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The thermal cycling life of direct bonded aluminum (DBA) and active metal brazing (AMB) substrates with two types of plating—Ni electroplating and Ni–P electroless plating—was evaluated by thermal shock tests between −50 and 250 °C. AMB substrates with Al2O3 and AlN fractured only after 10 cycles, but with Si3N4 ceramic, they retained good thermal stability even beyond 1000 cycles, regardless of the metallization type. The Ni layer on the surviving AMB substrates with Si3N4 was not damaged, while a crack occurred in the Ni–P layer. For DBA substrates, fracture did not occur up to 1000 cycles for all kind of ceramics. On the other hand, the Ni–P layer was roughened and cracked according to the severe deformation of the aluminum layer, while the Ni layer was not damaged after thermal shock tests. In addition, the deformation mechanism of an Al plate on a ceramic substrate was investigated both by microstructural observation and finite element method (FEM) simulation, which confirmed that grain boundary sliding was a key factor in the severe deformation of the Al layer that resulted in the cracking of the Ni–P layer. The fracture suppression in the Ni layer on DBA/AMB substrates can be attributed to its ductility and higher strength compared with those of Ni–P plating.

Because transparent polymers exhibit weak linear absorption in the visible and near-infrared range, conventional ultrashort-pulse Gaussian direct writing often produces shallow, tapered microchannels with low ablation efficiency. In this work, systematic experiments were carried out on the fabrication of microchannels in transparent Polymethyl methacrylate (PMMA) based on the Laser-induced plasma assistance (LIPA) technique. A femtosecond infrared fiber laser was focused on an oxygen-free copper substrate to generate plasma, and localized energy coupling was achieved at the PMMA and Oxygen-Free Copper (OFC) interface, which effectively improved the etching efficiency and morphological quality of the microchannels. The experimental results show that a 1035 nm femtosecond fiber laser is focused at the PMMA/OFC interface to generate a dense plasma that couples energy and pressure into the polymer. When the laser power density increases from 2.3×10 8 to 7.0×10 8 W/m 2 at a scan speed of 0.1 mm/s, the single-pass channel depth rises from 28 to 41 μm and the width from 18 to 25 μm. Subsequent electroless copper plating forms continuous conductive tracks with a resistance of 18 Ω and a minimum line width of 14.2 μm. These results show that femtosecond LIPA enables deeper microchannels and integrated metallization on transparent polymers, offering a compact route for rapid manufacturing of microfluidic–electronic devices.

Chemical plating has recently been employed for the preparation of flexible piezoresistive sensors; however, plating solutions and processes that affect the sensitivity still need further exploration. In the study, a sponge-based flexible sensor with copper as its conductive material is prepared using electroless plating. The variation in sponge resistance and sensitivity changes with different plating times are studied. It is found that, with the increasing plating time, the conductivity increases and the resistance of sample will decrease. Moreover, the range of resistance difference will decrease under compression, thus the sensitivity decreases. Furthermore, the sensor’s applications were assessed, verifying the practicability of the developed preparation method. This study may bring ideas for the new development of flexible pressure sensors.

An efficient method is described to fabricate carbonized wood fibers (CWF)-based electrode materials decorated with Ag particles (CWF-Ag) through electroless plating, and further carbonization from natural biomass poplar catkin and poplar fiber. Intrinsic physical advantages of poplar catkin fibers provide a chance of evenly dispersed Ag layer in addition to successful modulation of porosity and conductivity. However, the separation process resulted in cross-linked structures defect of poplar fibers, which impeded Ag particles to uniformly disperse. CWF-Ag from poplar catkin (CWF-Ag-poplar catkin) displays well-defined electrochemical performance for supercapacitors on account of its large specific surface area (745 m 2 /g), and hierarchical porous structure. Remarkably, CWF-Ag-poplar catkin achieves a high specific capacitance of 250 F/g at a current density of 1 A/g in 1 M KOH electrolyte that is about 1.3 times higher than CWF-Ag-poplar fiber (190 F/g). The result is due to uniform loading of silver on fibers. CWF-Ag-poplar catkin shows good rate capability and outstanding cycling stability up to 5000 times (only 5% loss of capacitance). The present study provides a simple and efficient approach (electroless plating) to design a high capacitance and stable supercapacitor electrode from natural biomass without treatment. Graphic abstract The present study provides a simple and efficient approach (electroless plating) to design a high capacitance and stable supercapacitor electrode from natural biomass, poplar catkin.

In order to make the Polyimide (PI) film material have good surface conductivity and meet its application in aerospace fields, for example, radar antenna, in this paper, the highly chemically inert PI material on the surface was modified by alkaline etching, and the metal layer on the surface of PI film was then deposited by electroless copper plating technology, to give PI good surface conductivity and meet its application in aerospace fields, for example, radar antenna. The microstructure and properties of surface metal layer of PI film before and after surface modification were characterized by SEM, contact angle tester and resistance tester. After alkaline etching at room temperature, there is a staggered and evenly distributed protrusion structure with dendritic and rivet structures on the surface of PI. However, the PI film surface etched at 60 °C presents pits with different sizes and depths of etching holes, and the hydrophilicity of the PI film surface is enhanced after etching. The coating on the PI is uniform and dense, and has good conductivity. This research realizes the preparation of high conductivity and high bonding force metal layer on the surface of PI film under alkaline etching, which provides technical support for the application of polyimide in aerospace fields.

