Papers by Keyword: Wettability

Abstract: Anodic aluminium oxide (AAO) is a well-known material for nanofabrication. To obtain highly ordered nanoporous array, there is anodization process. AAO were fabricated by anodization method utilizing high purity aluminium foil as the substrate. The substrate was degreased with ultrasonic cleaner for 15 minutes. Then the substrate was anodized in an electrolyte of 0.3 M oxalic acid with various potentials: 10, 20, 30, and 40 V and various durations: 10, 30, 60, 120, and 180 minutes at room temperature. Field emission scanning electron microscope (FE-SEM) was used to investigate surface morphology of nanoporous aluminium oxide film. The wettability of nanoporous aluminium oxide surface was estimated by measuring water contact angle (WCA) of water droplets on the nanoporous aluminium oxide surface. The FE-SEM images showed that the pore size was in the range of 12 - 81 nm. This result can indicated that nanopore size of AAO film increased with the increasing of anodization potentials and anodization time. The water contact angle of AAO samples were approximately 90.55 - 44.33 degrees. The result of measurement proved that super hydrophilic surface obtained with the increasing of nanopore size and high porosity of AAO.

Abstract: Presented work is focused on the time depend wettability deterioration of plasma treated polymeric macro-fibers. The commercial fibers designed especially for reinforcement of concrete composites – Concrix ES (made from polyolefin) and BeneSteel (polyethylene and polypropylene mixture) were surface modified by oxygen cool low-pressure coupled plasma to attain their water wettability enhancement. The wettability development of thus treated fibers was observed through contact angle sizes between fiber surfaces and distilled water using a direct horizontal optical static method. Contac angle measurements were realized (i) immediately, after (ii) 1 day, (iii) 7 days and (iv) 30 days over the treatment execution, while fibers were stored on the air on standard laboratory condition in the meantime (temperature ~22 °C, moisture ~50 %). Both, the treated Concrix ES and BeneSteel fibers exhibited significant wettability increase. The enhanced wettability of modified fibers stayed approximately constant even after 30 days over the treatment execution in the case of BeneSteel, while in the case of Concrix ES the wettability decreased almost to the reference (no treated) samples, respectively.

Abstract: In present study, Sn–9Zn, Sn–9Zn–xCu and Sn–9Zn–xNi solders (x = 1.0, 2.0 and 3.0 wt%) were prepared via melting process. Effects of Cu and Ni addition on microstructure, thermal behavior, wettability and corrosion resistance of Sn–9Zn solders were investigated. The experimental result showed that microstructure of the Sn–9Zn was composed of β–Sn and Zn–rich phases. Addition of Cu to the Sn–9Zn solders, Cu₆Sn₅ and Cu₅Zn₈ IMCs were observed. While addition of Ni to the Sn–9Zn solders, Ni₃Sn₄ and Ni₅Zn₂₁ IMCs were observed. It was also found that, amount of those IMCs obviously increased with increasing of Cu and Ni contents. The results obtained from thermal analysis showed that melting temperature of the Sn–9Zn solder was 199.6°C. While melting temperatures of the Sn–9Zn–1.0Cu and Sn–9Zn–1.0Ni solders were 199.9°C and 204.2°C, respectively. The Cu and Ni contents had little effect on both spread rate and wetting angle of the Sn–9Zn–xCu and Sn–9Zn–xNi solders. However, increasing of Cu and Ni contents significantly increased the corrosion potentials of the Sn–9Zn–xCu and Sn–9Zn–xNi solders.

Abstract: Presented work deals with the surface treatments and its effect on micro fibers using as randomly dispersed reinforcement in many types of composite materials. Cool oxygen plasma was used to surface wettability modification of chopped glass fibers having diameter equal to 14 μm. Plasma treatments were carried out at three different times of exposition equal to 4 min, 8 min and 16 min. The influence of executed treatments was observed by the horizontal direct optical method enabling static contact angle measurements on micro fibers which were submerged in a distilled water. The identified differences between the contact angles size of original fibers and the treated fibers were equal to several tens of percent.

Abstract: In order to improve the wetting ability of metal to ceramic, silica coatings on alumina/ mullite ceramics were prepared with tetraethyl orthosilicate (TEOS) by sol-gel method. The preparation processing was optimized. Furthermore, the interactions between the aluminum melt and the ceramic with or without silica coating were investigated. The results showed that the silica coatings could be successfully prepared. The molten aluminum melt reacted with silica, and alumina was formed at the interface between ceramic and metal. The ceramic (alumina/ mullite) substrates could be infiltrated by aluminum melts due to the existence of mullite. The silica coatings conduced to the infiltration and improved the combination between the ceramic and aluminum at the interface.

