Alumina Filler Research Articles

Balancing Interfacial Toughness and Intrinsic Dissipation for High Adhesion and Thermal Conductivity of Polymer-Based Thermal Interface Materials.

In recent years, adhesive thermal interface materials have attracted much attention because of their reliable adhesion properties on most substrates, preventing moisture, vibration impact, or chemical corrosion damage to components and equipment, as well as solving the heat dissipation problem. However, thermal interface materials have a huge contradiction between strong adhesion and high thermal conductivity. Here, we report a polymer-based thermal interface material consisting of polydimethylsiloxane/spherical aluminum fillers, which possesses both adhesion properties (adhesion strength of 3.59 MPa and adhesion toughness of 1673 J m-2 and enhanced thermal conductivity of 3.90 W m-1 K-1). These excellent properties are attributed to the modified chain structure by introducing acrylate accelerators into the polydimethylsiloxane network, thereby striking a balance between interfacial toughness and intrinsic dissipation. The addition of thermally conductive aluminum fillers not only increases the thermal conductivity but also improves the bulk energy dissipation of the thermal interface material. This work provides a novel strategy for designing a novel thermal interface material, leading to new ideas in long-term applications in high-power electronics.

Thermal Interface Materials with High Adhesion and Enhanced Thermal Conductivity via Optimization of Polydimethylsiloxane Networks and Aluminum Fillers

Thermal Interface Materials with High Adhesion and Enhanced Thermal Conductivity via Optimization of Polydimethylsiloxane Networks and Aluminum Fillers

Analyzing the Influence of Titanium Content in 5087 Aluminum Filler Wires on Metal Inert Gas Welding Joints of AA5083 Alloy

As the demand for lightweight structures in the transportation industry continues to rise, AA5083 aluminum alloy has become increasingly prominent due to its superior corrosion resistance and weldability. To facilitate the production of high-quality, intricate AA5083 components, 5087 aluminum filler wire is commonly utilized in metal inert gas (MIG) welding processes for industrial applications. The optimization of filler wire composition is critical to enhancing the mechanical properties of AA5083 MIG-welded joints. This study investigates the effects of modifying 5087 aluminum filler wires with different titanium (Ti) contents on the microstructure and weldability of AA5083 alloy plates using MIG welding. The influence of Ti contents was systematically analyzed through comprehensive characterization techniques. The findings reveal that the constitutional supercooling induced by the Ti element and the formation of Al3Ti facilitate the heterogeneous nucleation of α(Al), thereby promoting grain refinement. When the Ti content of 5087 filler wire is 0.1 wt.%, the grain size of the weld center was 78.48 μm. This microstructural enhancement results in the improved ductility of the AA5083 MIG-welded joints, with a maximum elongation of 16.64% achieved at 0.1 wt.% Ti addition. The hardness of the joints was the lowest in the weld center zone. This study provides critical insights into the role of Ti content in MIG welding and contributes to the advancement of high-performance filler wire formulations.

Characterisation and properties of Nanohybrid Dental Composite (NhDC) reinforced with zirconia and alumina

A trial nanohybrid dental composite (NHDC) was developed using silica extracted from biowaste rice. Aim: This study aims to test the effect of mixture of the silica and other filler which is zirconia and alumina, focusing on the characterization and their properties. Nano-silica obtained from rice husk was used as NHDC filler. Methods: Nanosilica white powder, derived from rice husk, was used. There were three groups: Group I, Zr (2%) and Al (3%); group II, Zr (3%) and Al (2%); and group III, Zr (3%). The distribution of filler particles and the chemical structure of filler particles were determined by FESEM images and FTIR test. Then, testing on Vickers hardness (VHN) and fracture strength (FS) of the samples was performed. Results: The distribution of filler particles showed a uniform distribution, and each peak element of the fillers was shown in the FTIR spectrum images. There was significantly increased on VHN and FS after addition of zirconia and alumina. Conclusion: This study concluded that zirconia and alumina strengthen the NHDC properties with addition of zirconia and alumina filler.

Towards high-performance polydimethylsiloxane-based materials for thermal management: A molecular dynamics study

To efficiently design high-performance polymer-based thermal interface material (TIM), it is imperative to investigate how microstructural influences thermal transport. Utilizing molecular dynamics (MD) simulations, this study examined the effects of crosslinking degree (10–40%) and alumina (Al2O3) filler doping ratios (0–23.13 wt%) on the thermomechanical behaviors of PDMS. Our findings indicated that increasing the degree of crosslinking significantly enhances thermal conductivity at lower doping rates by creating additional heat transfer channels. However, at higher doping rates, thermal conductivity improvement is mitigated due to the potential hindrance caused by fillers. Optimal thermal conductivity was observed with a 20% crosslinking degree and 14.67 wt% Al2O3 doping, achieving an 18% enhancement compared to systems without crosslinking. These results underscore the complex interplay between crosslinking and filler content in optimizing the thermal performance of PDMS-based TIMs, contributing to the advancement of materials for efficient thermal management in microelectronic devices.

