Papers by Keyword: Wettability

Abstract: The effect of bismuth (Bi) micro-alloying additions on wettability and mechanical properties of Sn-0.7Cu lead-free solder were explored. This paper also investigates the influences of various Bi percentages on the suppression of intermetallic compound formation. Scanning electron microscope (SEM) was used to observe the microstructure evolution of solder joint including the thickness of interfacial intermetallic layers. Overall, with the addition of Bi to Sn-0.7Cu solder, the size of primary Cu₆Sn₅ become smaller and suppresses the thickness of interfacial intermetallic compound between solder and the Cu substrate. Microhardness value and wetting properties also increased with Bi addition which resulted in smaller size of β-Sn and Cu₆Sn₅.

Abstract: Acrylic coatings were modified by adding 0.5 and 1.0% (v/v) of epoxysilane-treated (aluminosilicate, muscovite, nepheline syenite, and wollastonite) and alkoxysilane-treated (aluminosilicate) mineral fillers. Corrosion behavior of coated carbon steel specimens was studied using polarization method. Wetting behavior and adhesion of specimens were evaluated by static contact angle and cross-cut tape test. Addition of silane-treated mineral fillers dramatically improved the corrosion resistance of acrylic coating, with composite coating filled with alkoxysilane-treated aluminosilicate at 0.5% concentration showing significantly low corrosion tendency and rate in 2 M HCl solution. Contact angle also increased with the addition of fillers, with composite coating containing alkoxysilane-treated aluminosilicate at 0.5% yielding the highest mean value. Adhesion of acrylic coatings was enhanced after addition of fillers at 0.5%, with composite coatings filled with wollastonite and alkoxysilane-treated aluminosilicate giving the lowest percent area removed after application of adhesive tape. Alkoxysilane-treated aluminosilicate was found consistent in improving the anti-corrosion characteristics, water resistance, and adhesion to carbon steel of acrylic coatings.

Abstract: In this paper, the researcher synthesis a super-hydrophobic nanosilica to alter the wettability of the sandstone surface from hydrophilic to super-hydrophobic. Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used to test the characterization of the products, and the wettability were examined by contact angle measurement, glass capillary tube rise measurement and spontaneous imbibition tests. The results shows that the water contact angle is over 150°,the liquid level is down to-42mm and the spontaneous volume is only 0.025mL after the surface modified with super-hydrophobic nanosilica which means the surface wettability is altered to be super-hydrophobic.

Abstract: Changes in fluids contact angle in the interaction with materials surface can play a critical role in enhancement of hydro-machine components and pipelines efficiency and/or service lifetime. However most nowadays used materials and/or coatings are made from polymers or ceramic polymer composites produced by highly sophisticated and/or very expensive techniques. Unfortunately there are a lack of mechanical properties. With the aim to study the role of the surface topography on the water contact angle changes, the representatives of wear resistant coatings (WC10Co4Cr, Cr₂O₃+5SiO₂+3TiO₂ and Al₂O₃) were produced by means of atmospheric plasma spraying. Wettability of the coatings surface was studied by adding the liquid droplet on as sprayed, grinded and polished coating's surface by measuring the changes of its contact angle. To estimate the coatings phase composition and topography XRD technique and optical profilometer were used. The contact angle of water was measured by sessile droplet method. To obtain the complex information of the cross-sectional coatings microstructure the conventional metallographic analysis approaches and optical microscopy were also used.

Abstract: One of the major challenges in the fabrication of glass-metal Joint is the wettability of glass sealant over the metal surface. The aim of the work was to study the wetting and spreading behavior of borosilicate glass sealant over austenitic stainless steel SS 304 and copper substrates with different surface roughness and oxidation conditions. During the wettability study of borosilicate glass sealant over the metal specimen, glass pallets were melted over the different oxidized metal specimens. The wetting behavior of borosilicate glass over metal specimen was measured in terms of contact angle and spreading area. The types of oxide and change in microstructure after oxidation were examined with the help of XRD analysis and optical microscopy. Tensile strength and hardness of the metal substrates after oxidation was also evaluated .

