scholarly journals Microstructure of Ag Nano Paste Joint and Its Influence on Reliability

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1537
Author(s):  
Dongsheng Yang ◽  
Yilong Huang ◽  
Yanhong Tian
Keyword(s):  
Shear Strength ◽  
Interfacial Crack ◽  
Bonding Interface ◽  
Bonding Layer ◽  
Ag Nps ◽  
Separation Ratio ◽  
Sintering Time ◽  
Ag Particles ◽  
Interfacial Defects ◽  
Higher Temperature

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 synthesized using the redox reaction method. To tightly stack the Ag NPs in nano paste, Ag NPs with sizes of 30~50 nm and submicron-sized Ag particles were mixed. It was found that increasing the sintering temperature or sintering time can reduce the porosity of the bonding layer and the interfacial crack simultaneously, resulting in higher shear strength. When sintering at a temperature of 250 °C, a complete bonding interface was formed, with a 0.68 μm interdiffusion layer. At a higher temperature (300 °C), the bonding interface reached 1.5 μm, providing 35.9 ± 1.7 MPa of shear strength. The reliability of the die attachment was analyzed under thermal shocking from −65 °C to 150 °C for 50 cycles. As the crack could quickly grow through the interfacial defects, the separation ratio was 85% and 67% when sintered at 150 °C and 200 °C, respectively. Because of the reliable bonding interface between the die and the substrate, the Ag nano paste joint formed a slight crack on the edge of the die when sintering at 250 °C. When the joint was sintered at 300 °C, the small voids became large voids, which featured lower resistance to crack growth. Thus, instead of further improved reliability, the separation ratio increased to 37%.

scholarly journals Influence of monometallic and bimetallic phytonanoparticles on physiological status of mezquite

2019 ◽  
Vol 14 (1) ◽  
pp. 62-68 ◽  
Author(s):  
Daniel Gonzalez-Mendoza ◽  
Benjamín Valdez-Salas ◽  
Erick Bernardo-Mazariegos ◽  
Olivia Tzintzun-Camacho ◽  
Federico Gutiérrez-Miceli ◽  
...  
Keyword(s):  
Bimetallic Nanoparticles ◽  
Positive Impact ◽  
Photochemical Efficiency ◽  
Localized Surface Plasmon ◽  
Physiological Status ◽  
Ag Nps ◽  
Zeta Potentials ◽  
Minimum Particle Size ◽  
Ag Particles ◽  
The Impact

AbstractThe present study was conducted to evaluate the impact of monometallic and bimetallic nanoparticles (NPs) of copper (Cu) and silver (Ag) from Justicia spicigera on the photochemical efficiency and phenol pattern of Prosopis glandulosa. In this study, the existence of localized surface plasmon resonance absorption associated with the nano-sized nature of Ag, Cu and Cu/Ag particles was confirmed by the presence of a single peak around 487, 585, and 487/580 nm respectively. Zeta potential and electrophoretic mobility were found to be 0.2 mV and 0.02 μmcm/(Vs) for synthesized NPs indicating less stability and thus tendency to agglomerate, and broad distribution of particles. Cu-NPs and Cu/Ag-NPs demonstrate that the dispersed phase is stable and has a minimum particle size at zeta potentials above –30 mV. Changes in phenolic compounds, total chlorophyll, and photochemical efficiency in leaves exposed to Ag, Cu and Cu/Ag phyto-nanoparticles were evaluated up to 72 hours. The results revealed that Ag-NP and Cu-NP from J. spicigera at 100 mg/L showed significant reduction in chlorophyll, epidermal polyphenol content and photochemical efficiency of P. glandulosa. In contrast, the application of bimetallic Cu/Ag-NP from J. spicigera showed a positive impact on physiological parameters of P. glandulosa after 72 h of exposure.

Densification of TiCN Matrix Cermets by Microwave Sintering

2011 ◽  
Vol 216 ◽  
pp. 579-582 ◽  
Author(s):  
Si Wen Tang ◽  
Hou An Zhang ◽  
Jian Hui Yan
Keyword(s):  
Relative Density ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Protective Atmosphere ◽  
Densification Process ◽  
Sintering Time ◽  
Vacuum Microwave ◽  
Prepared Material ◽  
Higher Temperature ◽  
Reduce Energy Consumption

TiCN matrix cermets were prepared by using traditional sintering and microwave sintering. The effect of sintering methods, sintering temperature and protective atmosphere to the densification process of as prepared material were discussed. The results show that microwave sintering can short the sintering time than the traditional sintering, but it need higher temperature to obtain approximate density. At 1500°C,holding 5min, vacuum microwave sintering can gain relative density of 99.5%. The relative density of TiCN matrix cermets under argon shield is lower than vacuum microwave sintering, and the microscopic particles is more small, but the uniformity of pore is reduced. Microwave sintering can greatly reduce energy consumption.

scholarly journals Study on the Static Performance of Prefabricated UHPC-Steel Epoxy Bonding Interface

