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Highlights: The (001)-oriented ferromagnetic La0.67Sr0.33MnO3 films are stuck onto the (011)-oriented ferroelectric single-crystal 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 substrate with 0° and 45° twist angle. By applying a 7.2 kV cm−1 electric field, the coexistence of uniaxial and fourfold in-plane magnetic anisotropy is observed in 45° Sample, while a typical uniaxial anisotropy is found in 0° Sample. Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering. In recent years, lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations. Moreover, twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures. A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process, which could provide some insight in to the physical phenomena. In this work, the La0.67Sr0.33MnO3 (001)/0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (011) (LSMO/PMN-PT) heterostructures with 45º and 0º twist angles were assembled via water-etching and transfer process. The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO < 110 >. A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO [110] easy axis is observed for the 45° Sample by applying a 7.2 kV cm−1 electrical field, significantly different from a uniaxial anisotropy with LSMO [100] easy axis for the 0° Sample. The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45° twist angle causes different lattice distortion of LSMO, thereby enhancing both the fourfold and uniaxial anisotropy. This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures. [ABSTRACT FROM AUTHOR]

Conductive fillers made from metal nanoparticles offer many advantages for the fabrication of a variety of electronic devices, but when they have a porous structure, their poor conductivity limits their adoption in many applications. In this study, an Ag-coated Cu micro-nanoparticle paste is used to achieve compact filling of blind vias on flexible copper clad polyimide laminates through a multistep filling and sintering technique. The filled blind vias achieve a resistivity as low as 6.2 μΩ·cm, which is comparable that of electroplated blind vias. Higher sintering pressure and temperature promote the filling performance, while the conductivity deteriorates at a via depth/diameter ratio greater than 1:1. Finite element simulations reveal a stress inhomogeneity in vias with large depth/diameter ratios, which is the key to understanding the evolution of the conductive properties of a paste-filled via. This study provides an effective method for high-performance microvia filling as well as insights into the mechanism that influences its performance. [ABSTRACT FROM AUTHOR]

As a traditional interconnect material, silver alloy bonding wires are widely used in electronic packaging, but their propensity to vulcanize quickly has not been sufficiently addressed. The current surface anti-oxidation and anti-sulfidation treatments are often accompanied by a decline in bonding performance, which hinders the use of silver alloy bonding wires in new applications. In the present paper, we develop a new cathodic passivation treatment in a Pd-containing solution for silver bonding wires, which not only significantly improves their vulcanization resistance, but also maintains their bonding performance. The surface of the treated wires remains unaffected after vulcanization in 0.3 μg/m3 of ammonium sulfide for 60 min. Compared to a Pd-free passivation treatment, the bonding strength of the wire passivated with the Pd-containing solution improves from 0.20 to 0.27 N. XPS analysis confirms the existence of Pd on the surface of the wire. The solder ball formed an obtuse angle instead of a sharp angle on the pad, which is beneficial for bonding strength. [ABSTRACT FROM AUTHOR]

In this work, we developed an eco-friendly and facile microvia filling method by using printing and sintering of Cu-Ag core-shell nano-microparticles (Cu@Ag NMPs). Through a chemical reduction reaction in a modified silver ammonia solution with L-His complexing agent, Cu@Ag NMPs with compact and uniform Ag shells, excellent sphericity and oxidation resistance were synthesized. The as-synthesized Cu@Ag NMPs show superior microvia filling properties to Cu nanoparticles (NPs), Ag NPs, and Cu NMPs. By developing a dense refill method, the porosity of the sintered particles within the microvias was significantly reduced from ~30% to ~10%, and the electrical conductivity is increased about twenty-fold. Combing the Cu@Ag NMPs and the dense refill method, the microvias could obtain resistivities as low as 7.0 and 6.3 μΩ·cm under the sintering temperatures of 220 °C and 260 °C, respectively. The material and method in this study possess great potentials in advanced electronic applications. [ABSTRACT FROM AUTHOR]

