Microcrystal structure evolution of mesophase pitch-based carbon fibers with enhanced oxidation resistance and tensile strength induced by boron doping

2019 ◽  
Vol 45 (9) ◽  
pp. 11734-11738 ◽  
Author(s):  
Xiaoling Zhai ◽  
Junqing Liu ◽  
Yuxia Zhang ◽  
Qinna Fan ◽  
Zhanhua Li ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Oxidation Resistance ◽  
Carbon Fibers ◽  
Boron Doping ◽  
Structure Evolution ◽  
Mesophase Pitch ◽  
Enhanced Oxidation

scholarly journals Mesophase Pitch-Based Carbon Fibers: Accelerated Stabilization of Pitch Fibers under Effective Plasma Irradiation-Assisted Modification

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6382
Author(s):  
Yuanshuo Peng ◽  
Ruixuan Tan ◽  
Yue Liu ◽  
Jianxiao Yang ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Heating Rate ◽  
Carbon Fibers ◽  
High Performance ◽  
Low Cost ◽  
Tensile Modulus ◽  
Mesophase Pitch ◽  
Stabilization Time ◽  
Plasma Irradiation

Stabilization is the most complicated and time-consuming step in the manufacture of carbon fibers (CFs), which is important to prepare CFs with high performance. Accelerated stabilization was successfully demonstrated under effective plasma irradiation-assisted modification (PIM) of mesophase pitch fibers (PFs). The results showed that the PIM treatment could obviously introduce more oxygen-containing groups into PFs, which was remarkably efficient in shortening the stabilization time of PFs with a faster stabilization heating rate, as well as in preparing the corresponding CFs with higher performance. The obtained graphitized fiber (GF-5) from the PF-5 under PIM treatment of 5 min presented a higher tensile strength of 2.21 GPa, a higher tensile modulus of 502 GPa, and a higher thermal conductivity of 920 W/m·K compared to other GFs. Therefore, the accelerated stabilization of PFs by PIM treatment is an efficient strategy for developing low-cost pitch-based CFs with high performance.

scholarly journals Carbon Fiber Composite Molecular Sieves for Gas Separation

1994 ◽  
Vol 344 ◽  
Author(s):  
M. Jagtoyen ◽  
F. Derbyshire ◽  
N. Brubaker ◽  
Y. Q. Fel ◽  
G. Kimber ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Carbon Fibers ◽  
Molecular Sieves ◽  
High Performance ◽  
Fiber Composite ◽  
High Strength ◽  
Mesophase Pitch ◽  
High Concentration ◽  
Carbon Fiber Composite ◽  
Temperature Oxidation

IntroductionCarbon fibers are produced commercially from rayon, phenolics, polyacrylonitrile (PAN), or pitch. The last are further divided into fibers produced from isotropic pitch precursors, and those derived from pitch that has been pretreated to introduce a high concentration of carbonaceous mesophase. Over the past few decades, interest in research and manufacturing carbon fibers has overwhelmingly centered on producing fibers with high tensile strength and high modulus for lightweight, high performance composites, where polymers, metals, and carbon can form the continuous matrix. The fibers most commonly used in advanced materials are produced from PAN or mesophase pitch. Graphitized mesophase pitch fibers tend to have higher modulus and lower tensile strength than the PAN-based equivalents. They have advantages in applications requiring high stiffness, high electrical and thermal conductivity, low thermal expansion, and high temperature oxidation resistance, while PAN fibers are employed where high strength is required.

scholarly journals Preparation of MCrAlY–Al2O3 Composite Coatings with Enhanced Oxidation Resistance through a Novel Powder Manufacturing Process

2019 ◽  
Vol 28 (3) ◽  
pp. 433-443 ◽  
Author(s):  
Mingwen Bai ◽  
Bo Song ◽  
Liam Reddy ◽  
Tanvir Hussain
Keyword(s):  
Oxidation Resistance ◽  
Manufacturing Process ◽  
Composite Powder ◽  
Composite Coatings ◽  
Submicron Particles ◽  
Second Phase ◽  
Mcraly Coatings ◽  
Powder Feedstock ◽  
Enhanced Oxidation ◽  
Powder Manufacturing

