The Effect of Various Reinforcements on the Ablation, Thermal and Microstructural Properties of Phenolic Matrix Composites

The ablation properties, thermal resistance and micro structural behavior of the phenolic resin (Resole) composites have been investigated in this research. Different materials, such as carbon fabrics, glass fabrics, also silica and zirconia powders have been used as reinforcements for synthesis of the composites. The specimens were prepared with three sets of compositions. The first set was produced with 37.5 wt% of Resole and 62.5 wt% of reinforcements. Another set of specimens were produced with 40wt% Resole, 40 wt% of silica and 20 wt% of zirconia. Also to achieve high insulation index in Resole/carbon fabrics composites a thin film of zirconia coated at the back side of the specimens. To explore the ablation characteristics of the composites in terms of insulation index, erosion rate and microscopic pattern of ablation, an oxyacetylene torch flame with heat flux of 10 Mw/m2 at approximately 2800°C was used. The ablation behavior and microstructure of the burnt-through specimens were also observed, using scanning electron microscopy. It was found from ablation test that the erosion rates of the Resole/carbon fabric specimens are 20% lower than the other specimens. Additionally the high insulation index of the Resole/carbon fabrics coated with zirconia indicates that these composites are the best ablative materials in the present study. It has been also reported that those specimens filled with zirconia have the highest insulation index. Although the erosion rate of the Resole/silica composites were 20% higher than the Resole/glass fabrics, but a 5mm depth hole (from 10 mm thickness of the whole specimen) was seen at the center of the Resole/glass Fabric specimens. SEM observations show that proper adhesion between reinforcements and matrix is important to achieve improved ablative properties, it was also reported many changes in diameter, shape and the surface of the carbon fibers through the ablated area. These changes can be reduced from surface to back side of the specimens.

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Study of the ablative properties of phenolic/carbon composites modified with mesoporous silica particles

Journal of Composite Materials ◽

10.1177/0021998318776716 ◽

2018 ◽

Vol 52 (30) ◽

pp. 4139-4150 ◽

Cited By ~ 1

Author(s):

L Asaro ◽

LB Manfredi ◽

ES Rodríguez

Keyword(s):

Carbon Black ◽

Mesoporous Silica ◽

Carbon Fibers ◽

Erosion Rate ◽

Phenolic Resin ◽

Dynamic Mechanical Properties ◽

Silica Particles ◽

Carbon Composites ◽

Modified Polymer ◽

Mass Erosion

Mesoporous silica particles and carbon black were selected as fillers for a resol-type phenolic resin, to be used as a matrix for ablative materials. Composites were processed with the modified polymer and carbon fibers were used as continuous reinforcement. The ablative properties of the materials obtained were studied by the oxyacetylene torch test and the ablated samples were observed by scanning electron microscopy. Composites with 30 wt. % of carbon black achieved the lowest linear erosion rate and the highest insulation index, denoting the ability of the char produced to protect the virgin material. Considering that such composite has 44% by volume of carbon fibers, it could be inferred that its properties could be improved by increasing the fiber content and maintaining the amount of carbon black. The composite with 20 wt. % of mesoporous silica particles exhibited the lowest mass erosion rate, indicating a better stabilization of the char. Regarding dynamic-mechanical properties, the addition of particles induced a decrease in the modulus and glass transition temperature of all the systems studied.

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ZrO2f-coated Cf hybrid fibrous reinforcements and properties of their reinforced ceramicizable phenolic resin matrix composites

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2020.08.034 ◽

2021 ◽

Vol 41 (3) ◽

pp. 1810-1816

Author(s):

Zhenyue Zou ◽

Yan Qin ◽

Huadong Fu ◽

Di Zhu ◽

Zhuangzhuang Li ◽

...

Keyword(s):

Phenolic Resin ◽

Resin Matrix ◽

Matrix Composites

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Characterization of the Structure, Mechanical Properties and Erosive Resistance of the Laser Cladded Inconel 625-Based Coatings Reinforced by TiC Particles

Materials ◽

10.3390/ma14092225 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2225

Author(s):

Aleksandra Kotarska ◽

Tomasz Poloczek ◽

Damian Janicki

Keyword(s):

Laser Cladding ◽

Inconel 625 ◽

Matrix Composites ◽

Erosion Rates ◽

Laser Cladding Process ◽

Composition Variation ◽

The Matrix ◽

Reinforcing Material ◽

Inconel 625 Superalloy

The article presents research in the field of laser cladding of metal-matrix composite (MMC) coatings. Nickel-based superalloys show attractive properties including high tensile strength, fatigue resistance, high-temperature corrosion resistance and toughness, which makes them widely used in the industry. Due to the insufficient wear resistance of nickel-based superalloys, many scientists are investigating the possibility of producing nickel-based superalloys matrix composites. For this study, the powder mixtures of Inconel 625 superalloy with 10, 20 and 40 vol.% of TiC particles were used to produce MMC coatings by laser cladding. The titanium carbides were chosen as reinforcing material due to high thermal stability and hardness. The multi-run coatings were tested using penetrant testing, macroscopic and microscopic observations, microhardness measurements and solid particle erosive test according to ASTM G76-04 standard. The TiC particles partially dissolved in the structure during the laser cladding process, which resulted in titanium and carbon enrichment of the matrix and the occurrence of precipitates formation in the structure. The process parameters and coatings chemical composition variation had an influence on coatings average hardness and erosion rates.