In this article, a universal and concise theoretical model is proposed to quantify the effect of gravity on packaging warpage by considering the competition between the thermal and chemical shrinkage of packaging materials and the flexural stiffness of packaging structures. Experimental study and finite element simulation for the warpage distributions of two fan-out panel-level packaging structures with sizes of 310 mm × 320 mm are carried out to verify the effectiveness of the proposed model. Under the ideal gravity-free condition, the warpage is proportional to the square of the packaging structure size. Under the gravity effect, the warpage follows a brief quartic expression of the packaging structure size. The gravity can reduce the bending moment in the structure and thereby lead to the decrease of the total warpage. For larger-size structures, the effect of gravity on warpage is more pronounced. It is found that the predictions by the model fit well with both experimental and simulation results. The theoretical model in our work can provide an effective tool to predict the warpage with consideration of the gravity effect and will promote further development and design of large-scale packaging structures. [ABSTRACT FROM AUTHOR]

In this paper, a facile method was introduced to fabricate fine conductive patterns by low-temperature selective laser sintering of Cu nanoparticles. By virtue of a nanosecond-pulsed ultraviolet laser source, fine circuits with a thickness of ∼8 μm and a conductivity of 3–6.5 × 106 S m−1 was successfully fabricated from Cu nanoparticle paste with a high metal content >80 wt.% on a flexible substrate at a wide scan rate range of 5–500 mm s−1. The sintered circuits exhibited a special sandwich morphology, with fully melted features in the centre and thermally sintered neck-connected features on the edges. A twofold linear relationship between the width of thermally sintered region and the reciprocal of the laser scan rate was revealed, indicating a heat dissipation mode transition from metal layer dominated dissipation to substrate dominated dissipation with the decrease of the laser scan rate. Finite element simulations were carried out to study the evolutions of temperature field and heat dissipation with changing laser scan rate and power, and the results fitted well with experimental results. On this basis, a relational expression was further proposed to determine the optimal processing window for laser sintering of metal nanoparticle layers. Our method extends the producible thickness and improves the fabrication efficiency of laser-printed circuits with desirable conductivity. The findings of this study can provide a guidance for understanding and controlling the sintering and heat transfer process of printing methods with similar materials and techniques. [ABSTRACT FROM AUTHOR]

• Ellipse criterion theory clarifies the deep notch enhancement mechanism in MGs. • Highly dispersed and relatively low stress/strain field near the notch is revealed. • Positive third principal stress will result in increased failure angle and strength. • A shear to tensile failure mode transition is predicted at the center of the notch. • Parameter Δ can provide an effective index to predict the failure mode of MGs. Deeply-notched metallic glasses can achieve significantly enhanced nominal tensile strain and strength under tension, and show the characteristics of dimples and "cup-and-cone" morphology on the fractographs. It has been expected that this deep-notch enhancement effect is resulted from the suppressed shear banding. In this study, we provided another interpretation for this effect through stress/strain field analyses based on the ellipse criterion. The results revealed the existence of relatively low but highly dispersed stress/strain instead of highly enhanced and localized stress/strain in deeply-notched metallic glasses, and therefore the actual stress is much lower than the nominal value. Owing to the positive third principal stress condition, the failure angle predicted by the ellipse criterion shifted from 45° at the edge of the notch to 90° at the center of the specimen, which was consistent with the "cup-and-cone" fracture morphology. These findings clarify the very high nominal stress/strain and special fracture process in deeply-notched metallic glasses. Our work provides a useful method to predict the shear-to-tensile failure mode transition of metallic glasses under complex loading conditions. [ABSTRACT FROM AUTHOR]

As one of the most important convergence layer (CL) protocol for delay/disruption-tolerant networking (DTN), Licklider transmission protocol (LTP) is designed for deep space communications, but it has rarely been considered for near earth applications. In this paper, LTP is proposed instead of TCP as CL with Bundle protocol (BP) for future application in GEO-relayed space networks (GRSN). Analytical models are built to estimate the file delivery time of LTP in GRSN. Experiments are also conducted on our computer based testbed in emulation of the basic scenarios during data transmission from LEO satellite to a ground station in GRSN. The results show that in transmission efficiency BP with LTPCL outperforms other protocols, such as BP with TCPCL, direct terrestrial TCP (TCP Cubic) and TCP variants (TCP Hybla) for space segments in most scenarios. It could be envisioned that DTN with LTPCL for space segment is currently the best choice for future GEO-relayed space internetworking. Moreover, performance of two different networking schemes,i.e. the on-board DTN routers and the bent-pipe relays are compared. It is observed that bent-pipe relays outperform the on-board DTN routers scheme when the channel condition is good, while the on-board DTN routers scheme performs better with high data loss ratio. [ABSTRACT FROM AUTHOR]