Abstract: Interface reactions and wettability between melt superalloys and ceramic mould materials were investigated by using a sessile drop experiment. The wetting angle of the melt alloy on the ceramic material was calculated and the microstructure of the alloy interface was investigated by metalloscope as well as SEM. It was found that active element C in the alloy is an important factor that influences the interface reactions and the wettability. Alloys with C content lower than 0.07wt.% were almost stable on the ceramic material and no interface reaction products were found. However, alloys with C content higher than 0.16wt.% reacted with the ceramic materials. Purple reaction products were found on the alloy surface and sand adhesions were observed at the alloy-ceramic interface. In the non-reactive system, the wetting angle is in the range of 135^o-150^o. In the reactive system, the wetting angle is lower than 120^o.

Abstract: Wettability alteration of rock by surfactant has been considered as feasible method for recovery of oil reservoirs by modifying the wettability of rock surface from oil-wet to water-wet condition. The impact of surfactant can be enhanced by adding nanoparticles. Cationic surfactant performed well in carbonate rock by forming ion pairs between cationic head and acidic component of the crude. Meanwhile, nanoparticles will form continuous wedge film between the liquid and solid surface. In this paper, Al₂O₃ and ZrO₂ nanoparticles were used as enhanced oil recovery (EOR) agents. The impact of these two nanoparticles on contact angle and interfacial tension was studied. Besides that, adsorption Cetyltrimethylammonium Bromide (CTAB) surfactant on rock surface was also investigated. The results show a significant change in water-oil contact angle after application of surfactant and nanoparticles. Initial water-oil contact angle for 6 dolomites demonstrate oil-wet condition. Then, the dolomites were submerged in prepared solution for 48 hours. The result shows that, dolomites 2, 5 and 6 changes drastically to more water-wet condition with contact angle 56°, 40° and 47° respectively. For surfactant adsorption, the adsorption is very fast at the beginning. The adsorption rate after 5 minutes was 50 mg/g and after 60 minutes the adsorption rate was 310 mg/g. The adsorption rate slowed down after 60 minutes and after 180 minutes the adsorption rate was 315 mg/g in which the rate of adsorption achieve equilibrium. Nanoparticles retention test and Zeta potential shows that Al₂O₃ is more stable than ZrO₂. The results for interfacial tension (IFT) also show a significant reduction. The IFT value reduces from 8.46 mN/m to 1.65 mN/m and 1.85 mN/m after the application of Al₂O₃ and ZrO₂ nanofluids respectively

Abstract: In order to clarify the effect of the addition of Mg to Sn-Ag-Cu solder on the wettability and the microstructure of the solder, the reaction between Sn-Ag-Cu-Mg solder and a substrate was investigated. Sn-3.5mass%Ag-1.0mass%Cu-xMg solders (x =0, 0.2 and 0.4 mass%) was specially prepared in this study. For the reflow process, specimens were heated in a radiation furnace at 250 oC for 120 s to evaluate the wettability of the solder on a substrate and the microstructure of the solder matrix and the intermetallic compound layer at the interface. The results showed that the spreading area of Sn-Ag-Cu-Mg solder is almost similar with that of Sn-Ag-Cu solder regardless of oxygen concentration. In the case of Sn-Ag-Cu-Mg solders, it was observed that intermetallic compounds (IMCs) containing Mg were formed in the solder matrix and near the interface. The IMC formation at the interface for Sn-Ag-Cu-Mg solders was almost similar with that for Sn-Ag-Cu solder.

Abstract: A nanoporous copper (NPC) sample with well-ordered porosity of 20 nm was fabricated by an electrochemical dealloying single-phase Cu0.4Mn0.6 with an external potential of-0.5 V (MSE). The electrochemical mechanism of the dealloying process on the Cu-Mn surface was studied by a liner sweep voltammetry experiment, and an optimized applied voltage for the Cu-Mn system was recommended. The properties of the monolithic NPC, including morphology, chemical composition, surface area and wettability were systematically characterized. The specific surface area around 11.86 m2/g of the as-dealloyed NPC was measured by BET-nitrogen method. The micro/nanoscale bi-continuous 3D porous structures of NPC not only increase the surface area, but also improve the wettability of NPC surface since the increase in surface roughness.

Abstract: Wettability for lead free solder 99.0Sn-0.3Ag-0.7Cu (SAC237) with addition of different weight percentage carbon nanotube after thermal treatment was investigated. SAC 237 solder powder with flux was mixed with 0.01%, 0.02%, 0.03% and 0.04% carbon nanotubes (CNTs) to form SAC-CNTs solder paste. Printed solder paste on test board with Cu surface finish was then reflow under 270°C temperature and isothermal aging at 150°C for 0,200 and 400 hours. Wettability of SAC-CNT solder was determined by measuring contact angle using optical microscope and image analyzer. As a result, from reflow process right through 400 hours of thermal aging, SAC237 with 0.04% CNT has the lowest contact angle as compared to other SAC-CNTs and SAC237 solder. As a conclusion, addition of carbon nanotubes into solder SAC237 improved their wettability on Cu substrate, especially at 0.04% of CNTs.