Changes in Flexural Strength and Electrical Resistivity of Bulk Graphite According to the Viscosity of Impregnant

2021 ◽  
Vol 31 (2) ◽  
pp. 108-114
Author(s):  
Sang-Min Lee ◽  
◽  
Sang-Hye Lee ◽  
Jae-Seung Roh
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Bulk Graphite

Effect of micro silica on fiber-reinforced self-compacting composites containing ceramic waste

2020 ◽  
Vol 55 (1) ◽  
pp. 95-107
Author(s):  
Alireza Mansoori ◽  
Mohammad Mohtasham Moein ◽  
Ehsan Mohseni
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Drying Shrinkage ◽  
Silica Particles ◽  
Ceramic Waste ◽  
Funnel Flow ◽  
Micro Silica ◽  
The Impact

This paper aims to evaluate the impact of ceramic waste powder (CWP), micro silica (MS) and steel fiber (SF) on self-compacting mortar. CWP at ratios of 10 and 20%, and MS at 1 and 5% by weight of cement were replaced the cement. Beside, SF was added at ratios of 0.5 and 1% of cement. Mini slump flow diameter and mini V-funnel flow time tests were carried out to determine the workability of fresh composites. Compressive strength, flexural strength, water absorption, electrical resistivity and drying shrinkage tests were performed on hardened mortars. Scanning electron microscope (SEM) technique was employed to assess the microstructure. The results indicated that CWP reduced the mechanical properties by about 20% and increased permeability by about 14%. However, inclusion of micro silica particles improved the properties outstandingly. Compressive strength increased about 30% by inclusion of MS. It was also observed that the addition of fibers from 0.5% to 1% increased the flexural strength. This improvement was more obvious in samples with higher contents of micro silica. It can be reported that by including the both micro silica and steel fibers, the bonding between the cement paste and fibers was developed. Replacement of micro silica led to increase of electrical resistivity by about 99% in samples containing 20% ceramic waste powder. The microstructure studies confirmed the significant increase of density and uniformity of the hydration products in the presence of micro silica particles.

Characterization of exfoliated graphite nanoplatelets/polycarbonate composites: electrical and thermal conductivity, and tensile, flexural, and rheological properties

2011 ◽  
Vol 46 (9) ◽  
pp. 1029-1039 ◽  
Author(s):  
Julia A King ◽  
Michael D Via ◽  
Faith A Morrison ◽  
Kyle R Wiese ◽  
Edsel A Beach ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
Ultimate Tensile Strength ◽  
Flexural Strength ◽  
Rheological Properties ◽  
Flexural Modulus ◽  
Exfoliated Graphite ◽  
Graphite Nanoplatelets ◽  
Exfoliated Graphite Nanoplatelets

Exfoliated graphite nanoplatelets (GNP) can be added polymers to produce electrically conductive composites. In this study, varying amounts (2–15 wt%) GNP were added to polycarbonate (PC) and the resulting composites were tested for electrical conductivity (1/electrical resistivity), thermal conductivity, and tensile, flexural, and rheological properties. The percolation threshold was approximately 4.0 vol% (6.5 wt%) GNP. The addition of GNP to polycarbonate increased the composite electrical and thermal conductivity and tensile and flexural modulus. The 8 wt% (5.0 vol%) GNP in polycarbonate composite had a good combination of properties for electrostatic dissipative applications. The electrical resistivity and thermal conductivity were 4.0 × 107 ohm-cm and 0.37 W/m · K, respectively. The tensile modulus, ultimate tensile strength, and strain at ultimate tensile strength were 3.5 GPa, 58 MPa, and 3.5%, respectively. The flexural modulus, ultimate flexural strength, and strain at ultimate flexural strength were 3.6 GPa, 108 MPa, and 5.5%, respectively. Ductile tensile behavior is noted in pure polycarbonate and in samples containing up to 8 wt% GNP. PC and GNP/PC composites show shear-thinning behavior. Viscosity of the composite increased as the amount of GNP increased dueto a volume-filling filler effect. The viscosity of the GNP/PC composites are well described by a Kitano-modified Maron-Pierce model.

The Study of Volume Electrical Resistivity and Mechanical Property of Double Continuous Phase PVDF/CBT Composite Containing Carbon Black and Graphite

2013 ◽  
Vol 838-841 ◽  
pp. 107-110 ◽  
Author(s):  
Jian Bin Song ◽  
Yu Mei Zhong ◽  
Song Yue Lin ◽  
Lin Sheng Lan ◽  
Wen Bin Yang
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Carbon Black ◽  
Vinylidene Fluoride ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Continuous Phase ◽  
Graphite Content ◽  
Poly Vinylidene Fluoride ◽  
Material Testing Machine

The Poly(vinylidene fluoride)(PVDF)/Cyclic Butylene Terephthalate (CBT)/carbon black (CB)/graphite (GR) composites were prepared by melting blend method and were studied by milliohmmeter and material testing machine. The results showed that due to the formation of CB and GR conductive network, the volume electrical resistivity of PVDF/CBT/CB/GR composites linearly decreased as graphite content increased at below 4 wt% of graphite, but it in turn increased when graphite content was higher than 4 wt%. Flexural strength showed an increase at below 1.6 wt% of GR and gradually decreased as GR content increased further. Differently, flexural modulus of composites declined as GR content increased. In all composites, the flexural strength was more than 25 MPa, which satisfied with the requirements of bipolar plates.

