Surface Treatment Of Carbon Fibers Research Articles

Effect of surface treatments of short carbon fibers on the properties of pitch-based C/C composites

C/C composites were fabricated in air using mold pressing and semi-carbonization shaping technology.The effects of surface treatment methods for short carbon fibers on the density and mechanical properties of the C/C composites were investigated by an electronic universal testing machine and a scanning electron microscope.Results showed that the compressive strength of the as-fabricated C/C composites increased with an enhancement in intensity of surface treatment for short carbon fibers.The compressive strength of the C/C compo～sites with surface-treated carbon fibers was increased by 138.5% compared with that of the C/C composites without surface treatment.

Effects of carbon fiber surface treatment on the tribological properties of 2D woven carbon fabric/polyimide composites

Effects of carbon fiber surface treatment on the tribological properties of 2D woven carbon fabric/polyimide composites

Effects of carbon fiber surface treatment on the tribological properties of 2D woven carbon fabric/polyimide composites

Polyacrylonitrile (PAN)-based carbon fabric (CF) was modified with strong HNO3 oxidation and then introduced into polyimide (PI) composites. The friction and wear properties of the carbon fabric reinforced polyimide composites (CFRP), sliding against GCr15 stainless steel rings, were investigated on an M-2000 model ring-on-block test rig under dry sliding. Experimental results revealed that the carbon fiber surface treatment largely reduced the friction and wear of the CFRP. Compared with the untreated ones, the surface-modified CF can enhance the tribological properties of CFRP efficiently due to the improved adhesion between the CF and the PI matrix. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) study of the carbon fiber surface showed that the fiber surface became rougher and the oxygen concentration increased greatly after surface treatment, which improved the adhesion between the fiber and the PI matrix and improved the friction-reduction and anti-wear properties of the CFRP.

The oxidation‐treated interface on tribological properties of carbon fibers‐reinforced PTFE composite under oil‐lubricated condition

AbstractThe effect of air oxidation and ozone surface treatment of carbon fibers (CF) on tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites under oil‐lubricated condition was investigated. Experimental results revealed that ozone treated CF reinforced PTFE (CF–PTFE) composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air‐oxidated composites. X‐ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that, after ozone treatment, oxygen concentration was obviously increased, and the amount of oxygen‐containing groups on CF surfaces was largely increased. The increase in the amount of oxygen‐containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with PTFE matrix and large scale rubbing‐off of PTFE was prevented, therefore, the tribological properties of the composite were improved. Copyright © 2009 John Wiley & Sons, Ltd.

Interfacial studies on the ozone and air‐oxidation‐modified carbon fiber reinforced PEEK composites

AbstractIn this work, ozone modification method and air‐oxidationwere used for the surface treatment of polyacrylonitrile(PAN)‐based carbon fiber. The surface characteristics of carbon fibers were characterized by XPS. The interfacial properties of carbon fiber‐reinforced (polyetheretherketone) PEEK (CF/PEEK) composites were investigated by means of the single fiber pull‐out tests. As a result, it was found that IFSS (interfacial shear strength) values of the composites with ozone‐treated carbon fiber are increased by 60% compared to that without treatment. XPS results show that ozone treatment increases the amount of carboxyl groups on carbon fiber surface, thus the interfacial adhesion between carbon fiber and PEEK matrix is effectively promoted. The effect of surface treatment of carbon fibers on the tribological properties of CF/PEEKcomposites was comparativelyinvestigated. Experimental results revealed that surface treatment can effectively improve the interfacial adhesion between carbon fiber and PEEK matrix. Thus the wear resistance was significantly improved. Copyright © 2009 John Wiley & Sons, Ltd.

Effects of carbon fiber surface treatment on the friction and wear behavior of 2D woven carbon fabric/phenolic composites

To improve the friction and wear behavior of carbon fabric reinforced polymer composites (CFRP), nano-SiO 2 was deposited on the fabric surface. The friction and wear behavior of the resulting composites were investigated on a model ring-on-block test rig. Experimental results revealed that fiber surface treatment contributed to largely improve the tribological properties of the CFRP composites. Scanning electron microscope (SEM) investigation showed that the worn surface of the surface modified CFRP composite was smoother under given load and sliding rate. Field emission scanning electron microscopy (FESEM), FTIR and X-ray photoelectron spectroscopy (XPS) studies of the carbon fiber surface showed that nanostructured Sio 2 thin film can be obtained by SiO 2 sols deposition, which improved the adhesion between the fiber and phenolic matrix and hence to improve the friction-reduction and anti-wear properties of the CFRP composite.

