Surface Of Composite Material Research Articles

Microstructural Analysis of Granular Metal-Ceramic Composite Materials of Matrix Type

The cluster structure of microphotographs of the metal-ceramic composite materials surface samples has been analyzed. Cluster analysis has been performed with the help of a self-organizing feature map in a four-dimensional feature space, built from textural visualizations of a microphotograph. As a result of our studies, two types of cluster structure elements were found: small-scale and large-scale clusters. The assumption has been made that two main features of the deformation graph can be associated with the destruction of the cluster elements of both kinds. As a result of multifractal analysis, it was found out that the difference in technology does not significantly affect the multifractal spectra, but it proves to be significant for multifractal dimensions.

Tailoring surface and structural properties of composite materials by coupling Pt-decorated graphene oxide and ZIF-8-derived carbon

Ultrasonication is used to obtain new nanoporous composites consisting of Pt-decorated graphene oxide (Pt-GO) and zeolitic imidazolate framework (ZIF-8)-derived carbon with improved surface and structural properties as evidenced by high hydrogen uptake of 0.44 mmol/g at 25 °C and 1 bar. At the same conditions, the bare ZIF-8-derived carbon (CZIF-8) and ZIF-8 showed hydrogen uptakes of 0.13 mmol/g and 0.05 mmol/g, respectively. This significant enhancement in hydrogen adsorption on Pt-GO/CZIF-8 is attributed to spillover mechanism. Moreover, adsorption affinity of CZIF-8 toward diverse gases is examined. CZIF-8 adsorbed larger amounts of CH4 (1.8 mmol/g at 20 °C), CO2 (5.7 mmol/g at 0 °C) and H2 (9.9 mmol/g at cryogenic temperature) at 1 bar in comparison to those obtained for parent ZIF-8. This study shows that the ultrasonication-assisted coupling of Pt-GO and MOF-derived carbons can be used for fabrication of composites with tailored surface and structural properties for adsorption, catalytic and photocatalytic applications.

Mechanical properties of Easy Fill composites after storage in mouthwashes

Purpose: The aim of the presented work was to investigate the influence of different mouthwashes on the chosen mechanical properties of different dental restorative composites. The null hypothesis was that the mouthwashes have influence on these properties. Design/methodology/approach: Four different restorative composites were used (Easy Fill Nano, Easy Fill Micro Hybrid, Easy Fill Flowable, Easy Fill Bulk). Samples were conditioned in different media: mouthwashes (Listerine Total Care with ethanol, Listerine Total Care Sensitive – alcohol-free) and distilled water. The samples were polymerized in Teflon moulds. The compressive strength, diametral tensile strength (DTS) and Vickers microhardness were examined. Findings: The research showed that the surface of composite materials was particularly sensitive to the action of mouthwashes. Both types of solutions, containing ethanol and without it lowered the microhardness values. The mouthwashes may also decrease other mechanical properties, like compressive strength of diametrical tensile strength. The results of the carried out investigations showed good mechanical properties of the tested materials, analogous to other materials of this type. Research limitations/implications: Other important properties of dental filling storied in mouthwashes should be analysed in future, including microgap between tooth and filling. Practical implications: The result contradicts the popular view that mouthwashes that do not contain ethanol are in general safer for composites in the context of reduction of mechanical properties. Both types of mouthwashes may reduce mechanical properties. Originality/value: The results of mechanical properties investigations of Easy Fill composites were presented and compared to other commercial materials. The changes of mechanical properties were also analysed after storing in different types of mouthwashes. So far, there has been no such research for these materials.

Influence of alcohol-containing mouthwash and alcohol-free mouthwash towards the hybrid composite restoration materials surface hardness

Mouthwash is widely used by the community to maintain oral health. Beside the benefit provided, both alcohol-containing mouthwash and alcohol-free mouthwash have negative effects on the composite resin restorative materials, which can affect the surface hardness. One of composite types is hybrid type which is superior in physical and mechanical properties as a restorative material. The aim of this study was to determined the effect of alcohol-containing mouthwash and alcohol-free mouthwash towards the surface hardness of hybrid composite restorative material. This study used 15 disc-shaped specimens of hybrid composite with the size of 6 mm diameter and 4 mm thickness and divided into three treatment groups immersion, in the alcohol-containing mouthwash (A), alcohol-free mouthwash (B), and artificial saliva (C) as control for 12 hours, which surface hardness was further tested using Vickers hardness test. The mean of hardness values of group: A 24.9 VHN; B: 27.2 VHN; and C: 28.4 VHN. The results of statistical tests One-Way ANOVA showed there were significant differences in the hardness values among the three treatment groups (p<0,05). From this study concluded that both alcohol-containing mouthwash and alcohol-free mouthwash were decreasing the surface hardness of hybrid composite restorative material.

