Papers by Keyword: Coating

Abstract: In this study, low-thermal emissivity coatings were developed using aluminum leafing particles dispersed in an acrylic binder. The aluminum particles were modified through a ball milling process to enhance their leafing properties, with milling times ranging from 5 to 15 h. The effects of milling time on particle size, morphology, and leafing degree were examined using scanning electron microscopy (SEM) and laser diffraction analysis. Coatings with different particle volume concentrations (PVC) and thickener contents were prepared, and their thermal emissivity was evaluated. Results showed that milling time significantly affected the leafing behavior of the aluminum particles, with longer milling times leading to improved dispersion and lower emissivity values. The addition of a thickener enhanced particle distribution, but excessive concentrations resulted in void formation due to hindered solvent evaporation. The lowest thermal emissivity was achieved at a milling time of 15 hours and 10% PVC, providing valuable insights for the design of effective low-emissivity coatings for thermal management applications.

Abstract: In polymer studies, biocomposite now draws attention as an exciting material obtained from combining natural fiber and matrix, which is an environmentally friendly material with biodegradable properties. One of the natural fibers often used in polymer filler is banana stem fiber. This study aims to prepare carbon-coated waste-dried banana fiber. The waste of banana stems was used as raw material for preparing cellulose-rich banana stem fiber. The banana fiber was soaked in an alkaline solvent, 1% NaOH, to remove the lignin content. The dried banana fiber was then coated with activated carbon and graphite by immersion in the carbon dispersion in ethanol with PVA glue binder added. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) spectra show different profiles on raw and carbon-coated banana fibers, indicating successful carbon coating. The burning test and thermal analysis results show that carbon-coated banana fibers have better thermal properties than raw banana fiber. This suggests that carbon covered on the fiber surface could enhance its thermal property due to intramolecular bonds between fibers and carbon particles. Graphite-coated banana fibers have the longest burning time and are concluded to have the best fire-retardant properties among all samples. The findings confirmed the potential use of carbon-coated banana fiber as filler material for reinforcing conventional composites.

Abstract: A modification cutting tool is a type of cutting tool that can be altered or adjusted to change its cutting properties. This can include changing the angle or shape of the cutting edge, adjusting the depth of cut, or modifying the material or coating used on the tool. These modifications allow for greater precision and efficiency in cutting operations, particularly in industries for manufacturing and construction different products. Ceramic materials can be used in coatings to provide a variety of benefits, such as corrosion, wear resistance , and thermal insulation. They also offer high hardness, low friction, and chemical stability. Ceramic coatings can be applied to various substrates including metals and ceramic. Modification of cutting tools using nanomaterial deposition is a promising approach to enhance their performance and durability. The process involves depositing one or more layer of nanosized particles onto the surface of the cutting tool, which can improve its mechanical, thermal, and tribological properties. Keywords: Ceramic materials ; coating ;cutting tools; coating process.

Abstract: In this paper, the effect of heat treatment temperature on the resultant composition of composite Al-Si coatings on ZK60A alloy investigated. The coatings were developed using magnetron sputtering deposition. These coatings can serve as an effective anti-corrosion barrier for Mg alloys in aqueous mediums. The magnetron target composition was 80% Al and 20% Si, while in the deposited coating it was 78% Al and 18% Si, with the rest being atoms from the substrate. The as-deposited coatings had pores and the Al-Si composite was deposited in the form of globules. The sputtered coatings were subjected to heat treatment for 1.5 hours at 420 °C (HT1) and 350 °C (HT2). The ratio of elements in the heat-treated coatings changed significantly due to diffusion between substrate-coating interface and migration through the pores that exist in the coating. It was found that Mg migrates into the coating and Si into the substrate. Al/Mg ratio reduced by 81.2 and 60.6 %, respectively, in the coating after the HT1 and HT2.

Abstract: The present research aimed to evaluate the effect of nickel-based electrochemical metallization (EMNi) on the quality and performance of electric motor components, compared to high-velocity oxy-fuel (HVOF) thermal spray coating, the most widely used coating in the mining industry. The experiment was conducted using motor components comprised of 4340 VCN steel, 4140 VCL steel, 1045 steel, and stainless steel, which underwent both treatments. The surface temperature of the components was monitored during the processing stage, followed by evaluations of their Rockwell hardness (HRC) and surface characteristics (taper, ovality, parallelism, finish, wear) at the onset (day 0) and after 2 years of use the results indicate that EMNi delivers electric motor components with superior finishes and extended warranty and service life in comparison to HVOF.

