Synergistic thermal conductivity enhancement of PC/ABS composites containing alumina/magnesia/graphene nanoplatelets

Graphene nanoplatelets (GNPs) have attracted considerable attention in the field of thermal management materials due to their unique structure and exceptional thermal conductive properties. In this work, we demonstrate a significant synergistic effect of GNPs, alumina (Al₂O₃), and magnesia (MgO) in improving the thermal conductivity of polycarbonate/acrylonitrile‐butadiene‐styrene polymer alloy (PC/ABS) composites. The thermal conductivity of the composites prepared through partial replacement of Al₂O₃ and MgO with GNPs could increase dramatically compared with that without GNPs. The maximum thermal conductivity of the composite is 3.11 W mK⁻¹ at total mass fraction of 70% with 0.5 wt% GNPs loading. It increases 60% compared with that without GNPs (1.95 W mK⁻¹). The synergistic effect results from the compact packing structure formed by Al₂O₃/MgO and the bridging of GNPs with Al₂O₃/MgO, thus promoting the formation of effective thermal conduction pathways within PC/ABS matrix. More importantly, together with the intrinsically high thermal conductivity of GNPs, boosted and effective pathways for phonon transport can be created, thus decrease the thermal resistance at the interface between fillers and PC/ABS matrix and increase the thermal conductivity of composites. POLYM. COMPOS., 38:2221–2227, 2017. © 2015 Society of Plastics Engineers     

A Concurrent Enhancement of Both In-Plane and Through-Plane Thermal Conductivity of Injection Molded Polycarbonate/Boron Nitride/Alumina Composites by Constructing a Dense Filler Packing Structure

In this work, a facile strategy is proposed to concurrently enhance both in-plane and through-plane thermal conductivity of injection molded polycarbonate (PC)-based composites by constructing a dense filler packing structure with planar boron nitride (BN) and spherical alumina (Al₂O₃) particles. The state of orientation of BN platelets is altered with the presence of Al₂O₃, which is favorable for improving both in-plane and through-plane thermal conductivity of subsequent moldings. Rheological analysis showed that the formation of intact thermal conductive pathways is crucial to the overall enhancement of thermal conductivity. Both in-plane and through-plane thermal conductivity of PC/BN(20 wt%)/Al₂O₃(40 wt%) composites reached as high as 1.52 and 1.09 W mK⁻¹, which are 485% and 474% higher than that of pure PC counterparts, respectively. Furthermore, the prepared samples demonstrated excellent electrical insulation and dielectric properties which show potential application in electronic and automotive industries.     

Melt compounded polylactic acid-hexagonal boron nitride-aluminum oxide hybrid composites for electronic applications: impact of hybrid fillers on thermophysical,dielectric, optical,and hardness properties

ABSTRACT

The dielectric, thermophysical, optical, and hardness of pure polylactic acid (PLA) and hBN micropowder and Al₂O₃ nanopowder (1% to 30%) reinforced PLA hybrid composites were investigated. Hybrid composites exhibit improved thermal conductivity (k – 0.54 W/mK), permittivity (?? – 4.6720 @ 1 MHz to 1 GHz) with very low loss tangent (tan δ < 0.02). High absorption in UV region was observed for all hybrid composites. Overall, the prepared hybrid composites can be used as a bio-based dielectric substrates, enclosures, thermal interface material for low temperature applications and UV-absorbable coating materials for fabric, packaging, and storage applications.     

Biphenyl liquid crystal epoxy containing flexible chain: Synthesis and thermal properties

A biphenyl type liquid crystal epoxy (LCE) monomer 4,4′-di(2,3-epoxyhexyloxy)biphenyl (LCBP4) containing flexible chain was synthesized and the curing behavior was investigated using 4,4′-diaminodiphenylmethane (DDM) as the curing agent. The effect of curing condition on the formation of the liquid crystalline phase was examined. The cured samples show good mechanical properties and thermal stabilities. Moreover, the relationship between thermal conductivity and structure of liquid crystalline domain was also discussed. The samples show high thermal conductivity up to 0.28–0.31 W/(m*K), which is 1.5 times as high as that of conventional epoxy systems. In addition, thermal conductive filler, Al₂O₃, was introduced into LCBP4/DDM to obtain higher thermal conductive composites. When the content of Al₂O₃ was 80 wt%, the thermal conductivity of the composite reached to 1.86 W/(m*K), while that of diglycidyl ether of bisphenol A (Bis-A) epoxy resin/DDM/Al₂O₃ was 1.15 W/(m*K). Compared with Bis-A epoxy resin, the formation of liquid crystal domains in the cured LCE resin enhanced the thermal conductivity synergistically with the presence of Al₂O₃. Furthermore, the introduction of Al₂O₃ also slightly increased the thermal stabilities of the cured LCE.     