Abstract MCrAlY–Al2O3 composite coatings were prepared by high-velocity oxygen fuel thermal spraying with bespoke composite powder feedstock for high-temperature applications. Powder processing via a suspension route was employed to achieve a fine dispersion of α-Al2O3 submicron particles on the MCrAlY powder surface. This was, however, compromised by ~ 50% less flowability of the feedstock during spraying. Nevertheless, the novel powder manufacturing process introduced in this study has shown potential as an alternative route to prepare tailored composite powder feedstock for the production of metal matrix composites. In addition, the newly developed MCrAlY–Al2O3 composite coatings exhibited superior oxidation resistance, compared to conventional MCrAlY coatings, with the formation of nearly exclusively Al2O3 scale after isothermal oxidation at 900 °C for 10 h. The addition of α-Al2O3 particles in the MCrAlY coatings as a second phase was found to have promoted the formation of YAG oxides (YxAlyOz) during spraying and also accelerated the outwards diffusion of Al, which resulted in enhanced oxidation resistance.

scholarly journals Absorption and Strength Properties of Short Carbon Fiber Reinforced Mortar Composite

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 300
Author(s):  
Md. Safiuddin ◽  
George Abdel-Sayed ◽  
Nataliya Hearn
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Water Absorption ◽  
Carbon Fibers ◽  
Strength Properties ◽  
Fiber Content ◽  
Test Results ◽  
Air Content ◽  
Entrapped Air ◽  
Short Carbon

This paper presents the water absorption and strength properties of short carbon fiber reinforced mortar (CFRM) composite. Four CFRM composites with 1%, 2%, 3%, and 4% short pitch-based carbon fibers were produced in this study. Normal Portland cement mortar (NCPM) was also prepared for use as the control mortar. The freshly mixed mortar composites were tested for workability, wet density, and entrapped air content. In addition, the hardened mortar composites were examined for compressive strength, splitting tensile strength, flexural strength, and water absorption at the ages of 7 and 28 days. The effects of different carbon fiber contents on the tested properties were observed. Test results showed that the incorporation of carbon fibers decreased the workability and wet density, but increased the entrapped air content in mortar composite. Most interestingly, the compressive strength of CFRM composite increased up to 3% carbon fiber content and then it declined significantly for 4% fiber content, depending on the workability and compaction of the mortar. In contrast, the splitting tensile strength and flexural strength of the CFRM composite increased for all fiber contents due to the greater cracking resistance and improved bond strength of the carbon fibers in the mortar. The presence of short pitch-based carbon fibers significantly strengthened the mortar by bridging the microcracks, resisting the propagation of these minute cracks, and impeding the growth of macrocracks. Furthermore, the water absorption of CFRM composite decreased up to 3% carbon fiber content and then it increased substantially for 4% fiber content, depending on the entrapped air content of the mortar. The overall test results suggest that the mortar with 3% carbon fibers is the optimum CFRM composite based on the tested properties.

scholarly journals Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Low Cost ◽  
Deposition Process ◽  
Processing Parameters ◽  
Yarn Diameter ◽  
Thermoplastic Matrix ◽  
Anisotropic Mechanical Properties ◽  
Long Carbon Fiber

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

Core structure of vapor grown carbon fibers and morphology dependence of tensile strength

Carbon ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 343-349 ◽  
Author(s):  
T Hashishin ◽  
H Iwanaga ◽  
M Ichihara ◽  
S.R Mukai
Keyword(s):  
Tensile Strength ◽  
Carbon Fibers ◽  
Core Structure

Using Embossing to Create a Fiber Reinforced Honeycomb Composite

2005 ◽  
Vol 127 (2) ◽  
pp. 257-262 ◽  
Author(s):  
William Jordan
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Carbon Fibers ◽  
Flexural Modulus ◽  
Testing Machine ◽  
Charpy Impact ◽  
Tensile Tests ◽  
Hydraulic Testing ◽  
Charpy Impact Toughness ◽  
Bend Tests

This research project used hot embossing to create a strong and tough polymeric based composite structure. A honeycomb type structure was created by pressing small grooves into thin polycarbonate sheets. A trapezoidal die was used to create hexagonal shaped channels in the polymeric sheet. A number of these sheets were then bonded together to form a composite material. Carbon fibers were embedded into the channels in some of the laminates. The embossing process was carried out at an elevated temperature in an environmental chamber attached to an MTS servo hydraulic testing machine. The grooved structure had a 31% to 45% decrease in the apparent density compared to the ungrooved specimens. Bend tests, tensile tests, and Charpy impact tests were performed on laminates made from this material. The specific values of tensile strength, flexural modulus, and Charpy impact toughness were increased. A small percentage of fibers significantly increased both the stiffness and strength of the laminate.

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