Air dielectric barrier discharges plasma surface treatment of three-dimensional braided carbon fiber reinforced epoxy composites

The deposition of coatings on the surface of three-dimensional braided carbon fiber reinforced epoxy (C 3D/EP) composites will be helpful to their applications. However, they are unsuitable to be deposited due to their low surface free energies, poor wettabilities and poor adhesions. Since treatment of polymers or composites by non-thermal plasmas is a fast, versatile and environmentally friendly surface modification technique, the plasma treatment of C 3D/EP composites is investigated in this paper. Dielectric barrier discharges (DBD) in ambient air are used. C 3D/EP ( V f = 36%) samples with thickness of 2 mm are placed into the plasma configuration. Time for plasma treatment is 30 s, 60 s and 120 s. The chemical and physical changes induced by the treatments on C 3D/EP surface are examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The water advancing contact angles of the plasma-treated C 3D/EP samples change from 98.6° for the untreated sample to the lower value 45.7° after plasma treatment of 30 s and 42.7° of 120 s. XPS results reveal that the composites modified with the DBD at an atmospheric pressure show a significant increase in oxygen-containing and nitrogen-containing groups, such as C–O, O–C=O and NO 2. The AFM images of the untreated and plasma-treated C 3D/EP samples show that the composites surfaces roughen. The roughness of the untreated C 3D/EP is 1.6 nm, while after plasma treatment of 30 s, 60 s and 120 s the values are 2.4 nm, 3.0 nm and 3.9 nm respectively. These results demonstrate that the surfaces of the C 3D/EP samples are more active, hydrophilic and rough after plasma treatments using a DBD operating in ambient air.

Effect of rare earths surface treatment on tribological properties of carbon fibers reinforced PTFE composite under oil-lubricated condition

The effect of rare earths (RE) surface treatment of carbon fibers (CF) on tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites under oil-lubricated condition was investigated. Experimental results revealed that RE treated CF reinforced PTFE (CF/PTFE) composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air-oxidated composites. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that, after RE treatment, oxygen concentration increased obviously, and the amount of oxygen-containing groups on CF surfaces were largely increased. The increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers; carbon fibers were strongly bonded with PTFE matrix, and large scale rubbing-off of PTFE be prevented, therefore, tribological properties of the composite was improved.

Effect of surface treatment on the tribological performance of carbon fiber reinforced thermoplastic polyimide composites

AbstractThe effect of rare earth solution (RES) surface treatment of carbon fibers (CFs) on the tensile strength and tribological properties of CF‐reinforced polyimide (CF/PI) composite was investigated. Experimental results revealed that the tensile strength of RES‐treated CFs reinforced PI composite was improved by about 19% compared with that of untreated composite, while 7% improvement was achieved by air oxidation. Compared with the untreated and air‐oxidated CF/PI composite, the RES‐treated composite had the lowest friction coefficient and specific wear rate under given applied load and reciprocating sliding frequency. RES treatment effectively improved the interfacial adhesion between CFs and PI. The strong interfacial adhesion of the composite made CFs not easy to detach from the PI matrix and prevented the rubbing‐off of PI, and accordingly improved the friction and wear properties of the composite. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Effect of carbon fiber surface treatments on the flexural strength and tribological properties of short carbon fiber/polyimide composites

AbstractPitch‐based short carbon fibers (CFs) were treated by air oxidation and cryogenic nitrogen, respectively. Thereafter the treated and untreated CFs were incorporated into polyimide (PI) matrix to form composites. The CFs before and after treatment were examined by XPS and SEM.The flexural strength of the specimen was determined in a three‐point test machine and the tribological properties of PI composites sliding against GCr15 steel rings were evaluated on an M‐2000 model ring‐on‐block test rig. The results show that the surface of the treated CFs became rougher. Lots of active groups formed on the CF surface after air oxidation.The treatment can effectively improve the mechanical and tribological properties in their PI composites due to the enhanced fiber‐matrix interfacial bonding. Copyright © 2008 John Wiley & Sons, Ltd.