Pullulan as a potent green inhibitor for corrosion mitigation of aluminum composite: Electrochemical and surface studies

This work emphasizes the corrosion inhibition ability of pullulan, an environmentally benign fungal polysaccharide on acid corrosion of 6061Aluminum-15%(v) SiC(P) composite material (Al-CM). The electrochemical measurements such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) studies were carried out for the corrosion inhibition studies. Conditions were optimized to obtain maximum inhibition efficiency, by performing the experiment at varying concentrations of inhibitor, in the temperature range of 308K- 323K. Surface morphology studies were done to reaffirm the adsorption of inhibitor on the surface of composite material. Pullulan acted as mixed type of inhibitor with a maximum efficiency of 89% at 303K for the addition of 1.0 gL−1 of inhibitor. Evaluation of kinetic and thermodynamic parameters revealed that inhibitor underwent physical adsorption onto the surface of Al-CM and obeyed Freundlich adsorption isotherm. The surface characterization like SEM-EDX, AFM confirmed the adsorption of pullulan molecule. Pullulan can be considered as effective, eco friendly green inhibitor for the corrosion control of Al-CM.

Achieving high quality surface of laminated glass-reinforced plastics during milling

Milling is one of the most common ways of workpiece machining, but obtaining a high quality surface of laminated composite materials is difficult due to their layered structure, high strength characteristics and low heat conductivity. This poses a problem of creating a milling technology that provides a high quality surface. This research investigates STEF -1 glass-fiber plastic with fine grain structure processed on the equipment with high cutting speed. The object of the research is roughness Ra as a quality criterion. Our glass-fiber plastic milling experiments demonstrate that the surface quality depends to a large extent on the cutting modes and the wear level of the tool cutting edge which is determined by the size of the wear bevel on the flank surface. The blade of the cutting tool is established to wear unevenly during glass-fiber plastic processing as it interacts with two different materials. We recommend the wear bevel on the flank surface to be less than 0.35 mm to ensure the high quality of the laminated composite material surface. The cutting modes should be within the following range: feed per tooth is 0.15 ÷ 0.17 mm/tooth, cutting depth is 0.5 ÷ 0.9 mm, cutting speed is above 45 m/s, with the cutting part of the tool being made of high-strength instrumental materials.

Surface Structure Analysis of Syntactic Metal Foams Machined by Milling

In the automotive and aerospace industries the engineers are encouraged to develop new materials, having special features mainly for the purposes of mass reduction, favourable (specifi) mechanical properties, appropriate strength, heat resistance, and environmental impacts, becoming even more critical technically. The matrix of the metal matrix composite, being the subject of our research, is an AlMgSi1 aluminum alloy: it contains 50-55 volume per cent of Al2O3 particles as reinforcement, having an average diameter of 100 - 150 μm. After machining, the surface of materials, having such large particles, is divided by open cavities, therefore other methods have to be used in order to describe and characterise the surface structure than in the case of steel or aluminum components, having a homogeneous structure. In our present article the aim is to analyse the microgeometrical properties of the surface of metal matrix composite materials, produced to the tests and machined with shoulder milling; furthermore, the measures, being able to evaluate the produced surface in an exact way, will be determined.

Investigation of the Process of Formation of Hafnium Carbide on Carbon-Carbon Composite Material in the System HfCl4–CH4–Ar

The first stage in the development of the technique for producing thin coatings of hafnium carbide on carbon-carbon composite material (CCCM) surfaces at relatively low synthesis temperatures for reducing the arising thermal stresses is presented. The process of formation of hafnium carbide on the surface of CCCM in the HfCl4–CH4–Ar system was investigated at 1050°C and atmospheric pressure. The rate of sublimation of hafnium (IV) chloride was studied at different flow rates of the carrier. Histograms showing the particle size distributions of hafnium carbide particles were constructed. A polydisperse distribution of particles on the surface of the CCCM was established with two maxima for the average diameters of 5.4 μm and 295 nm.