Self‐healing, low oil leakage and recyclable thermally conductive Al2O3/boron nitride@siloxane composites based on reversible dynamic network

AbstractIn order to overcome the commercialized silicone‐based thermal interface materials' issues such as oil leakage and mechanical damage, we developed a thermoset silicone rubber matrix (SR) achieved through the condensation reaction of hydroxyl silicone oil and tetraethyl silicate. Additionally, we constructed a self‐healing and recyclable silicone rubber matrix (SCNR) by incorporating heat reversible ionic and hydrogen bonds between carboxyl and amino functionalized polydimethylsiloxane. Finally, the flexible, low oil leakage, self‐healing, and recyclable composites Al2O3/BN@SR/SCNR was prepared by adjusting the ratio of SR/SCNR and the spherical alumina and boron nitride (BN) fillers. The results indicated that with SR/SCNR mass ratio of 1/0.075 and filler content of 70 wt%, the thermal conductivity of the composite reaches 1.866 W m−1 K−1, 646% increasing over the SR/SCNR matrix. The self‐healing efficiency reaches 97% and the thermal conductivity remains essentially unchanged after being recycled for three times. The composites can be bent and twisted multiple times and still return to their original shape. Notably, the oil leakage of the Al2O3/BN@SR/SCNR composites is significantly lower than that of additive silicone composites. Therefore, the recyclable thermal conductivity composite developed in this study provides a promising solution for improving the durability of heat dissipation materials in electronic devices.

Soft, Tough, Antifatigue Fracture Elastomer Composites with Low Thermal Resistance through Synergistic Crack Pinning and Interfacial Slippage.

Soft elastomer composites are promising functional materials for engineer interfaces, where the miniaturized electronic devices have triggered increasing demand for effective heat dissipation, high fracture energy, and antifatigue fracture. However, such a combination of these properties can be rarely met in the same elastomer composites simultaneously. Here a strategy is presented to fabricate a soft, extreme fracture tough (3316J m-2) and antifatigue fracture (1052.56J m⁻2) polydimethylsiloxane/aluminum elastomer composite. These outstanding properties are achieved by optimizing the dangling chains and spherical aluminum fillers, resulting in the combined effects of crack pinning and interfacial slippage. The dangling chains that lengthen the polymer chains between cross-linked points pin the cracks and the rigid fillers obstruct the cracks, enhancing the energy per unit area needed for fatigue failure. The dangling chains also promote polymer/filler interfacial slippage, enabling effective deflection and blunting of an advancing crack tip, thus enhancing mechanical energy dissipation. Moreover, the elastomer composite exhibits low thermal resistance (≈0.12K cm2 W-1), due to the formation of a thermally conductive network. These remarkable characteristics render this elastomer composite promising for application as a thermal interface material in electronic devices.

High Frequency Breakdown Characteristics of Alumina Filler Content Epoxy Resin

Power electronic transformers have high insulation frequency and compact insulation structure, and insulation performance is one of the main factors restricting their further development. Epoxy resin is an important insulating material in the electrical industry, its thermal conductivity and mechanical properties can not meet the needs of high-frequency transformers, usually metal oxide (Al2O3, etc.) is added to form composite insulation material. It is of great reference value for the insulation design of power electronic transformer to study the insulation performance of composite insulation materials with different filler content ratio under high-frequency AC. The effects of power supply frequency and alumina filler content on the breakdown performance of the composite were investigated experimentally. The results show that the breakdown voltage of pure epoxy resin decreases exponentially with frequency. At any filler content, the breakdown voltage of epoxy resin decreases with the increase of frequency, and the decreasing trend gradually slows down when the frequency increases from 50Hz to 1000Hz, and the decreasing trend gradually increases when the frequency increases to 2000Hz. The breakdown voltage of epoxy resin showed a down-rise-down trend with the increase of filler content, and the effect of filler content on breakdown voltage gradually weakened with the increase of frequency.

