Electroless Ag Research Articles

Investigation of microstructural, hardness, and wear properties of AlCrCuFeNi high entropy alloys produced by hot-pressing with the enhancement of manufacturability through electroless Ag incorporation

This study involves the production of HEA materials using low-temperature and high-pressure principles by mechanical-alloying AlCrCuFeNi high-entropy alloy powders, followed by electroless Ag coating for enhanced interface properties and hot-pressing without additional sintering. The Ag interface significantly improved the bonding of HEA powders. While increasing temperature causes a 10 % weight gain due to oxidation in HEA samples, this rate is only 1.5 % in those produced with Ag-coated HEA. The Ag interface improved the hardness of the HEAs by 50 %. The wear rate was reduced by more than twofold due to the Ag-interfaces. Ag exhibited a self-lubricating effect due to the Ag layers that repeatedly emerge during sliding, resulting in a low friction coefficient of 0.19 and excellent wear resistance.

Development of Surface-enhanced Raman Scattering Substrate Using Melt-blown Nonwoven Fabric Subjected to Electroless Ag Plating: A Basic Study

Development of Surface-enhanced Raman Scattering Substrate Using Melt-blown Nonwoven Fabric Subjected to Electroless Ag Plating: A Basic Study

Hierarchically structured composite with superhydrophobicity and radiative cooling for energy-saving buildings

Passive daytime radiative cooling (PDRC) with zero energy consumption and green is regarded as one of the most feasible solutions to replace conventional electrical cooling by reflecting sunlight spontaneously and radiating excess heat through atmospheric transparency windows to universe natural heat sink. However, traditional cool building materials are still very limited in practical applications due to contamination by dust, rain, etc., which reduces the cooling capacity in outdoor environments. Herein, we fabricate a hierarchically designed superhydrophobic daytime radiative composite (Al2O3-PDMS/Al2O3-PDMS@Ag/Al2O3-PDMS/SiO2) via facile bladeing film and electroless Ag plating methods, which have strong visible light reflectivity ∼91 % and high mid-infrared emissivity ∼97 %, effectively producing an ambient temperature drop of 13.8 °C on sunny days in direct outdoor sunlight. What's more, the composite has satisfactory superhydrophobicity with a water contact angle of 154°, making the composite self-cleaning so that the composite is not contaminated and effectively maintains splendid radiative cooling properties. Meanwhile, after prolonged immersion in hydrochloric acid and water shock, the composite retains superhydrophobicity and significant radiative cooling properties, which are of great significance for the sustainable development of energy-saving buildings.

The Effect of Ni Interlayer Formation Plating Bath on the Suppression of Oxidation of Ag-Coated Cu Flakes

To suppress Ag dewetting from around 200 oC in Ag-coated Cu (Cu@Ag) flakes, Ag and Ni-coated Cu (Cu@Ni@Ag) flakes were fabricated by successive Ni and Ag electroless plating. The Ni bath type was an important consideration to induce differences in the Ag dewetting and resultant Cu oxidation. An acid Ni bath contained succinic acid as a complexing agent and sodium hypophosphite as a reductant, and an alkaline Ni bath contained sodium citrate as a complexing agent and sodium hydroxide as a pH adjuster as well as sodium hypophosphite. A hydrazine-based Ni bath contained sodium citrate, sodium hydroxide, and hydrazine hydrate as a reductant. The acid Ni bath provided amorphous coatings with a P content of approximately 10 wt%. The Cu@Ni@Ag flakes started the Ag dewetting and Cu oxidation at 350 oC, together with the formation of the Ni3P phase. Meanwhile, the alkaline Ni bath created Ni-5 wt% P amorphous Ni coatings, which transformed into a crystalline phase after heating at 350 oC. The Ag shell was dewetted at 450 oC, which caused oxidation of the flakes. Finally, the hydrazine-based Ni bath formed crystalline coatings without P, which induced rapid mixing with the core Cu. The Ag shells on the mixed Cu-Ni alloy showed repressed dewetting behavior, and thus the dewetting and oxidation temperature was the highest, such as 500 oC. Enhancing the high oxidation resistance at approximately 300 oC will enable the use of Cu@Ni@Ag flakes as a low-cost filler material in conductive pastes, especially for long-time or high-temperature curing.