Spherical hybrid filler BN@Al2O3 via chemical adhesive for enhancing thermal conductivity and processability of silicon rubber

Hexagonal boron nitride (h-BN) is an ideal candidate material for electrical and electronic systems due to its excellent performance. However, the addition of platelet-like h-BN leads to a dramatic increase of viscosity of composites and anisotropic thermal conductivity of composites. Herein, modified h-BN (m-BN) was coated onto spherical α-Al₂O₃ via chemical adhesive, and core-shell structured hybrid spherical filler (m-BN@Al₂O₃) was prepared. Furthermore, the microstructure, rheology, mechanical properties, and thermal conductivity of hybrid filler/polydimethylsiloxane (PDMS) were studied. At 60 vol% filler loading, the thermal conductivity of m-BN@Al₂O₃/PDMS is up to 2.23 W·m⁻¹·K⁻¹, which is 86% higher than that of Al₂O₃/PDMS and the ratio of in-plane diffusivity to through-plane diffusivity decreases from 2.0 to 1.0. At meanwhile, the viscosity of m-BN@Al₂O₃/PDMS is about one fourth of the viscosity of m-BN/Al₂O₃/PDMS. This simple and versatile strategy opens a pavement for enhancing the thermal conductivity of polymer and has great potential in high-frequency communication.     

Process induced alignment of carbon nanotube decreases longitudinal thermal conductivity of Al2O3 based porous composites

Alumina (Al₂O₃) based porous composites, reinforced with zirconia (ZrO₂), 3 and 8 mol% Y₂O₃ stabilized ZrO₂ (YSZ) and 4 wt% carbon nanotube (CNT) are processed via spark plasma sintering. The normalized linear shrinkage during sintering process of Al₂O₃-based composite shows minimum value (19.2–20.4%) for CNT reinforced composites at the temperature between 1650 °C and 575 °C. Further, the combined effect of porosity, phase-content and its crystallite size in sintered Al₂O₃-based porous composite have elicited lowest thermal conductivity of 1.2 Wm⁻¹K⁻¹ (Al₂O₃-8YSZ composite) at 900 °C. Despite high thermal conductivity of CNT (∼3000 Wm⁻¹K⁻¹), only a marginal thermal conductivity increase (∼1.4 times) to 7.3–13.4 Wm⁻¹K⁻¹ was observed for CNT reinforced composite along the longitudinal direction at 25 °C. The conventional models overestimated the thermal conductivity of CNT reinforced composites by up to ∼6.7 times, which include the crystallite size, porosity, and interfacial thermal resistance of Al₂O₃, YSZ and, CNT. But, incorporation of a new process induced CNT-alignment factor, the estimated thermal conductivity (of <6.6 Wm⁻¹K⁻¹) closely matched with the experimental values. Moreover, the high thermal conductivity (<76.1 Wm⁻¹K⁻¹) of the CNT reinforced porous composites along transverse direction confirms the process induced alignment of CNT in the spark plasma sintered composites.     

Influence of ball milling contamination on properties of sintered AlN substrates

The AlN substrate was fabricated by the tape casting process, and its thermal conductivity and electrical conductivity were investigated for various ball milling times and types of milling media. The oxygen content was measured after ball milling, de-binding process, and sintering. The oxygen content after the de-binding process was 1.2–2.3 wt%, similar to that after milling. After the de-binding process, the specimens were sintered at 1850 ℃ for 3 h in nitrogen atmosphere. The thermal conductivity of the sintered specimens decreased from 158 W m⁻¹ K⁻¹ to 100 W m⁻¹K⁻¹ with increasing milling time. Simultaneously, the electrical conductivity decreased from approximately 10⁻⁷ Ω⁻¹ cm⁻¹ to 10⁻⁹ Ω⁻¹ cm⁻¹ at 500 °C when Al₂O₃ or ZrO₂ balls were used, whereas the electrical conductivity did not decrease when Si₃N₄ balls were used.     