DLC: Flexible bridge across heterogeneous interface between alumina filler and epoxy resin matrix

The heterogeneous interface between filler and matrix within composites often acts as a bottleneck for material performance. Carbon materials, particularly Diamond-Like Carbon (DLC), are representing a novel trend in interface design. This study investigates the nanoscale mechanical and electrical properties of the heterogeneous interface between DLC-coated alumina fillers and an epoxy resin matrix. The results demonstrate that the DLC layer is instrumental in creating a harmonious modulus transition between materials that exhibit significant variance in their elastic moduli, characterized by an exponential relationship, and approximately 50% enhancement in interfacial adhesion. Additionally, the DLC layer exhibits elevated sensitivity in dielectric response, attributed to a small RC time constant. This interface transition technology offers new tools for composite material design.

The curing kinetics and properties of self-healing and thermally conductive polymeric composites based on ethylene vinyl acetate copolymer filled with nano alumina

We have investigated a self-healing thermally conductive Ethylene-vinyl acetate (EVA) hot melt adhesive (NAEDS, which denotes the addition of nano-alumina and disulfide bonded EVA hot melt adhesives) that can be used to effectively solve adhesive layer separation problem in photovoltaic (PV) modules and the difficulty of recycling. More specifically, we used diallyl disulfide as a cross-linking agent for EVA and alumina nanofillers as a reinforcing phase. The nano alumina filler gave the EVA better thermal conductivity. We used FTIR, SEM, and DSC to characterize and analyze NAEDS properties. The disulfide bonds in NAEDS underwent a rearrangement reaction under ultraviolet light, resulting in the self-healing of the resin (self-healing efficiency of 78.8%). The added nano alumina not only reduced the resin curing activation energy, improving its curing performance but also enhanced its thermal conductivity, achieving a 2.61 W/(m*k) thermal conductivity coefficient. The overall NAEDS performance is improved.

Enhancing gamma and neutron radiation shielding efficiency of LDPE/PVC polymers using cobalt, aluminum, and magnesium oxide fillers

A procedure for creating and assessing LDPE/PVC polymers using Co, Al, and Mg oxides as fillers for use as radiation shielding material was conducted. The SEM/EDX equipment was utilized for elemental analysis and mapping in order to visually represent the morphology of the produced polymers. The characterizations indicate that the MgCo2O4 particles possess an irregular and tiny morphology, displaying a spherical form with an average diameter of less than 100 nm. In addition, the Al2CoO4 particles are characterized as being aggregated, diminutive, and exhibiting a spherical morphology, with an average diameter of less than 150 nm. The current study involved experimental investigation, simulation using FLUKA-MC code, and theoretical calculations using Phy-X-PSD code to examine the radiological properties of the shielding material. The results depend on several factors, including the half-value layer (HVL), the effective atomic number (Zeff), the effective electron number (Neff), the effective conductivity (Ceff), the exposure buildup factor (EBF), the energy-absorption buildup factor (EABF), and the fast neutron macroscopic removal cross-section (FNRC). The SR-NIEL-7 platform has been utilized to compute the mass-stopping power for protons (H+) and alpha particles (He++) based on their kinetic energy. The experimental findings indicate that the density of LDPE/PVC filled with MgCo2O4 is greater than that of Al2CoO4. Furthermore, polymer filled with MgCo2O4 exhibits higher values for MAC, LAC, and FNRCs than Al2CoO4 filler. The measured LAC and MAC conform to the simulated values.

Estimating the wear behavior of hdpe composites reinforced with nano alumina fillers using taguchi method

Estimating the wear behavior of hdpe composites reinforced with nano alumina fillers using taguchi method

Investigation of melt flow index and tensile properties of dual metal reinforced polymer composites for 3D printing using machine learning approach: Biomedical and engineering applications

This study investigates the enhancement of mechanical properties of metal/polymer composites produced through fused deposition modeling and the prediction of the ultimate tensile strength (UTS) by machine learning using a Classification and Regression Tree (CART). The composites, comprising 80% acrylonitrile butadiene styrene matrix and 10% each of aluminum (Al) and copper (Cu) fillers, were subjected to a comprehensive exploration of printing parameters, including printing temperature, infill pattern, and infill density using the Taguchi method. The CART unveiled a hierarchical tree structure with four terminal nodes, each representing distinct subgroups of materials characterized by similar UTS properties. The predictors’ importance was assessed, highlighting their role in determining material strength. The model exhibited a high predictive power with an R-squared value of 0.9154 on the training data and 0.8922 on the test data, demonstrating its efficacy in capturing variability. The optimal combination of parameters for maximizing UTS was a zigzag infill pattern, a printing temperature of 245 °C, and an infill density of 10%, which is associated with the highest UTS of 680 N. The model’s reliability was confirmed through a paired t-test and test and confidence interval for two variances, revealing no significant difference between the observed and predicted UTS values. This research contributes to advancing additive manufacturing processes by leveraging CART analysis to optimize printing parameters and predict material strength. The identified optimal conditions and subgroup characteristics pave the way for developing robust and predictable metal/polymer composites, offering valuable insights for material design in the era of advanced manufacturing technologies.