Research on the Surface Treatment of Carbon Fibers Used in Fabrication of MMCs Wire

MMCs wire can be produced by infiltration of molten metal into carbon fiber bundles. To protect the fibers from damage, the desized fibers must be pretreated before fabrication into wire. This paper deals with the formation of SiO2 coating on the carbon fibers using plasma chemical method and compares the coating produced by plasma method with the one by sol-gel method. The SiO2 coating produced by the sol-gel method on the carbon fibers is very rough. It is also discovered that the quality of the SiO2 coating is controlled by the power of plasma equipment and the flow rate of plasma gases. As the power of the plasma equipment and the flow rate of plasma gases increased, the coating surface became smoother.

The effect of surface treatment of carbon fiber on the flexural property of thermoplastic polyimide composite

Rare earth solution (RES) surface modification and air-oxidation methods were used to improve the interfacial adhesion of the carbon fiber reinforced polyimide (CF/PI) composite. The flexural property of the PI composites reinforced by the carbon fibers treated with different surface modification methods was comparatively investigated. Results showed that the flexural strength of CF/PI composite was improved after RES treatment. The improvement of impact and flexural property of the CF/PI composite was mainly due to the improvement in interfacial adhesion after RES treatment. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the oxygen concentration was obviously increased after RES treatment. The increase in the amount of organic functional groups increased the interfacial adhesion between CF and PI matrix.

Friction and wear properties of surface-treated carbon fiber-reinforced thermoplastic polyimide composites under oil-lubricated condition

Carbon fibers (CF) were surface treated with air-oxidation and rare earth solution (RES), respectively. The friction and wear properties of the polyimide (PI) composites filled with differently surface-treated carbon fibers (20 vol.%), sliding against GCr15 steel under oil-lubricated condition, were investigated on a ball-on-block reciprocating UMT-2MT tribometer. Experimental results revealed that RES treatment largely reduced the friction and wear of CF reinforced PI (CF/PI) composites. Scanning electron microscope (SEM) investigation of worn surfaces of CF/PI composites showed that RES treated CF/PI composite had the strongest interfacial adhesion and the smoothest worn surface under given load and reciprocating sliding frequency. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the oxygen concentration was obviously increased after RES treatment. The increase in the amount of organic functional groups increased the interfacial adhesion between CF and PI matrix, and accordingly lowered coefficients of friction and wear rates.

Influence of CVI treatment of carbon fibers on the electromagnetic interference of CFRC composites

Abstract Short carbon fibers were treated at temperatures around 1100 °C in a furnace through chemical vapor infiltration technology. The fiber surface was observed by scanning electron microscopy. The reflectivity of electromagnetic radiation by the composites that were reinforced by surface-treated carbon fibers and by as-received ones was measured in the frequency range of 8.0–18.0 GHz. The reflectivity for different carbon fiber contents of 0.2%, 0.4%, 0.6% and 1.0 wt% was investigated. Results showed that the reflectivity of the composites that were reinforced by untreated carbon fibers tended to increase with the increasing fiber contents. The minimum reflectivity was −19.3 dB, far less than −10 dB, when the fiber content was 0.4% and there were wave-absorbing properties. However, after surface treatment, the minimum reflectivity was −8.1 dB for the same fiber content of 0.4%, indicating significant wave-reflecting properties. The achieved reflectivity values after surface treatment were generally greater than those without treatment.

Tribological properties of PTFE composites filled with surface-treated carbon fiber

Carbon fibers (CF) were surface treated with concentrated HNO3, silane coupling agent, rare earth solution and rare earth sol, respectively. The friction and wear behavior of polytetrafluoroethylene (PTFE) filled with differently surface treated CF were studied. The worn surfaces of CF/PTFE composites were then examined with scanning electron microscope (SEM). It is found that the wear volume loss of the rare earth sol treated CF filled PTFE composites reaches the lowest value when the modifier concentration is 10 wt%. It is only about 65% of the wear volume loss of the PTFE filled with untreated CF. Among all the treatments to CF, rare earth sol treatment is the most effective and the lowest friction and wear volume loss of CF/PTFE composite is exhibited.