Delay/disruption tolerant networking (DTN) was proposed as a networking architecture for reliable data delivery in space vehicle communications despite long propagation delays and/or lengthy link disruptions. As one of the main data transport protocols of DTN, Licklider transmission protocol (LTP) was proposed by the NASA for reliable data delivery in challenging space environments in which the existing transport protocols of DTN, TCP, and UDP do not perform effectively. Pair-wise comparisons among LTP, TCP, and UDP running in the DTN stack have previously been done using statistical methods; evaluation results and performance analysis are available in the existing LTP research literature. However, there is as yet no solid analytical model of LTP performance in the presence of link disruptions. In this paper, we present an analytical method to predict transmission performance of LTP for reliable file delivery in space vehicle communications with focus on the expected file delivery delay (or latency) over space channels characterized by random link disruptions. Realistic file-transmission experiments using a PC-based infrastructure are presented to validate the analytical models. The analysis and study results presented in this paper are expected to be useful in understanding the impact of transmission conditions and configurations, on the efficiency of LTP when deployed for reliable data delivery in space missions using communication links that are subject to frequent and random interruptions. [ABSTRACT FROM AUTHOR]

Delay/disruption tolerant networking (DTN) was proposed as a networking architecture for reliable data delivery despite an extremely long propagation delay and frequent/lengthy link disruptions. The challenging problem of mission control and data delivery in deep-space explorations is a typical application scenario of the DTN technology. Reliable data delivery of DTN relies heavily on its core bundle protocol (BP). Performance evaluation and improvement of BP for deep-space communications are presently underway. The setting of the retransmission time-out (RTO) timer of BP is critical for reliable and highly efficient file transfer in a deep-space communication environment. In this paper, we present analytical modeling of an optimal RTO timer interval for the best goodput performance of BP in deep-space communications characterized by a very long signal propagation delay and lossy data links. A model is developed to compute the RTO timer interval that will result in the best goodput performance of BP normalized with respect to the total data load transmitted in order to achieve successful delivery of an entire file. Experimental validation using a PC-based testbed indicates that the RTO timer interval indicated by the model achieves the best normalized goodput performance of BP. The model predicts performance in all the experimented scenarios. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were employed to investigate the effect of void defect on the shear band nucleation in a Cu 64 Zr 36 metallic glass. Unlike uniform samples, the samples with void defects can form shear bands at a much lower strain. Finite element simulation revealed stress concentration near the voids, which can explain the early formation of shear bands. The shear band behaviors are also influenced by the size, shape and distribution of the defects. These findings can provide simulation support to understand the shear band heterogeneous nucleation process of metallic glasses in the real case. [ABSTRACT FROM AUTHOR]

Ag-coated Cu particles (Cu@Ag particles) are highly anticipated bimetallic materials with wide electronic applications. However, it is still crucially challenging to obtain well-covered Ag shells and facilitate the synthetic process, and the sintering/migration behaviors of Cu@Ag particles are also poorly understood. In this study, we develop a facile Ag coating method for Cu@Ag particles with the assistance of double complexing agents. Electrochemical analysis reveals that the complexing effect can effectively reduce the potential difference of the Cu-Ag replacement reaction, and thereby improve the coating quality. Cu@Ag particles with compact and uniform Ag shells are obtained, with Ag contents as low as ~10 at%. The as-prepared Cu@Ag particles show significantly improved oxidation resistance and reliable sintering property. Moreover, the Cu@Ag particles exhibit superior ion migration resistance even better than both Cu and Ag particles under an oxygen-containing environment. The results could provide helpful basis for understanding the synthesis, sintering and migration processes of Cu@Ag particles. The comprehensive performance of Cu@Ag particles makes them a promising interconnected material in future electronic industry. [Display omitted] • Well-covered Cu@Ag particles were synthesized by a facile one-step method. • Desirable morphology, coating quality, oxidation resistance were obtained. • Significantly improved shear strength than previous reports is achieved. • Complexing effect promotes the formation of compact and uniform Ag shell. • New evidence that Cu@Ag structure could lead to superior migration resistance. [ABSTRACT FROM AUTHOR]