Novel heat‐conductive composite silicone rubber

The silicone rubber with good thermal conductivity and electrical insulation was obtained by taking vinyl endblocked polymethylsiloxane as basic gum and thermally conductive, but electrically insulating hybrid Al₂O₃ powder as fillers. The effects of the amount of Al₂O₃ on the thermal conductivity, coefficient of thermal expansion (CTE), heat stability, and mechanical properties of the silicone rubber were investigated, and it was found that the thermal conductivity and heat stability increased, but the CTE decreased with increasing Al₂O₃ fillers content. The silicone rubber filled with hybrid Al₂O₃ fillers exhibited higher thermal conductivity compared with that filled with single particle size. Furthermore, a new type of thermally conductive silicone rubber composites, possessing thermal conductivity of 0.92 W/mK, good electrical insulation, and mechanical properties, was developed using electrical glass cloth as reinforcement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2478–2483, 2007     

Multi-contact hybrid thermal conductive filler Al2O3@AgNPs optimized three-dimensional thermal network for flexible thermal interface materials

In this work, a multi-contact Al₂O₃@AgNPs hybrid thermal conductive filler was synthesized by in-situ growth method to fill high thermal conductivity polydimethylsiloxane (PDMS)-based composites to prepare TIMs. And the thermal conductivity, electrical conductivity, and mechanical properties of the composite materials were studied. During the synthesis process of the multi-contact hybrid filler, different concentrations of silver ions were reduced to generate silver nanoparticles and attached to the surface of Al₂O₃. Al₂O₃@AgNPs/PDMS thermally conductive composites were prepared by changing the filler addition. Using SEM, XPS, and XRD is used to characterize the morphology and chemical composition of Al₂O₃@AgNPs hybrid filler. The thermal conductivity of PDMS-based composites with different AgNPs content under 70 wt% filler loading was studied. The results show that the thermal conductivity of PDMS-based composites filled with 7owt%Al₂O₃@3AgNPs/PDMS multi-contact hybrid filler is 0.67 W/m·K, which is 3.72 times that of pure PDMS, and is higher than that of unmodified Al₂O₃ with the same addition amount. /PDMS composite material has a high thermal conductivity of 24%. This work provides a new idea for the design and manufacture of high thermal conductivity hybrid fillers for TIMs.     

A study of phase evolution and crystal growth for nano-sized monoclinic Y4Al2O9 as a novel thermal barrier coatings

Nano-sized monoclinic Y₄Al₂O₉ was produced by sol-gel process as a novel potential candidate material for thermal barrier coatings. The thermal behavior, structural evolution of the products and the morphological characteristics of the compacted bodies were investigated by Thermogravimetric analysis and differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Field emission scanning electron microscopy (FESEM). Qualitative analyses indicate that monoclinic Y₄Al₂O₉ was formed at about 1000 °C, and exhibited good phase stability throughout the annealing temperature ranging from 1000 °C to 1400 °C. The thermophysical properties of Y₄Al₂O₉ ceramics were also evaluated compared with 8YSZ and La₂Zr₂O₇. The determined activation energy of crystal growth is about 72.71 ± 0.31 kJ mol⁻¹. Meanwhile, Y₄Al₂O₉ represents low thermal conductivity (1.71 W m⁻¹ K⁻¹), moderate thermal expansion coefficient (8.73 × 10⁻⁶ K⁻¹), and high sintering-resistance ability. Such results reveal that nano-sized Y₄Al₂O₉ is favorable for the application of TBCs.     

Poly(methyl methacrylate)-functionalized reduced graphene oxide-based core–shell structured beads for thermally conductive epoxy composites

Thermally conductive epoxy nanocomposite with core–shell structured filler beads has been prepared. The core represents plasma-treated poly(methyl methacrylate) bead, and the shell, amine-functionalized reduced graphene oxide (frGO) sheets. The negatively charged core and the positively charged shell form core–shell unified structure through electrostatic attraction and the conductive bridges are formed among neighboring filler particles in the composite mass. The epoxy composite prepared with these core–shell structured filler shows a thermal conductivity of 0.72 W m⁻¹ K⁻¹ for an overall frGO concentration of as low as 0.96 wt %. Pal model has been applied to evaluate the effective thermal conductivity of frGO sheets that have been realized in the epoxy composition. Assuming the maximum possible volume packing fraction of the spherical beads for random jamming to be equal to 0.63, the effective thermal conductivity has been estimated as 280 W m⁻¹ K⁻¹. Evaluation of the effective thermal conductivity is a step forward to in-depth study of real contribution of the highly conductive fillers in the polymer composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47377.     

