scholarly journals Influence of Conditions for Production and Thermo-Chemical Treatment of Al2O3 Coatings on Wettability and Energy State of Their Surface

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 681 ◽  
Author(s):  
Mateusz Niedźwiedź ◽  
Władysław Skoneczny ◽  
Marek Bara
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Chemical Treatment ◽  
Sessile Drop ◽  
Energy State ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Sodium Sulphate ◽  
Oxide Coatings

This article presents the influence of the anodizing parameters and thermo-chemical treatment of Al2O3 coatings made on aluminum alloy EN AW-5251 on the surface free energy. The oxide coating was produced by DC (Direct Current) anodizing in a ternary electrolyte. The thermo-chemical treatment of the oxide coatings was carried out using distilled water, sodium dichromate and sodium sulphate. Micrographs of the surface of the Al2O3 coatings were characterized using a scanning microscope (SEM). The chemical composition of the oxide coatings was identified using EDS (Energy Dispersive X-ray Spectroscopy) microanalysis. Surface free energy (SFE) calculations were performed by the Owens–Wendt method, based on wetting angle measurements made using the sessile drop technique. The highest value of surface free energy for the only anodized coatings was 46.57 mJ/m2, and the lowest was 37.66 mJ/m2. The contact angle measurement with glycerine was 98.06° ± 2.62°, suggesting a hydrophobic surface. The thermo-chemical treatment of the oxide coatings for most samples contributed to a significant increase in SFE, while reducing the contact angle with water. The highest value of surface free energy for the coatings after thermo-chemical treatment was 77.94 mJ/m2, while the lowest was 34.98 mJ/m2. Taking into account the contact angle measurement with glycerine, it was possible to obtain hydrophobic layers with the highest angle of 109.82° ± 4.79° for the sample after thermal treatment in sodium sulphate.

scholarly journals THE CONTACT ANGLE CONTROL OF THE SOLDER FOR IMPROVING THE SOLDERING QUALITY

2021 ◽  
pp. 161-166
Author(s):  
Чуйко М.М. ◽  
Завальський В.
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Electrical Contact ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Soldering Process ◽  
Basic Parameters ◽  
The Right

High quality of the soldering process can be achieved with the right choice of the necessary soldering materials. Since wetting determines the further nature of the connection between the solder and the main soldering material, the contact angle  measurement  is the basis for quality control of soldering materials, provided that the basic requirements of the technological process. The determination of the contact angle value is carried out by the indirect method of the sessile drop, by measuring the basic parameters of the drop using infrared transducer. A smaller value of the contact angle corresponds to a better interaction of materials, and hence a better electrical contact

Determination of Surface Free Energy and Contact Angle for Hydrolyzed Shellac

2012 ◽  
Vol 506 ◽  
pp. 270-273 ◽  
Author(s):  
P. Kraisit ◽  
S. Limmatvapirat ◽  
J. Nunthanid ◽  
Manee Luangtana-Anan ◽  
K. Terada ◽  
...  
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Polar Group ◽  
Sessile Drop Technique ◽  
Hydrolysis Process ◽  
Polar Force ◽  
Drop Technique

The purpose of this research was to determine surface free energy and contact angle of hydrolyzed shellac by using sessile drop technique. It is a method for determination of contact angle by placing a drop of liquid on a substrate and the surface free energy is then calculated by using the Wus equation. The substrate in this study was the hydrolyzed shellac prepared by hydrolysis of the native shellac at various times; 0, 15, 30 and 45 min using 2.0 %w/w sodium hydroxide. Water, formamide and ethylene glycol were liquids used for the investigation of the contact angle and surface free energy. The effect of hydrolysis time tended to reduce the contact angle and increase in the total surface free energy and polar force of hydrolyzed shellac. The result could be due to the breaking of the ester bonds of shellac during the hydrolysis process causing the higher free carboxyl group giving the higher polar group indicating by higher polar force and surface free energy. Therefore, the contact angle and surface free energy detected by sessile drop technique could be of benefit for the determination of hydrolysis process.