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yang Zou ◽  
Jinlong Jiang ◽  
Zhixiang Zhou ◽  
Xifeng Wang ◽  
Jincen Guo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Shear Test ◽  
Interfacial Shear Strength ◽  
Interfacial Shear ◽  
Bonding Interface ◽  
Tensile Shear ◽  
Epoxy Bonding ◽  
Shear Coupling

Prefabricated UHPC-steel composite structure can make full use of the two materials’ mechanical and construction performance characteristics, with super mechanical properties and durability, which has been proved to be a very promising structure. However, using traditional mechanical connectors to connect prefabricated UHPC and steel not only is inconvenient for the prefabrication of UHPC components but also introduces heavy welding work, which is detrimental to the construction speed and antifatigue performance of the composite structure. Bonding UHPC-steel interface with epoxy adhesive is a potential alternative to avoid the above problem. In order to explore the mechanical properties of the prefabricated UHPC-steel epoxy bonding interface, this study carried out the direct shear test, tensile test, and tensile-shear test of the UHPC-steel epoxy-bonded interface (prefabricated UHPC-steel epoxy bonding interface). The results show that the interface failure is mainly manifested as the peeling of the epoxy-UHPC interface and the destruction of part of the UHPC matrix (the failure of the UHPC's surface). In pure shear and pure tension state, the interfacial shear strength is 5.14 MPa and the interfacial tensile strength is 1.18 MPa. In the tensile-shear state, the interfacial shear strength is 0.61 MPa and the interfacial tensile strength is 1.06 MPa. The stress-displacement curves of the interface normal and tangential direction are all in the shape of a two-fold line. The ultimate displacement was within 0.1 mm, showing the characteristics of brittle failure. Finally, a numerical model of the tensile specimen is established based on the cohesive interface element, and the interfacial tensile-shear coupling failure mechanism (tensile-shear coupling effect) is analyzed.

Atomic Study on Copper–Copper Bonding Using Nanoparticles

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Xiaohui Song ◽  
Rui Zhang ◽  
Huadong Zhao
Keyword(s):  
Grain Growth ◽  
Bonding Temperature ◽  
High Surface ◽  
Hold Time ◽  
External Pressure ◽  
Bonding Layer ◽  
Degree Of Deformation ◽  
Thermocompression Bonding ◽  
Higher Temperature ◽  
Effects Of Temperature

Abstract Thermocompression bonding of copper to copper using copper nanoparticles is studied using molecular dynamics. The bonding interface formation process is investigated frst. For the bonding process, the effects of temperature and external pressure are examined. Also, we examine the grain growth at the interface. The results show that the nanoparticles with high surface energy and low compressive strength provide the active atoms to bond with copper. Pressure determining the degree of deformation of nanoparticles transfers atoms from the interior to the surface of nanoparticles and provide more surface atom to form bonds with bulk copper. While continuous pressure increase does not help bonding, higher temperature will facilitate formation of vacancies by breaking the bonds and driving the metal atoms into these vacancies. In addition, a higher temperature promotes grain growth at the interface. These behaviors indicate that using nanoparticles as a bonding layer in metal bonding can effectively reduce bonding temperature and pressure. It is necessary to select appropriate pressure at initial bonding stage and provide continuous high-temperature hold time.

scholarly journals Effect of Sintering Conditions on the Mechanical Strength of Cu-Sintered Joints for High-Power Applications

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2105 ◽  
Author(s):  
Jeong-Won Yoon ◽  
Jong-Hoon Back
Keyword(s):  
Shear Strength ◽  
Low Cost ◽  
Sintering Process ◽  
Bonding Pressure ◽  
Sintering Time ◽  
Sinter Bonding ◽  
Sintering Conditions ◽  
Metallic Bonding ◽  
Mechanical Strengths ◽  
Direct Bond Copper

In this study, the feasibility of low-cost Cu-sintering technology for power electronics packaging and the effect of sintering conditions on the bonding strength of the Cu-sintered joint have been evaluated. A Cu paste with nano-sized Cu powders and a metal content of ~78% as a high-temperature bonding material was fabricated. The sinter-bonding reactions and mechanical strengths of Cu-sintered joints were evaluated at different sinter bonding pressures, temperatures, and durations during the sintering process. The shear strength of the Cu-sintered joints increased with increasing sintering pressure. Good interfacial uniformity and stable metallurgical microstructures were observed in the Cu joints sintered at a high sintering pressure of 10 MPa, irrespective of the sintering time. It was confirmed that a high-pressure-assisted sintering process could create relatively dense sintered layers and good interfacial uniformity in the Cu-sintered joints, regardless of the sintering temperatures being in the range of 225–300 °C. The influence of the sinter bonding pressure on the shear strengths of the Cu-sintered joints was more significant compared to that of the sintering temperature. Durations of 10 min (at 300 °C) and 60 min (at 225 and 250 °C) are sufficient for complete sintering reactions between the Si chip and the direct bond copper (DBC) substrate. Relatively good metallic bonding and dense sintered microstructures created by a high sintering pressure of 10 MPa resulted in high shear strength in excess of 40 MPa of the Cu-sintered joints.

scholarly journals Low-Temperature Sintering Bonding Using Silver Nanoparticle Paste for Electronics Packaging

