Mechanical Grinding Research Articles

Laser processing of titanium alloys to increase the strength of adhesive joint with cfrp

Titanium alloys are hard-to-bond materials due to the fact that a thin oxide film is always present on their surface, which prevents the formation of interatomic and intermolecular bonds between the adhesive and the substrate. In the load-bearing structures of spacecraft (SC), an adhesive bond between a titanium alloy and a composite material is often used. But the strength of such knots is relatively small compared to the mechanical connection. The purpose of this work is to increase the strength of the adhesive joint, due to laser processing of the working surface of the titanium alloy for gluing. Texturing of the surface of the titanium alloy OT-4 was carried out on an ytterbium pulsed fiber laser in 4 processing modes. The treated surface was glued with KMU-4 carbon fiber over an area of 300 mm2 using a VK-9 three-component adhesive. The adhesive strength test was carried out on a Eurotest T-50 tensile tester. The test showed that the strength of the laser-treated samples increased by more than 80% relative to the average value of mechanical grinding. The highest value of shear strength was shown by samples with laser processing No. 1 and No. 3. This is due to the greatest increase in the area of bonding of the surface, as well as the mechanical locking of the adhesive in the microrelief of the structure. The increase in shear strength caused by laser surface treatment is a mixed effect of increasing surface area, mechanically locking the adhesive, and changing the surface chemistry. The chemical composition of the surface structure under the influence of laser scanning is gradually transformed from Ti and Ti2O3 to crystalline TiO2. The nature of the destruction of the adhesive joint in the samples with laser processing is predominantly cohesive, but samples with the destruction of the carbon fiber material were also observed, that is, the shear stress in the composite material exceeded the adhesive strength. The effect ofpretreatment of the composite material on the strength of the adhesive joint was not considered in this work.

Zwitterionic metal covalent organic frameworks constructed from lithium salts to reinforce poly(ethylene oxide)/poly(propylene carbonate) composite polymer electrolytes

Li+ was coordinated with zwitterionic part (squaric acid) of HUT4 by mechanical grinding to form metal covalent organic frameworks (HUT4Li), which was used as filler of PEO and PPC to improve the ionic conductivity of composite polymer electrolytes.

Mechanical Activation of OPC for Lower Strength UHPC with Reduced Silica Fume Content

Ultra-High-Performance Concrete (UHPC) traditionally exhibits compressive strength exceeding 150 MPa. However, variants have been identified with slightly lesser strengths that still surpass those of standard concrete; these are termed Lower Strength Ultra-High-Performance Concrete (LSUHPC). This study focused on the strategic utilization of Ordinary Portland Cement (OPC) in LSUHPC formulation while significantly curtailing the extensive use of silica fume, which is a common practice in UHPC production. Typically, high-performance concrete, with strengths ranging from 120-150 MPa, is produced using fine aggregates, heavy doses of silica fume, superplasticizer, and fiber. Contrary to this traditional method, our research developed an LSUHPC mix design with a significantly reduced volume of silica fume. For the current research stage, the use of steel fiber was omitted. To counteract the reduction in silica fume, the OPC was subjected to mechanical grinding to enhance its particle fineness and reactivity. Additionally, a low volume of class F fly ash was incorporated into the mixture to improve its workability. This adjustment was theorized to diminish inter-particle voids, reduce the water requirement, and increase the mixture’s density. With a fixed superplasticizer dosage of 4%, the aim was to minimize the water-to-binder ratio, maintaining workability and achieving enhanced particle packing and compressive strength. Following a series of grinding, particle fineness analyses, mix design formulations, and consistency tests, it was confirmed that the strategic application of OPC, combined with fly ash and reduced silica fume levels in the LSUHPC formulation, can achieve the targeted high compressive strength. This approach opens the door for cost-efficient LSUHPC production by drastically reducing the use of silica fume.

Recycling waste as raw material for powder coatings

According to global market analysis, annual production of polymer composites is expected to increase by an average of 6%, reaching a volume of 13-14 million tonnes by 2024, primarily in the building industry and mechanical engineering sectors. Recycling of polymer composites can be achieved through secondary use or recycling of solid waste. In Russia, about 160 out of 343 polymer producers are engaged in polymer recycling, with a focus on thermoplastics. However, recycling of thermoplastics is a complex process due to the strong polymer matrix structure, varying fillers, and resistance to thermal and chemical degradation. Mechanical grinding of waste polymer composites in powder form is a promising way to obtain a secondary product for decorative and protective coatings. Powder coating is a mixture of polymer powders with target and staining pigments, which sprayed onto the surface of a product and then polymerized at 150-220 °С. This paper compares a commercial polymer powder coating with a powder coating derived from recycled glass-reinforced plastic (GRP) on an epoxy binder. The study shows that the polymer powder coating composition obtained from recycled GRP is comparable to commercial powder coatings in terms of uniformity of distribution over the coated surface.

