices, ensuring a reliable connection between wide-bandgap (WBG) chips and their substrates at temperatures above 200 °C is crucial. Therefore, easily processable chip-attach materials wit...
Conductive silver paste is a key material in the fields of printed circuits and printed electronic devices. However, the preparation of conductive silver paste with low-cost and volatile organic compounds (VOCs) is still a challenge. In this work, co...
In this work we present research results on a new paste NPCuXX (where: NP—new paste, CuXX—component, XX—a modifier consisting of Ni and other important elements) based on a copper composite (CuXX) for fabrication of front electrodes...
Silver-coated copper (Cu@Ag) core–shell nanoparticles are promising interconnect materials for electronic packaging due to their high conductivity, oxidation resistance, and reduced use of precious metals. However, the key factors governing the...
Metal nanoparticles (NPs) have attracted growing attention in recent years for electronic packaging applications. Ag NPs have emerged as a promising low-temperature bonding material owing to their unique characteristics. In this study, we mainly revi...
Alterations in rice qualities during ageing are related to changes in starch molecular structures. However, if and how storage temperature determines starch structure–function relations remain unknown. This study applied four storage temperatur...
In the back-side metallization process of the passivated emitter and rear cell (PERC), the contact between the Ag rear electrode and Al rear electrode is an important factor for cell efficiency. In this paper, we report on the effect of Ag paste cont...
In the temperature-sensitive components, such as perovskite solar cells, large-area electrical connections with high electrical conductivity are also required. To fulfill the requirements, low-temperature evaporation was realized by preparing binder-...
A silver-rich lead alloy was obtained through the recycling of two metallurgical wastes: these are lead paste obtained from spent lead–acid batteries and a jarosite residue obtained from the hydrometallurgical production of zinc. Mixtures of bo...
In this study, the contact mechanism between Ag–Al and Si and the change in contact resistance (Rc) were analyzed by varying the firing profile. The front electrode of an n-type c-Si solar cell was formed through a screen-printing process using...
To test whether fructooligosaccharide (FOS) and inulin (INU) molecules can improve the hardness of cooked rice through forming a hydrogel network, we added FOS or INU at 0%, 3%, 5%, 7%, and 10% concentrations to two cooking japonica rice and compared...
The rheological properties of concrete paste significantly influence its tensile creep behavior. In this study, the tensile creep behavior of high-volume fly ash concrete (HVFAC) employing the same cementitious pastes was experimentally investigated,...
A 3–5 μm Cu@Sn core-shell powder was prepared by chemical plating. Based on the mixture of this Cu@Sn and Ag NPs (nanoparticles), a soldering material for third-generation semiconductors was prepared. The joints prepared with this soldering...
This study introduced the SiC micro-heater chip as a novel thermal evaluation device for next-generation power modules and to evaluate the heat resistant performance of direct bonded copper (DBC) substrate with aluminum nitride (AlN-DBC), aluminum ox...
With the assistance of Pt-catalyzed formic acid vapor, robust Ag-Cu bonding was realized at an ultra-low temperature of 160 °C under 3 MPa for 30 min via the sintering of Ag nanoparticles in situ generated from Ag2O microparticles. The Cu oxide l...
Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs), flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO) shows high transmittance (90%) at low sheet re...
Cement-based materials, especially those with low water-cement ratios, often experience premature cracking due to plastic shrinkage in the early curing stages. In this study, the development mechanism of early-age plastic shrinkage of cement paste, a...
Cu-Ag composite pastes consisting of carboxylate-capped Ag nanoparticles, spray-pyrolyzed Ag submicron particles, and copper formate were developed in this study for low-temperature low-pressure bonding. The joints between the Cu, Ni/Au, and Ag finis...
To promote the sustainable development of eco-efficient calcium sulfoaluminate (CSA) cements through the partial replacement of the CSA clinker with supplementary cementitious waste products, the effects of coal fly ashes on the early-age and mature-...
In this paper, the issue of an aging process’s influence on power LEDs’ properties is considered. Some measured DC characteristics of these devices and their thermal and optical parameters obtained are presented after considering differen...
Microstructure development of concrete, mortar, and paste scale of cement-based material (CBM) during the early hydration stage has a significant impact on CBM’s physical, mechanical, and durability characteristics at the high maturity state. The res...
For cementitious materials, electrical resistivity is often used in the study of the cement hydration process at early age, as one of the few indicators that can be continuously and non-destructively monitored. Variation characteristics of resistivit...
6 September 2023
Cigar smoking remains a public health issue in the United States (U.S.), with a heterogeneous prevalence based on sociodemographic characteristics. Nationally representative data suggest changes in cigar smoking over time, with some evidence for soci...
Recently, the production of new photocatalytic materials has attracted considerable attention as a promising strategy to mitigate anthropogenic environmental degradation. In this study, cement paste composites (water/cement ratio = 0.5) were prepared...
The early-age properties of nano-metakaolin (NMK) cement paste were examined from 15 min to 24 h, contacted between cement and water based on the electrochemical impedance spectroscopy (EIS) method. The effects of a superplasticizer and chloride ions...
In the United States, approximately 10 billion gallons of mixing water is required annually to produce close to 400 million cubic yards of concrete. In response to the declining supply of freshwater in some locations and with the goal of decreasing t...
One of the major concerns of concrete industries is to develop materials that consume less natural virgin resources and energy to make sustainable construction practices. Efforts have been made and even implemented to use the waste/by product materia...
The objective of this paper is to investigate the effect of calcium nitrite (CN) on improving the mechanical properties and microstructures of early-frozen cement paste. Cement pastes containing 1%, 1.5%, 2%, 2.5%, and 3% CN were prepared. One batch...
In order to study the synergistic effects of organic and inorganic thickening agents on the rheological properties of cement paste, the rheological parameters, thixotropy cement-paste containing limestone powder (LP), re-dispersible polymer powder (R...
This study presents a new approach towards the production of sol-gel silica-coated Bi2O3/Gd2O3 cement additives towards the improvement of early mechanical performance and radiation attenuation. Two types of silica coatings, which varied in synthesis...
To explore the feasibility of the application of steel slag powder (SSP) in steam-cured precast concrete, 0% and 20% SSP were used to replace cement and prepare cement paste, and the early age performance of steam-cured (80 °C for 7 h and 7 d) SS...
13 June 2017
Dental age estimation (AE) tests are routinely done on living and deceased persons. There is anecdotal evidence suggesting an increase in age estimations due to the refugee crisis. Our aim is to determine the reasons and methods for performing dental...
Physical activity and exercise contribute to the accumulation of cognitive reserve, which is instrumental for preserving cognitive health in old age. In a large sample of 701 older adults (mean age = 70.36 years), we investigated whether the relation...
Photodynamic therapy (PDT) has been approved as a therapeutic modality for the management of neovascular age-related macular degeneration (nAMD). PDT can treat macular neovascularization with minimal effects on normal tissue, reducing lesion size and...
Among the most significant causes of concrete degradation is ESA (external sulfate attack). The majority of studies are currently conducted on samples that have been saturated and matured. Concrete structures, however, are exposed to the environment...
In this study, the effects of pregelatinization on the physicochemical properties of corn grits and the quality of cooked waxy corn wrapped in plant leaves were investigated. This investigation was conducted to address the issues of partial gelatiniz...
In marine environments, chloride salt ingress into concrete having a porous structure can lead to physical salt attack (PSA) deterioration. However, the slow deterioration of cement-based materials caused by PSA under current laboratory conditions li...
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