Topic
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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20 Dec 1994-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a series of Ni-based brazing alloys without addition of active elements was investigated for the wetting of a sintered silicon nitride and the results showed that Ni-CrSi alloys with Ni/Cr ratio of 3.5 and XSi < 0.25 will react with and wet Si3N4 ceramics at 1220 °C (1493 K) and PN2 = 15 Pa.
Abstract: Through thermodynamic modelling of the reaction at ceramic-metal interface, wetting of a sintered silicon nitride was investigated with a series of Ni-based brazing alloys without addition of active elements. The thermodynamic calculations showed that NiCrSi alloys with Ni/Cr ratio of 3.5 and XSi < 0.25 will react with and wet Si3N4 ceramics at 1220 °C (1493 K) and PN2 = 15 Pa. Environment verifications using sessile drop method confirmed the validity of the calculations and the assumptions made in the wetting model.
25 citations
TL;DR: A recent communication by Gray illustrates a possible pitfall in the use of the theories of Fowkes and Good and Girifalco to estimate surface energies, and the various components of surface energy, from contact angles as discussed by the authors.
Abstract: A RECENT communication by Gray1 illustrates a possible pitfall in the use of the theories of Fowkes2–5 and Good and Girifalco6,7 to estimate surface energies, and the various components of surface energy, from contact angles. This source of error is the incorrect identification of the surface tension terms, and the equating of the contact angle in a contaminated, experimental system to that in a system composed of properly pure components. Thus, Gray wrote Fowkes's equation in the form and used his observed contact angle data for mercury on polyethylene, paraffin wax and polytetrafluoroothylene, together with Fowkes's estimates of γds for the solids and of γdL for mercury, to calculate values for γL for mercury. The fact that the values of γL turned out to be very much larger than 485 dynes/cm was then taken to be an unexplained discrepancy in the theory. In his discussion, Gray apparently also misinterpreted a remark of Fowkes5 about the effect of a contaminant in the mercury on the observed contact angle.
25 citations
TL;DR: In this article, the authors used meniscography and an improved sessile drop method to measure the wetting from the initial contact in all the systems (Cu/Hg, Graphite/Al and Al-Si alloys, MgO/Al, and AlN/Al), and obtained similar wetting curves as a function of time.
Abstract: In order to establish a method for estimation of the wetting of ceramics accompanied by interfacial reaction, the authors'previous work has been rearranged. The wetting was estimated using meniscography and an improved sessile drop method both of which were devised to measure the wetting from the initial contact. Using a logarithmic time scale, in all the systems (Cu/Hg, Graphite/Al and Al-Si alloys, MgO/Al and AlN/Al), similar wetting curves were obtained as a function of time
25 citations
Patent•
28 Apr 1989TL;DR: In this paper, a laser beam is directed onto the interface line between the liquid and the plane solid surface in such a way that a first part of the laser beam reflected by the solid surface and a second part by the liquid surface.
Abstract: The invention relates to a method of measuring the contact angle of wetting liquids on a solid surface with which a high measuring accuracy and better reproduceability of the measurement results is achieved. The method resides in that a laser beam is directed onto the interface line between the liquid and the plane solid surface in such a manner that a first part of the laser beam is reflected by the solid surface and a second part by the liquid surface. The second partial beam is used as measuring beam by determining the angle (δ) made between the measuring beam and the solid surface, said angle being in a fixed geometrical relationship to the contact angle (r). The contact angles which can be determined very accurately with this measuring method provide information on wetting properties of materials, the exact knowledge of which is of great significance for example for semiconductor fabrication.
25 citations
TL;DR: In this article, the surface tension of thin uncured epoxy films spun-cast onto oxidized silica wafers was analyzed as a function of their thickness in the range of 5 to 75 nm.
Abstract: The surface tension of thin, uncured epoxy films spun-cast onto oxidized silica wafers was analyzed as a function of their thickness in the range of 5 to 75 nm. Based on contact angle measurements with polar and apolar liquids, the surface free energies of various films were analyzed and compared using Lifshitz–van der Walls/acid–base (LW/AB), harmonic mean (of Wu), geometric mean, and Zisman approaches. Results of harmonic mean and Zisman surface tension analyses, in spite of significant changes in contact angle attributed to changes in thickness, did not show significant changes. However, geometric mean and LW/AB methods did reveal limited changes in free energy of epoxy surface attributed to variations in thickness. The surface tension components showed a similar trend to that of contact angle changes. It seems that it is better to use surface free energy analysis methods, which use several liquids with different polarities, to reveal the accumulative effect of different group free energy densities on total surface free energy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1972–1980, 2004
25 citations