Explore the vast range of titles available.

In the present study, vinyltrimethoxysilane was used to modify high-ortho novolac resin (NR) to obtain a vinyl silicone-modified phenolic oligomer (Si-mod NR). Subsequently, this oligomer is polymerized with methyl methacrylate. The mid-products (NR and Si-mod NR) and synthesized silicone-modified phenolic/acrylic resin (Ac/Si-mod NR) were characterized by Fourier transform infrared spectroscopy, and thermal properties were investigated by using thermal gravimetric analysis and differential scanning calorimetry techniques. In addition, the surface coating properties, including drying, hardness, adhesion, impact resistance, gloss, acid, alkaline, water, and solvent resistance of the films prepared from these products, were comparatively investigated. The results showed that the modification reactions yield a novel resin (Ac/Si-mod NR), which can be easily used as a surface coating material with high thermal resistance, flexibility, and excellent film properties.

This study aimed to use an in-air micro-particle-induced X-ray/gamma emission (in-air µPIXE/PIGE) system to evaluate tooth-bound fluoride (T-F) in dentin following the application of fluoride-containing tooth-coating materials. Three fluoride-containing coating materials (PRG Barrier Coat, Clinpro XT varnish, and Fuji IX EXTRA) and a control were applied to the root dentin surface of human molars (n = 6, total 48 samples). Samples were stored in a remineralizing solution (pH 7.0) for 7 or 28 days and then sectioned into two adjacent slices. One slice of each sample was immersed in 1M potassium hydroxide (KOH) solution for 24 h and rinsed with water for 5 min for the T-F analysis. The other slice did not undergo KOH treatment and was used to analyze the total fluoride content (W-F). The fluoride and calcium distributions were measured in all the slices using an in-air µPIXE/PIGE. Additionally, the amount of fluoride released from each material was measured. Clinpro XT varnish demonstrated the highest fluoride release among all the materials and tended to show high W-F and T-F and lower T-F/W-F ratios. Our study demonstrates that a high fluoride-releasing material shows high fluoride distribution into the tooth structure and low conversion from fluoride uptake by tooth-bound fluoride.

The flame resistance of applied coating materials affects the safety of innovative technological solutions. Silicone-containing polymeric materials are one of the most economical solutions in the field of coatings due to the effect of the unique combination of very good thermal, resistance, and surface properties. The rich chemistry of silicon compounds, which results in their very good thermal stability, allows their use as flame-resistant coating materials or as flame retardants in polymer composites. In this review, the flame resistance of PDMS systems based on their thermal degradation data, as well as possible paths of thermal degradation depending on external conditions including the effect of additives, flame resistance of hybrid silicone-containing coating materials and most important innovative applications of these materials, are reviewed. Very good results from the use of organic silicon compounds as fire retardants in polymers obtained by many research teams are one of the promising ways of overcoming the health, safety, and availability concerns of traditional halogenated fire retardants.

Nano-coating has been a hot issue in recent years. It has good volume effect and surface effect, and can effectively improve the mechanical properties, corrosion resistance and wear resistance of the coatings. It is important to improve the wear resistance of the material surface. The successful preparation of nano-coatings directly affects the application of nano-coatings. Firstly, the preparation methods of conventional surface coatings such as chemical vapor deposition and physical vapor deposition, as well as the newly developed surface coating preparation methods such as sol-gel method, laser cladding and thermal spraying are reviewed in detail. The preparation principle, advantages and disadvantages and the application of each preparation method in nano-coating are analyzed and summarized. Secondly, the types of nano-coating materials are summarized and analyzed by inorganic/inorganic nanomaterial coatings and organic/inorganic nanomaterial coatings, and their research progress is summarized. Finally, the wear-resistant mechanism of nano-coatings is revealed from three aspects: grain refinement, phase transformation toughening mechanism and nano-effects. The application prospects of nano-coatings and the development potential combined with 3D technology are prospected.

Laser cladding (LC) is a laser-based surface modification technique widely adopted to develop a thin coating or remanufacture worn-out mechanical components that work in extreme conditions. LC helps to generate superior surface properties and surface integrity on the substrate surface, improving the service life. This review paper provides a comprehensive overview of the LC process, different powder feeding methods, and the uniqueness of LC over other coating techniques. More specifically, the current state-of-the-art of the LC process on carbon steel and high-alloy steel-based mechanical components operating in diverse industries was elucidated. Furthermore, the effect of LC processes on mechanical properties such as wear, corrosion and fatigue properties are discussed. In addition, the LC process’s influence on microstructural features and microstructural modifications is explained. Finally, this study explores some potential applications of the LC process in diverse industries.