Pressureless Sintering and Properties of Cu/Ti3AlC2 Composites

2008 ◽  
Vol 368-372 ◽  
pp. 998-1000 ◽  
Author(s):  
Zhen Ying Huang ◽  
Hong Xiang Zhai ◽  
Ming Xing Ai ◽  
Yi Wang ◽  
Hong Bing Zhang
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Vickers Hardness ◽  
Layered Structure ◽  
Volume Content ◽  
Al Alloy ◽  
Pressureless Sintering ◽  
Copper Powders ◽  
Interface Bond

The Cu/Ti3AlC2 composites were fabricated by pressureless sintering a mixture of Ti3AlC2 and copper powders. Their microstructures and properties were investigated. It was found that the molten Cu accelerating the decomposition of Ti3AlC2, inducing the interfacial exfoliation to generate, and forming a sub-micro-layered structure making up of TiCx layers and Cu-Al alloy layers within a Ti3AlC2 grain. The flexural strength of the composites is reduced with the increase of the volume content of Ti3AlC2 from 50 % to 90 %. The highest flexural strength reaches to as high as 915 MPa. The fracture mode was changed from ductile to brittle with increase in the content of Ti3AlC2. The higher flexural strength can be attributed to a stronger interface bond between TiCx and Cu-Al phase. The electrical resistivity and Vickers hardness of the composites were also measured.

Factors inducing degradation of properties after long-term oxidation of Si3N4–MoSi2 electroconductive composites

2004 ◽  
Vol 19 (5) ◽  
pp. 1567-1574 ◽  
Author(s):  
V. Medri ◽  
A. Bellosi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Flexural Strength ◽  
Room Temperature ◽  
Material Surface ◽  
Oxide Scales ◽  
Silicate Phase ◽  
Degradation Of Properties ◽  
Glassy Silicate

The effects of heat treatments on strength and electrical conductivity after 100 h in air up to 1500 °C were evaluated on hot-pressed Si3N4–35 vol% MoSi2 composite. The long-term oxidation involves microstructural changes at the material surface and subsurface, such as the formation of oxide scales and of a multilayered microstructure. At T ⩾ 1200 °C, a glassy silicate phase is formed, which embeds cristobalite grains and highly textured Y2Si2O7 crystals. At the same time, MoSi2, assisted by oxygen, reacts with Si3N4 forming Mo5Si3, Si2N2O, and SiO2. The decrease of the room temperature flexural strength reached about 25% in the samples exposed at 1000 °C for 100 h, compared to the as-produced materials. On the contrary, after treatments at higher temperatures, the strength decrease is lower at 1500 °C, the residual strength is 836 ± 62 MPa with a strength decrease of about 8%. The surface oxide scale is an insulator and, consequently, the electrical resistivity of the composite rises from 10-3 to 107–109 Ωcm.

The Influence of Cu on the Electrical Properties of Ti(C, N)-Based Cermets

2011 ◽  
Vol 399-401 ◽  
pp. 792-795
Author(s):  
Li Juan Pang ◽  
Gang Deng ◽  
Xue Feng Zhang ◽  
Hui Rong Li ◽  
Min Xian Fang ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Powder Metallurgy ◽  
Electrical Properties ◽  
Flexural Strength ◽  
Wetting Angle ◽  
Vacuum Condition ◽  
Powder Metallurgy Method

Cermets Ti(C，N)80%Co(10-x)% TiC10% Cux%(wt%，x=0，1，2，3， 4， 5) were prepared by powder metallurgy method under vacuum condition at 1500°C and the effects of Cu element to the electrical resistivity and flexural strength were studied in this paper. It turns out the electrical resistivity of the samples obviously decreases with the introduction of Cu element, but the electrical resistivity of the samples increases when the amount of Cu element in the samples becomes more. The flexural strengths of the samples decrease with the amount of Cu element increasing. Ti（C，N）80% Co9%TiC10% Cu1% shows the lowest electrical resistivity and the biggest flexural strength, 7.35*10-7Ω•m and 50.6Mpa. This may be due to the big wetting angle between Cu and the powders of the based body. With the amount of Cu element increasing, the obvious interfaces are made thus the electrical resistivity becomes bigger.