Nanoscale Ag-Decorated Hollow Porous CuO/SnO2 Heterojunctions for Isopropanol Detection

Nanoscale Ag-decorated CuO/SnO2 heterojunctions with coralloid hollow porous structure (ACSO HPs) were successfully synthesized though a hydrothermal route with electroless Ag plating followed by the calcination and acid-washing. Detailed microstructural characterizations confirmed that the hollow porous structure comprised CuO/SnO2 and Ag/SnO2 nanoheterojunctions, and the SnO2 surface was decorated primarily with nano-Ag, which was the outer layer of the structure. The ACSO HPs sensor displayed a higher response to isopropanol compared to toluene, acetone, benzene, ethanol, and methanol than other samples. For 100 ppm isopropanol, the ACSO sensor exhibited a faster response time (6 s) and a higher recovery time (34 s) than undecorated Ag samples. The improved sensing performance of ACSO samples was ascribed to the synergistic effect of the CuO/SnO2 nanoheterojunctions with the dramatic sensitization of the decorated nano-Ag, as well as the HPs.

Improving Electroless Ag Plating by Depositing Graphene Oxide/Polymer Composite Film on the Ag Layer for Corrosion Protection

Improving Electroless Ag Plating by Depositing Graphene Oxide/Polymer Composite Film on the Ag Layer for Corrosion Protection

Eco-friendly, cost-effective electroless Ag plating based on a novel Ni–P activation process on magnesium titanate ceramic

An eco-friendly, cost-effective route for fabrication of silver (Ag) coatings on the surface of magnesium titanate ceramic by electroless plating (EP) based on a novel Ni–P activation process was developed successfully. Coarsened ceramic surface was implanted in situ abundant nano-scale Ni–P spherical active particles via facilely soaking in aqueous solution containing nickel sulphate as Ni source, sodium hypophosphite as major reducing agent and introducing a trace of sodium borohydride to induce initial deposition. The validity of the novel activation process was confirmed by the subsequent experimental fact that Ag EP coatings could deposit smoothly. The surface and cross-section micro-morphologies of typical samples and their element constituent as well as distribution were characterized by SEM and EDS. The deposition rate of Ag coatings and their comprehensive performances including appearance, electric conductivity, adhesion and microhardness were evaluated. The results indicates that the novel Ni–P process could provide the best activating effect to ensure the deposition of high-quality Ag coatings by comparison with traditional Ni–B activation and classical stannous activation.

Electroless Ag films for ionic liquid lubricated electrical contact

Two kinds of plating solutions, i.e. a standard plating solution and a commercially available plating solution, are employed for the preparation of electroless Ag film. The commercially available plating solution enables fast film deposition within several minutes and is highly selective for deposition onto Cu substrate, and cost-effective (reusable solution, and much less Ag consumption) compared to the standard plating solution. Both electroless Ag films prepared have distinct microstructure, surface chemistry, and bulk chemistry. The film from standard plating solution is composed of nano-grains with an average grain size of 300 nm and homogeneity. The film prepared with commercially available plating solution is composed of equiaxed grains (140 nm in size), and ribbon fish-like grains (80 nm in size and 0.5-2 μm in length) and shows microstructural inhomogeneity. The tribological properties of these electroless Ag films in presence of flooded 1-methyl-3-octylimidazolium hexafluorophosphate are investigated on a reciprocating tribometer with a pin-on-disk configuration under electrical contact. The results demonstrate that both electroless Ag films show better tribological property than Cu-on-Cu contact. Due to their dissimilar microstructure the tribological properties of the two electroless Ag films are quite different. For the standard plated film, local adhesion and tear-up in an annular shape on pin result in many plate-like wear debris in the early stage of the sliding test. For commercially the plated film from a commercial solution, compact and thin tribo-film on the worn surfaces of pin and disk as well as little or no wear debris are observed. The microstructural effect also has an influence on the design of the tribo-interface.