A metastable molecular array guided by the synergy of confinement and charge repulsion for piezochromic sensors

Piezochromic fluorescent materials have attracted the interest of the scientific community due to their obvious fluorescence emission or color change in response to external pressure or mechanical grinding stimulation.

Dicationic copper(I) complexes bearing ENE (E = S, Se) pincer ligands; catalytic applications in regioselective cyclization of 1,6-diynes.

Two novel dicationic binuclear Cu(I) complexes of the type [{(BPPP)E2}Cu]2[BF4]2 (E = S (3a); Se (3b)) bearing (BPPP)E2 (BPPP = bis(diphenylphosphino)pyridine) pincer systems were isolated, and structurally characterized. The solid-state structures of 3a/3b display the presence of intermolecular cuprophilic (Cu⋯Cu) interactions between the two monocationic species, and consist of weak Cu⋯S bonding between the two cations. Besides, complex 3a was introduced as a molecular copper(I) catalyst in cyclization reactions, and new protocols were developed for the synthesis of a series of new oxazole and triazole derivatives bearing alkyne-phenyl propargylic ether substituents. 3a was also found to be active in achieving these two classes of heterocyclic compounds by the mechanical grinding method. One of the key intermediate copper-azide species was detected by the high-resolution mass spectrometry technique, which supports the proposed catalytic pathway. All the reported transformations were accomplished sustainably by employing a well-defined, earth-abundant, and cheap copper(I) catalytic system.

Analysis of grain tribology and improved grinding temperature model based on discrete heat source

A high grinding temperature will cause thermal damage to a workpiece surface and deterioration of surface integrity, which is the bottleneck of grinding. The present grinding temperature theoretical model is based on grain homogeneity and the continuous heat source distribution in the grinding zone. However, the random change in interference between the effective grains and a workpiece during the machining process causes a change in the grain tribological properties, resulting in varying transient grinding temperatures. Based on the current situation, the grain tribological mechanism and an improved temperature model based on a discrete heat source are proposed to reveal the temperature variation law of a workpiece in an actual grinding process. First, the surface topography model of a grinding wheel is established based on the geometric characteristics of grains, and the determination mechanism of effective grains is revealed. Furthermore, the interference mechanical behavior of the grains and workpiece is analyzed according to the kinematic law of grains in the sliding, plowing, and cutting stages. The mechanical model and specific grinding energy model at different stages are established, and the thermal distribution mechanism of effective grains is revealed. Finally, a temperature field mathematical model of a discrete heat source is established, and numerical simulation is performed to demonstrate the dynamic temperature change process of different grains. A new experimental method for measuring temperature at different positions of the workpiece with a bipolar thermocouple array is designed, and a regional numerical simulation and experimental temperature comparison method is innovatively proposed. Experimental results show that the grinding temperature measured under different cutting depth conditions is in good agreement with the numerical results, and the variation law is consistent. The minimum error in 64 groups of experimental measuring and numerical calculation comparison zones can reach 4.9%, and the proportion of zones with errors less than 10% can approach 86%. This study will provide a theoretical basis for the accurate suppression of workpiece surface thermal damage and the development of precision grinding in engineering discipline and machinery industry.

Microstructure Evolution and Formation of Gradient Structures in Single Crystal Nickel-Based Superalloy by Surface Mechanical Creep-Feed Grinding Treatment.