The Study of Volume Electrical Resistivity and Mechanical Property of CBT/Carbon Black/Aluminum Composites

2013 ◽  
Vol 838-841 ◽  
pp. 115-118
Author(s):  
Jian Bin Song ◽  
Yu Mei Zhong ◽  
Lin Sheng Lan ◽  
Song Yue Lin ◽  
Wen Bin Yang
Keyword(s):  
Mechanical Property ◽  
Electrical Resistivity ◽  
Flexural Strength ◽  
Carbon Black ◽  
Testing Machine ◽  
Material Testing ◽  
Aluminum Composites ◽  
Al Content ◽  
Maximum Value ◽  
Material Testing Machine

Cyclic Butylene Terephthalate (CBT)/carbon black (CB)/aluminum composites were prepared by melting blend method and their conductivity and mechanical property were studied by Milliohmmeter and material testing machine. The results showed that at below 1.6 wt% of flake aluminum（Al）, volume electrical resistivity and flexural strength of composites increased with Al content increases and reached the maximum value at 1.6 wt% of Al. Composites containing 18.4 wt% of CB and 1.6 wt% of aluminum exhibited excellent comprehensive performance (electrical resistivity, 20.3 Ω.cm; flexural strength, 40.0 MPa).

Electrical Resistivity and Flexural Strength of Plastic Composites Reinforced with Pineapple Leaf Particles

2011 ◽  
Vol 8 (2) ◽  
pp. 1
Author(s):  
Masitah Abu Kassim ◽  
Shahril Anuar Bahari ◽  
Mohd Khairi Yahya ◽  
Khairul Safuan Muhammad ◽  
Rahimi Baharom
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Electrical Resistance ◽  
Physical Contact ◽  
Matrix Stiffness ◽  
Plastic Composites ◽  
Particle Ratios ◽  
Plastic Materials ◽  
The Matrix ◽  
Plastic Matrix

The electrical resistivity and flexural strength of plastic composites reinforced with pineapple leaf particles (PCPLP) is presented. PCPLP were produced using different plastic materials; Polyethylene (PE) and Polypropylene (PP), and different plastic-pineapple leaf particle ratios; 50:50 and 70:30. The PCPLP were tested and evaluated with respect to electrical resistivity and flexural strength according to ASTM D257 and D790, respectively. The results indicate that PCPLP made from PP exhibits better electrical resistance than PE, which may be attributed to the better frequency insulation behaviour of PP. PCPLP using the higher ratio of 70:30 also exhibited better electrical resistance than the lower 50:50 ratio. Cellulose materials inherently influence the electrical resistance of plastic composites, due to their natural propensity to absorb moisture. The PCPLP produced using a ratio of 50:50 for both PP and PE composites exhibited better MOE results than the 70:30 composites, however the converse is true with respect to the MOR. MOE of PCPLP was increased with increasing pineapple leaf particles content due to the greater matrix stiffness of this natural particle with respect to plastic matrix. However, high percentage of filler particles in the matrix (70:30 ratio) has reduced the toughness in the composite structure due to the lost of physical contact between high accumulated particles.

scholarly journals Enhanced Surface Energetics of CNT-Grafted Carbon Fibers for Superior Electrical and Mechanical Properties in CFRPs

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1432
Author(s):  
Arash Badakhsh ◽  
Kay-Hyeok An ◽  
Byung-Joo Kim
Keyword(s):  
Electrical Resistivity ◽  
Flexural Strength ◽  
Epoxy Resin ◽  
Weight Ratio ◽  
Chemical Vapor ◽  
Work Of Adhesion ◽  
Ductility Index ◽  
Reinforced Plastic ◽  
Surface Energetics ◽  
Growth Formation

Surface enhancement of components is vital for achieving superior properties in a composite system. In this study, carbon nanotubes (CNTs) were grown on carbon fiber (CF) substrates to improve the surface area and, in turn, increase the adhesion between epoxy-resin and CFs. Nickel (Ni) was used as the catalyst in CNT growth, and was coated on CF sheets via the electroplating method. Surface energetics of CNT-grown CFs and their work of adhesion with epoxy resin were measured. SEM and TEM were used to analyze the morphology of the samples. After the optimization of surface energetics by catalyst weight ratio (15 wt.% Ni), CF-reinforced plastic (CFRP) samples were prepared using the hand lay-up method. To validate the effect of chemical vapor deposition (CVD)-grown CNTs on CFRP properties, samples were also prepared where CNT powder was added to epoxy prior to reinforcement with Ni-coated CFs. CFRP specimens were tested to determine their electrical resistivity, flexural strength, and ductility index. The electrical resistivity of CNT-grown CFRP was found to be about 9 and 2.3 times lower than those of as-received CFRP and CNT-added Ni-CFRP, respectively. Flexural strength of CNT-grown Ni-CFRP was enhanced by 52.9% of that of as-received CFRP. Interestingly, the ductility index in CNT-grown Ni-CFRP was 40% lower than that of CNT-added Ni-CFRP. This was attributed to the tip-growth formation of CNTs and the breakage of Ni coating.

Sign in / Sign up

Export Citation Format

Share Document