The effect of sintering temperature on Cu-CNTs nano composites properties produced by PM method (original) (raw)
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Advances in Natural Sciences: Nanoscience and Nanotechnology, 2011
Metal matrix nanocomposites have become popular in industrial applications. Carbon nanotubes (CNTs), since theirs appearance, with their unique properties such as exceptionally small diameters and high Young's modulus, tensile strength and high chemical stability, are considered to be an attractive reinforcement material for lightweight and high-strength metallic matrix composites. The powder metallurgy method allows nanocomposite materials, notably metal-ceramic composites, to be produced by sintering a mixture of powders.
Synthesis of Cu-CNTs nanocomposites via double pressing double sintering method
Metallurgical and Materials Engineering, 2018
In this research, copper (Cu)-carbon nanotubes (CNTs) nanocomposites were synthesized with different weight percentages of CNTs by double pressing double sintering (DPDS) method as well as conventional sintering method. A planetary ball mill was used to disperse CNTs in Cu matrix. The milled powders were first cold pressed to 450 MPa in a uniaxial stainless-steel die with cylindrical compacts (diameter: 12 mm and height: 5 mm). The effect of CNTs content and the DPDS method on the properties of the nanocomposites were investigated. The microstructure and phase analysis of Cu-CNTs nanocomposite samples were studied by FESEM and X-Ray Diffraction. The electrical conductivity of nanocomposites was measured and compared to both sintering methods. Mechanical properties of Cu-CNTs nanocomposites were characterized using bending strength and micro-hardness measurements. Enhancements of about 32 % in bending strength, 31.6 % in hardness and 19.5 % in electrical conductivity of Cu-1wt. % CNTs nanocomposite synthesized by DPDS method were observed as compared to Cu-1wt. % CNTs nanocomposites fabricated under the similar condition by a conventional sintering process.
AN OVERVIEW OF PROCESSING AND PROPERTIES OF CU/CNT NANO COMPOSITES
Elseviers, 2017
Carbon nanotubes (CNTs) are known for their extraordinary mechanical, electrical and thermal properties. These properties make them ideal reinforcements in the metal matrix. Particularly, the combination of Cu/CNT is interesting in view of excellent thermal, electrical and physical properties of copper. In this overview, the reports on Cu/CNT composites are critically analyzed with respect to the process techniques, mechanical and tribological properties. Powder metallurgy coupled with spark plasma sintering is found to be a most widely used process to fabricate Cu/CNT composites. Comparatively, a small amount of CNTs is sufficient to improve the properties of composites as against the conventional micron size particle reinforced composites. The strength, wear resistance and corrosion resistance of the composites increase significantly with an increase of volume fraction of CNTs. The density and thermal conductivity reduce with an increase of CNTs. There exists a critical volume fraction above that both the mechanical properties and the thermal conductivity are drastically reduced due to the problems of CNTs agglomeration and the increase of process related defects such as porosity, delamination and so on. Fracture surface features of Cu/CNT composites show that the fracture mode transits from ductile to brittle fracture with an addition of CNTs.
Sintering behaviour of Copper/carbon nanotube composites and their characterization
Advanced Powder Technology, 2019
The potential usage of Copper (Cu) is very limited, where combined mechanical and thermal properties are desirable, which can be overcome by using carbon nanotube (CNT) as a reinforcement. An attempt was made to synthesize Cu/CNT composites by varying CNT diameter and its concentration through a molecular level mixing technique followed by uniaxial compaction and conventional sintering. The sintering behaviour of Cu and Cu/CNT composites was studied to understand the influence of different parameters. The sintering duration of Copper was decreased with an increase of CNT diameter. The maximum enhancement of properties was achieved at 0.25 wt.% CNT irrespective of its diameter, where the thermal conductivity and hardness were obtained as 328 W/mK at 20-40 nm diameter CNT composites and 81.2 ± 2.9 VHN at 40-60 nm diameter CNT composites, respectively. The conventional method of synthesize can generate the desired characteristics of composites at par with high end techniques, such as SPS.
Effect of CNTs dispersion on the thermal and mechanical properties of Cu/CNTs nanocomposites
Modified technique of metal injection molding (MIM) was used to fabricate multiwalled carbon nanotube (CNT) reinforced Cu nanocomposites. The effect of adding different amount of CNTs (0-10 vol.%) on the thermal and mechanical behaviour of the fabricated nanocomposites is presented. Scanning electron microscope analysis revealed homogenous dispersion of CNTs in Cu matrices at different CNTs contents. The experimentally measured thermal conductivities of Cu/CNTs nanocomposites showed extraordinary increase (76% higher than pure sintered Cu) with addition of 10 vol.% CNTs. As compared to the pure sintered Cu, increase in modulus of elasticity (Young’s modulus) of Cu/CNTs nanocomposites sintered at 1050qC for 2.5 h was measured to be 48%. However, in case of 7.5 vol.% CNTs, Young’s modulus was increased significantly about 51% compared to that of pure sintered Cu.