In this study, we explore the structure-property relationship of sintered metal nano/microparticles from the perspective of the agglomerate size effect. Through sintering experiments and mechanical tests of Cu particle pastes with different solvents, a linear correlation between the agglomerate size in the particle paste (L a) and the size of large-scale cavities in the sintered structure (L c) is revealed, and a negative correlation between the cavity size and the shear strength of the sintered structure is discovered. Based on these results, a quantitative model is proposed to predict the overall strength of the sintered structure (τ f). A relationship τ f = τ c /(1 + √(2 L cmax / d)) is established, which fits the experimental results very well. The model reveals that the relative agglomerate size (L a / d) or relative cavity size (L c / d) plays a more important role than the particle size (d) itself in terms of defining the final sintering properties of metal nano/microparticles. [Display omitted] • The structure-property relation of sintered metal particles is explored • A linear correlation between agglomerate size and sintered cavity size is revealed • The cavity size and shear strength follow a relation of τ c / 1 + 2 L cmax / d • The relative cavity size (L c / d) is the key to determining the strength [ABSTRACT FROM AUTHOR]

In this study, a facile and nontoxic synthetic method of well-covered Cu-Ag core-shell nanoparticles (Cu@Ag NPs) was determined. Through chemical reduction reaction in a modified silver ammonia solution with gelatin additive, the as-synthesized Cu@Ag NPs showed attractive comprehensive characteristics, including small and narrow size distribution, low proportion of Ag, dense and uniform Ag shell, good dispersibility, good sphericity, and desirable oxidation resistance. Based on electrochemical analysis, a complexing model was proposed to explain the effects of gelatin on the deposition of Ag. It revealed that the gelatin acted as not only the steric hindrance but also the complexing agent and diffusivity modifier. The gelatin addition could increase the stability and decrease the decoupling rate of complexed Ag ions, thus leading to significant negative shift of the deposition potential and decrease of the deposition rate, promoting the formation of finer and thinner Ag shell. Our study proposes an applicable approach for the synthesis of Cu@Ag core-shell nanoparticles, and the complexing model can provide a theoretical tool to describe the effects of complexing agent on the synthesis of Cu@Ag and other bimetallic nanoparticles. [Display omitted] • Well-covered Cu@Ag nanoparticles were synthesized by a facile one-step method. • Desirable morphology, coating quality and oxidation resistance were achieved. • Complexing effect is the key controlling the formation of fine and thin Ag shell. • Gelatin additive increases the complex stability and decrease the decoupling rate. • A complexing model was proposed and the prediction consisted well with experiments. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the effects of a short-term high-calorie diet and the regulation mechanism of Raphanus sativus L. seeds (RSL seeds) on the intestinal motility of young rats. We fed 20 Specific Pathogen Free (SPF) 4-week-old male Sprague-Dawley (SD) rats special high-calorie diet for 3 days and then randomized them to a high-calorie diet group (HCG, 10 rats) and an RSL seeds treatment group (TG, 10 rats). Ten rats of the same age served as the control group (CG). HCG and TG rats continued to be fed high-calorie feed. All of the rats were weighed every 2 days. After 3 days of treatment, the effects of RSL seeds on the regulation of intestinal motility in rats consuming a high-calorie diet were examined. After 3 days of consuming a high-calorie diet, body weight was significantly lower in the HCG group than in the control group, and body weight of the HCG group increased slowly with time. Serum substance P (SP) and ghrelin levels were significantly lower, while the nitric oxide (NO) level was significantly higher. There were no differences in hematoxylin-eosin (HE) staining of colon sections between the groups. The expression levels of Cx43 and BDNF protein and mRNA in colon tissue were significantly lower in the HCG group. There were no significant differences in body weight between the CG and TG groups. Serum SP and ghrelin indexes in TG group were higher than those in the HCG group, and the NO index was significantly decreased. The expression levels of Cx43 and BDNF proteins and mRNA in the colon tissue were also significantly greater. Consumption of a short-term high-calorie diet may result in intestinal motility dysfunction and reduced intestinal motility. RSL seeds may improve the intestinal motility by regulating the secretion of gastrointestinal motility hormones and the expression of intestinal motility-related proteins, such as Cx43 and BDNF. [Display omitted] • Short-term high-calorie diet caused abnormal intestinal motility. • RSL seeds improved the abnormal gastrointestinal function and motility caused by a high-calorie diet. • TSL seeds affected the secretion of gastrointestinal motility-related neurotransmitters and brain–gut peptide hormones. • RSL seeds regulated the quantity and functions of BDNF and Cx43. [ABSTRACT FROM AUTHOR]

