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Non-wetting to Wetting Transition Temperatures of Liquid Tin on Surfaces of Different Steel Samples Corresponding to their Spontaneous Deoxidation

Varanasi D., Aldawoudi K. E, Baumli P., Koncz-Horvath D., Kaptay G.

Archives of Metallurgy and Materials

2021

Vol. 66, iss. 2

469--476

The goal of this paper is to measure the non-wetting to wetting transition temperatures of liquid tin on surfaces of different steel samples in vacuum with residual pressure of 10-8 bar. The experiments were conducted on four steels (C45, S103, CK60 and EN1.4034) of varying compositions using pure tin (99.99%) by the sessile drop method. Non-wetting to wetting transition (contact angle decreasing below 90°) by liquid tin was observed as function of increasing temperature in the range of 820-940 K for low alloyed steels C45, S103 and CK60, while it was considerably higher (around 1130 K) for high chromium EN1.4034 steel. it is concluded that at about the same temperatures, the surfaces of the steel samples are spontaneously deoxidized due to the combined effect of high temperature, low vacuum and C-content of steels. After the oxide layer is removed, the contact angles of liquid tin on steel surfaces were found in the range of 45-80° for low alloyed C45, S103 and CK60 steels and around 20° for high chromium EN1.4034 steel. These relatively high contact angle values compared to other metal/metal couples (such as liquid Cu on steels) are due to the formation of not fully metallic intermetallic compounds (FeSn and FeSn2) at the interface (such do not form in the Cu/Fe system).

Effects of fields and anchoring on biaxial nematic ordering

Yasen M., Torikai M., Yamashita M.

Opto-Electronics Review

2009

Vol. 17, No. 2

89-94

Symmetry of a nematic liquid crystal phase is broken by an anchoring wall and also by an external field. Nematic system sandwiched between biaxial anchoring walls is introduced as a correspondent to a bulk nematic system exposed to a couple of fields, an electric field and a magnetic one in directions perpendicular to each other, and thermal behaviours of the system are studied. The crossover between a homeotropic structure and homogeneous one occurs, similarly to the bulk system in the fields, in which the anchoring condition of coexistence is shown to have the same expression as the one at the bulk. As to a characteristic phenomenon at the sandwiched system, it is proved that an appearance of a biaxial nematic order suppresses a uniaxial nematic order. A surface transition, i.e., a wetting phenomenon is shown to occur also in the biaxial nematics, even though the uniaxial order is suppressed therein.

Localization of the wetting transition for finite systems with a long-range wall-fluid potential

Drzewiński A., Parry A. O., Szota K.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

2006

Vol. 5, nr 1

15-22

The properties of a simple fluid, or Ising magnet, confined in an Lx ∞ geometry, are studied by means of numerical density-matrix renormalization-group techniques. We have proposed and have verified a few criterions to determine the wetting transition phase boundary with different ranges of surface forces.