In this study, we developed a novel cerium/ascorbic acid/iodine active species to design a redox flow battery (RFB), in which the cerium nitrate hexahydrate [Ce(NO3)3·6H2O] was used as a positive Ce3+/Ce4+ ion pair, and the potassium iodate (KIO3) containing ascorbic acid was used as a negative I2/I− ion pair. In order to improve the electrochemical activity and to avoid cross-contamination of the redox pair ions, the electroless plating and sol–gel method were applied to modify the carbon paper electrode and the Nafion 117 membrane. The electrocatalytic and electrochemical properties of the composite electrode using methanesulfonic acid as a supporting electrolyte were assessed using the cyclic voltammetry (CV) test. The results showed that the Ce (III)/Ce (IV) active species presented a symmetric oxidation/reduction current ratio (1.09) on the C–TiO2–PdO composite electrode. Adding a constant amount of ascorbic acid to the iodine solution led to a good reversible oxidation/reduction reaction. Therefore, a novel Ce/ascorbic acid/I RFB was developed with C–TiO2–PdO composite electrodes and modified Nafion 117–SiO2–SO3H membrane using the staggered-type flow channel, of which the energy efficiency (EE%) can reach about 72%. The Ce/ascorbic acid/I active species can greatly reduce the electrolyte cost compared to the all-vanadium redox flow battery system, and it therefore has greater development potential.

Here, copper nanoparticles were in situ synthesized on polyester fabric using cost effective chemicals, without stabilizing and sensitizing agents through a simple click electroless plating method to attain the electrical conductive fabric. Central composite design based on response surface methodology was applied to study the influence of copper salt precursor and reducing agent concentration on the electrical resistivity. The best sample with the lowest electrical resistivity was chosen and analyzed and then similar processing conditions were applied under ultrasonic condition besides final fabrics were subjected to the diverse characterizations. Findings suggested the potentiality of the one-pot sonoplating method for fabrication of copper nanoparticles on polyester fabric. The successful synthesis of copper nanoparticles on the polyester fabric was verified by scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns. A remarkable low electrical resistivity of 0.5 Ω·cm obtained on the sonotreated samples produced with incorporation of copper nanoparticles. Further, good results indicated on the mechanical properties of the copper treated fabrics. All of the observations perceive the great potential applications of the product in electrical, medical and smart textiles industries.

The ultraprecision machining of the mold surface is important because the performance of optical components produced using optical injection is related to the surface roughness and shape precision of the mold core. To process hard-to-cut mold core materials such as stainless steel, electroless nickel-phosphorus (NiP) plating is applied to the surface of the substrate, and ultraprecision processing is performed on the plating surface using diamond turning (DT) and magnetorheological finishing (MRF). Although MRF processing can remove tool marks caused by diamond turning and improve shape accuracy, it suffers from poor processability for NiP. In this paper, an ultraprecision processing method with a heat treatment process was presented to improve the MRF processability of electroless NiP. The plating was heat-treated under each condition and subjected to DT processing followed by MRF. The surface roughness and reflectance were measured and evaluated after processing. As a result, the surface roughness of NiP subjected to a 1-h heat treatment at 450 °C significantly decreased from Ra 7.0 nm to Ra 1.5 nm when compared to the specimen that did not undergo any heat treatment. An improvement in surface roughness confirmed that reflectance improved by more than 9% and 18%, respectively, compared to that for the diamond-turned and non-heat-treated specimen. These results confirmed that the MRF performance was improved through the NiP heat treatment process and contributed to quality improvements in ultraprecision injection optical parts. Furthermore, this technology can be applicable to various fields that used NiP plating, including the manufacturing of metal reflectors in the visible and ultraviolet regions.

This study conducts a systematic comparison of binary Ni-P, ternary Ni-W-P, and ternary Ni-Ce-P electroless coatings on 6061-T6 aluminum alloy, focusing on the effects of post-plating heat treatment at 300, 350, and 400 °C. The originality of this work lies in its direct comparison of W and Ce doping under identical conditions and its identification of a critical brittle transition that decouples hardness from wear resistance. All coatings achieved peak hardness at 350 °C, with Ni-W-P reaching approximately 1691 ± 45 HV0.1 due to Ni3P precipitation and solid-solution strengthening. However, a key finding is the severe embrittlement of the Ni-P coating at 300 °C, where its wear rate increased by over 50 times despite a hardness increase. Treatment at 400 °C degraded wear performance across all systems, likely due to precipitate coarsening and substrate over-aging. The best overall performance within the tested window was achieved with the Ni-Ce-P coating heat-treated at 350 °C for 1 h, which exhibited a fine nodular structure and reduced the wear rate by 98.9% compared to the bare substrate. These results highlight the importance of balancing hardness and toughness, identifying an optimized processing window for enhancing the tribological performance of lightweight aluminum components.

When fabricating high-entropy alloy particle-reinforced metal matrix composites via friction stir processing, the relatively low heat input led to insufficient interfacial diffusion between the particles and matrix, thereby compromising the composite properties. To address this issue, this study introduced an electroless copper plating step followed by heat treatment to produce Cu-coated HEA particles with an interfacial diffusion layer. These modified particles were then incorporated into a copper matrix via friction stir processing to form composites with an intentionally designed interfacial diffusion layer. The results indicate that the diffusion layer structure contributed to excellent interfacial bonding. The resulting composite exhibited a simultaneous enhancement in both strength and ductility. The tensile strength and elongation reached 372.5 MPa and 34.2%, respectively, representing increases of 20.4% and 54% compared to pure copper. The wear rate of the composite reduced by 33.7% relative to pure copper. Quantitative analysis indicated that the contribution of fine-grain strengthening, Orowan strengthening, dislocation strengthening, and load transfer strengthening to the overall strength was 41.2 MPa, 0.3 MPa, 12.7 MPa, and 15.7 MPa, respectively.