Gradient structures have been created in single crystal nickel-based superalloys (SX alloys) via surface mechanical creep-feed grinding treatment (SMCGT). It has been found that these gradient structures are mainly composed of nano-sized grains, sub-micron-sized grains, dislocation structures, and the matrix material of single crystals along the depth from the treated surface. In addition, the evolution of such structures is found to be dominated by the dislocation movements which run through both γ channels and γ' precipitates, subdividing the two types of microstructures into various dislocation structures, and eventually introducing the refined grains into the surface layer. Furthermore, the evolution process of gradient structures primarily originates from the mechanical effect between abrasive grits and workpiece material, owing to the large grinding force (up to 529 N) and low grinding temperature (less than 150 °C) during the unique creep-feed grinding treatment in the present investigation. Due to the typical grain refinement, the hardness of the nanostructures exhibits the largest value of around 10 GPa in the surface layer, approximately 26% higher than that of the matrix material. This study further enhances the understanding of the microstructure-property relationship of SX alloys subjected to creep-feed grinding treatment and contributes to achievement of high-performance components.

Palladium Hydroxide (Pearlman's Catalyst) Doped MXene (Ti3C2Tx) Composite Modified Electrode for Selective Detection of Nicotine in Human Sweat.

High concentrations of nicotine (40 to 60 mg) are more dangerous for adults who weigh about 70 kg. Herein, we developed an electrochemical transducer using an MXene (Ti3C2Tx)/palladium hydroxide-supported carbon (Pearlman's catalyst) composite (MXene/Pd(OH)2/C) for the identification of nicotine levels in human sweat. Firstly, the MXene was doped with Pd(OH)2/C (PHC) by mechanical grinding followed by an ultrasonication process to obtain the MXene/PHC composite. Secondly, XRD, Raman, FE-SEM, EDS and E-mapping analysis were utilized to confirm the successful formation of MXene/PHC composite. Using MXene/PHC composite dispersion, an MXene/PHC composite-modified glassy carbon electrode (MXene/PHC/GCE) was prepared, which showed high sensitivity as well as selectivity towards nicotine (300 µM NIC) oxidation in 0.1 M phosphate buffer (pH = 7.4) by cyclic voltammetry (CV) and amperometry. The MXene/PHC/GCE had reduced the over potential of nicotine oxidation (about 200 mV) and also enhanced the oxidation peak current (8.9 µA) compared to bare/GCE (2.1 µA) and MXene/GCE (5.5 µA). Moreover, the optimized experimental condition was used for the quantification of NIC from 0.25 µM to 37.5 µM. The limit of detection (LOD) and sensitivity were 27 nM and 0.286 µA µM-1 cm2, respectively. The MXene/PHC/GCE was also tested in the presence of Na+, Mg2+, Ca2+, hydrogen peroxide, acetic acid, ascorbic acid, dopamine and glucose. These molecules were not interfered during NIC analysis, which indicated the good selectivity of the MXene/PHC/GCE sensor. In addition, electrochemical determination of NIC was successfully carried out in the human sweat samples collected from a tobacco smoker. The recovery percentage of NIC in the sweat sample was 97%. Finally, we concluded that the MXene/PHC composite-based sensor can be prepared for the accurate determination of NIC with high sensitivity, selectivity and stability in human sweat samples.

Enhanced thermoelectric power factor in the Cu2Se system by the incorporation of GO/MWCNT

The current study examines the transport capabilities of the thermoelectric material of copper selenide (Cu2Se), and its GO (Graphene oxide)/MWCNT (Multi-Walled Carbon Nano Tubes) nanocomposites synthesized using a cost-effective and straightforward chemical reduction method followed by a simple mechanical grinding process. Raman spectra, Field Emission Scanning Electron Microscopymicrographs, High-Resolution Transmission Electron Microscopy images, and the X- Ray Diffraction peak intensity of the all composites showed the existence of GO/MWCNT in the as-prepared samples. The power factor rose with the addition of GO/MWCNT, reaching maximum values of 881μ W/mK2 and 1120μ W/mK2 at 450 °C for Cu2Se-GO and Cu2Se-MWCNT, respectively. According to the findings, the highest thermopower of the Cu2Se-MWCNT composite was around 90 % greater (almost double) than that of bare Cu2Se. This article outlines an efficient and inexpensive process for producing carbon-related thermoelectric composite materials and a viable technique for increasing the power factor to enhance synergistic thermoelectric performance.