Effect of alumina fillers on physical and mechanical properties of luffa/groundnut shell natural fiber reinforced polymer composites

AbstractThis study aims to investigate the physical and mechanical properties of epoxy composites reinforced with hybrid luffa waste and groundnut shell waste natural fibers and to evaluate the effect of different filler loadings of alumina on the mechanical behavior of the hybrid composites. The luffa fibers were made to undergo mercerization in 10% NaOH solution. All the treated fibers and the alumina fillers were characterized using X‐ray diffraction analysis (XRD). The study used three different filler loadings of alumina (Al2O3) (5%, 10%, and 15% by volume) and three different fractions of treated luffa‐waste groundnut shell hybrid fibers (10%, 30%, and 50% by volume). The composites were fabricated using the hand layup technique, and the prepared test specimens were subjected to mechanical and physical properties testing as per ASTM standards. The experimental findings indicated that the inclusion of Al2O3 filler improved the physical and mechanical characteristics of the natural fiber‐reinforced hybrid composites. The results showed that the composites with 30 vol. % fibers (1:1 luffa fiber: groundnut shell fiber) and 10 vol. % Al2O3 content showed enhanced tensile, flexural, shear, and impact strength and hardness. Besides, a good synergy between the alumina fillers, natural fibers, and the polymer matrix was observed in the surface morphology of the composite specimen. The developed composites can be used in low and medium‐load‐bearing structural and non‐structural applications.Highlights Development of hybrid polymer composites with luffa and novel groundnut shell fibers Hybridization of alumina ceramic particles with natural fiber hybrid composites Assessment of physical and mechanical properties of the polymer composites

Fabrication, characterization and investigation of flexible light weight nylon-6 based silicon rubber composites for radiation attenuation

Lead, the conventional choice for wearable radiation shielding, faces growing health and occupational concerns. This prompts the search for a lighter, more flexible alternative. Nylon 6, prized for its mechanical prowess, emerges as a reinforcement in wearable composites. This study focuses on creating silicon rubber composites using Nylon 6 reinforcement and varying proportions of Bismuth oxide and aluminium fillers. Mechanical Parameters such as Tensile strength and Elongation at break, are studied and the quality of fabrication is assessed using a Scanning Electron Microscope. Studies on various combinations of nylon 6-based silicon rubber with varying percentages of bismuth oxide and aluminium fillers have been studied and radiation parameters have been assessed. TSN-4 (60% wt. bismuth oxide along with 50% wt. aluminium powder) showed the highest tensile strength of 25.13 MPa having 79.3% of elongation at break followed by TSN-1 & TSN-3. The results reveal good mechanical properties as well as satisfactory radiation attenuation properties. The combination of Nylon 6-based with 60% wt. bismuth oxide along with 50% wt. aluminium powder (TSN4) was considered optimal for the energy range from 140 keV to 511 keV with HVL of 2.06 cm, TVL 6.86 cm, and MAC of 0.093 gm/cm2 and also bearing good mechanical properties. Further, the fabricated samples can be compared with the Monte Carlo Simulation method for further improvements in the fabricated composites. The produced composites have the potential to be used as lead-free protective wearables and wearing devices in nuclear medicine following further investigation.

Extrusion-based additive manufacturing of aluminium-filled ethylene vinyl acetate for electrically conductive 3D part printing

Addition of carbon-based fillers to enhance electrical conductivity is quite popular but addition of metal fillers is still a challenge due to oxidation and unavailability of metal nano-powders. In this paper, fabrication of flexible electrically conductive parts is proposed using aluminium metal powder as filler material. Aluminium metal powder is mixed with ethylene vinyl acetate (EVA) by chemical mixing process. Cyclohexane is used as a mixing medium in which EVA is dissolved and aluminium powder is added by weight. An in-house developed material extrusion tool mounted on CNC milling machine is used for printing of flexible electrically conductive samples. Pellet-based extrusion process is used for printing flexible parts as conventional filament-based 3D is not suitable due to buckling. Composite with filler loading in 5%, 10%, 20% and 30% were made and samples were printed. Investigations were made on printability of composite and its electrical conductivity. The aluminium fillers presence and dispersion in polymer were ensured. The samples were printed in temperature range of 130–140 °C through 0.4 mm diameter nozzle. It was found that the resistivity drops by around 60% on varying the filler concentration from 20% to 30%; 81.6 kΩ is the lowest resistance observed with 30% filler concentration. A simulation study on thermal behaviour of material extrusion tool has been done and is validated practically. The application of flexible electrically conductive parts lies in fabrication of various electronic devices like antenna, display boards, solar panels, and wearable health monitoring devices.