[Display omitted] • The influencing mechanism of ultrasound on the size of Cu nanoparticles is studied. • The mean size and size dispersion are significantly reduced ultrasound treatment. • A competition model between surface energy and ultrasonic force is proposed. • An exponential relation of between particle size and ultrasonic power is revealed. • Ultrasonic power and surface energy are keys to control the final particle size. Ultrasonic treatment is an effective method for size refinement and dispersion of nanomaterials during their synthesis process. However, the quantitative relationship between ultrasonic conditions and particle size in the synthesis of metal nanoparticles has not been fully revealed. In this study, Cu nanoparticles were synthesized via the wet-chemical redox method under ultrasonic treatment, and statistical analysis on the evolution of particle size distribution was carried out. It was found that the particle size decreased exponentially with increasing ultrasonic power. A quantitative model was then proposed to describe the influence of ultrasonic power on the size distribution of metal nanoparticles from the perspective of the competition between the surface energy and the ultrasonic force. A relational expression of R c ∝ γ 4 7 P - 3 7 was revealed, and it was proved to fit well with the experimental results. Our study provides new experimental basis and theoretical method for understanding the mechanism of ultrasonic-induced size refinement of metal nanoparticles. [ABSTRACT FROM AUTHOR]

Advancements in wearable electronics and Internet of Things (IoT) sensors have catalyzed the need for effective micro‐energy harvesting. Piezoelectric nanogenerators (PENGs) are ideal due to their high conversion efficiency and durability. However, the contrast between the high piezoelectric coefficients of brittle inorganic ceramics and the lower coefficients of superior flexibility and biocompatibility of organic polymers poses a significant challenge. This work introduces a novel multilayer composite PENG, integrating a single‐crystal BaTiO3 (BTO) film between poly(vinylidene fluoride‐co‐trifluoroethylene) (PVDF‐TrFE) layers. The PVDF‐TrFE/BTO/PVDF‐TrFE PENGs demonstrate substantially improved energy harvesting performance, with outputs reaching up to 15.1 V, 2.39 µA, and power density of 17.33 µW cm−2 during bending deformation. This power density represents a significant increase compared to pure PVDF‐TrFE and nanoparticle BTO‐doped PVDF‐TrFE PENGs. Durability tests show consistent performance, with a stable ∼15.0 V output across 2000 bending cycles. Additionally, when attached to the human body, these PENGs efficiently convert body motions into electrical responses. This work demonstrates a significant enhancement in the performance of PENGs using sandwich‐structured composite of PVDF‐TrFE and freestanding single‐crystal BTO films, showing its potential to address the power requirements of wearable and flexible electronic devices. [ABSTRACT FROM AUTHOR]