Heterojunction Design between WSe2 Nanosheets and TiO2 for Efficient Photocatalytic Hydrogen Generation

Design and fabrication of efficient and stable photocatalysts are critically required for practical applications of solar water splitting. Herein, a series of WSe2/TiO2 nanocomposites were constructed through a facile mechanical grinding method, and all of the nanocomposites exhibited boosted photocatalytic hydrogen evolution. It was discovered that the enhanced photocatalytic performance was attributed to the efficient electron transfer from TiO2 to WSe2 and the abundant active sites provided by WSe2 nanosheets. Moreover, the intimate heterojunction between WSe2 nanosheets and TiO2 favors the interfacial charge separation. As a result, a highest hydrogen evolution rate of 2.28 mmol/g·h, 114 times higher than pristine TiO2, was obtained when the weight ratio of WSe2/(WSe2 + TiO2) was adjusted to be 20%. The designed WSe2/TiO2 heterojunctions can be regarded as a promising photocatalysts for high-throughput hydrogen production.

A highly efficient melamine/red phosphorus flame retardant for polyurethane‐based foams

AbstractA highly dispersed melamine/red phosphorus (MA/RP) composite flame retardant was prepared by means of simple mechanical grinding. After co‐thermal pretreatment with polyether polyol (PPG‐2000) at 135°C, organic–inorganic hybrid foams (MA/RP/HF) containing MA/RP flame retardant were prepared by the one‐step method using main raw materials such as polyisocyanate and sodium silicate. When 0.5 wt% MA/RP with the mass ratio of 1:5 is added, MA can realize the uniform dispersion of RP in the substrate and enhance its flame retardancy, and the obtained MA/RP/HF presents uniform and closed pores and excellent basic properties. The TG results reveal that MA/RP/HF shows good thermal stability and the corresponding char residual rate reaches 37.9% at 800°C. The flame retardant test results prove that MA/RP/HF is capable of passing the V‐0 grade, with the LOI value being 26.8%. According to the cone calorimeter analysis, its peak heat release rate and total heat release decrease by 30.1% and 51.7% compared with those of rigid polyurethane‐based foam and by 40.1% and 30.0% compared with those of pure HF, respectively. Finally, the synergistic flame retardancy mechanism of MA and RP on polyurethane‐based foam was discussed.

Microstructural, Corrosion Resistance, and Tribological Properties of Al2O3 Coatings Prepared by Atmospheric Plasma Spraying

An usual material, EN-GJL-250 cast iron, used for automotive braking systems, was covered with a ceramic material (105NS-1 aluminium oxide) using an industrial deposition system (Sulzer Metco). The main reason was to improve the corrosion and wear (friction) resistance properties of the cast-iron. Samples were prepared by mechanical grinding and sandblasting before the deposition. We applied two and four passes (around 12-15 µm by layer) each at 90° obtaining ceramic coatings of 30 respectively 60 µm. The surface of the samples (with ceramic coatings) was investigated using scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD). Scratch and micro-hardness tests were performed using CETR-UMT-2 micro-tribometer equipment. The better corrosion resistance of the base material was obtained by applying the ceramic coating. The results present a better corrosion resistance and a higher coefficient of friction of the coated samples.

Mechanical grinding activation of modified magnesium slag and its use as backfilling cementitious material

The utilization of industrial solid waste with potential cementitious activity to prepare low carbon, economic and environmental backfilling cementitious materials is an urgent issue in cemented paste backfill (CPB). In this work, the mechanical grinding activation of modified magnesium slag (MMS), including grinding kinetics, crystallinity, and the influences on backfilling paste characteristics, have been investigated systematically. The indexes of particle size distribution (PSD), fineness, and sieve residue indicate that the grinding efficiency of MMS is high when grinding time ranges [20,80] min. The particle coarsening appears when the grinding time increases to 120 min from 100 min. A fitted grinding kinetics function of MMS has been established based on the measured PSDs with six grinding time. The XRD shows that the diffraction peak intensities of CaSO4 and SiO2 phases decreases with the increasing of grinding time, indicating the increasing of lattice defects and amorphization degree. Both of grinding dispersion refinement and amorphization increase of MMS contribute to the activation of cementitious reactivity. Grinding time has a great influence on the properties of modified magnesium slag-based (MMS-based) backfilling pastes. The fresh backfilling pastes conformed to both of the H-B model and revised Bingham model well. The critical shear rate, critical apparent viscosity, and extended degree increase with the increasing of grinding time, indicating that the fluidity decreases. The TG-DTG, SEM tests show that hydration rate of the MMS-based backfilling pastes is slow and there are many interconnected micropores when the grinding time is below 60 min. Besides, the uniaxial compressive strengths (UCS) of MMS-based backfilling mortar samples also show a similar pattern. All tests showed that grinding for 60 min could stimulate most of the potential cementitious reactivity of MMS. Meanwhile, the corresponding backfilling paste behaves good working condition. Taken together, 60 min is suggested as the optimal grinding time for MMS in consideration of energy consumed and technical benefits, and the corresponding specific surface area (SSA) and 45 µm sieve residue (SR) are 503 m2/kg and 3.83 %, respectively.