Electrical conductivity and thermal properties of spark plasma sintered Al2O3-SiC-CNT hybrid nanocomposites

In this study, we report the electrical conductivity and thermal properties of Al₂O₃-SiC-CNT hybrid nanocomposites processed via ball milling (BM) and spark plasma sintering (SPS). The initial powders and consolidated samples were characterized using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM), respectively. A multifunction calibrator and a high-resolution digital multimeter were used to measure the electrical conductivity. The thermal properties were measured using a thermal constants analyser. The SiC and CNT-reinforced alumina hybrid nanocomposites exhibited a significant increase in their room-temperature electrical conductivity, which made them suitable for electrical discharge machining. The Al₂O₃-5SiC-2CNTs had a high electrical conductivity value of 8.85 S/m compared to a low value of 6.87×10⁻¹⁰ S/m for the monolithic alumina. The addition of SiC and CNTs to alumina decreased its room-temperature thermal properties. The increase in temperature resulted in a decrease in the thermal conductivity and thermal diffusivity but an increase in the specific heat of the monolithic alumina and the hybrid nanocomposites. These properties were correlated with the microstructure, and possible transport mechanisms were discussed.     

Thermal and electrical properties of epoxy composites at high alumina loadings and various temperatures

Epoxy microcomposites with high loading micro alumina (Al₂O₃, 100–400 phr) were prepared by casting method and their thermal and electrical properties were studied at temperatures from 25 to 150 °C. The electric resistance device and the dielectric electrode device were designed to measure the electrical properties of the composites. Thermogravimetric analysis (TGA) and scanning electron microscopic proves the homodispersion of Al₂O₃ microparticles in epoxy. TGA indicates that the temperature of 5 % weight loss of epoxy/Al₂O₃ (100 phr) composite is 366 °C, 34 °C higher than that of pure epoxy. Differential scanning calorimetry shows that the glass transition temperature of epoxy/Al₂O₃ composite (400 phr) increases to 114.7 °C, 9.2 °C higher than that of pure epoxy. Thermal conductivity test demonstrated that with increasing Al₂O₃ content at 25 °C, thermal conductivity of epoxy/Al₂O₃ composites increased to 1.382 W/(m K) which is 5.62 times that of pure epoxy. Electrical tests demonstrate that by increasing of Al₂O₃ content and temperature, the electric resistance and dielectric properties of the composites show great dependencies on them. Resistivities of all the specimens decreased with the increasing of temperature owing to the increasing molecular mobility in the higher temperature. Resistivity of pure epoxy at 25 °C is about 9.56 × 10¹⁶ Ω cm, about one order of magnitude higher than that of pure epoxy at 125 °C and two orders of magnitude higher than that of pure epoxy at 150 °C. These results can give some advice to design formulations for practical applications in power apparatus.     

Screening rare-earth aluminates as promising thermal barrier coatings by high-throughput first-principles calculations

Thermal barrier coatings (TBCs) play an important role in gas turbines to protect the turbine blades from the high-temperature airflow damage. In this work, we use first-principles calculations to investigate a specific class of rare-earth (RE) aluminates, including cubic-REAlO₃ (c-REAlO₃), orthorhombic-REAlO₃ (o-REAlO₃), RE₃Al₅O₁₂, and RE₄Al₂O₉, to predict their structural stability, bonding characteristics, and mechanical and thermal properties. The polyhedron structures formed by the Al–O bonds are stronger and exhibit rigid characteristics, whereas the polyhedra formed by the RE–O bonds are relatively weak and soft. The alternating stacking of AlO₄ tetrahedra, AlO₆ octahedra, and RE–O polyhedra, as well as the selection of RE elements, shows intensive influences on the expected mechanical and thermal properties. The B, G, and E of these four types of aluminates decrease in the order of c-REAlO₃ > o-REAlO₃ > RE₃Al₅O₁₂ > RE₄Al₂O₉. REAlO₃ and RE₄Al₂O₉ are brittle and quasi-ductile ceramics, respectively, whereas RE₃Al₅O₁₂ is tailorable. The minimum thermal conductivity is in the range of 1.4–1.5 W m⁻¹ K⁻¹ for c-REAlO₃, 1.3–1.4 W m⁻¹ K⁻¹ for o-REAlO₃, 1.25–1.35 W m⁻¹ K⁻¹ for RE₃Al₅O₁₂, and 0.8–0.9 W m⁻¹ K⁻¹ for RE₄Al₂O₉. RE₄Al₂O₉ with low thermal conductivity and damage tolerance is predicted to be the potential candidates for next-generation TBC materials.     