• LaB 6 modified sub-nanometer µ-phase strengthening carbon-free FeCoMo steel prepared by SPS technique. • LaB 6 improves the precipitation efficiency of the µ-phase. • LaB 6 inhibits the formation of impurities and reduces their effect on mechanical properties. • FeCoMo steel with 0.2 wt% LaB 6 have excellent hardness, wear resistance and red hardness. LaB 6 -modified carbon-free FeCoMo steels with nano-precipitated phase strengthening have shown excellent sintering and mechanical properties, which enhances their application potential. The results showed that LaB 6 promoted the precipitation of sub-nanometer μ-phase particles from the matrix and reduced the formation of impurity phases during the sintering process. The addition of 0.2 wt% LaB 6 increased the hardness, wear resistance and red hardness of FeCoMo steel by 5.1 %, 26.3 % and 12.6 %, respectively. This study creates conditions for the application of carbon-free FeCoMo steels by introducing LaB 6 to improve their sintering properties and precipitated phase strengthening efficiency. [ABSTRACT FROM AUTHOR]

Lightweight high-entropy alloys (HEAs) are a new class of low-density, high strength-to-weight ratio metallic structural material. Understanding their corrosion behavior is crucial for designing microstructures for their practical applications. This work investigates the electrochemical corrosion behavior of lightweight HEAs AlCrTiV0.5Cux (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) in a 0.6 M NaCl solution. These HEAs were produced by vacuum arc melting. In contrast to 304L stainless steel, all of the alloys exhibited lower current density levels caused by self-corrosion, with AlCrTiV0.5 demonstrating the highest corrosion resistance (0.131 μA/cm2). Corrosion resistance decreased along with the content of copper because copper segregation accelerated local corrosion throughout the alloy. [ABSTRACT FROM AUTHOR]

A green method for the synthesis of in situ Cu paste is developed. Cu particles are prepared through chemical reduction by selecting a special copper source, reducing agent, and solvent. Then the reaction solution is directly concentrated to obtain an in situ Cu paste. The synthesis of Cu particles and the preparation of Cu paste are conducted simultaneously, and the process of separation, purification, drying, storage, and re-dispersion of powder are reduced. Particles are not directly exposed to air, thus the oxidation of micro/submicron -Cu is effectively prevented, and the agglomeration of particles caused by drying and dispersion operations is simultaneously reduced. Furthermore, the proposed method has a certain universality, and different types of Cu sources can be used to prepare in situ paste with different sizes and morphologies. The entire preparation process is simple, efficient, green, and the yield can reach 99.99%, which breaks through the bottleneck of the application of traditional micro/submicron-Cu materials. Copper acetate-based in situ paste is sintered for 30 min at 260 °C and 2 MPa in a reducing atmosphere. The shear strength, resistivity, and thermal conductivity reach 55.26 MPa, 4.01 × 10â€"8 Ω·m, and 92.75 W/(m·K), respectively, which could meet the interconnection application of power semiconductor devices. [ABSTRACT FROM AUTHOR]

By the low cyclic reversed loading tests for damped infill wall-frame, bare frame and conventional infill wall-frame, the hysteretic behavior, bearing capacity, deformation capacity, ductility, stiffness degradation, energy dissipation and damage characteristic of damped infill wall-frame were studied comparatively. The results indicate that the damped infill wall contributes to the hysteretic energy of structure with its masonry units shearing the damped layer circularly, and plays good role in energy dissipating. The hysteretic loops of the frame structure with damped infill wall is plumper, the energy dissipation capacity is excellent, the equivalent viscous damping coefficient reaches above 0.1. The damped infill wall is capable of enhancing the lateral force resistance capacity and the lateral stiffness of the frame structure. But its stiffness effect and confined effect is much weaker than that of the conventional infill wall which prevent the frame columns from shear damage effectively. The damped infill wall-frame's strength degradation rate and the stiffness degradation rate are much slower than that of the conventionally infill frame. Its ultimate inter-story drift ratio is basically the same as that of the bare frame. The damped infill wall frame has good ductility and deformation capacity. [ABSTRACT FROM AUTHOR]