Comparison of Surface Free Energy Calculation Methods

2015 ◽  
Vol 791 ◽  
pp. 259-265 ◽  
Author(s):  
Jacek Domińczuk ◽  
Anna Krawczuk
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Surface Preparation ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Free Energy Calculation ◽  
Boundary Phase ◽  
Polar Component ◽  
Energy Calculation ◽  
Liquid Boundary

The paper presents the main methods of surface free energy calculation of solids based on the contact angle measurement. The basic of splitting the surface free energy into components as well as interactions at the solid-liquid boundary phase considered while developing calculation models were presented. Basing on test results of surface free energy of 0H18N9T stainless steel, the relation between the method of surface preparation and the surface free energy were shown. The analysis focuses on change of the polar part. Differences between methods were indicated and it was pointed that skipping the polar component in analysis of adhesive joints strength results in deterioration of prediction model.

Surface Free Energy of Boron-Compounds Modified Poplar Veneer

2013 ◽  
Vol 753-755 ◽  
pp. 843-847 ◽  
Author(s):  
Chen Chen Li ◽  
Zhi Yong Qin ◽  
Qian Zhang ◽  
Jiang Zhang Li
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Untreated Wood ◽  
Initial Contact ◽  
Boron Compounds ◽  
Acid Base ◽  
The Difference ◽  
Better Than

The contact angle of three different reference liquids (i.e. distilled water, diiodomethane, and formamide) was measured by the sessile drop method by gently placing droplet onto the surface of the boron-compounds treated poplar veneer in this study. The permeability of the modified poplar veneer was evaluated. The surface free energy, as well as two components, namely, Lifshizvander Waals(LW) and Acid-base(AB), were calculated by the Acid-base theory, whereas the polar and nonpolar components were calculated according to the OWRK theory. The result shows that the initial contact angle of boron-compounds modified poplar veneer are significantly less than the untreated wood, which indicates that the wettability of boron-compounds polar veneer is better than the untreated wood. The same situation applies to the permeability. In addition, the surface free energy of boron-compounds modified poplar veneer is reduced, but the difference is very small.

Assessing Effect of the Migration of A Paraffin Wax on the Surface Free Energy of Natural Rubber

2009 ◽  
Vol 82 (1) ◽  
pp. 113-120 ◽  
Author(s):  
A. Ansarifar ◽  
G. W. Critchlow ◽  
R. Guo ◽  
R. J. Ellis ◽  
Y. Haile-Meskel ◽  
...  
Keyword(s):  
Free Energy ◽  
Natural Rubber ◽  
Surface Free Energy ◽  
Storage Time ◽  
Secondary Ion Mass Spectrometry ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Paraffin Wax ◽  
Rubber Surface ◽  
Secondary Ion

Abstract The effect of the migration of paraffin wax on the surface free energy of natural rubber (NR) was investigated. The rubber was mixed with the wax and then stored at ambient temperature for up to 168 hrs before its surface free energy was measured using contact angle measurement. Static secondary ion mass spectrometry was also used to provide a chemical fingerprint of the rubber surfaces. The surface free energy decreased as a function of storage time because of the migration of the wax to the rubber surface. The highest rate of reduction was recorded up to 3 hrs and thereafter, the surface free energy decreased at a much slower rate, reaching a plateau after 48 hrs in storage. In total, the surface free energy reduced by approximately 46% as a result of the migration of the wax to the rubber surface. The reduction in surface free energy could adversely affect ability of the rubber to stick to itself and to other dissimilar elastomers.

scholarly journals Potentials of lignocellulosic agricultural residues in paper production

2021 ◽  
Vol 11 (3) ◽  
pp. 72-77
Author(s):  
Ivana Plazonić ◽  
Maja Rudolf ◽  
Valentina Radić Seleš ◽  
Irena Bates ◽  
Katja Petric Maretić
Keyword(s):  
Contact Angle ◽  
Free Energy ◽  
Surface Free Energy ◽  
Sessile Drop ◽  
Surface Characteristics ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Hydrophilic Material ◽  
Printing Processes ◽  
High Absorption

Surface characteristics of printing substrates are of the utmost importance to all types of paper that interact with ink. During all types of printing processes, the behaviour of the liquid phase (ink or dye) on the paper is directly defined by the paper cellulose-based surface. The printed ink spreads and penetrates more into paper fibres when the paper surface is rougher and more permeable. Contact angle measurements by sessile drop method are considered the most appropriate for determining the paper sheet surface energy. Paper as hydrophilic material has a high absorption rate resulting in a low contact angle. The objective of this study was to evaluate the surface free energy of laboratory-made papers containing straw pulp obtained from residues after the harvest of the most cultivated cereals in Croatia (wheat, barley and triticale). The obtained surface free energy results are promising for straw pulp usage in the manufacture of printing paper.

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