Effect of nanoparticles on the performance of thermally conductive epoxy adhesives

Microsized or nanosized α‐alumina (Al₂O₃) and boron nitride (BN) were effectively treated by silanes or diisocyanate, and then filled into the epoxy to prepare thermally conductive adhesives. The effects of surface modification and particle size on the performance of thermally conductive epoxy adhesives were investigated. It was revealed that epoxy adhesives filled with nanosized particles performed higher thermal conductivity, electrical insulation, and mechanical strength than those filled with microsized ones. It was also indicated that surface modification of the particles was beneficial for improving thermal conductivity of the epoxy composites, which was due to the decrease of thermal contact resistance of the filler‐matrix through the improvement of the interface between filler and matrix by surface treatment. A synergic effect was found when epoxy adhesives were filled with combination of Al₂O₃ nanoparticles and microsized BN platelets, that is, the thermal conductivity was higher than that of any sole particles filled epoxy composites at a constant loading content. The heat conductive mechanism was proposed that conductive networks easily formed among nano‐Al₂O₃ particles and micro‐BN platelets and the thermal resistance decreased due to the contact between the nano‐Al₂O₃ and BN, which resulted in improving the thermal conductivity. POLYM. ENG. SCI., 50:1809–1819, 2010. © 2010 Society of Plastics Engineers     

Thermal,electrical, and mechanical properties of addition-type liquid silicone rubber co-filled with Al2O3 particles and BN sheets

The addition-type liquid silicone rubber (ALSR) co-filled with spheroidal Al₂O₃ and flaky BN was prepared by the mechanical blending and hot press methods to enhance the thermal, electrical, and mechanical properties for industrial applications. Morphologies of ALSR composites were observed by scanning electron microscopy (SEM). It was found that the interaction and dispersion state of fillers in the ALSR matrix were improved by the introduction of BN sheets. Thermal, electrical, and mechanical performances of the ALSR composites were also investigated in this work. The result indicated that the thermal conductivity of ALSR can reach 0.64 W m⁻¹ K⁻¹ at the loading of 20 wt% Al₂O₃/20 wt% BN, which is 3.76 times higher than that of pure ALSR. The addition of Al₂O₃ particles and BN sheets also improve the thermal stability of ALSR composites. Moreover, pure ALSR and ALSR composites showed relatively lower dielectric permittivity (1.9–3.1) and dielectric loss factor (<0.001) at the frequency of 10³ Hz. The insulation properties including volume resistivity and breakdown strength were improved by the introduction of flaky BN in the ALSR matrix. The volume resistivity and characteristic breakdown strength E₀ are 6.68 × 10¹⁵ Ω m and 93 kV/mm, respectively, at the loading of 20 wt% Al₂O₃/20 wt% BN. In addition, the mechanical characteristics including elongation at break and tensile strength of ALSR composites were also enhanced by co-filled fillers. The combination of these improved performances makes the co-filled ALSR composites attractive in the field of electrical and electronic applications.     

Simultaneously enhanced mechanical properties and thermal properties of ultrahigh‐molecular‐weight polyethylene with polydopamine‐coated α‐alumina platelets