Surface modification and adhesion of wood-plastic composite (WPC) treated with UV/ozone

Because of the surfaces of wood-plastic composite (WPC) materials are enriched in polymers of low surface energy, they exhibit low adhesion properties. UV/ozone is proposed as surface treatment for increasing the surface energy and adhesion of WPC materials made with different polymers (polyethylene, polypropylene and polyvinyl chloride). UV lamp-WPC surface distance and time of UV exposure were varied for optimizing UV/ozone treatment of WPC, and UV dose used ranged between 2.02 × 10−14 and 5.05 × 10−12 J·s/m2. UV/ozone treatment created new carbon-oxygen polar groups in WPC surfaces and increased their surface energy, mainly their polar component. Furthermore, ablation of the outermost WPC surface was produced, more noticeably by reducing the distance between WPC surface and UV lamp and by increasing the duration of the treatment. Noticeable increase in 180° peel adhesion was obtained in the joints made with UV/ozone treated WPC at 10–30 mm distance during 1–5 min (i.e., UV dose between 5.61 × 10−14 and 2.53 × 10−12 J·s/m2). Although 180° peel strength of joints made with acrylic adhesive tape and UV/ozone treated WPC for 10 min and 10 mm distance (UV dose: 5.05 × 10−12 J·s/m2) was not increased because of dominant effect of ablation over creation of polar groups, the cross-hatch adhesion to different coatings was highly improved, irrespective of the polymer used and the wood content of WPC; however, the surface modifications and adhesion of UV/ozone treated WPC were more marked when its wood content was higher and by using UV dose between 0.10 × 10−12 and 2.53 × 10−12 J·s/m2.

Акустична емісія при зносі обробного інструменту з не керованою глибиною різання

Мета: Метою роботи є дослідження акустичної емісії при механічній обробці композиційного матеріалу з не керованою глибиною різання і зносі ріжучого інструменту з композиційного матеріалу. Методи дослідження: В основі досліджень лежить моделювання акустичного випромінювання, яку виникає при руйнуванні поверхневого прошарку оброблюваного композиційного матеріалу і зносі обробного інструменту. Розглядався випадок переважного механічного руйнування поверхневого прошарку оброблюваного композиційного матеріалу, а знос інструменту відбувається без зміни глибини різання. Була проведена статистична обробка амплітудних параметрів акустичної емісії при відсутності і виникненні зносу обробного композиційного матеріалу. Був проведений аналіз закономірностей зміни амплітудних параметрів акустичної емісії, а також їх чутливості до зносу обробного композиційного матеріалу при не керованій глибині механічної обробки. Результати: Визначено, що зростання зносу обробного композиційного матеріалу супроводжується зменшенням статистичних амплітудних параметрів акустичної емісії – середнього рівня амплітуди, його стандартного відхилення та дисперсії. Отримано закономірності зменшення амплітудних параметрів акустичної емісії при зростанні зносу обробного композиційного матеріалу. Визначено процентне зменшення амплітудних параметрів акустичної емісії при зростанні зносу обробного композиційного матеріалу, по відношенню до їх значень без зносу інструменту. Показано, що зменшення дисперсії середнього рівня амплітуди акустичної емісії випереджає зменшення середнього рівня амплітуди и його стандартного відхилення. Обговорення: Проведено моделювання акустичного випромінювання при переважному механічному руйнуванні поверхневого прошарку оброблюваного композиційного матеріалу з не керованою глибиною різання і зносі обробного композиційного матеріалу. Показано, що зростання зносу інструменту приводить до зменшення статистичних амплітудних параметрів акустичного випромінювання. Визначено, що зменшення дисперсії середнього рівня амплітуди сигналів акустичної емісії випереджає зменшення середнього рівня амплітуди і його стандартного відхилення. Зменшення середнього рівня амплітуди акустичного випромінювання і величини його розкиду обумовлено різним вкладом складових сигналів акустичної емісії, які виникають при руйнуванні оброблюваного і зносі обробного композиційних матеріалів. Очевидно, що при зменшенні площі руйнування оброблюваного композиційного матеріалу зменшення амплітудних параметрів виникаючих сигналів випереджає зростання амплітудних параметрів сигналів, які виникають при зростанні зносу обробного композиційного матеріалу. Результати проведених досліджень можуть бути використані при розробці методів контролю стану ріжучого інструменту і управлінні параметрами технологічного процесу механічної обробки. Дані методи представляють інтерес в роботизованих технологічних процесах, контроль і управління якими можливо проводити через нейронні мережі.

