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Sessile drop technique

About: Sessile drop technique is a research topic. Over the lifetime, 2827 publications have been published within this topic receiving 68943 citations.


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Journal ArticleDOI
TL;DR: In this paper, a generalized formulation is used to predict the flow patterns at any time during evaporation taking into account all these effects, including the substrate properties, the moisture of the surrounding air and the heating conditions.

38 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that some Pb-free alloys, for which information on the surface tension is indispensable to develop as environmental-friendly material, can be listed in this special category, and experimental results and the thermodynamic analysis of the temperature dependence of those alloys are discussed in the paper.
Abstract: It is usually known that the surface tension of liquid metals and alloys decreases with increasing temperature, i.e., the temperature dependence of the surface tension is negative. We found, however, that some liquid alloys, which have large difference of the surface tension of pure components, show positive temperature dependence in certain composition ranges. Some Pb-free alloys, for which information on the surface tension is indispensable to be developed as environmental-friendly material, can be listed in this special category. The experimental results and the thermodynamic analysis of the temperature dependence of those alloys are discussed in the paper.

38 citations

Journal ArticleDOI
TL;DR: In this paper, the impregnation of 2D-SiC/SiC preforms by aluminum is modeled, and the effect of both the contact angle decrease and local temperature rise on the impeding of the preforms, e.g., by gravity casting, is established.
Abstract: SiC-ceramic materials, either as flat substrates or porous fiber preforms, are spontaneously wetted by aluminum at 700 °C to 800 °C when they have been pretreated with an aqueous solution of K2ZrF6. The wetting enhancement effect results from exothermic chemical reactions occurring at the SiC/Al interface. The first phenomenon thought to occur is a disruption of the alumina film covering liquid aluminum due to a reaction of A12O3 with K2ZrF6. Then alumina is totally dissolved at low temperatures by potassium/aluminum mixed fluorides, giving rise to a very fluid cryolitic liquid spreading out on the surface of liquid aluminum and to the true SiC/Al interface. Simultaneously, a large evolution of heat occurs, mainly due to the reduction of K2ZrF6 by aluminum and the formation of Al3Zr. The impregnation of 2D-SiC/SiC preforms by aluminum is modeled, and the effect of both the contact angle decrease and local temperature rise on the impregnation of the preforms, e.g., by gravity casting, is established.

38 citations

Journal ArticleDOI
TL;DR: Air-polishing as well as other polishing procedures increased surface roughness values in all materials except zirconium dioxide and polyetheretherketone, and displayed greatest change in contact angle values after air-polished treatment.
Abstract: Available chair-side surface treatment methods may adversely affect prosthetic materials and promote plaque accumulation. This study investigated the effects of treatment procedures on three resin restorative materials, zirconium-dioxide and polyetheretherketone in terms of surface roughness and hydrophobicity. Treatments were grinding with silicon carbide paper or white Arkansas stone, blasting with prophylaxis powder and polishing with diamond paste. Surface roughness was assessed using confocal laser scanning. Hydrophobicity as measured by water contact angle was determined by computerized image analysis using the sessile drop technique. All of the specific surface treatments performed led to significant changes in contact angle values and surface roughness (Ra) values. Median contact angle values ranged from 51.6° to 114°. Ra values ranged from 0.008 µm to 2.917 µm. Air-polishing as well as other polishing procedures increased surface roughness values in all materials except zirconium dioxide. Polyetheretherketone displayed greatest change in contact angle values after air-polishing treatment.

38 citations

Journal ArticleDOI
TL;DR: In this paper, the temperature dependence of surface tension and density for Fe-Cr-Mo (AISI 4142), FeCr-Mn-Ni, and TRIP/TWIP high-manganese liquid alloys were investigated using the conventional maximum bubble pressure (MBP) and sessile drop (SD) methods.
Abstract: The temperature dependence of surface tension and density for Fe–Cr–Mo (AISI 4142), Fe–Cr–Ni (AISI 304), and Fe–Cr–Mn–Ni TRIP/TWIP high-manganese (16 wt% Cr, 7 wt% Mn, and 3–9 wt% Ni) liquid alloys are investigated using the conventional maximum bubble pressure (MBP) and sessile drop (SD) methods. In addition, the surface tension of liquid steel is measured using the oscillating droplet method on electromagnetically levitated (EML) liquid droplets at the German Aerospace Centre (DLR, Cologne). The data of thermophysical properties for Fe–Cr–Mn–Ni is of major importance for modeling of infiltration and gas atomization processes in the prototyping of a “TRIP-Matrix-Composite.” The surface tension of TRIP/TWIP steel increased with an increase in temperature in MBP as well as in SD measurement. The manganese evaporation with the conventional measurement methods is not significantly high within the experiments (∆Mn < 0.5 %). The temperature coefficient of surface tension (dσ/dT) is positive for liquid steel samples, which can be explained by the concentration of surface active elements. A slight influence of nickel on the surface tension of Fe–Cr–Mn–Ni steel was experimentally observed where σ is decreased with increasing nickel content. EML measurement of high-manganese steel, however, is limited to the undercooling state of the liquid steel. The manganese evaporation strongly increased in excess of the liquidus temperature in levitation measurements and a mass loss of droplet of 5 % was observed.

38 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202354
2022106
202189
2020105
2019100
2018116