Effects of recycling and hygrothermal environment on mechanical properties of thermoplastic composites

Recyclability of nine types of composites including natural and mineral fillers in polypropylene and nylon matrix have been studied through injection molding and mechanical grinding. No significant degradation in mechanical properties of natural fiber composites occurred after recycling or water absorption tests. In contrast, glass fiber composites showed decrease in tensile strength and modulus by up to 45% and 40%, respectively after five rounds of recycling mainly due to severe fiber attrition. Glass bubbles breakage occurred after recycling, which diminished its ability to provide lightweighting. Only glass fiber reinforced nylon composites were affected by hygrothermal conditioning, which were characterized as a function of recycling. At saturation point, water absorption for nylon composites was 7.7% by wt. after 45 days of immersion, which significantly affected the mechanical properties. Tensile strength and modulus of glass fiber nylon composites reduced from 88.4 MPa and 5.6 GPa to 36.2 MPa and 1.8 GPa, respectively.

Air-thermal oxidation of diamond nanopowders obtained by the methods of mechanical grinding and detonation synthesis

In this work, using the methods of X-ray phase analysis, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy, the features of the impact of annealing in air within the temperature range of t = 200÷÷550 °C on the morphology, elemental and phase composition, chemical state and structure of primary particles of nanopowders obtained by grinding natural diamond and the method of detonation synthesis are studied. It is shown that heat treatment in air at given values of temperature and heating time does not affect the elemental composition and atomic structure of primary particles of nanopowders obtained both by the methods of detonation synthesis (DND) and natural diamond grinding (PND). Using XPS, Raman spectroscopy, and transmission electron microscopy, it has been found that annealing in air within the temperature range of 400–550 °C results in the effective removal of amorphous and graphite-like carbon atoms in the sp2- and sp3-states from diamond nanopowders by oxidation with atmospheric oxygen. In the original DND nanopowder, containing about 33.2 % of non-diamond carbon atoms of the total number of carbon atoms, after annealing for 5 h at a temperature of 550 °C, the relative number of nondiamond carbon atoms in the sp2-state decreased to ~21.4 %. In this case, the increase in the relative number of carbon atoms in the sp3-state (in the lattice of the diamond core) and in the composition of oxygen-containing functional groups ranged from ~39.8 % to ~46.5 % and from ~27 % to ~32.1 %, respectively. In the PND nanopowder, which prior to annealing contains about 10.6 % of non-diamond carbon atoms in the sp2-state of the total number of carbon atoms, after annealing under the same conditions as the DND nanopowder, their relative number decreased to 7.1 %. The relative number of carbon atoms in the sp3-state increased from 72.9 % to 82.1 %, and the proportion of carbon atoms in the composition of oxygen-containing functional groups also slightly increased from 10.2 % to 10.8 %. It is demonstrated that the annealing of PND and DND nanopowders in air leads to a change in their color, they become lighter as a result of oxidation of non-diamond carbon by atmospheric oxygen. The maximum effect is observed at a temperature of 550 °C and an annealing time of 5 h. In this case, the weight loss of PND and DND nanopowders after annealing was 5.37 % and 21.09 %, respectively. The significant weight loss of DND nanopowder compared to PND is primarily caused by the high content of non-diamond carbon in the initial state and the high surface energy of primary particles due to their small size.

Structure and properties of titanium hydride powder obtained from titanium sponge by SHS hydrogenation