Original Research. Surface Roughness Changes of Different Restoration Materials after Tooth Brushing Simulation Using Different Toothpastes

Abstract Background: The need for the whitening effects of toothpastes became primary for most users. Changes in the surface roughness of restoration materials after tooth brushing are inevitable, and the abrasion is known to increase the possibility of dental plaque accumulation. Aim of the study: To evaluate in vitro surface roughness changes of different dental restorative materials after tooth brushing simulation. Material and methods: Fifty specimens of two composite materials (Evicrol, Super-Cor), two glass ionomer materials (Glassfill, Kavitan Cem) and a silicate cement (Fritex) were prepared according to the manufacturer’s instructions. Each group of specimens was divided in three subgroups for tooth brushing simulation: using two different types of toothpaste and without toothpaste. Before and after 153 hours of tooth brushing simulation with a custom-made device, the surface roughness was measured with a surface roughness tester. Statistical analysis was performed after collecting the data. Results: All materials exhibited changes in surface roughness after the use of both toothpastes. The self-curing composite showed the less change and glass ionomer materials showed the greatest changes in surface roughness. Conclusions: The surface changes of dental materials depended on their composition and the cleaning procedure. Although self-curing composite was the most resistant to surface changes, its surface roughness values were high. Light-curing composite presented the lowest surface roughness values, even after brushing with toothpastes. The “medium” labeled toothbrush caused significant changes without toothpaste on the surface of light-curing composite, glass ionomer and silicate cement materials.

The influence of zeolites fly ash bead/TiO2 composite material surface morphologies on their adsorption and photocatalytic performance

A low cost zeolite fly ash bead/TiO2 (ZFABT) composite materials with various surface structure features were prepared for describing those structures importance on TiO2 coating, adsorbability and photocatalytic performances. The results indicated that fly ash bead (FAB) surface was significantly altered by the precipitation/growth of secondary zeolite phases after alkali activation, which generates abundant open pores and stacked petal-liked spherical beads (∼2μm, Sodalite zeolites). More importantly, this porosity increases as activation time was increased from 2h to 12h, through the precipitation of sodalite and then Na-P1 (lamellar crystals) and Na-X (octahedral crystals) zeolite structures. Compared to those of unsupported TiO2 or inactivated support/TiO2 samples, all of ZFABT samples exhibited a higher adsorption capacity and photocatalytic efficiency for RhB removal. However, adsorption is not only one factor to influence TiO2 surface reaction, the intraparticle diffusion rate of rhodamine B (RhB) molecules, and light penetration are also important parameters. Alkali activated 4h ZFABT sample exhibited the highest photocatalytic activity, indicating its pore structure provided a better balance for those parameters to achieve a synergistic adsorption/photocatalytic process. The kinetics model suggested its high intraparticle diffusion rate allowed for more RhB molecules to easily reach the reaction surface, which is more important for high efficiency photocatalysis.

Evaluation of Mechanical and Erosive wear Characteristics of TiO2 and ZnO Filled Bi-Directional E-glass Fiber Based Vinyl Ester Composites

This article presents the evaluation of mechanical and erosive wear characteristics of bi-directional E-glass fiber based vinyl ester composites filled with TiO2 (titanium oxide) and ZnO (zinc oxide) of 10 wt.% and 20 wt.% respectively. The mechanical characterization of these composites is performed. The erosion rates of these composites have been evaluated at different impingement angles (30 ∘, 60 ∘ and 90 ∘). The particles used for the erosion measurements were silica sand with the diameters of 300, 425 and 600 μm and impact velocities of 30, 50 and 70 m/s were used. A plan of experiments, based on the Taguchi design, was performed to acquire data in a controlled way. An orthogonal array L27 (3 13) and Analysis of variance (ANOVA) have been applied to investigate the influence of process parameters on the erosive wear behaviour of these composites. The tensile strength of composite specimens is found to decrease with filler loading while hardness, flexural strength, inter-laminar shear strength (ILSS) and impact strength increase. TiO2 filled composites were observed to perform better than ZnO filled composites under erosive wear situations. The dominant wear mechanism is studied on the basis of micrographs of the worn-out surface of composite materials. Performance optimization of composites is done by using the VIKOR method.

Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material

In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity.

Adsorption isotherm and kinetics of paraquat removal using activated carbon/iron oxide composite material

A composite material between activated carbon (AC) and iron oxide in nanoscale was used to remove paraquat from contaminated water. The surface area of AC/iron oxide nanoparticles was in the range of 754.39 to 775.81 m²/g for the ratio 1:1 to 10:1 AC:iron oxide nanoparticles. The maximum adsorption capacity was found at pH 11. Adsorption of paraquat increases with increase in temperature indicating an endothermic process. Sorption behaviour of paraquat onto AC/iron oxide nanoparticles was evaluated using the Langmuir and Freundlich isotherm. The adsorption behaviour of paraquat was well described by Freundlich isotherm indicated that AC/iron oxide nanoparticles posed heterogeneous surface with heterolayer paraquat coverage on the surface of composite material. First and second order kinetic models were tested. The paraquat adsorption rate fits a pseudo-second-order kinetic model where the rate-limiting step is assumed to be chemical sorption between the adsorbate and adsorbent. The AC/iron oxide nanoparticles can readily be separated from the solution using a permanent magnet.

