Pavel Protsenko

The role of intermetallics in wetting in metallic systems

Abstract Formation of intermetallic seems to improve strongly wetting of a solid metal by a liquid one. The aim of this study is to identify the reasons of this improvement. For this purpose, wetting of Fe is determined at the same experimental conditions for two liquid metals, one reactive (Sn), the other non-reactive (Pb).

Wetting of Fe–7.5%Cr steel by molten Pb and Pb–17Li

Wetting of an Fe–7.5wt%Cr martensitic steel by molten lead has been studied as a function of temperature in the range 400–900 C by the sessile drop and dispensed drop techniques. Two different furnace atmospheres (high vacuum and an He–H2 gas mixture) and different heat treatments of the steel prior to test allowed the wetting for both oxidised and deoxidised steels. The influence of addition of Li, a metal with a high affinity for oxygen, to Pb on wetting has also been investigated. 2002 Elsevier Science B.V. All rights reserved.

Grain boundary wetting in polycrystals: wettability of structure elements and liquid phase connectivity (part I)☆

Abstract A model is proposed describing the wetting of internal structure elements of polycrystals (grain boundaries, triple lines and quaternary nodes). The assumption is made that the only driving force for wetting is the minimization of interfacial solid–solid and solid–liquid energies. The former is assumed to be more scattered than the latter, as a function of the grain boundary misorientation. The well known Gibbs–Smith condition for grain boundary wetting is extended to grain edges and vertices, by introducing a parameter defined as the ‘characteristic free energy’ of these elements. Also suggested is a simple method allowing one to find relative amounts of wetted and non-wetted faces, edges and vertices. The percolation theory is employed to evaluate the critical solid–liquid to solid–solid energy ratio at which liquid phase inclusions become interconnected in a polycrystal of any size.

Grain Boundary Wetting in Zn Bicrystals by a Sn-Based Melt

The kinetics and morphology of the grain boundary grooving of Zn bicrystals with 16° <1010> tilt GB by Sn(Zn) melt has been studied at 325°C in equilibrium conditions in vacuum. It is shown that grooving process is interface controlled at least on the first stage. Groove walls mobility is evaluated. Changing of GB grove shape from “faceted walls” corner for annealing time < 78 h to concave “Mullins type” groove for annealing time > 78 h at the same experimental temperature was observed for the first time.

Misorientation Effects on Grain Boundary Grooving of Ni by Liquid Ag

The mechanisms of grain boundary grooving of polycrystalline Ni in cont a t with molten Ag at 1313 K in pure He are studied. Distribution of groove depths over a w ide range of values are observed and explained by misorientation of grain boundaries. A method is proposed allowing to evaluate the anisotropy of grain boundary energy by measuring the angular and li ne r imensions of grooves.

Selective wetting in a hydrocarbon liquid-perfluorocarbon liquid-solid system

Selective (displacement) wetting is, for the first time, investigated in a hydrocarbon liquid-perfluorocarbon liquid-fluorinated polyethylene system. Contact angles upon the selective wetting are shown to be quite sensitive to the presence of fluorocarbon groups on the surface of the polymer, and wetting inversion takes place when the surface concentration of fluorine is increased above 10−4 kg/m2.

Grain Boundary Wetting Phase Transition and Analysis of the Energy Characteristics of Grain Boundaries in the Sns -(Zn/Sn) l System

Regularities of the interaction of tin grain boundaries (special Σ5 and general Σ17 〈001〉) and a Sn-Zn melt of equilibrium composition were studied. The grain boundary wetting phase transition temperature was determined; for Σ5 and Σ17, it is 216°C. More than 90% of the general grain boundaries were completely wetted by the melt over a range of temperatures, from the eutectic melting temperature to the tin melting temperature. It was shown that the anisotropy of interphase energy at the solid tin-Zn-Sn melt interface is 64 ± 10 mJ m−2 at 216°C. The energies of the Σ5 and Σ17 grain boundaries in the range of 201–216°C were obtained on the basis of the experimental dependence of the dihedral angle on temperature.

The effect of the degree of ionicity of ceramic materials on their wettability by melted sodium chloride

The sessile drop method has been used to study the wettability of hexagonal boron nitride, sapphire, quartz, and polycrystalline silicon carbide by melted sodium chloride in a reducing He–H2 atmosphere. Melted NaCl completely spreads over sapphire and quartz surfaces and form finite contact angles equal to 51° ± 10° and 77° ± 5° on silicon carbide and hexagonal boron nitride, respectively. The calculated works of salt adhesion to the ceramic substrates increase with the magnitude of the ionic component of ceramic material surface energy.