Sintering and Dimensional Analysis of Cu/CNTs via a Powder Metallurgy Route
Journal of Mechanical Engineering
Recently, carbon nanotubes (CNTs) reinforced metal matrix composites (MMCs) have attracted an increasing interest, due to their promising properties such as high Young’s modulus and tensile strength. CNTs are considered to be an attractive reinforcement material for lightweight and high-strength metallic matrix composites. When powder metallurgy (PM) is used to form these MMCs (such as Cu/CNTs composites), the sintering parameters are crucial in obtaining good final parts. This work attempts to investigate the effect of sintering parameters on physical properties in these MMCs. The process comprised of mixing of Cu powder with CNTs, compacting of the powder mixture to form green parts and sintering using a quartz tube furnace under argon atmosphere. In this study, four trials of heating rate were performed and evaluated before sintering process was conducted. Finally, the green body was initially heated isothermally at 100°C for 1 hour with heating rate of 1.0 °C/min and sintered at...
Electrical and mechanical properties of Cu-CNT nanocomposites sintered by microwave technique
Metallurgical and Materials Engineering
In this research, multiwall carbon nanotubes were dispersed in a copper matrix using a planetary ball mill. The mixed powders were compacted using a uniaxial hydraulic presser. A novel method of microwave sintering was applied to consolidate Cu-CNT nanocomposites Conventional sintering method was also used to sinter samples to investigate the effects of applied methods on the properties of the sample. Sintering time was reduced to 20 min using microwave sintering method. The morphology and phase analysis of nanocomposites were studied by FESEM and XRD. The physical and mechanical properties of Cu-CNT nanocomposites were characterized using electrical conductivity, bending strength, and micro-hardness. The results show that the mechanical properties of Cu-CNT nanocomposites are improved significantly by microwave route. The optimum hardness and bending strength were obtained for 4 vol. % CNT as an optimum amount of reinforcement.
Acta Physica Polonica A, 2019
In this study the effect of carbon nanotube content on the wear behaviours of Cu-carbon nanotube composites produced by powder metallurgy method was investigated. In the scope of the study five different amounts of carbon nanotube (0.5%, 1.0%, 1.5%, 2.0%, 2.5%) were added into pure Cu powders and mechanically milled for 360 min. The mechanically milled Cu-carbon nanotube powders were cold pressed under 600 MPa load and sintered in atmosphere-controlled furnace at 1000 • C for 1 h. Microstructure examinations, hardness measurements, and wear tests were carried out. In this study, the hardness values were found to have increased with increasing carbon nanotube content up to 1.5%. Then it decreased with increasing carbon nanotube content. Wear test results were compatible with hardness results. The lowest weight losses were measured with 1.5% carbon nanotube content.
Carbon nanotubes (CNTs) reinforced copper (Cu) matrix nanocomposites prepared via advanced fabrication method is presented. Functionalization and ultrasonication processes have been applied to enhance the dispersion of purified CNTs and creates sidewalls groups that have the potential to bond CNTs to the metal matrix. The main part of this approach was metal injection molding (MIM) technique, which is a combination of powder metallurgy and plastic injection molding technique. Preparation of MIM feedstock required a melting and mixing process of binder system (polymers) with the solid loading, which has been carried out using a twin screw rotor machine. This machine provides a viscous media of the molten binder with high shear forces that allow the additives (carbon nanotubes/copper powder) to be mixed properly and exfoliate the CNTs clusters with uniformdispersion inside the Cu matrix. Subsequently, to prove our expected results, observation tests of TEM, SEM, FESEM and CNTS were employed and discussed literally.
Carbon nanotubes (CNTs) with its exceptional thermal and mechanical properties hold the promise of delivering high performance nanocomposite materials. To utilize CNTs as effective reinforcement in metal nanocomposites, appropriate dispersion and robust interfacial adhesion between individual CNT and metal matrix have to be certain. This work presents a novel combined technique of nanoscale dispersion (NSD) of functionalized multiwalled carbon nanotubes (MWCNTs) in copper (Cu) matrix composite followed by powder injection molding (PIM). MWCNTs contents were varied from 0 to 10 volume fraction. Evidences on the existence of functional groups and microstructural analysis of the fabricated nanocomposites were determined using TEM, EDX, FESEM and FTIR. Thermal conductivity and elasticity measurements were also performed. The results showed that the impurities of the pristine MWCNTs such as Fe, Ni catalyst, and the amorphous carbon have been significantly removed after sonication process. FESEM and TEM observations showed high stability of MWCNTs at elevated temperatures and uniform dispersion of MWCNTs in Cu matrix at different volume fractions and sintering temperatures (950, 1000 and 1050 C). The experimentally measured thermal conductivities of Cu/MWCNTs nanocomposites showed remarkable increase (11.25% higher than pure sintered Cu) with addition of 1 vol.% MWCNTs, while the modulus of elasticity (Young’s modulus) of Cu/MWCNTs nanocomposites sintered at 1050 C for 2 h was increased proportionally to the increment in MWCNTs contents.