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Guo ◽  
Zhi Zeng ◽  
Xiaoying Zhang ◽  
Peng Peng ◽  
Shanping Tang
Keyword(s):  
Shear Strength ◽  
Low Temperature ◽  
Chemical Reduction ◽  
Thermal Characteristics ◽  
Electronics Packaging ◽  
Low Temperature Sintering ◽  
Ag Nps ◽  
Scanning Calorimetry ◽  
Joint Shear Strength ◽  
Average Shear Strength

Ag nanoparticles (NPs) with about 40 nm diameter covered with 5–8 nm organic shell were prepared by chemical reduction reaction. The thermal characteristics of Ag nanoparticle (NP) paste were measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The low-temperature sintering bonding processes using Ag NP paste were carried out at the temperature range of 150–350°C for 5 min under the pressure of 3 MPa. The microstructures of the sintered joint and the fracture morphology were evaluated by scanning electron microscopy (SEM). The shear strength was used to evaluate the mechanical property of the sintered joint. TGA-DSC test showed that the Ag content is approximately 95.5 mass% in Ag NP paste. The average shear strength of the joint fabricated at 250°C for 5 min under the pressure of 3 MPa was about 28 MPa, which could meet the requirements of electronics packaging working at high temperature. The joint shear strength increased with the increase of the sintering temperature due to much denser sintered Ag NPs and more comprehensive metallurgical bonds formed in the joint.

Micro-Analysis of Railway Ballast Bond Effects

2012 ◽  
Vol 446-449 ◽  
pp. 2492-2496 ◽  
Author(s):  
Guo Qing Jing ◽  
Lei Shao ◽  
Ya Di Zhu ◽  
Liang Gao
Keyword(s):  
Shear Strength ◽  
High Speed ◽  
Bonding Layer ◽  
High Speed Train ◽  
Layer Depth ◽  
Railway Ballast ◽  
Microscopic Mechanism ◽  
Mechanism Research ◽  
Real Size ◽  
Micro Analysis

Ballast glue is a material to adjust ballast stiffness and stabilize ballast from flying due to high speed train winds; its ballast-glue system is less of microscopic mechanism research. In this paper, 3D DEM method is used to produce sleeper-ballast box model, ballast is made of real size irregular clumps, the ballast glue is represented by bonds to simulate the tensile and shear strength, it works at the ballast-ballast particles interaction contacts physically. The sleeper induced monotonic loadings results show the ballast-sleeper microscopic contact force chain distribution is altered due to ballast glue bonding effects, the glue results in tension forces among ballast system. The ballast-box bearing ability is improved with ballast global stiffness increase; ballast-box global stiffness increases with the glue bonding layer depth non-proportional, and is governed by the top 10cm layer.

Advances in Bonding Technology for Electronic Packaging

1993 ◽  
Vol 115 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Chin C. Lee ◽  
Chen Y. Wang ◽  
Goran Matijasevic
Keyword(s):  
Cross Section ◽  
Recent Progress ◽  
High Strength ◽  
Acoustic Microscopy ◽  
Bonding Layer ◽  
Alloy Formation ◽  
Advantages And Disadvantages ◽  
Bonding Technology ◽  
Higher Temperature ◽  
Good Uniformity

Recent progress in bonding materials is briefly reviewed with highlights of some of the advantages and disadvantages of the various attachment processes. The principle and experimental results of bonding with multilayer structures of Au-Sn and Au-In are presented. Using solid state as well as liquid phase diffusion of the multilayers, bonding temperatures less than the final melting point of the alloy can be used. This technique therefore allows reversal of the conventional soldering step hierarchy allowing a higher temperature process to follow the multilayer bonding step. Proper deposition of the multilayers inhibits oxidation of tin or indium. Die attachment experiments confirmed that high quality bonding can be obtained as seen in the void-free bonding layer images done by scanning acoustic microscopy. Cross-section examinations with SEM and EDX show near-eutectic alloy formation of good uniformity. Thermal shock tests confirmed the high strength of these solder alloys.

Preparation of YBa2Cu3O6+x by a formic acid method

1990 ◽  
Vol 5 (7) ◽  
pp. 1388-1391 ◽  
Author(s):  
J. C. Otamiri ◽  
A. Andersson
Keyword(s):  
Formic Acid ◽  
Acid Solutions ◽  
Dilute Solutions ◽  
Short Intervals ◽  
Temperature Range ◽  
Sintering Time ◽  
Acid Method ◽  
Higher Temperature ◽  
Lower Temperature

Synthesis of YBa2Cu3O6+x from formic acid solutions of stoichiometric amounts of the initial materials has been investigated in the temperature range 750–950°C. The reaction is strongly influenced by the concentration of formic acid. Dilute solutions favor synthesis of purer samples under moderate conditions of temperature and sintering time. At lower temperature the same effect can be achieved if sintering time is longer, while at higher temperature, multiple grinding and heating at very short intervals are necessary to avoid formation of Y2BaCuO5. The observed effect of HCOOH concentration is explained by the different mechanisms involved in the decomposition of the formates obtained.

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