The results of the study of the structure and properties of titanium hydride powders obtained from titanium sponge by SHS hydrogenation and mechanical grinding are presented. Hydrogenation was carried out in a reactor at a constant hydrogen pressure of 3 MPa. After passing the combustion wave, the hot titanium sponge was cooled to room temperature in a hydrogenatmosphere. As a result, titanium hydride spongy granules with a hydrogen content of 4.2 wt.% were obtained. Titanium hydride was ground in a ball mill and divided into 4 fractions corresponding to the fractional composition of titanium powder PTK, PTS, PTM and PTOM. Particle size analysis showed that the samples of the PTK and PTOM powders have a narrower particle distribution in comparison with the PTS and PTM ones. Further, obtained powders chemical composition and surface morphology studies were carried out and bulk density, compaction, pycnometric density and specific surface area were determined. According to the chemical analysis results the content of carbon and oxygen impurities decreases during SHS-hydrogenation and the iron content slightly increases during mechanical grinding depending on the grinding time. The study of morphology showed that the hydride titanium particles have an irregular fragmentary shape, such morphology is characteristic of powders obtained by this technology. The surface structure has partially preserved structure of the initial titanium sponge and consists of elongated oriented grains. It is established that with a decrease in the particle size, the bulk density decreases, and the compaction increases. Pycnometric density and specific surface area values are approximately equal for all powder samples.

Precipitation Behavior during Aging Operations in an Ultrafine-Grained Al–Cu–Mg Alloy Produced by High-Strain-Rate Processing

An ultrafine-grained (UFG) Al-Cu-Mg alloy (AA2024) was produced by surface mechanical grinding treatment (SMGT) with a high strain rate, and the precipitation behavior inside the grain and at the grain boundary was investigated. During SMGT, element segregation at the boundary was rarely observed, since the solute atoms were impeded by dislocations produced during SMGT. During early aging, the atomic fraction of Cu at the grain boundary with SMGT alloys was approximately 2.4-fold larger than that without SMGT alloys, the diffusion rate of Cu atoms from the grain toward the grain boundaries was accelerated with SMGT alloys, because a higher local elastic stress and diffusion path were provided by high-density dislocations. The combined action, in terms of the composition of the alloy, the atomic radius, the diffusion path, and the diffusion driving force provided by high-density dislocations with SMGT alloys, led to a Cu/Mg atomic ratio of approximately 6.8 at the grain boundary. The average size of the precipitates inside the grain was approximately 2- and 10-fold larger than that formed after later aging with and without SMGT alloys, due to more nucleation sites at dislocation located inside the grain with SMGT alloys having attracted and captured numerous solute atoms during the aging process.

Recycling of ferronickel slag tailing in cementitious materials: Activation and performance

As an industrial by-product containing pozzolanic components, recycled ferronickel slag (FNS) has the potential to be supplementary cementitious materials (SCMs) to reduce the massive carbon footprint of the cement industry, however, the main limitation of ferronickel slag as SCMs is the low hydration rate at an early age. In this study, the pozzolanic activity property results indicate that if the proportion is more than 10 %, FSN can hardly participate in the cement hydration reaction during the early stage, even the mechanical strength of FNS-mortar decreases obviously with the higher proportion of ferronickel slag. Therefore, mechanical grinding and steam curing at an early age are applied to promote the reaction activity of the recycled ferronickel slag tailing in this study. Compared with standard curing, the compressive strength of hardened FNS-cement paste with steam curing at 60 °C or 80 °C increased by 8.2 % or 33.8 %, and the connected porosity decreased by 18.9 % or 17.3 %. And MgO in the ferronickel slag exists as Mg2SiO4 in raw materials and enters the C-S-H gel with the formation of M-S-H gel during the secondary hydration stage. This study provides a theoretical basis for solid waste-based concrete and promotes the recycling, conservation, and resources of solid waste in building materials.

Advancement of Polyaniline/Carbon Nanotubes Based Thermoelectric Composites.

Organic thermoelectric (TE) materials have been widely investigated due to their good stability, easy synthesis, and high electrical conductivity. Among them, polyaniline/carbon nanotubes (PANI/CNTs) composites have attracted significant attention for pursuing enhanced TE properties to meet the demands of commercial applications. In this review, we summarize recent advances in versatile PANI/CNTs composites in terms of the dispersion methods of CNTs (such as the addition of surfactants, mechanical grinding, and CNT functional group modification methods), fabrication engineering (physical blending and in-situ polymerization), post-treatments (solvent treatments to regulate the doping level and microstructure of PANI), and multi-components composites (incorporation of other components to enhance energy filtering effect and Seebeck coefficient), respectively. Various approaches are comprehensively discussed to illustrate the microstructure modulation and conduction mechanism within PANI/CNTs composites. Furthermore, we briefly give an outlook on the challenges of the PANI/CNTs composites for achieving high performance and hope to pave a way for future development of high-performance PANI/CNTs composites for sustainable energy utilization.