Tin Whisker Growth Suppression Using NiO Sublayers Fabricated by Dip Coating

Whiskers are small crystalline growths, which can grow from certain metals or alloys. Reaching up to several millimeters long, whiskers have the potential to cause device failures due to short circuits and contamination by debris. Tin (Sn) is one such metal that is particularly prone to whisker development. Until the 2006 RoHS Initiative, lead (Pb) was added to tin in small amounts (up to 2%) to greatly reduce the growth of whiskers. Since then, however, industry has switched to lead-free tin solders and coatings, and the issue of whisker growth on tin has attracted new interest. A reactive-sputtering-deposited nickel oxide sublayer was shown recently to strongly suppress the growth of whiskers from an overlaying tin layer. This paper reports on using nickel oxide films, obtained by a sol–gel dip coating method, as whisker suppressing sublayers. The proposed method is simple, low-cost, and can easily be scaled up for manufacturing purposes. The properties of the sol–gel deposited nickel oxide film were examined using SEM, EDS, and Raman spectroscopy. Samples containing the nickel oxide sublayer were observed through SEM periodically over several months to examine the surfaces for whisker development, and the results show that such layers can be very effective in suppressing whisker growth.

Preliminary Studies for One-Step Fabrication of Metallic Iron-Based Coatings on Magnesium as Temporary Protection in Biodegradable Medical Application

Iron and magnesium are being considered as promising candidates for biodegradable materials in medical applications, both materials having their specific advantages and challenges. A hybrid of metallic iron and magnesium in a layered composite is studied in the present work, to combine the merits of both metals. A single-step dip-coating method was employed to prepare the layered composite material. Morphology, composition, crystal structure and corrosion behavior of the Mg/Fe sheet were assessed by SEM, EDX, XRD, and electrochemical measurements. The Mg/Fe layered composite sheet is composed of the magnesium substrate, a 1–2 µm metallic iron coating, and a pompon-like Mg(OH)2/MgO top layer. Long-term open-circuit potential measurements revealed that the Mg/Fe sheet samples exhibit a “self-healing” effect in Dulbecco’s modified Eagle’s medium.

The strong interfacial coupling effect of Nafion between LaFeO3/electrolyte for efficient photoelectrochemical water reduction

Insufficient reduction capability and scanty active substance limit the application of LaFeO3 (LFO) in the field of photoelectrochemical (PEC) water splitting. In this work, a judicious combination of LFO/Nafion composite to improve the PEC performance by a special dip-coating method on the FTO is demonstrated. The photocurrent density of the LFO electrode coated with two layers Nafion increased to -23.9 μA/cm2 at 0.47 V vs RHE, which is 4.1 times that of the pristine LFO. Based on the experimental data and theoretical analysis,the improvement of the PECproperties is attributed to the construction of organic/inorganic units, which would enable strong electronic coupling and favor interfacial charge transfer, resulting in a 30mV downward shift of its flat band potential. Thus, conduction band gets closer to the proton reduction potential of H+ to H2 after decoration with Nafion, resulting in stronger photogenerated electron reduction ability. Our study provides insights that organic materials modify semiconductor photoelectrodes for accelerating the charge kinetics.

Integrated 3D Ionic Electrets Electronic Skin (e-Skin) For Harvesting of TENG Energy Through Push-Pull 3D Ionic Electrets and Ion-ion Hopping Mechanism

The development of highly durable, stretchable, and steady triboelectric nanogenerators (TENGs) is highly desirable to satisfy the tight requirement of energy demand. Here, we presented a novel integrated polymeric membrane that is designed by PEDOT:PSSa-naphthalene sulfonated polyimide (PPNSP)-EMI. BF4 Electronic skin (e-skin) for potential TENG applications. The proposed TENG e-skin is fabricated by an interconnected architecture with push-pull 3D ionic electrets that can threshold the transfer of charges through an ion-hopping mechanism for the generation of a higher output voltage (Voc) and currents (Jsc) against an electronegative PTFE film. PPNSP was synthesized from the condensation of naphthalene-tetracarboxylic dianhydride, 2, 2’-benzidine sulfonic acid, and 4,4’diaminodiphenyl ether through an addition copolymerization protocol, and PEDOT:PSSa was subsequently deposited using the dip-coating method. Porous networked PPNSP e-skin with continuous ion transport nano-channels is synthesized by introducing simple and strong molecular push-pull 3D interactions via intrinsic ions. In addition, EMI. BF4 ionic liquid (IL) is doped inside the PPNSP skin to interexchange ions to enhance the potential window for higher output Voc and Iscs. In this article, we investigated the push-pull dynamic interactions between PPNSP-EMI.BF4 e-skin and PTFE and tolerable output performance. The novel PPNSP- EMI.BF4 e-skin TENG produced upto 49.1 V and 1.03 µA at 1 Hz, 74 V and 1.45 µA at 2 Hz, 122.3 V and 2.21 µA at 3 Hz and 171 V and 3.6 µA at 4 Hz, and 195 V and 4.43 µA at 5 Hz, respectively. The proposed novel TENG device was shown to be highly flexible, highly durable, commercially viable, and a prospective candidate to produce higher electrical charge outputs at various applied frequencies.

