Mechanical Properties Of Composite Coatings Research Articles

Effect of graphene and niobium carbide on microstructure and mechanical properties of Ni60 composite coatings prepared by laser cladding

Niobium carbide (NbC) is often used as a reinforcing phase to improve the mechanical properties of composite coatings, but its low thermal conductivity makes the flow of molten pool poor, and the cladding layer is prone to defects such as non-fusion and slag inclusion. Therefore, in this paper, Ni60-NbC composite coatings with different NbC content were prepared by laser cladding technology, and the 10 vol.% graphene-20 vol.% NbC-70 vol.% Ni60 composite coatings were prepared under the optimal NbC component. The effects of the addition of NbC and graphene on the microstructure and microhardness of the coating were systematically discussed. The results show that the microhardness of 20 vol.% NbC composite coating is increased from 680.1 HV to 882.9 HV compared with Ni60 coating without NbC.The composite coating with both NbC and graphene has a microhardness of up to 1048HV, which is 18% higher than the composite coating with only 20 vol.% NbC. The mechanism is that the addition of graphene promotes the formation of chromium carbide (Cr23C6, Cr7C3) and increases the fluidity of the molten pool, which causes small niobium carbide particles to dissolve and recondense to form large particles. Large niobium carbide particles and chromium carbide jointly inhibit the excessive growth of other grains. This study provides a new idea for laser cladding of nickel-based composite coatings.

Structural, mechanical, and tribological studies of Ni-B-TiN composite coating: effect of SDS concentration

In industrial applications, it has been desired to be durable and used for a long time in harsh working conditions. As an alternative study, the effects of surfactants on TiN particle distribution, particle content in the coating, microstructure, surface morphology, hardness, and wear resistance were investigated. Scanning electron microscopy (SEM) was used to characterize the surface and cross-section images of Ni-B-TiN composite coatings. The SDS concentration in the electrolyte affects the TiN particle distribution, resulting in a uniformly distributed surface morphology of the composite coating. The crystal properties of the elements in the composite coating were examined using X-ray diffraction (XRD). The surfactant directed the Ni crystal in the (111) plane, affecting the preferred direction of the grains. The distribution of TiN particles in the Ni-B alloy matrix with Zeta potential was investigated. The mechanical properties of composite coatings were evaluated over average values by performing tests from different zones under a max. 50 mN load using the Nanoindentation technique. The tribological behavior of Ni-B-TiN composite coatings sliding towards Al2O3 balls (Ø 6 mm) was investigated with a CSM tribometer device void of lubrication at room temperature. In this study, the usability of SDS (sodium dodecyl sulfate)-anionic surfactant for Ni-B-TiN metal matrix composites deposited on mild steel substrates by the electrodeposition method has been explained.

Correlation between low-temperature anticorrosion performance and mechanical properties of composite coatings reinforced by modified Fe3O4

In this study, the glycidyl methacrylate (GMA) decorated Fe3O4 nanoparticles (G-Fe3O4) were successfully prepared through free-radical copolymerization technology, and incorporated in an epoxy coating. The composite coatings reinforced by modified Fe3O4 nanoparticles were prepared, and the correlation between the low-temperature anticorrosion performance and the mechanical properties of the coatings was explored. The mechanical properties including adhesion, tensile strength, and low-temperature flexibility of the epoxy coatings are significantly improved by the addition of the nanofillers, especially G-Fe3O4. During the normal spray test and alternating test of freezing and salt spray test, the G-Fe3O4/EP coating exhibits the most excellent anticorrosion performance among the four kinds of coatings, and the freezing treatment could distinctly worsen the barrier effect of the coatings.