Composite Material Surface Analysis based Image Texture Analysis

Now a days surface analysis have many application in various knowledge fields and one of the important field is material surface analysis. This approach is concentrated on the image enhancement to arise and detect small obstacles during the surface. This approach allows individual features and details of the specimen to become visible In addition many statistical measures are applied to evaluate this performance of this approach. In the obtained measures, the signal-to-noise ratio must be large enough to be interpreted in terms of the formation of a coherent image.

Core–nanoshell magnetic composite material for adsorption of Pb(II) in wastewater

The core–nanoshell magnetic composite material was synthesized to remove Pb(II) from wastewater by adsorption method. The sample was characterized by XRD, SEM, VSM and FTIR. The results show that the sample was prepared successfully. Batch experiments were carried out to investigate the parameters affecting the Pb(II) adsorption as well as adsorption kinetics. The optimum parameters for Pb(II) removal were found to be: pH 7, 80min, respectively. The removal rate reached about 99.7%. The kinetic data were found to follow the pseudo-second-order model closely, revealing chemisorption as the dominant mechanism. The results of FTIR characterization revealed that the adsorption mechanism might be the reactions of ion exchange or complexation between the Pb(II) and some functional groups on the core–nanoshell magnetic composite material surface, and the adsorption is a both physical and chemical process.

Surface Resistance of Jute Fibre/Polylactic Acid Biocomposite to Wet Heat

Jute fibre/polylactic acid (PLA) composite is of special interest because both resin and reinforcement come from renewable resources. Thus, it could be a more eco-friendly alternative to glass fibre composite [1] and to conventional wood-based panels made with phenol–formaldehyde resin which present many drawbacks for the workers and the environment [2]. Yet the water affinity of the natural fibres, the susceptibility of PLA towards hydrolysis and the low glass transition of the PLA raise a question about the surface resistance of such composites to wet heat in service condition for a furniture application [3]. In this work, the surface resistance of PLA/jute composite alone and with two different varnishes are investigated in regard to an interior application following the standard test method in accordance to BS EN 18721:2009: “Furniture: assessment of surface resistance to wet heat”. It is compared to two common wood based panels, plywood and hardboard. After test, the composite material surface is found to be more affected than plywood and hardboard, but it becomes resistant to wet heat when a layer of biosourced varnish or petrol-based polyurethane varnish are applied on the surface.

Volume Resistivity and Mechanical Behavior of Epoxy Nanocomposite Materials

Electrical and mechanical properties of polymer composite materials are investigated through the determination of resistivity and hardness for composites samples. Epoxy composite samples have been prepared with different concentrations of certain inorganic fillers such as; Titanium dioxide (TiO2) and Silica (SiO2), of various size (micro, nano and hybrid) to study the electrical and mechanical behavior. The volume resistivity reaches 3.23×1014 ohm.cm for the micro silica composite. Surface of composite material has been mechanically examined by hardness test. The results show that the resistivity of microcomposites and nanocmposites are increased with the decrease of filler concentration. But the resistivity of hybrid composites is increased with the increase of filler concentration. Maximum hardness value was obtained from hybrid silica composite with 0.1% filler concentration.

Polymeric Graphitic Carbon Nitride Doped with CuO Dispersed on Dealuminated Clinoptilolite (CuO/HCP): Synthesis and Characterisation

CuO dispersed on dealuminated clinoptilolite (CuO/HCP) and further doped with polymeric graphitic carbon nitride (CuO/HCP‐g‐C3N4) was synthesized through 2 facile routes: precipitation method for CuO/HCP and impregnation through ultrasonication method for the hybrid composite material. The hybrid composite material crystalline phase, surface morphology, and structural and thermal properties were investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and thermal analysis. The formation of the hybrid composite material was confirmed by XRD showing crystalline phase of CuO and g‐C3N4 present on the surface of dealuminated clinoptilolite (HCP). SEM images analysis depicts no aggregation of the mixed metal oxide semiconductor nanoparticles at the center of HCP. The hybrid composite material, CuO/HCP‐g‐C3N4, with a good homogeneously dispersed metal oxide conductor having excellent catalytic activities has been synthesized.