Synthesis and Properties of (Bi, Cd)-doped CuMn2O4 thin films by sol-gel dip-coating method

The present work is carried out within the framework of a research project launched within the physical engineering laboratory at the University of Tiaret in Algeria. The objective is to optimize the conditions for producing thin films of pure spinel oxides doped with different metallic elements. Thus, in this part, we prepared thin films of pure CuMn2O4 and doped with Bi and Cd at rates of 6 and 9% by the sol-gel Dip-coating method. The materials obtained exhibit acceptable crystallinity, excellent optical transmittance with bandgap energies of between 1.64 eV and 1.9 eV and good electrical conductivity.

The effect of chemically treated all-cellulose composites (ACCs) with dodecyltriethoxysilane (DTES) solution on the structural-property relationship

Cellulose is the most abundant natural polymer on the Earth that is widely used in bio-based composites due to its high mechanical properties, availability and biodegradability. All-cellulose composites (ACCs) are known as a new class monocomponent of biocomposites due to both reinforcing and matrix phases that are based on cellulose. However, a technical challenge for ACCs is observed due to their propensity for high moisture absorption (water uptake), leading to the instability and deterioration of the mechanical properties. Therefore, this research focussed towards the improvement of the surface of ACCs in order to increase the resistance to water absorption. Prior to the characterisations, ACCs were chemically treated using dodecytriethoxysilane (DTES) coating solution by dip coating method. In this present study, the effects of two control factors: (i) DTES concentration (1.5, 7.5, and 12.5 vol%), and (ii) heating temperature (50, and 100 °C), were investigated on the ACCs. Upon completion of this treatment, three possible characterisations were conducted including of Fourier Transform Infrared (FTIR) spectroscopy analysis, scanning electron microscopy (SEM), and water absorption (WA) testing. Creation of polysiloxane layer was expected to reduce the tendency to absorb water in ACCs while being applied in the outdoor applications.

Optimization of the formation technology of tripolyphosphate coating on mild steel

Tripolyphosphate conversion coatings are promising due to the active type of anti-corrosion protection. However, to be introduced into production, it is necessary to optimize the technology of tripolyphosphate coating deposition. Coatings were deposited to samples of st05kp cold-rolled sheet steel (analogs G10050, G10060, 1CR, 2CR, D6-2, DG-2) from aqueous solutions of sodium tripolyphosphate (4 %, 6 %, 10 %, 12 %, 14 %) at t=80 °C by dip coating and sputtering. The specific weight and morphology of the coating were determined. The corrosion-protective capability was studied in the G-4 climatic chamber at 90 °C and 100 % humidity using Akimov's test. The prospects of the dip coating and sputtering methods were shown. It was revealed that in the dip coating method, the specific weight of the coating was 1–4 g/m2 and increased linearly at a rate of 0.3–0.35 g/m2 by 1 % (wt.) Na5P3O10. For the sputtering coating method, it was revealed that at 4–8 % Na5P3O10, the growth rate of the specific weight was 0.2 g/m2 by 1 % Na5P3O10 and the specific weight exceeded that of the coating obtained by the dip coating method, due to accelerated oxygen access and increased coating formation rate. At 10–14 % Na5P3O10, the growth rate of the specific weight was 0.55–0.65 g/m2 by 1 % Na5P3O10. However, the specific weight was lower than that of the coating obtained by the dip coating method, due to the self-compaction of the iron tripolyphosphate matrix and decreased mass of the Na5P3O10 filler. Using accelerated corrosion testing methods, the optimum Na5P3O10 concentration to obtain a coating with the highest corrosion-protective capability was 6 %–10 % (wt.). The correlation of the protective capability of the coating samples with the coating defects and cracks was revealed

Preparation of Degradable Superhydrophobic Mg/P/Z/F/H Composite Materials and Their Anticorrosion

In this study, the degradable superhydrophobic Mg/P/Z/F/H (magnesium/poly(-caprolactone)/zinc oxide/1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES)/heating process) composite materials were prepared through dip-coating method and heating process, for enhancing the corrosion resistance of the AZ91D magnesium alloys. The electrochemical measurements revealed that the Mg/P/Z/F/H materials significantly improved the corrosion resistance of the magnesium alloys in 3.5 wt.% NaCl. The Mg/P/Z/F/H composite materials exhibited efficient self-cleaning properties, good adhesion strength, and stability in wet atmosphere.