MATHEMATICAL MODELS OF COATING PROPERTIES UNDER DIFFERENT TECHNOLOGICAL MODES OF PEO

The issue of mathematical modeling of the coating thickness, current and corrosion potential depending on the type of pulsed electrical processing mode, pulse frequency and processing duration is considered.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application

Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(Trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 400 nm excitation. Furthermore, they can be completely dried within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

Modelling of the Motion and Interaction of a Droplet of an Inkjet Printing Process with Physically Treated Polymers Substrates

This study examines the effect of energetic surface treatment on the adhesion strength of high-density polyethylene (HDPE), polypropylene (PP) and polyethylene terephthalate (PET) substrates. The purpose of this work is to determine the surface wettability of polymers suitable for food contact. These plastics have been treated with various pre-treatment methods to improve surface tension and good adhesion for inkjet printing and avoid any visual changes. It is important to determine the adhesion of the ink to the polymer surface to improve post-consumer recycling. Digital inks have been tested on various treated plastics to analyse coating properties and adhesion forces in accordance with DIN ISO 2409 standards. The impact of the inkjet droplet on the treated and non-treated surface was also investigated using the COMSOL computer simulation software.

Microstructure and Properties of Atmospheric Plasma Sprayed (Al,Cr)2O3–TiO2 Coatings from Blends

Coatings prepared from chromia-rich (Al,Cr)2O3 solid solution (ss) feedstock powders are intended to improve the properties of Cr2O3 coatings, but are rarely studied so far. In this work, the processability of a commercial (Al,Cr)2O3 solid solution (ss) powder containing 78 wt.% Cr2O3 by atmospheric plasma spraying (APS), the corresponding coating microstructures and properties were investigated. Possible further improvements were expected by blending with 2, 23 and 54 wt.% TiOx powder. For comparison, plain Cr2O3 and TiOx coatings were studied as well. The microstructures were analyzed using SEM, EDS and XRD measurements. Hardness (HV0.3) was measured, as well as the dry unidirectional sliding wear resistance and the abrasion wear resistance (ASTM G65). Moreover, the corrosion and electrical insulating properties were measured. The (Al,Cr)2O3 ss showed only a small change of the composition, and the formation of γ-Al2O3, as found for alumina-rich (Al,Cr)2O3 ss powders, was avoided. Compared to the plain chromia coating, some improvements of the processability and coating properties for the ss (Al,Cr)2O3 coating were found. The most balanced coating performance was achieved by blending the ss (Al,Cr)2O3 with 2 wt.% TiOx, as this coating showed both a high sliding and abrasion wear resistance, in combination with a high corrosion resistance.

Influence of Carbon Nanowalls Interlayer on Copper Deposition

This research deals with the deposition of copper on a steel substrate. Two different methods were investigated: electrochemical and magnetron sputtering. The deposition parameters were optimized to obtain a coating layer with uniform granular structure and good adhesion to the substrate. As a novelty, carbon nanowalls (CNW) were used as reinforcement in copper coatings on the steel surface. The morphology of the coatings, adhesion and Vickers microhardness were performed to emphasize the CNW influence on the coating properties. Open circuit potential and Tafel analysis were used for electrochemical characterization. These kinds of CNW-copper composite with improved hardness and adhesion and surface electrical resistance around 1 Ω·cm could have miscellaneous applications in different domains such as aerospace, electronics, automotive and power-generation.

A Novel Waterborne Acrylic Coating Incorporation TIO2 Nanoparticles Modified With Silane Coupling Agent and Ag/zn Zeolite: Mechanical Properties, Thermal Stability, Artificial Weathering Durability and Antibacterial Activity

Effect of rutile TiO2 nanoparticles modified with 3-(trimethoxysilyl) propyl methacrylate silane - TMSPM (m-TiO2) and Ag/Zn zeolite on the properties, and durability of acrylic waterborne coatings was studied. The obtained results indicated that m-TiO2 nanoparticles and Ag/Zn zeolite could disperse regularly in the acrylic polymer matrix. Consequently, the abrasion resistance of the acrylic coating was improved in the presence of m-TiO2 or/and Ag/Zn zeolite. The abrasion resistance of the acrylic coating depended on the content of m-TiO2 nanoparticles as well as the initial TMSPM content for modification of rutile TiO2 nanoparticles. The abrasion resistance of the acrylic coating filled by m-TiO2 was higher than that of the acrylic filled by unmodified TiO2 nanoparticles. The acrylic coating filled by 2 wt.% TiO2 modified with 3 wt.% TMSPM had the highest abrasion resistance value, leveling off at 187.16 L/mil. The abrasion resistance of acrylic coating reduced with increasing too high initial TMSPM content for TiO2 modification and m-TiO2 nanoparticles content. The starting temperature of weight loss of acrylic coating filled by m-TiO2 was lower than that of the neat acrylic coating. In comparison with the m-TiO2 nanoparticles, the Ag/Zn zeolite particles showed a lower improvement for acrylic coating properties, i.e. abrasion resistance, weathering durability, but the Ag/Zn zeolite particles expressed an excellent antibacterial activity. Hence, combination of the m-TiO2 nanoparticles and Ag/Zn zeolite particles could enhance the properties of the acrylic waterborne coatings. The acrylic coating filled by 2 wt.% m-TiO2 nanoparticles and 1 wt.% Ag/Zn zeolite particles illustrated high abrasion resistance, good weather durability, and superior antibacterial activity for both of negative gram bacteria (E. Coli) and positive gram bacteria (S. Aureus). This coating is promising for environmental friendly building materials application.