This paper investigates the thermal barrier coating (TBC) performance of La 2 Zr 2 O 7 /ZrO (2-8 wt.%) Y 2 O 3 coatings (LZ/YSZ TBCs) deposited using atmospheric plasma spray (APS) over high velocity oxy-fuel (HVOF) NiCoCrAlYTa coated on Inconel 625. On the outermost surface of the double-layered coating, a laser glazing method was used to treat the TBC systems. Specifically, a Nd:YAG pulsed laser was used to change the surface layer of plasma-sprayed La 2 Zr 2 O 7 top coatings. The study found that the laser glazing treatment resulted in a higher number of temperature cycles needed to generate 5-20% spallation of the top surface of coatings, with 100 cycles compared to 30 cycles in the as-sprayed coatings. This improvement in performance was attributed to the dense surface of the laser-glazed LZ topcoat, which led to a lower thermally grown oxide (TGO) layer growth rate and improved TBC lifetime. Furthermore, the strain adaptation through segmented cracks that were created by laser glazing may have contributed to the enhanced TBC performance.

Ni60 alloy is one of the important brands of nickel-based self-fusing alloys. It is widely used in industries such as metallurgy, mining, and other fields for the repair and protection of fragile parts. However, there is little literature on the effect of C content on its properties. In this study, two Ni60 alloy coatings with different C contents prepared by flame spraying and remelting were investigated by means of XRD, SEM, EBSD, friction wear testing, thermodynamic calculation, etc. The results showed that the calculated freezing range (FR) of Ni60 decreased from 983-1165.90 °C to 980-1154.28 °C and the melting range (MR) of Ni60 decreased from 966.27-1089.28 °C to 958.91-1045.41 °C when the C content increased from 0.72 wt.% (S1) to 1.01 wt.% (S2). Besides, the Cr 7 C 3 phase size of the Ni60 layer increased with the increase of C addition. The coating shrinks during the remelting and solidification process, and the inner pores do not have sufficient time to escape, caused by the decreased FR, leading to the generation of holes and the degradation of surface quality in S2. However, the hardness of the S2 was 66 HV higher than that of S1, and the wear resistance of the S2 coating was superior as well because of more precipitated carbides therein. This work would give a hint at balancing the processability and mechanical properties for the development of high-performance coatings.

The aim of this research was to determine the optimal conditions for the process of the microencapsulation of phenol-rich grape pomace extract (GPE) using spray drying and goat whey protein (GW) as a coating. The encapsulation was carried out with the aim of protecting the original bioactive components extracted from grape pomace to ensure their stability and protection from external agents, as well as antioxidant activity, during the conversion of the liquid extract into powder and during storage. Using the response surface methodology, an inlet air temperature of 173.5 °C, a GW ratio of 2.5 and a flow rate of 7 mL/min were determined as optimum process parameters. Under these conditions, a high yield (85.2%) and encapsulation efficiency (95.5%) were achieved with a satisfactorily low moisture content in the product (<5%). The amount of coating had the greatest influence on the MC properties. GW showed a more pronounced stabilising effect on the phenolic compounds in GPE during a longer storage period compared to anthocyanins. The results obtained indicate the potential of GW as a coating and are an example of the possible upcycling of GPE and GW, which can lead to a high-quality product that can be a functional ingredient.

A thin layer of protective coating material is applied on the surface of offshore concrete structures to prevent its degradation, thereby extending the useful life of the structures. The main reasons for the reduction in the protective capability of coating layers are loss of adhesion to concrete and flattening of the coating layer wall. Usually, the state of the coating layer is monitored in the setting of water immersion using ultrasonic inspection methods, and the method of inspection still needs improvement in terms of speed and accuracy. In this study, the ultrasonic pulse echo method was used in a water immersion test of the coated specimens, and continuous wavelet transform (CWT) with complex Morlet wavelets was implemented to define the received waveforms’ time of flight and instantaneous center frequency. These allow one to evaluate the thickness of the coating layer during water immersion. Furthermore, phases of reflected echoes at CWT local peaks were computed using a combination of Hilbert transforms (HT) and wave parameters derived from CWT. In addition, three relative wave parameters of echoes were also used to train deep neural networks (DNN), including instantaneous center frequency ratio, CWT magnitude ratio, and phase difference. With the use of three relative waveform parameters of the DNN, the debonded layer detection accuracy of our method was 100%.

A study on the physical and mechanical properties of beeswax (BW), candelilla wax (CW), paraffin wax (PW) and blends was carried out with the aim to evaluate their usefulness as coatings for cheeses. Waxes were analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), permeability, viscosity, flexural and tensile tests and scanning electron microscopy. Cheeses were coated with the waxes and stored for 5 weeks at 30 °C. Measured parameters were weight, moisture, occurrence and degree of fractures, and dimensional changes. The crystal phases identified by XRD for the three waxes allowed them to determine the length of alkanes and the nonlinear compounds in crystallizable forms in waxes. FTIR spectra showed absorption bands between 1800 and 800 cm−1 related to carbonyls in BW and CW. In DSC, the onset of melting temperature was 45.5 °C for BW, and >54 °C for CW and PW. Cheeses coated with BW did not show cracks after storage. Cheeses coated with CW and PW showed microcraks, and lost weight, moisture and shrunk. In the flexural and tensile tests, BW was ductile; CW and PW were brittle. BW blends with CW or PW displays a semi ductile behavior. Cheeses coated with BW blends lost less than 5% weight during storage. The best waxes were BW and the blends.