Vapor Infiltration Research Articles

Abnormal mechanical hysteresis behavior of Tyranno-ZMI SiC/SiC containing Ti3Si(Al)C2

Abnormal mechanical hysteresis behavior of Tyranno-ZMI SiC/SiC containing Ti3Si(Al)C2

Preparation and properties of SiC/SiC-SiYC with excellent water-oxygen corrosion resistance

Preparation and properties of SiC/SiC-SiYC with excellent water-oxygen corrosion resistance

Controllable reduction of absorbance and two-step reaction for 3D-printed SiC ceramics with micron-level periodic structure

Controllable reduction of absorbance and two-step reaction for 3D-printed SiC ceramics with micron-level periodic structure

The effect of deposition temperature of BN interphase on the tensile properties of SiC fibers

The effect of deposition temperature of BN interphase on the tensile properties of SiC fibers

Bidirectional periodic pore structure Si-C-N multiphase ceramic with high thermostability and excellent microwave absorption properties over a wide temperature range

Bidirectional periodic pore structure Si-C-N multiphase ceramic with high thermostability and excellent microwave absorption properties over a wide temperature range

Effect of Nanoscale in Situ Interface Welding on the Macroscale Thermal Conductivity of Insulating Epoxy Composites: A Multiscale Simulation Investigation.

Insulating thermally conductive polymer composites are in great demand in integrated-circuit packages, for efficient heat dissipation and to alleviative short-circuit risk. Herein, the continuous oriented hexagonal boron nitride (h-BN) frameworks (o-BN@SiC) were prepared via self-assembly and in situ chemical vapor infiltration (CVI) interface welding. The insulating o-BN@SiC/epoxy (o-BN@SiC/EP) composites exhibited enhanced thermal conductivity benefited from the CVI-SiC-welded BN-BN interface. Further, multiscale simulation, combining first-principles calculation, Monte Carlo simulation, and finite-element simulation, was performed to quantitatively reveal the effect of the welded BN-BN interface on the heat transfer of o-BN@SiC/EP composites. Phonon transmission in solders and phonon-phonon coupling of filler-solder interfaces enhanced the interfacial heat transfer between adjacent h-BN microplatelets, and the interfacial thermal resistance of the dominant BN-BN interface was decreased to only 3.83 nK·m2/W from 400 nK·m2/W, plunging by over 99%. This highly weakened interfacial thermal resistance greatly improved the heat transfer along thermal pathways and resulted in a 26% thermal conductivity enhancement of o-BN@SiC/EP composites, compared with physically contacted oriented h-BN/EP composites, at 15 vol % h-BN. This systematic multiscale simulation broke through the barrier of revealing the heat transfer mechanism of polymer composites from the nanoscale to the macroscale, which provided rational cognition about the effect of the interfacial thermal resistance between fillers on the thermal conductivity of polymer composites.

The oxide-layer configuration alteration and pseudo-ductile crack propagation mechanisms in composites induced by different relative thicknesses of CVI HfC-SiC multiphase matrix

The oxide-layer configuration alteration and pseudo-ductile crack propagation mechanisms in composites induced by different relative thicknesses of CVI HfC-SiC multiphase matrix

Calculating the penetration depth of reaction in chemical gas-phase deposition of boron nitride within porous bodies

The thermodynamic calculations conducted using the TERRA software package for the B–Cl–N–H system revealed that the inclusion of hydrogen into the B–Cl system significantly diminishes the thermodynamic stability of BCl3 with the possibility of boron formation in the condensed phase. On the other hand, the introduction of ammonia, which includes hydrogen, results in the synthesis of boron nitride across a broad temperature spectrum. The analysis of kinetic relationships uncovered three distinct regions in the boron nitride deposition process: K – kinetic region (up to 1400 K), D – diffusion region (above 1800 K) and T – transition region. The activation energy for the kinetic region was calculated as Ea = 134 kJ/mol. Within the temperature range of 1023–1123 K, linear dependences were observed. The computation of the penetration depth for the boron nitride deposition process assumed a gas mixture of boron trichloride, ammonia, and argon (BCl3 + NH3 + 30Ar). The results indicated that boron trichloride governs the extent of penetration. The depths of penetration for the chemical vapor infiltration boron nitride (CVI-BN) process, conducted at 0.1 kPa within the temperature range of 1100–1400 K, were determined for pore diameters of 1, 10, 30, 100, 200 and 300 µm. When porosimetry data for a specific preform is available, the acquired penetration depth relationships for the CVI-BN process under specific parameters and process temperatures facilitate the estimation of essential parameters for interphase formation using pyrolytic boron nitride.