Influence of pulse frequency on corrosion resistance and mechanical properties of Ni-W/B4C composite coatings

In this research, the effects of different pulse frequencies on the properties of Ni-W/B4C composite coatings are investigated in detail. First, we evaluate Ni-W coatings prepared from different bath compositions and select suitable electrolyte as bath solution. Then, the purchased boron carbide nanoparticles are characterized and their dispersion and suspension properties in bath electrolyte are verified. After that, Ni-W/B4C composite coatings are manufactured through different pulse frequencies (1, 10, 100 and 1000 Hz) and the prepared alloy coatings are characterized in detail. The results show that when the pulse frequency is increased from 1 Hz to 1000 Hz, the grain size of coatings decreases by 40%, the content of nickel in the coating decreases 3%, the content of W increases by 1.5%, the content of B4C particles is increased, and the roughness of the coating decreases significantly. In addition, the micro-hardness test, tensile test, impact test, bending test and reciprocating wear test are used to explore the mechanical properties of composite coatings, the water contact angle test and porosity test are used to study the surface properties, and the electrochemical test are adopted to predict the corrosion resistance. The results show that the composite coating prepared at 1000 Hz has the best mechanical properties, while the composite coating prepared at 100 Hz has the best corrosion resistance.

Effect of annealing temperature on microstructure and mechanical properties of plasma sprayed TiC-Ti5Si3-Ti3SiC2 composite coatings

In this study, Ti-Si-C based composite coatings were fabricated by plasma spraying of aggregated powders of Ti/SiC/graphite. These coatings were subsequently annealed in an Ar atmosphere at 500–1000 °C to study the evolution of the microstructure and properties of the composite coatings. The coatings were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and micro-hardness tests. The results revealed that the composite coatings before and after annealing were mainly comprised of Ti 3 SiC 2 , Ti 5 Si 3 and TiC phases. The annealing treatment had no significant effect on the phase types but contributed to the formation of more uniform microstructures with reduced porosities and increased micro-cracks. The annealed coatings exhibited an improved microhardness and fracture toughness as the temperature increased, and the highest values recorded were of 1419 HV and 3.00 MPa·m 1/2 , respectively. Compared with the limited reaction time during the spraying process, the post-annealing treatment extended the reaction time, and the reaction proceeded further. The more uniform microstructure, the increase of Ti 3 SiC 2 content and the micro-crack toughening effect contributed to improving the mechanical properties of composite coatings. • Post-annealing treatment was conducted on the plasma sprayed TiC-Ti 5 Si 3 -Ti 3 SiC 2 composite coatings. • The as-annealed composite coatings achieved more uniform microstructure with reduced porosities. • The as-annealed composite coatings showed increased microhardness and fracture toughness with increasing temperature.

Deformation Mechanisms of NiP/Ni Composite Coatings on Ductile Substrates

NiP/Ni composite coatings with different thicknesses were prepared on coarse-grained Ni substrates by electrodeposition. The tensile tests show that compared with the substrate, the toughness and strength of the samples with multilayer composite coatings are greatly improved. The uniform elongation is increased from 24% to 43%, and the yield strength is increased from 108 to 172 MPa. In the deformation process, the geometrically necessary dislocations accumulate, resulting in long-range back stress, leading to strain hardening, showing synergistic strength and ductility. The mechanical properties of composite coatings are strongly affected by the layer thickness. Molecular dynamics studies show that there is a more uniform distribution of the shear strain in thinner coatings, and the propagation of shear transformation zones (STZs) is restrained, preventing the formation of a large shear band. With the decrease of thickness, the deformation of the NiP layer changes from shear fracture to the coexistence of uniform deformation and shear deformation. The interface resistance of the multilayer structure increases the resistance of crack propagation and alleviates the effects of NiP layer cracking on substrate cracking. Multilayer amorphous/crystalline coatings therefore may increase the toughness of the Ni substrate.

Механические свойства композитного покрытия SiC на графите, полученного методом замещения атомов

The mechanical properties of composite coatings made of silicon carbide on graphite are studied for the first time. For the deposition of coatings, a new method of annealing the initial graphite was used, which was in contact with a silicon melt in an atmosphere of carbon monoxide.The samples were studied by nanoindentation and scanning electron microscopy. It is shown that the formed coating consists of a continuous film of monocrystalline silicon carbide lying on the surface, dendrites and crystalline druses, with roots going deep into the sample through a system of pores. It is shown that the coating significantly increases the mechanical characteristics of the graphite surface, including the microhardness.