Study on Glucose Sensing Materials Based on CNT/Graphene-Ag Composite for Nano-Electrode Sensor

Sensors are already part of everyday life, and they are based on a mechanical and electronic pattern such as what humans see, hear and do, and they have a wide range of uses and a wide variety of types. The material that forms a sensor and its structure are very important to perform the sensing role. Electrochemical method is a kind of technology that has been promoted in modern environmental pollutant detection technology. It attracts the attention and interests of many researchers with various advantages. There are many kinds of pollution, and the persistent organic pollutants are especially harmful. Therefore, there is an urgent need to be able to quickly and accurately detect environmental pollution in the in situ method. With the development of nanotechnology, great potential has been created for the design of low-energy consumption, low-cost, high-sensitivity sensors. Due to the properties of carbon nano tube (CNT) and graphene, the combination between C-C and C-C is hexagonal in the nanostructures, which has a great reactivity and are also very stable in high temperature, high pressure, and acid conditions.Carbon Nano Tube (CNT) as nanomaterials have excellent electrical conductivity, high specific surface area and hollow structure, so it can be ideal sensor materials. Based on the excellent properties of the CNT, if the composite material is constructed, this type of material has many new properties at the same time. If such a composite material is used as an electrode, an oxidation-reduction reaction occurs between the contaminant and the electrode, which achieves the purpose of an electrochemical sensor.Synergy effect is achieved by making Metal Nano Composite based on CNT/graphene nanomaterials.These composites have both the characteristics of CNT / graphene and metal, and to make composite with these properties, uniformly plated process and surface treatment technology are required. To manufacture these composite materials, we fabricate Ag-CNT/graphene, optimized the Ag electroless plating (ELP) method for uniform aggregation on CNT/graphene, and optimize the process for the plating solution using the Raman in-situ method. The technique of analyzing the reaction process has been attracting attention from the past. It is very difficult to analyze the process in a chemical reaction because the chemical reaction causes a real-time change in molecular vibration due to a change in binding force. Therefore, there is an urgent need to be able to quickly and accurately detect a chemical reaction in in-situ method. Many electrodes can be formed by electro-less plating (ELP) technique in the sensor process, which enables low-cost and high-efficiency processing. In particular, the greatest advantage of the ELP process is that it can form layers on the nanoscale. In order to uniformly deposit Ag nanoparticles with antimicrobial activity on the surfaces of commercially available nanofilters, it is necessary to process the deposition process in real time and analyze easily.This work mainly studies the application of Multi walled CNT (MWCNT) and MWCNT composite modified electrode in the electrochemical sensor. We aimed to maximize the sensitivity of the sensor by proceeding with silver electroless plating for MWCNT and MWCNT composite. Oxidation of MWCNT showed a stronger plating effect and the pretreatmented MWCNT has a better effect.

Silver mirror films deposited on well plates for SERS detection of multi-analytes: Aiming at 96-well technology

96-Well technology is associated with automated sample preparation and simultaneous analysis based on the low-cost well plate format. To explore the potential applications of 96-well technology in SERS detection, we examined the surface-bound electroless deposition procedure for the preparation of uniform and stable Ag mirror films on polydopamine (PDA)-coated well plates as active-SERS substrates. In the presented procedure, small Ag seeds assembled on PDA coating were employed as the surface-bound catalyst and provided the active sites for electroless Ag deposition. The high-quality Ag mirror films showed high performance in terms of sensitivity, uniformity, reproducibility and stability using rhodamine 6G (R6G) as the probe molecule. A remarkable enhancement factor of 3.41 × 108 was obtained. The relative standard deviations against well-by-well and batch-by-batch reproducibility were less than 5%. The SERS films on well plates were successfully used to quantify the amounts of organic dyes (R6G and malachite green) in environmental water samples and small biological molecules (adenosine triphosphate and adenine) in urine matrix, displaying satisfactory sensitivity, selectivity and recovery. Their limit of detection values were at nanomolar, even picomolar concentration.