Abstract: This paper describes an investigation of the surfactant influence on zinc sulfide wetting and the pressure leaching of zinc concentrates. For this, a variety of anionic and cationic surfactants with different chemical structures were tested. The methodology for mineral preferential wettability determination via establishing correlation between the spreading coefficients was proposed. It allows determining the surfactant potential efficiency. The influence of contrastively functional reagents on zinc concentrate pressure leaching was reviewed. It is found that simultaneous usage of stabilizers and dispersing agents allows enhancing zinc extraction, eliminating pellet formation at lower reagent consumptions. The beneficial effect of surfactant mixture was seen through the increased zinc sulfide wetting by solution and colloid protection of sulfur particles via solvate-adsorption and structural factor of stabilization. The optimal composition of surfactant mixture was proposed and allowed to extract 95 % of zinc along with pellet formation elimination.

Abstract: The surface modification of microarc calcium phosphate coatings by boehmite nanoparticles deposition was studied. The powder of aluminium nitride AlN was deposited on the microarc calcium phosphate coatings, and then the hydrolysis reaction was initiated. The boehmite (AlO(OH)) was formed as a result of the reaction. The influence of boehmite nanoparticles deposition on the properties of calcium phosphate microarc coatings (i.e. the morphology, elemental and phase composition, wettability) was studied. Experimental results show that the introduction of boehmite nanoparticles affects the surface morphology and wettability of the coating.

Abstract: The outstanding performance of many aluminum matrix composites (AMCs) regarding specific stiffness makes AMCs attractive materials for lightweight construction. Low density boride compounds promise both an increase in stiffness and decrease in composite density. Therefore for this study AlB₂, B and B₄C were chosen for composite manufacturing. The composites were fabricated with the stir casting process. To avoid gas entrapment during mixing and ensure nonporous composites, partial vacuum was adapted during particle feeding and stirring. Poor wettability of used particle material in contact with liquid aluminum hindered particle incorporation, but alloying elements such as titanium were shown to affect wettability and particle incorporation for B₄C. Zn had no influence on wettability or reactivity and did not improve particle incorporation. In contrast to Zn, Ti improved adhesion and wettability, but particle incorporation was improved exclusively for B₄C. Besides alloying Ti, the use of high-shear force mixers improved particle incorporation enabling uniform particle distribution. AMCs with up to 12 vol.% of B₄C particles were produced via stir casting without alloying Ti.

Abstract: The dimension stone industry produces large amount of residue. An alternative to reduce this environmental liability is to apply as glaze in coating ceramic. This research is about the wettability between glaze and red ceramic, applying the sessile drop method. The waste and additives were mixed, pressed, and put over red ceramic plate previously sintered. The system was heated until the melting point of the glaze and the contact angle decreasing was measured in function of the temperature, and in a function of the time at 750 °C and 800 °C. The minimum contact angle value was near 6 ° at 994 °C in the testing changing the temperature, and presents 19 ° and 10 °, respectively, at 750 °C and 800 °C, when the time was varied. The longitudinal section of the samples was analyzed using optical microscopy, showing physical wettability in all testing. This glaze presents good wettability on red ceramic with potential as coating ceramic.

Abstract: The process of adding soy lecithin to milk (lecithination), followed by the agglomeration stage and drying, are the goal to increase the powder dispersion in water. This work studies the physical characteristics of milk lecithinated by the addition of raw and clarified lecithins with hydrogen peroxide, which was dried by lyophilization. The main objective was to compare the behavior between the particles of powdered milk, added 0.4% (w/v), 0.8% (w/v) and 1.0% (w/v) lecithin raw and clarified. The amount of added soy lecithin was determined on the basis of dry matter content of the full UHT milk used in the experiment. Lecithinated of fluid milk samples were put on aluminum forms and frozen by contact with liquid nitrogen and were placed inside the lyophilizer chamber. The lyophilization stage was carried out for approximately 7 hours under vacuum of 460 mmHg and temperature of -38 ° C. Dried samples were fragmented in porcelain pestle and kept in oven at 40°C until analyses. The powder milk added with lecithin clarified had shorter wettability to the concentration of 1.0% (w/v), the lowest percentage of retained insoluble after solubilization in water and the micrographs of the powder showed that most adding more clarified formed lecithin agglomerates of the milk powder added lecithin raw. So, the lecithin clarified give improvements in the particles for the milk added.