Abstract: Chitin is the second most abundant biopolymer in the world. Herein, deacetylated chitin nanofibers (dChNFs) through partial deacetylation were initially prepared, and dChNFs were subsequently added into chitosan (CS) to develop the biodegradable coatings to extend the shelf life of bananas. The degree of deacetylation and the average diameter of the obtained dChNFs were 29.12 % and 19.49 ± 3.1 nm, respectively. The addition of dChNFs into CS at the ratio of 50:50 decreased the water vapor permeability (WVP) from 4.56 × 10^–11 g/m·s·Pa to 3.81 × 10^–11 g/m·s·Pa. Moreover, three different suspensions of CS, dChNFs, and CS/dChNFs were applied as coatings on Hom–Thong bananas via the dipping technique. The application of the CS/dChNFs coating showed a significant postponement in the color change of the peel (from green to yellow) to 22 days, compared to 9 days for uncoated bananas. The weight of the bananas coated with CS/dChNFs exhibited a weight loss of 26.53 % day^–1, which was lower than that of the uncoated bananas (30.71 % day^–1). This suggested that the CS/dChNFs coating would be efficiently used to prolong the shelf life of bananas, reducing food waste.

Abstract: Traditional epoxy coatings used for water pipeline cathodic protection have several shortcomings, including limited availability, high cost, and carcinogenic concerns. To address these challenges, a new, food-grade epoxy coating that is affordable, meets all technical requirements, and is free of carcinogenic substances was developed.The study involved testing various kinds of reinforcing fillers, non-reinforcing pigments, red pigment, and BYK additives to formulate the epoxy-based coating. Curing experiments were then conducted by formulating the coating with a fixed ratio of curing agent and spraying the resins onto mild steel panels for testing.The results demonstrated that the new formulation has good compressive strength, adequate impact resistance, and Shore D hardness in the range of 60-70, which is expected for this type of application. The abrasion resistance of the coatings increased with increasing hardness.Overall, the new food-grade epoxy coating is a promising alternative to traditional epoxy coatings for water pipeline cathodic protection. It is affordable, meets all technical requirements, and is free of carcinogenic substances.Key words: Epoxy Resin, Coating, Food Grade, TETA

Abstract: A layered clay/epoxy coating was fabricated to investigate the effects of montmorillonite (MMT) and halloysite nanotube (HNT) loading at 0.5, 1.5, and 2.5 parts per hundred resin (phr) on the corrosion resistance and thermal stability of coated mild steel plates. The corrosion study was carried out by Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization. The |Z|_0.1Hz value, R_ct, and R_p of the layered/clay epoxy coatings containing 1.5 phr of HNT and MMT exhibited the best anticorrosion performance compared to other clay content levels. The |Z|_0.1Hz value for the epoxy coating filled with 1.5 phr of MMT (M1.5) is 2.132 × 10⁹ Ω·cm², while it is slightly higher for H1.5 coatings, i.e., 2.629 × 10⁹ Ω·cm². Water absorption trends were consistent with EIS and Tafel polarization studies. The presence of highly compatible nanocontainers clay reduced the total free volume and promoted cross-linking, enhancing anticorrosion performance. Thermal Gravimetry Analysis (TGA) showed that a 1.5 phr loading of MMT in layered/clay epoxy coating demonstrated better thermal stability than a coating embedded with HNT. This improvement can be attributed to the barrier effect of MMT, which retards the diffusion of oxygen molecules into the coating.

Abstract: The rapid development of the timber industry has caused the total capacity of the Indonesian timber industry to exceed the ability of production forests to provide raw materials sustainably. One of the industries that require a supply of wood as its main raw material is the furniture industry. The raw materials for furniture that are commonly used are logs and planks. In recent years, there has been the development of new materials that use natural fibers as polymer reinforcement, which can be used to replace wood materials. The material is a natural fiber composite. Composite materials reinforced with natural fibers are widely used in aerospace, automotive, circuit boards and other applications. One of the natural fibers that can be used as a composite is straw fiber. This high proportion of cellulose in straw fiber can be used for several things, one of which is composite materials. The utilization of rice straw fiber and epoxy as raw materials for making composites is an alternative to overcoming the increasing demand for wood. The purpose of this study was to determine and analyze the effect of volume fraction and alkalization treatment on the physical and mechanical characteristics of straw fiber composites, also to determine and analyze the effect of adding a coating of PE/SiO₂ on the hydrophobic characteristics of straw fiber composites. The physical and mechanical properties of the composites were evaluated based on the SNI 03-2059-2006 and SNI-01-4449-2006 standard. The volume fractions used are 40%, 50%, and 60%. The length of the fiber used is 5 mm. And the alkalization variables used were 5% and 10% NaOH with 4 and 8 hours of immersion. The compressive strength decreased by adding fiber volume fraction and increased by higher treatment alkalization. The coating method can produce composite with the contact angle value of more than 90^o.

Abstract: The paper presents an analysis of technologies for improving the quality parameters of the surface layers of parts, which were carried out by the method of electrospark alloying (ESA) and by additional saturation of surfaces with alloying elements from special process media (STM). The technology of sulfocementation was considered. Metallographic and hardness tests after sulfocementation by ESA showed that the treated surface consists of layers: "soft", hardened and base metal. As the discharge energy increases, the thickness, microhardness and integrity of the coating increase. The presence of sulfur in STM promotes the sulfidation process. It is shown that sulfur accumulates on the surface of the metal at a depth of up to 30 μm. This zone is characterized by reduced microhardness. A strengthened layer is formed under this layer, it has an increased carbon content and high microhardness.