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This article presents the manufacturing technology and mechanical properties of innovative pre-impregnated coatings (PCs). The base materials for PC are powders of metal oxides, non-metals, minerals and thermoplastic non-wovens. PC can be used in the manufacture of composites by methods such as vacuum infusion, autoclave curing or hand lamination. This is possible due to the novel PC structure consisting of a functional layer (FL) and a backing layer (BL). PCs are flexible so that they can be used on curved surfaces. In this work, five types of PC were subjected to a uniaxial tensile test. Depending on the powder used, failure force values ranging from 24.61 N to 28.73 N were obtained. In the next step, the pre-impregnated coatings were applied as a coating in “sandwich” composites made by vacuum infusion, which were subjected to three-point bending (3-PB) and adhesion tests. 3-PB tests proved that the coating remained integral with the substrate, even under high flexural deformation, while the adhesion achieved was in the range of 0.95 MPa to 1.57 MPa. PC can be used in many engineering products, e.g., for the coating of façade panels, roof tiles, automotive parts or rail vehicles, etc.

Polyethylene terephthalate (PET) is known to be highly inert, and this makes it difficult to be metallized. In addition, Pt electroless plating is rarely reported in the metallization of polymers. In this study, the metallization of biocompatible Pt metal is realized by supercritical CO2 (sc-CO2)-assisted electroless plating. The catalyst precursor used in the sc-CO2 catalyzation step is an organometallic compound, palladium (II) acetylacetonate (Pd(acac)2). The electrical resistance is evaluated, and a tape adhesion test is utilized to demonstrate intactness of the Pt layer on the PET film. The electrical resistance of the Pt/PET with 60 min of the Pt deposition time remains at a low level of 1.09 Ω after the adhesion test, revealing positive effects of the sc-CO2 catalyzation step. A tensile test is conducted to evaluate the mechanical strength of the Pt/PET. In-situ electrical resistances of the specimen are monitored during the tensile test. The fracture strength is determined from the stress value when the short circuit occurred. The fracture strength is 33.9 MPa for a specimen with 30 min of the Pt deposition time. As the Pt deposition time increases to 45 min and 60 min, the fracture strengths reach 52.3 MPa and 65.9 MPa, respectively. The promoted fracture strength and the decent electrical conductivity demonstrate the advantages toward biomedical devices.

Laser adhesion test (LASAT) is an emerging technology that uses the reverse tensile stress of laser-induced shock waves to test composites’ curing/bonding strength. In this research, the influence of laser power density and pulse width on delamination characteristics was investigated in the context of LASAT, and the process of delamination under laser shock was revealed. The study found that the delamination position moves toward the shock surface with the increase in power density and pulse width. However, excessive power density will cause shock surface damage. For LASAT, the laser power density should be controlled in the right range to avoid unnecessary damage to the material. The delamination region caused by laser shock is elliptic, with tensile fracture in the center of the ellipse caused by the coupled tensile stress and shear fracture in the edge region caused by the action of the transverse wave and the shock deformation.

In the process of aeroponics cultivation, the atomizer is one of the most important influencing factors on the cultivation process. This study presented the design of an ultrasonic atomization nozzle using contact charging and a root droplet adhesion test rig. The purpose of this study was to reveal the relationship between the main operating parameters of the high-voltage electrostatic ultrasonic atomization nozzle and the atomization effect using droplet adhesion measurements. In this study, the ultrasonic effect of nozzle was achieved by using Laval tube, and the design of the key parameters for the highvoltage electrostatic ultrasonic atomization nozzle were inlet pressure, electrostatic voltage root core electrode material and spray distance; the droplet size variation and root adhesion patterns were obtained through experiments. The best operating parameters were analyzed by using the orthogonal test method, and the droplet deposition distribution of the root system at different scales was investigated in the atomization chamber. The test results revealed that when the root core electrode material was coppe and the nozzle working parameters were at 0.4 MPa of inlet pressure, at 1.75 m the spray distance, at 12 kV of the electrostatic voltage, the root system has the highest droplet adhesion.

This paper deals with the evaluation of the surface of structural steel whose samples were deliberately contaminated with transparent spray primer, adhesive label glue, and welding sprays prior to hot-dip galvanizing. The galvanized samples were studied by optical microscopy, GDOES, adhesion tests, and condensation humidity tests. The effect of surface contamination on the quality of the zinc coating was found to be significant. In some cases, the zinc coating is damaged (after contamination with welding sprays), in others, it is completely absent (after contamination with spray primer or adhesive label glue).

This paper presents the results of testing the adhesion of geopolymer coatings and varnishes with ceramic additives to concrete and steel substrates. The measurement method used and described in this article was the pull-off method. The pull-off method test provides an easy way to evaluate the degree of adhesion of coatings to metal surfaces. The pull-off device provides values for the peel stress, which not only allows a quick determination of the adhesion of the coating to the substrate, but also makes it easier to compare the adhesion of several coatings to each other. However, this method requires appropriate preparation, so an attempt was made to determine its suitability for geopolymer layers. The results of testing the adhesion of a geopolymer layer to a geopolymer substrate and a concrete substrate are presented. As a result of this study, a higher adhesion strength of the geopolymer layer to the geopolymer substrate was found in comparison to geopolymer coatings applied on conventional concrete. Adhesion tests were also conducted for steel substrates to which both geopolymer and acrylic lacquer were applied.