Friction and wear of rare earths modified carbon fibers filled PTFE composite under dry sliding condition

Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The friction and wear properties of polytetrafluoroethylene (PTFE) composites filled with differently surface treated carbon fibers, sliding against GCr15 steel under dry sliding condition, were investigated on a block-on-ring M-2000 tribometer. Experimental results revealed that RE treatment largely reduced the friction and wear of CF reinforced PTFE (CF/PTFE) composites. The RE treated composite exhibited the lowest friction and wear under dry sliding. Scanning electron microscopy (SEM) investigation of worn surfaces and transfer films of CF/PTFE composites showed that RE treated CF/PTFE composites had the smoothest worn surface under given load and sliding speed, and a continuous and uniform transfer film formed on the counterface. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that the oxygen concentration was obviously increased after RE treatment, and more carboxyl groups were introduced onto CF surfaces after RE treatment. The increase in the amount of oxygen-containing groups increased the interfacial adhesion between CF and PTFE matrix, and accordingly increased the tribological properties of the composite.

Irradiation effects in carbon fibers after N +-ion irradiation

Surface treatment of high modulus carbon fibers by pulsed N +-ion beams has been carried out, and changes in morphology and structure of the carbon fibers ( d 002 and L a parameters) have been investigated by using scanning electron microscopy, RBS and X-ray diffraction.

Tribological properties of lanthanum treated carbon fibers reinforced PTFE composite under dry sliding condition

The effect of rare earth (RE) surface treatment of carbon fibers (CF) on bending strength and tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites was investigated. Experimental results revealed that the bending strength of CF reinforced PTFE (CF/PTFE) composite was largely improved by RE treatment. Compared with the untreated and air-oxidized CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under various applied loads and reciprocating sliding frequency. Scanning electron microscope (SEM) investigation showed that RE treated CF/PTFE composite had smooth worn surface under given load and sliding frequency, and a continuous and uniform transfer film formed on the counterface of the composite, which helped to reduce the wear of the counterpart. The improvement in bending strength and tribological properties of CF/PTFE composite may due to an improvement in interfacial adhesion between CF and PTFE after RE treatment. The strong interfacial coupling of the composite made CF not easy to detach from the PTFE matrix, and prevented the rubbing-off of PTFE, accordingly improved the friction and wear properties of the composite.

Flexural strength and tribological properties of rare earth treated short carbon fiber/polyimide composites

To investigate the influence of carbon fiber (CF) surface treatment on the flexural strength and tribological prop- erties of the short-cut CF/polyimide (PI) composites, pitch-based short-cut CF were treated by rare earth. The CF before and after treatment was examined by X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM). The flexural strength of the specimens was determined in a three-point test machine. The friction and wear behav- iors of PI composites sliding against GCr15 steel rings were evaluated on an M-2000 model ring-on-block test rig. The results show that the surface of the treated CF became rougher and there formed lots of active groups after rare earth treat- ment. The flexural strength of PI composites with rare earth treated CF was improved. The friction coefficient and wear rate of PI composites with rare earth treated CF were lower than that with untreated CF.

On the friction and wear behavior of PTFE composite filled with rare earths treated carbon fibers under oil-lubricated condition

Carbon fibers (CF) were surface treated with air-oxidation, air-oxidation followed by rare earths (RE) treatment and RE treatment, respectively. The friction and wear properties of the polytetrafluoroethylene (PTFE) composites filled with differently surface treated carbon fibers, sliding against GCr15 steel under oil lubrication, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the PTFE composites were examined using a scanning electron microscopy (SEM). Experimental results revealed that surface treatment of carbon fibers reduced the wear of CF-reinforced PTFE composites. Among all the treatments to carbon fibers, RE treatment was the most effective and lowest friction and wear rate of CF-reinforced PTFE composite was exhibited, owing to the effective improvement of the interfacial adhesion between the carbon fibers and PTFE matrix.