Long-term oxidation resistant SiC/SiC-SiHfBCN composites: A promising thermo-structural material aims for hypersonic roundtrip

Long-term oxidation resistant SiC/SiC-SiHfBCN composites: A promising thermo-structural material aims for hypersonic roundtrip

Microstructure control of BN interface and its effect on mechanical behavior of SiCf/SiC composites

Microstructure control of BN interface and its effect on mechanical behavior of SiCf/SiC composites

Preparation and long-term ablation behavior of Cf-reinforced ZrC-SiC coated C/C-ZrC-SiC composite

Preparation and long-term ablation behavior of Cf-reinforced ZrC-SiC coated C/C-ZrC-SiC composite

Porous Structure Inherited from Pine Wood and Stacking Defects Synergistically Enhancing Electromagnetic Wave Absorption of SiC

AbstractThe traditional electromagnetic (EM) absorbing materials suffers from the poor performance and instability at high temperature, greatly hindering their wide application. Herein, pine wood‐derived SiC with porous structure and plentiful defect sites was synthesized by carbonization and subsequent chemical vapor infiltration process. The influence of drying pretreatment way (freeze drying vs thermostatic drying), carbonization temperature and Si powder/carbon ratio on structure and electromagnetic (EM) wave absorption performance were studied in detail. The optimized SiC with plentiful pore structure and numerous stacking faults showed superior EM wave absorption abilities with a minimum RL value of −42 dB and the effective bandwidth of 14.4 GHz (3.6–18 GHz). The synergistic effect between porous structure inherited from pine wood and stacking faults distinctly enhanced EM wave absorbing performance of SiC. This work demonstrate that rationally design of biomass‐derived SiC material is a promising way of developing high performance absorber.

Ablation behavior of C/C-ZrC-SiC composite with gradient distribution of ZrC-SiC ceramics along the thickness

Ablation behavior of C/C-ZrC-SiC composite with gradient distribution of ZrC-SiC ceramics along the thickness

An innovative wood derived carbon-carbon nanotubes-pyrolytic carbon composites with excellent electrical conductivity and thermal stability

An innovative wood derived carbon-carbon nanotubes-pyrolytic carbon composites with excellent electrical conductivity and thermal stability

Multi-scale damage modeling and out-of-plane shear behavior of carbon/carbon honeycomb structure

Multi-scale damage modeling and out-of-plane shear behavior of carbon/carbon honeycomb structure

Fabrication process and growth mechanism of novel micro‐stack PyC interphase with different textures

AbstractPyrolytic carbon (PyC) interphase plays a crucial role in the mechanical properties of fiber‐reinforced ceramic matrix composites. In this research, a novel micro‐stack PyC interphase with different PyC textures was designed and fabricated by changing the deposition parameters during the chemical vapor infiltration process. The growth mechanism of the micro‐stack PyC interphase with different texture were also studied by experimental characterizations and kinetic calculations, and the results show that the content ratio of (C2H2 + C2H4) to C6H6 gas intermediate is a key parameter to control the texture types of PyC interphase. Furthermore, the value of orientation angle (OA) value, thickness, and modulus of the micro‐stack PyC interphase were further characterized by high resolution TEM (HRTEM), scanning electronic microscopy, and nanoindentation. Finally, the tensile testing of mini‐Cf/PyC/SiC composites was conducted, and the results showed that the tensile strength of mini‐Cf/PyC/SiC composites with micro‐stack PyC interphase is approximately 40% higher than that containing single high texture PyC interphase. The improvements on the tensile strength of Cf/PyC/SiC composites prove the significant advantages of micro‐stack PyC interphase.

The influence of grinding process on the mechanical behavior of SiC/SiC composite tubes under uniaxial tension

The influence of grinding process on the mechanical behavior of SiC/SiC composite tubes under uniaxial tension

The Kinetics of Chemical Vapor Infiltration of Pyrolytic Carbon from Propylene Using a Model Array of Capillaries

The Kinetics of Chemical Vapor Infiltration of Pyrolytic Carbon from Propylene Using a Model Array of Capillaries

Design of domain-limited CVI reactor for L-shaped C/C structure

Design of domain-limited CVI reactor for L-shaped C/C structure

Torsional failure analysis of C/SiC and SiC/SiC combined CMC torque tube

To overcome the inherent limitations of the ceramic matrix composite (CMC) process and increase the torque capacity of CMC torque tubes, this study investigated the failure causes of 2D woven chemical vapor infiltration (CVI) C/SiC and SiC/SiC combined CMC torque tubes. The CT test was used to describe the non-homogeneous density distribution of the CMC torque tubes. Using the Archimedes drainage method to evaluate density and porosity, we simulated the stress distribution and failure strength of CMC torque tubes using an FEM model. Fixtures suitable for universal material testing apparatuses were used for CMC torque tube torsional tests. The stress-strain curves showed that two distinct fiber types of CMC torque tubes displayed different torsional tendencies, and we examined the main causes of failure. The SiC fiber in the CMC torque tube increased maximum shear stress and modulus. Additionally, the strength of the SiC/SiC torque tube, rather than the interface between the C/SiC and SiC/SiC torque tubes, was the primary cause of combined CMC torque tube failure.