High Chemical and Thermal Stability of Ag Nanowire‐Based Transparent Conductive Electrodes Induced by Electroless Ag Nanoparticle Decoration

Although silver nanowires (AgNWs) are a promising material to replace indium tin oxide for use in transparent conductive electrodes (TCEs), they are easily degraded in contact with air and harsh environments due to surface corrosion and morphological instability. Herein, a facile approach is reported to improve both conductivity and stability of AgNW‐based TCEs (AG‐TCEs) in contact with atmospheric oxidation, water, alcoholic solutions, and acidic and alkaline environments without reducing their high transparency. This approach is based on very rapid electroless deposition of highly crystalline Ag nanoparticles (AgNPs) on AgNWs, uniformly decorating the surface of AG‐TCEs at room temperature. Field‐emission scanning electron microscopic images reveal the formation of strong junctions between AgNWs induced by AgNPs. Exposing the resulting AG‐TCEs to HCl and NaOH solutions remarkably reduces their initial sheet resistance (Rs0), leading to ΔRs/Rs0 (%) of −26% and −37%, respectively. Moreover, decorated AG‐TCEs show high thermal stability after being annealed at 180 °C for 12 h.

Electroless silver plating on modified fly ash particle surface

Ag-plated fly ash (FA) powders were prepared through modified electroless plating, which could be utilized for manufacturing conductive polymers for Electromagnetic interference (EMI) shielding applications. In order to improve the FA surface activity, alkali cleaning and coupling modification were employed. Extensive characterizations of Ag-plated FA particles were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques. The mechanism of electroless Ag plating was mainly studied by using XPS. The XPS results showed that the diammonia functional group from the coupling agent adsorbed silver ions to form the N-Ag coordination bond and produce pure Ag film. In addition, electrical conductivity and electromagnetic properties were studied by Four-probe resistance tester and vector network analyzer, respectively. The results indicated that uniform and compact Ag films were formed on FA particle surface strongly after alkali cleaning and coupling modification. The electrical conductivity of the as-prepared 0.6-FA-S-Ag particles with a coated thickness of 200 nm was about 8.2 × 10−5 Ω·cm. The electromagnetic parameters and calculated reflection loss indicate that Ag-plated FA powders have no magnetic conductivity and the main contribution of electromagnetic loss comes from dielectric loss.

Synthesis of polystyrene@polypyrrole-COOH@Ag (core@shell@shell) microspheres for potential application in anisotropic conductive paste

We demonstrate a fabrication scheme for the synthesis of conductive core-shell (core@shell) nanoparticles consisting of polystyrene (PS) microspheres in size of 613 nm with consecutive coatings of functionalized polypyrrole (PPy-COOH) and Ag. The PPy-COOH precursors undergo polymerization on PS microspheres forming PS@PPy-COOH microspheres, followed by sensitization and Ag electroless deposition to produce PS@PPy-COOH@Ag microspheres in size of 717 nm. The PPy-COOH serves as the adhesive for intimate bonding of PS and Ag. Images from scanning and transmission electron microscopes confirm a Ag coating of 41–50 nm which is consisted of clustered nanoparticles forming a mono-layered film. From X-ray diffraction pattern, the Ag adopts a polycrystalline fcc structure with grain size of 12 nm. Results from thermal gravimetric analysis indicate a Ag loading of 54 wt%. By four-point-probe, the bulk conductivity for PS@PPy-COOH@Ag is 10,170 S m−1. These microspheres show promising potential for anisotropic conductive paste.

Highly flexible and ultra-thin carbon-fabric/Ag/waterborne polyurethane film for ultra-efficient EMI shielding

We report in this work an ultra-thin and flexible carbon-fabric/Ag/waterborne polyurethane film (named CEF-NF/Ag/WPU film) that exhibits ultra-efficient EMI shielding property using electroless Ag plating combined with the enhanced-pressing process. The optimal CEF-NF/Ag/WPU film (0.183 mm) displays an ultra-high electrical conductivity of 11986.8 S/cm and a superior EMI-SE of 102.9 dB, which demonstrates the Ag deposition can effectively improve the electrical and EMI shielding performance. Compared with the film without an enhanced-pressing, the EMI-SE of a CEF-NF/Ag/WPU film with an enhanced-pressing showed an increase of about 37.5%. The porous structure deposited with Ag particles coating endows this composite film with remarkable EMI-SE at a thin thickness and lightweight (SSEt up to 5808.7 dB cm2 g−1) which outperforms most works. At last, this CEF-NF/Ag/WPU film performs outstanding reliability after ultrasound treatment, bending test and thermal reliability test. In summary, this film has great potential in the fields of wearable devices and flexible materials.