Molecular dynamics study of thermal transport at interface between alumina and epoxy resin

The study investigates heat transfer within a composite consisting of epoxy resin and alumina filler using all-atom molecular dynamics simulations. Various models of epoxy resin–alumina filler interfaces were analyzed, both with and without silane coupling agents (SCAs), to assess thermal conductivity and resistance. The results reveal that the presence of SCAs enhances heat transfer at the resin/filler interface. Conversely, models lacking SCAs exhibit a distinct temperature gap, indicating thermal resistance. In addition, the study suggests that effective heat transfer in polymer composites is influenced not only by molecular coupling at interfaces but also by the alignment of resin polymers.

Assessment of the performance of aluminum, copper, and graphene nanometer fillers filled woven glass fiber/epoxy composites

This study embedded graphene nanoplatelet (GNP), nano-sized aluminum and copper in epoxy-reinforced woven glass fiber. The 0.5 wt% nanofillers were incorporated into epoxy resin. Nanofilled glass fiber/epoxy hybrid composite laminates were fabricated using the hand layup technique. Fillers were dispersed in an epoxy matrix via the ultrasonic processor. The influence of the inclusion of these nanofillers on the physical and mechanical performance of glass fiber/epoxy composites was studied. The resulting hybrid nanocomposites illustrated good characteristics when compared to control specimens. The graphene nanophased glass fiber/epoxy composite achieved the maximum improvement of 59.2%, 91.5%, 74.7%, and 100% in in-plane shear, fracture toughness, impact, and interlaminar shear strength, respectively. Additionally, glass fiber/epoxy filled with GNP behaved as the lowest seawater absorption. Control filled with 0.5 wt% GNP showed strong fiber/matrix interfacial bonding in scanning electron microscopy images after being subjected to a fracture toughness test.

Characterisation of Nano Aluminium Oxide Filled Hybrid Cotton Glass FRP Composite Structures

Natural fiber-based composite manufacturing is now an expanding field of study, and it is the preferred option not only because of its exceptional qualities such as light weight, rigidity, low density and superior mechanical properties, but also because it is affordable, biodegradable, fully or mostly recyclable and renewable. A Glass Fibre is a type of Reinforced Polymer (GFRP) made of tiny glass fibers embedded in a plastic matrix. Hybridization of natural and synthetic fibres has to be done to overcome the shortfall of these fibres. When compared to single Fibre Reinforced Polymer (FRP) composites, fibre-reinforced hybrid composites offer improved mechanical, thermal, and damping characteristics. The goal of this research is to see how Nano Aluminum Oxide (Al2O3) fillers affect the characteristics of hybrid cotton-glass FRP composites. The vacuum bagging technique was used to make nano Al2O3 particles - hybrid cotton-glass FRP composites out of glass fibre chopped strand mat, cotton fabric, epoxy resin, and nano-Al2O3 fillers. The nano Al2O3 fillers were integrated in different weight (wt.) ratios in the FRP and the effect on tensile, flexural and impact properties were examined.

Analysis of the Effect of the Addition of Aluminum Powder on Polyester-Glass Composite Properties in Tensile and Hardness Test

The study aimed to analyse the influence of aluminum powder on the mechanical properties of polyester-glass composites. Composite materials were made of glass fibres with random fibre direction and polyester resin with the addition of aluminum powder as a filler. The strength parameters of materials obtained during the static tensile test and hardness test were compared. The results were subjected to statistical analysis, taking into account the change in the amount of filler, microstructure was also observed using optical microscopy. An analysis of the results showed that the addition of aluminum powder amounting to 2% of the weight of the composites reduces their hardness and, at the same time, the longitudinal modulus of elasticity.The addition of aluminum powder amounting to 5% and 10% of the weight of the composites increased the hardness of the composites while reducing the Young's modulus. The values of hardness measurements were subjected to statistical analyses at significance level α = 95. The Shapiro-Wilk test confirmed that the hardness variables for all tested samples were in normal distributions, and therefore the most powerful parametric tests were used to test the differences. Using the Student's t-test, it was confirmed that between pairs of variables in configurations: a standard sample with a modified sample, for all tested samples there are significant statistical differences in the distributions of hardness values. Studies have shown that the modification of the mechanical and strength properties of composite materials, through the use of an aluminum filler, makes it possible to obtain materials with variable parameters that can be useful and attractive in many new areas, depending on the application and user requirements.