Polydopamine (PDA) was employed to modify micrometric Al₂O₃ platelets to improve the interfacial compatibility between α‐Al₂O₃ powder and ultrahigh‐molecular‐weight polyethylene (UHMWPE). The structure of PDA‐coated Al₂O₃ and UHMWPE composites was investigated via Fourier transform infrared spectroscopy, scanning electron microscopy and X‐ray photoelectron spectroscopy. The thermal stability and mechanical performance of the samples were also evaluated. It is clear that UHMWPE/PDA‐Al₂O₃ composites exhibit better mechanical properties, higher thermal stability and higher thermal conductivity than UHMWPE/Al₂O₃ composites, owing to the good dispersion of Al₂O₃ powder in the UHMWPE matrix and the strong interfacial force between the macromolecules and the inorganic filler caused by the presence of PDA. The tensile strength and the tensile elongation at break of UHMWPE/PDA‐Al₂O₃ composite with 1 wt% PDA‐Al₂O₃ are 62.508 MPa and 462%, which are 1.96 and 1.98 times higher than those of pure UHMWPE, respectively. The thermal conductivity of UHMWPE/PDA‐Al₂O₃ composite increases from 0.38 to 0.52 W m^?1 K^?1 with an increase in the dosage of PDA‐Al₂O₃ to 20 wt%. The results show that the prepared PDA‐coated Al₂O₃ powder can simultaneously enhance the mechanical properties and thermal conductivity of UHMWPE. © 2018 Society of Chemical Industry     

Polymer composites with enhanced thermal conductivity via oriented boron nitride and alumina hybrid fillers assisted by 3-D printing

Herein, oriented boron nitride (BN)/alumina (Al₂O₃)/polydimethylsiloxane (PDMS) composites were obtained by filler orientation due to the shear-inducing effect via 3-D printing. The oriented BN platelets acted as a rapid highway for heat transfer in the matrix and resulted in a significant increase in the thermal conductivity along the orientation direction. Extra addition of spherical Al₂O₃ enhanced the fillers networks and resulted in the dramatic growth of slurry viscosity. This, together with filler orientation induced the synergism and provided large increases in the thermal conductivity. A high orientation degree of 90.65% and in-plane thermal conductivity of 3.64 W/(m∙K) were realized in the composites with oriented 35 wt% BN and 30 wt% Al₂O₃ hybrid fillers. We attributed the influence of filler orientation and hybrid fillers on the thermal conductivity to the decrease of thermal interface resistance of composites and proposed possible theoretical models for the thermal conductivity enhancement mechanisms.     

High lumen density of Al2O3-LuAG: Ce composite ceramic for high-brightness display

Thermally robust and highly efficient green-emitting luminescent ceramics are gradually attracting great attention as promising phosphors using in high-brightness laser phosphor display to reduce serious speckle noise as well as high cost. However, lumen density is still seriously restricting their potential applications especially under high-power density laser due to insufficient absorption of blue laser and significant thermal quenching. Here, we report an Al₂O₃-LuAG: Ce composite ceramic phosphor (CCP) for high-brightness laser phosphor display. Owing to good optical properties and high thermal conductivity of Al₂O₃, the Al₂O₃-LuAG: Ce CCP shows high photoluminescence quantum yield (79.6%), low thermal quenching (only 3.2% loss in luminescence at 200°C), and high thermal conductivity (18.9 W·m⁻¹·K⁻¹). Moreover, the Al₂O₃, as scattering centers, enhances the Rayleigh–Mie scattering of the blue laser, and hence the absorption of the Al₂O₃-LuAG: Ce CCP exhibits a remarkable improvement (~2.3 times) at 450 nm. Finally, with optimized thickness (0.3 mm) of Al₂O₃-LuAG: Ce CCP, an excellent luminous efficiency (216 lm·W⁻¹) and outstanding lumen density (6129 lm·mm⁻²) of the green-emitting light source was obtained by driving under a high-power density (28.33 W·mm⁻²) blue laser. All of those validate the suitability of the Al₂O₃-LuAG: Ce CCP for high-brightness display.     

Powder injection molding of complex-shaped aluminium nitride ceramic with high thermal conductivity

Aluminum nitride (AlN) is a promising material for heat sinks and microelectronic applications because of the advantages of high theoretical thermal conductivity, high mechanical strength, good electrical insulation, low dielectric constant and low thermal expansion coefficient. However, the difficulties in shaping complex-shaped parts with a high thermal conductivity have retarded the wide applications of AlN ceramic. Herein, we design a new binder system containing resin components and adopt the powder injection molding technology to fabricate complex-shaped AlN parts. After the debinding process, the special binder system would produce residual carbon, which could react with Al₂O₃ and result in decreasing oxygen impurity and forming the yttrium-rich aluminates. The yttrium-rich aluminates can accelerate the densification of AlN ceramic and fasten the oxygen on the triangular grain boundary, leaving the clean grain boundary beneficial for high thermal conductivity. The as-prepared AlN parts with complex shape possess a high thermal conductivity of 248 W m⁻¹ K⁻¹.