Energy Parameters of an Electron Beam and Structure and Mechanical Properties of Composite Coatings

An important parameter of non-vacuum electron-beam cladding is the surface density of the input energy that depends on the beam current and the specimen travel speed. The paper presents results of investigation of the effect of the heat input on the structure and properties of composite coatings fabricated by electron beam cladding. The modes of cladding with beam currents of 25 and 40 mA and specimen travel speed varying within 0.5–2.0 cm/s have been studied. It was revealed that the thickness, the dendrite grain size, and the microhardness of the coatings increased, and the volume fraction of the eutectic decreased with increasing specific electron beam power. It is shown that for a low heat input, an austenitic-martensitic structure is formed with carbides in the eutectic and martensite needles. For a large heat input, an austenitic structure with eutectic carbide network is formed. The martensitic structure is formed only along the coating-substrate interface as a result of intense heat removal deep into the substrate material.

The effect of pulse frequency on the microstructure and surface mechanical properties of composite coatings on the surface of AISI304

Abstract This study investigated the in-situ formation of TiC–Al2O3 and TiB2–TiC–Al2O3 composite coatings on the surface of austenitic 304 stainless steel by the use of 3TiO2-4Al-3C and 3TiO2-4Al-B4C powder and argon arc cladding technology. The effects of pulse frequency 0–200 Hz on microstructure and mechanical properties of coating are studied. Microstructural study of coatings showed that the high cladding temperature triggered the self-propagating high-temperature synthesis of reinforcement phases TiC, Al2O3, and TiB2 at the surface of 304 stainless steel. The use of pulsed current instead of direct current reduced the hardness of the coating by increasing the dilution. Also, in both groups of coatings, no significant difference was found between the hardness distribution over the coating layer in the specimens coated with pulsed currents at frequencies of 10 and 200 Hz.

Энергетические параметры электронного пучка, структура композиционных покрытий и их механические свойства

Энергетические параметры электронного пучка, структура композиционных покрытий и их механические свойства

Mechanical properties of composite coatings of chromium and nanodiamonds on aluminum

Aluminum offers engineers weight saving advantages in their product design. However, aluminum has poor wear and friction properties. In addition, the surface oxide layer of this chemically active metal, which gives it the corrosion resistance, makes it a very difficult metal to plate [1]. Specific pre-treatment must be applied to remove the oxide layer from the aluminum surface. The nanodiamond particles additionally facilitates the process of chromium deposition. The object of this study is to evaluate the impact of nanodiamonds on the mechanical properties of the chromium coating plated on

Effect of ultrasonic power and pulse-on time on the particle content and mechanical property of Co-Cr3C2 composite coatings by jet electrodeposition

In order to obtain metal matrix composite coating with high content of particles by selective electrodeposition, pulsed ultrasonic was introduced to prepare Co-Cr3C2 composite coatings by jet electrodeposition. The effects of ultrasonic power and pulse-on time on the microstructure and mechanical properties of composite coatings were investigated. The morphology of the coatings was observed by scanning electron microscopy, and the content of chromium in the coating was measured by EDS spectrometer. The coating hardness was measured by a micro-hardness tester, and the friction coefficient was evaluated by a tribotester. The results show that both the power and the mode of the ultrasonic had a significant influence on composite codeposition. With the optimized deposition parameters, the Co-Cr3C2 composite coating containing >30% Cr3C2 particles was obtained, which yields the highest hardness and the lowest friction coefficient.

ВПЛИВ ТВЕРДИХ ШАРУВАТИХ НАПОВНЮВАЧІВ НА ФІЗИКО-МЕХАНІЧНІ ВЛАСТИВОСТІ КОМПОЗИЦІЙНИХ ПОКРИТТІВ НА ОСНОВІ ФЕНІЛОНУ

Urgency of the research. Polymer materials have been used in many industries for a long time; they are often used as an alternative to metal parts. At the same time, polymeric materials can exceed traditional materials in some characteristics, but inferior in others. Recently, polymeric materials with increased adhesion properties have been developed, so the actual task is to study their physical and mechanical characteristics for estimation of their usage in industry perspectives.Target setting. Target is the physical and mechanical characteristics of the polymer materials with high adhesive properties.Actual scientific researches and issues analysis. There are many researches of physical and mechanical characteristics of different types of polymers; also, there are polymers with high adhesive characteristics developed.Uninvestigated parts of general matters defining. There are many researches of physical and mechanical characteristics of polymers, but there are not enough information about materials with increased adhesion characteristics based on phenilone.The research objective. The objective is an experimental study of the physical and mechanical properties of composite coatings based on phenilone, in particular various types of strength, elasticity, microstructure, etc.The statement of basic materials. In the beginning of the article, the general analysis of phenilone-based polymers is performed and necessity of its physical and mechanical characteristics study is shown. Then results of various types of strength, elasticity, microstructure, etc. characteristics experimental studies are presented.Conclusions. It is found, that insertion the most part of proposed fillers causes to increase of such parameters as microhardness, wear resistance, modulus of elasticity and some reduction of strong characteristics. An appearance of particle conglomerates on coating surface at filler part >20% is shown, that causes decrease of operational properties of the coatings.