Electroluminescence (EL) is the property of a semiconductor material pertaining to emitting light in response to an electrical current or a strong electric field. The purpose of this paper is to develop a flexible and lightweight EL device. Thermogravimetric analysis (TGA) was conducted to observe the thermal degradation behavior of NinjaFlex. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)—PEDOT:PSS—with ethylene glycol (EG) was coated onto polyester fabric where NinjaFlex was placed onto the coated fabric using three-dimensional (3D) printing and phosphor paste, and BendLay filaments were subsequently coated via 3D printing. Adhesion strength and flexibility of the 3D-printed NinjaFlex on textile fabrics were investigated. The TGA results of the NinjaFlex depict no weight loss up to 150°C and that the NinjaFlex was highly conductive with a surface resistance value of 8.5 ohms/sq.; the coated fabric exhibited a uniform surface appearance as measured and observed by using four-probe measurements and scanning electron microscopy, respectively, at 60% PEDOT:PSS. The results of the adhesion test showed that peel strengths of 4160 N/m and 3840 N/m were recorded for polyester and cotton specimens, respectively. No weight loss was recorded following three washing cycles of NinjaFlex. The bending lengths were increased by only a factor of 0.082 and 0.577 for polyester and cotton samples at 0.1-mm thickness, respectively; this remains sufficiently flexible to be integrated into textiles. The prototype device emitted light with a 12-V alternating current power supply.

In this study, a novel high-manganese steel (HMS) was borided at 850, 900 and 950 °C for 2, 4, and 6 h by the pack boriding process. Contrary to previous literature, borided HMS uncommonly exhibited saw-tooth morphology like low alloy steels, and manganese enhanced the boron diffusion. Another striking analysis is that the “egg-shell effect” did not occur. The present study demonstrated the silicon-rich zone for the first time in the literature by EDX mapping. Moreover, the formation mechanism of silicon-rich zones was explained and termed as “compact transfer of silicones (CTS)”. XRD analysis showed the existence of FeB, Fe2B, MnB and SiC phases. The boriding time and temperature increased the thickness of the boride layer from 31.41 μm to 117.65 µm. The hardness of the borided layer ranged from 1120 to 1915 HV0.05. The activation energy of borided HMS was found to be a very low result compared to high alloy steel investigated in the literature. The Daimler-Benz Rockwell-C adhesion test showed that adhesions of borided HMS surfaces are sufficient. The dry sliding wear tests showed that boriding treatment increased the wear resistance of untreated HMS by 5 times. The present study revealed that the boriding process extended the service life of HMS components.

Magnesium alloys are considered as potential biomaterials for use in orthopedic implantology. The main barrier to the use of Mg alloys in medicine is their overly fast and irregular degradation in body fluids. The use of protective calcium phosphate coatings to increase the corrosion resistance of Mg alloy (AM50 alloy: 4 wt.% Al, 0.3 wt.% Mn, 0.2 wt.% Zn, rest Mg) was examined in this study. The scientific goal of the study was the assessment of the influence of calcium phosphate layer morphology on the corrosion process in Ringer’s solution. Modification of the coating morphology was obtained by changing the chemical composition of the phosphatizing bath using NaOH (NaAM50 sample) or ZnSO4 (ZnAM50 sample). In practice, a more dense and uniform coating could be obtained by the immersion of AM50 alloy in a solution containing ZnSO4 (ZnAM50 sample). In this study, an adhesion test performed on the ZnAM50 sample indicated that the critical load was 1.35 N. XRD phase analysis confirmed that the obtained coatings included dicalcium phosphate dihydrate (CaHPO4*2H2O). The coatings prepared on the NaAM50 and ZnAM50 samples are effective barriers against the progress of corrosion deeper into the substrate. After 120 h immersion in Ringer’s solution, the volume of the evolved hydrogen was 5.6 mL/cm2 for the NaAM50 and 3.4 mL/cm2 for the ZnAM50 sample.

Silicon (Si) and silver (Ag) doped amorphous carbon (a-C) thin film were deposited on chrome nitrided 316 LVM stainless steel using filtered cathodic vacuum arc (FCVA) deposition technique to obtain Si:a-C and Ag:a-C thin film. The morphology of the films was evaluated using atomic force microscopy, X-ray diffraction, Raman spectroscopy, nanoindentation and nanoscratch tests. The surface quality of Ag:a-C film appeared inferior owing to the formation of Ag agglomerates on the surface. Raman studies indicated higher shifting and narrowing of G-band in Ag:a-C film resulting in increased sp 2 hybridization. Also, the I D /I G ratio of Si:a-C film (1.3) was lesser than Ag:a-C (2.3) film indicative of higher sp 3 content in the former. This has propounded to improved mechanical attributes such as hardness (24.5 ± 3.8 GPa), elastic modulus (241 ± 14 GPa), H/E (0.103 ± 0.11), H 3 /E 2 (0.282 ± 0.021 GPa) and fracture toughness (2.93 MPa.m 1/2 ) in Si:a-C film. Further, Ag:a-C film suffered severe radial cracks during indentation at higher load owing to debonding. On the other hand, Si:a-C film exhibited the formation of circumferential cracks during indentation attributed to higher compressive stress in the film. What is more, Si:a-C showcased better film adhesion in Rockwell-C adhesion test with lesser delamination at the impression edge. This is further corroborated by microscratch test depicting higher L c2 value and adhesive energy.