In this paper, a mixed sintering accelerator of colophony and cetyltrimethyl ammonium bromide (CTAB) was developed to improve the sintering properties of Cu nanoparticles (NPs) paste. With the synergy effect of the mixed sintering accelerator, Cu NPs paste could be well sintered at 260 °C for 30 min under a pressure of 2 MPa, and the shear strength was greatly improved from 15 to 33 MPa. The fracture morphology of the Cu NPs joint transformed from brittle interface failure features to ductile dimple features, and the porosity in the sintered layer was significantly reduced. XRD analysis further confirmed that the synergy of colophony and CTAB could effectively remove the oxides in the Cu NPs paste during sintering, and thereby improve the sintering properties. This work can provide an applicable approach to improve the sintering properties of metal NPs and help to understand the synergy effect of sintering accelerators on the bonding behaviors of metal nanoparticles at low temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-purity, spherical Ag NPs with a size of ∼5 nm are synthesized by spark ablation. • A solvent-assisted sintering method is developed to improve the sintering properties. • The shear strength of the sintered Ag NPs at 180 °C is improved from 0 to 37.1 MPa. • A compact and void-free sintered structure is obtained by the sintering method. • Correlations between solvent wettability, agglomerate size and void size are revealed. Through the spark ablation method, high purity, spherical silver nanoparticles (Ag NPs) with a size of 5 ± 3 nm are prepared. A solvent-assisted sintering method is developed to modulate the sintering structure and properties of the as-prepared Ag NPs. The effects of the solvents terpineol, polyethylene glycol-200, 1,2-propanediol, and ethylene glycol are explored. The results show that treatment with ethylene glycol causes the shear strength of the sintered Ag NPs at 180, 220, 260, and 300 °C to significantly improve from 0, 3.7, 22.1, and 64.6 MPa to 37.1, 56.1, 76.6, and 93.1 MPa respectively. Additionally, the size and number of voids in the sintered structure are significantly reduced. From the perspective of the capillary pressure induced by the solvent during sintering, a correlation between low solvent wettability and small agglomerate size of the Ag NPs is revealed, which reasonably explains the structure and properties of the sintered Ag NPs that were treated with different solvents. The spark ablation and solvent-assisted sintering methods provide a new approach for the fabrication and structure–property design of metal NPs for electronic applications. [ABSTRACT FROM AUTHOR]

Leveler is one of the most important additives for super-conformal copper electroplating, which has been widely applied in the fabrication of nanoscale (or microscale) interconnect features in integrated circuits (ICs) and printed circuit boards (PCBs). Because the structure-property relationship of the leveler is not clear, the development of novel leveler with high microvia filling performance is very time-consuming and challenging. In this study, a series of triphenylmethane-based (TPM-based) molecules with different nitrogen-containing groups have been designed, synthesized, and investigated as novel levelers for super-conformal copper electroplating. Their structure-property relationships are investigated by electrochemical analyses, contact angle measurements, and microvia filling electroplating experiments. It is found that the steric hindrance and the type of the nitrogen-containing groups (tertiary amine or quaternary ammonium with counter anions) in a leveler not only affect its adsorption ratio and strength on the copper interface, but also affect its adsorption preference on different copper crystalline plane. In combination with Cl−, polyethylene glycol (PEG, suppressor), and bis-(3-sulfopropyl) disulfide (SPS, accelerator), all TPM-based levelers show excellent microvia filling performances in copper electroplating and their effective concentrations are related to their antagonistic ability against the accelerator SPS. [Display omitted] [ABSTRACT FROM AUTHOR]

CoCrFeMnNi high entropy alloys (HEAs) based composites have been synthesized by laser melting deposition (LMD). Through TiC and WC particle additions, ex-situ TiC and in-situ M 23 C 6 precipitations are formed, respectively. The average grain size of the LMD-fabricated CoCrFeMnNi HEA is significantly reduced. With TiC and WC additions, appearing the combined effects of grain refinement and precipitation reinforcement, further to remarkably improve the tensile strength from 550 MPa to 610 MPa and 776 MPa for the HEAs, whereas the plasticity decreased from 52% to 47% and 37%, respectively. The HEAs with WC addition shows higher tensile strength, which probably results from the homogeneous distribution of the nano-scale M 23 C 6 reinforcement precipitates and a single deformation pattern. This work provides insight into the effects of different introduction modes of reinforced phases when it comes to the mechanical properties for HEA composites. • HEAs-based composites have been synthesized by laser melting deposition. • The tensile properties could be adjusted by precipitations reinforcement. • The HEA + WC samples showed a tensile strength of 776 MPa and a strain of 37%. [ABSTRACT FROM AUTHOR]