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Experimental study on the behavior of carbon-fabric reinforced cementitious matrix composites in impressed current cathodic protection

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.120655 ◽

2020 ◽

Vol 264 ◽

pp. 120655

Author(s):

Ran Feng ◽

Jingzhou Zhang ◽

Ji-Hua Zhu ◽

Feng Xing

Keyword(s):

Experimental Study ◽

Cathodic Protection ◽

Matrix Composites ◽

Carbon Fabric ◽

Cementitious Matrix ◽

Impressed Current ◽

Fabric Reinforced Cementitious Matrix ◽

Impressed Current Cathodic Protection

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Cumulative acoustic emission energy for damage detection in composites reinforced by carbon fibers within low-cycle fatigue regime at various displacement amplitudes and rates

Polymers and Polymer Composites ◽

10.1177/0967391120985709 ◽

2021 ◽

pp. 096739112098570

Author(s):

Mohammad Azadi ◽

Mohsen Alizadeh ◽

Seyed Mohammad Jafari ◽

Amin Farrokhabadi

Keyword(s):

Acoustic Emission ◽

Carbon Fibers ◽

Polymer Matrix Composites ◽

Low Cycle Fatigue ◽

Energy Parameter ◽

Fatigue Tests ◽

Matrix Cracking ◽

Matrix Composites ◽

Cycle Fatigue ◽

Cumulative Energy

In the present article, acoustic emission signals were utilized to predict the damage in polymer matrix composites, reinforced by carbon fibers, in the low-cycle fatigue regime. Displacement-controlled fatigue tests were performed on open-hole samples, under different conditions, at various displacement amplitudes of 5.5, 6.0, 6.5 and 7.0 mm and also under various displacement rates of 25, 50, 100 and 200 mm/min. After acquiring acoustic emission signals during cycles, two characteristic parameters were used, including the energy and the cumulative energy. Obtained results implied that the energy parameter of acoustic emission signals could be used only for the macroscopic damage, occurring at more than 65% of normalized fatigue cycles under different test conditions. However, the cumulative energy could properly predict both microscopic and macroscopic defects, at least two failure types, including matrix cracking at first cycles and the fiber breakage at last cycles. Besides, scanning electron microscopy images proved initially such claims under all loading conditions.

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Impacts of oak deforestation and rainfed cultivation on soil redistribution processes across hillslopes using 137Cs techniques

Forest Ecosystems ◽

10.1186/s40663-021-00311-1 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Shamsollah Ayoubi ◽

Nafiseh Sadeghi ◽

Farideh Abbaszadeh Afshar ◽

Mohammad Reza Abdi ◽

Mojtaba Zeraatpisheh ◽

...

Keyword(s):

Land Use ◽

Magnetic Susceptibility ◽

Soil Erosion ◽

Erosion Rate ◽

Land Use Changes ◽

Soil Samples ◽

Natural Forest ◽

Oak Forests ◽

Erosion Rates ◽

Rainfed Farming

Abstract Background As one of the main components of land-use change, deforestation is considered the greatest threat to global environmental diversity with possible irreversible environmental consequences. Specifically, one example could be the impacts of land-use changes from oak forests into agricultural ecosystems, which may have detrimental impacts on soil mobilization across hillslopes. However, to date, scarce studies are assessing these impacts at different slope positions and soil depths, shedding light on key geomorphological processes. Methods In this research, the Caesium-137 (137Cs) technique was applied to evaluate soil redistribution and soil erosion rates due to the effects of these above-mentioned land-use changes. To achieve this goal, we select a representative area in the Lordegan district, central Iran. 137Cs depth distribution profiles were established in four different hillslope positions after converting natural oak forests to rainfed farming. In each hillslope, soil samples from three depths (0–10, 10–20, and 20–50 cm) and in four different slope positions (summit, shoulder, backslope, and footslope) were taken in three transects of about 20 m away from each other. The activity of 137Cs was determined in all the soil samples (72 soil samples) by a gamma spectrometer. In addition, some physicochemical properties and the magnetic susceptibility (MS) of soil samples were measured. Results Erosion rates reached 51.1 t·ha− 1·yr− 1 in rainfed farming, whereas in the natural forest, the erosion rate was 9.3 t·ha− 1·yr− 1. Magnetic susceptibility was considerably lower in the cultivated land (χhf = 43.5 × 10− 8 m3·kg− 1) than in the natural forest (χhf = 55.1 × 10− 8 m3·kg− 1). The lower soil erosion rate in the natural forest land indicated significantly higher MS in all landform positions except at the summit one, compared to that in the rainfed farming land. The shoulder and summit positions were the most erodible hillslope positions in the natural forest and rainfed farming, respectively. Conclusions We concluded that land-use change and hillslope positions played a key role in eroding the surface soils in this area. Moreover, land management can influence soil erosion intensity and may both mitigate and amplify soil loss.

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Graphene oxide modified carbon fiber reinforced epoxy composites

Journal of Polymer Engineering ◽

10.1515/polyeng-2019-0247 ◽

2020 ◽

Vol 40 (5) ◽

pp. 415-420 ◽

Cited By ~ 1

Author(s):

Yasin Altin ◽

Hazal Yilmaz ◽

Omer Faruk Unsal ◽

Ayse Celik Bedeloglu

Keyword(s):

Graphene Oxide ◽

Carbon Fiber ◽

Carbon Fibers ◽

Spray Coating ◽

Sem Analysis ◽

Epoxy Composites ◽

Matrix Composites ◽

Fiber Reinforced ◽

Quick Method ◽

Carbon Fiber Reinforced

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.

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Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.706-708.95 ◽

2013 ◽

Vol 706-708 ◽

pp. 95-98

Author(s):

Mi Dan Li ◽

Dong Mei Liu ◽

Lu Lu Feng ◽

Huan Niu ◽

Yao Lu

Keyword(s):

Mechanical Properties ◽

Electrical Conductivity ◽

Flexural Strength ◽

Polymer Matrix ◽

Phenolic Resin ◽

Polymer Matrix Composites ◽

Resin Composites ◽

Matrix Composites ◽

Natural Graphite ◽

Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

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