Mussel-inspired construction of multifunctional cotton fabric with superhydrophobicity, conductivity and antibacterial activity

Using a facile strategy to fabricate multifunctional cotton fabrics with superhydrophobicity, conductivity and antibacterial activity is an important and urgent issue in the development of natural fabrics. Herein, a new type of cotton fabric, denoted as Cot@PDA/Ag/NDM, has been fabricated utilizing mussel-inspired polydopamine (PDA) chemistry, followed by electroless Ag plating and n-dodecyl mercaptan (NDM) self-assembly. The influence of dopamine (DA) and AgNO3 concentration on the surface morphology and conductivity, as well as NDM treatment time on the surface wettability of the fabric is systematically investigated. Cot@PDA/Ag/NDM not only exhibits superhydrophobicity with water contact angle of 155.9 ± 1°, but also possesses excellent self-cleaning and antifouling properties. In addition, the fabric has a highly conductive surface with sheet resistance as low as 10.2 Ω cm, and shows outstanding mechanical properties and antibacterial activity against Escherichia coli and Staphylococcus aureus.

Quasi layer by layer spray deposition of high-quality Ag coatings with excellent micro mechanical properties

In this paper, quasi layer by layer (quasi-LbL) spray deposition has been developed to produce pure and homogeneous metallic coatings on plastic surfaces. Comparing with Ag coatings by electroless deposition, the surfaces prepared by quasi-LbL show reflective and white characteristics that made of uniform nanoparticles of uneven size. By changing pH of spraying solution and spray passes, the surface morphology, roughness, composition, deposition weight and electrical properties of the Ag coatings by quasi-LbL were studies in details. The Ag coating with excellent electrical conductivity was face centered cubic (fcc) metallic state without any other phase, but with less oxides on the top surfaces than Ag coatings prepared by electroless plating. The deposition weight of Ag coatings would increase as the spray passes steps up, and Ag salts were the defining parameter for deposition weight even the spray atmosphere is air or N2. Nanoindentation tests were used to studies the micro mechanical properties. The modulus and the hardness of Ag coatings are 2.649 GPa and 0.118 GPa respectively, which are higher than those of electroless Ag coatings. The quasi-LbL method shows the possibility of producing high-quality metallic coatings and also be exploited to produce other kinds of metallic coatings, such as Ni and Cu.

Electric arc-induced damage on electroless Ag film using ionic liquid as a lubricant under sliding electrical contact

Abstract For Cu-on-Ag film contact, good boundary lubricating property of LP108 allows sliding with low friction coefficient, burnished worn surface and high load-bearing capacity. Under current-loading condition, mechanical separation and recontact of contacting surface produces electric arc and electric arc-induced damage on Ag film depends on polarity of pin and disk. For positive Cu pin against negative Ag film disk, rainbow-like film and transparent LP108 on Ag film are observed. While, for negative Cu pin against positive Ag film disk, removal of Ag film is observed and this produces dark ionic liquid-Ag suspension. In both cases, electric arc does not degrade LP108. Electric arc and electric arc-induced damage on Ag film can be eliminated by ensuring good contacting surface conformity.

Surface Morphology and Conductivity of Ag-Coated Cu Flakes Prepared by Electroless Ag Plating Using Different Additives

Surface Morphology and Conductivity of Ag-Coated Cu Flakes Prepared by Electroless Ag Plating Using Different Additives

Electroless Ag deposition on the cell walls of carbon foam by a displacement method

To obtain efficient metalization of the surface and cell walls of carbon foam, an electroless silver displacement deposition method was investigated, in which a copper layer was first electroless-deposited and then displaced by silver. The purity of the silver coating, and the morphology, microstructure, mechanical strength and electrical conductivity of the resulting carbon foams were characterized by SEM, EDS, XRD, mechanical and conductivity tests. Results indicate that a uniform and continuous silver film is formed on the cell walls of the carbon foam with a better adhesion to the carbon compared to that obtained using the traditional one-step silver plating method. The coating is crystalline silver without copper or silver oxide. The conductivity and mechanical strength of these carbon foams increase from 700 to 2055 S/cm and 0.54 to 1.05 MPa, respectively when the silver content is increased from 0 to15.5 wt%.

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복합적 열분해법을 이용한 구리 나노분말의 합성 및 무전해 은도금에 관한 연구