Modification of graphene with organic/inorganic silicon‐based materials and its reinforcement on the UV‐curing polyurethane composite coatings

Functionalized graphene (FGO) was prepared through the sol‐gel method and thiol‐ene reactions. FGO was subsequently incorporated into polyurethane (PUA) through UV‐curing process. The structural and morphological features of FGO/PUA composite coatings were characterized by transmission electron microscopy (TEM) as well as scanning electron microscope (SEM). The TEM and SEM results show that FGO nanosheets are homogeneous dispersed in the PUA matrix and form the strong interfacial interaction with PUA matrix due to the formation of chemical reaction between FGO and PUA matrix. Moreover, the incorporation of FGO could effectively enhance the thermal, flame retardant, and mechanical properties of composite coatings. The thermal stability of the PUA composite coatings with only 0.1 wt% FGO was increased by 18°C. Meanwhile, the incorporation of FGO could also reduce the peak heat release rate (pHRR) of PUA resins. Compared with pure PUA, the storage modulus and tensile strength of the composite coatings with 0.5 wt% FGO were also improved by 9% and 82%, respectively. By contrast, rGO/PUA composite coatings could not form homogeneous dispersion and exhibit significant accumulations. Consequently, the covalent modification of graphene presented herein will provide a feasible and effective approach to the modification of graphene and the obtained FGO could impart PUA with high performance. POLYM. COMPOS., 39:746–754, 2018. © 2016 Society of Plastics Engineers

Preparation and Properties of EPDM-Based Composite Coatings with Low Infrared Emissivity

AbstractLow-infrared-emissivity coatings were prepared using metallic particles (including Cu, Al, Ni, Ag, etc.) and an ethylene-propylene-diene monomer (EPDM) binder. The effects of size, shape, morphology, and content of metallic particles on infrared emissivity of the coatings were systematically investigated. The principles of the low-infrared-emissivity and low-solar-reflectance coatings are discussed in terms of reflection, emissions, and chemical structure. The thermal insulation performance of composite coatings is studied via a simulation model. Mechanical properties of composite coatings are studied by using circle-cut test and impact strength test. The composite coatings are also tested for corrosion behavior with potentiodynamic polarization. The results indicate that when the Cu particles and Al particles are flaky and high-leafing, they have the minimum coating emissivity, exhibiting infrared emissivity values of 0.33–0.40 and solar reflectance values of 0.38–0.53. The formation of low-infra...

Электрохимические и механические свойства композиционных покрытий, формируемых на сплаве МА8 в дисперсных электролитах с наночастицами ZrO2 и SiO2

Электрохимические и механические свойства композиционных покрытий, формируемых на сплаве МА8 в дисперсных электролитах с наночастицами ZrO2 и SiO2

Development and Characterization of Electrocodeposited Nickel-Based Composites Coatings

The objective of the article is to study the development and characterization of composite coatings using nickel-tungsten carbide (Ni-WC), nickel-silicon carbide (Ni-SiC), nickel-carbon black (Ni-CB), and nickel-carbon nanotube (Ni-CNT) materials using electrocodeposition technique by varying the composition of reinforcements. The electrochemical parameters such as current density, bath temperature, and pH of the solution were maintained at constant levels for all the coating configurations. The composition of the coating and its proportion were studied using x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Mechanical properties such as ultimate tensile strength and microhardness were studied. Morphology of the coatings and fracture surfaces were studied using scanning electron microscope. Improvement in mechanical properties of composite coatings was found due to the reduction in crystalline size of the composites coatings. Although loading of carbon nanotube was the least, it also shows good mechanical properties along with Ni-WC composite coatings.