Ablation Resistance Properties Research Articles

Ablation resistance and mechanical properties of C/C-HfC-SiC composites with a bulletproof-like layer

Two structural designs are based on the arapaima fish scale structure to enhance the performance of composites. A double-layer SiC/PyC coating was deposited to modify C/C-HfC-SiC composites by chemical vapor deposition. The introduction of PyC coating reduced the porosity and roughness of composites. Ar-O2-Al2O3 plasma ablation system was used to assess the composites. The composites with arapaima fish scale structure showed good flexural and ultra-temperature particle erosion resistance. The samples with the introduction of PyC layer showed higher flexural strength of 220 MPa, which is 40.13 % higher than that of without. After ablation 40 s, the linear ablation rates decreased from 5.95 μm/s to −4.6 μm/s. This study provides new ideas to develop C/C composites with improved ablation-resistant and mechanical properties.

Enhancing Ablation Resistance of TaB2-Based Ultra-High Temperature Ceramics by Mixing Fine TaC Particles and Dispersed Multi-Walled Carbon Nanotubes.

Ultra-high temperature ceramics (UHTCs) have been widely applied in many fields. In order to enhance the comprehensive properties of TaB2-based UHTCs, the first collaborative use of fine TaC particles and dispersed multi-walled carbon nanotubes (MWCNTs) was employed via spark plasma sintering (SPS) at 1700 °C. The derived UHTCs exhibited an average grain size of 1.3 μm, a relative density of 98.6%, an elastic modulus of 386.3 GPa, and a nano hardness of 21.7 GPa, leading to a greatly improved oxidation resistance with a lower linear ablation rate at -3.3 × 10-2 μm/s, and a markedly reinforced ablation resistance with mass ablation rate of -1.3 × 10-3 mg/(s·cm2). The enhanced ablation resistance was attributable to the physical pinning effect, sealing effect and self-healing effect. Thus, this study provides a potential strategy for preparation of UHTCs with bettered ablation resistance and physical properties.

Boron and Nitrogen Doping in Fused Silica Ceramics: Structural, High-Temperature Mechanical and Long-Term Ablation Resistance Properties of Si-B-O-N Ceramics

Boron and Nitrogen Doping in Fused Silica Ceramics: Structural, High-Temperature Mechanical and Long-Term Ablation Resistance Properties of Si-B-O-N Ceramics

The synthesis of high sinterability (Zr, Hf)C and SiC hybrid nanocrystalline particles by sol-gel method

Multi-phase UHTCs are favoured for their superior ablation resistance and mechanical properties. In this work, to improve the efficiency and decrease the sintering temperature and pressure, the (Zr, Hf)C and SiC hybrid nanocrystalline particles were prepared via the sol-gel method combining carbothermal reduction at 1600 °C. Utilizing their high sinterability, a relative density of 96.1% (Zr, Hf) C–SiC composite was obtained at the conditions of 1900 °C and 30 MPa using SPS technology. XPS and FT-IR results demonstrate that Zr, Hf, and Si were successfully trapped in the cross-linking structure of the precursors. Precursors of Zr, Hf, and Si reached a molecular-level mixture in the gel phase. SEM, XPS, and XRD characterization showed that the Si–C bond was formed preferentially, leading to the emergence of SiC whiskers and SiC wrapped (Zr, Hf)C with increasing temperature. And, the (Zr, Hf)C can be easily generated during solid solution reaction. Eventually, a nanoscale mixture of (Zr, Hf)C and SiC particles was successfully obtained at 1600 °C. The hardness and compressive strength of the (Zr, Hf)C–SiC composite were 12.94 GPa and 622 MPa, respectively. Comparing usual sintering processes (over 2000 °C and 35 MPa), the reason for the improved sinterability can be attributed to the high sintering activity of the (Zr, Hf)C and SiC hybrid particles, and the existence of the solid solution and nano-SiC.

Graphene-Enhanced CuW Composites for High-Voltage Circuit Breaker Electrical Contacts

To address the issue of over-standard short-circuit currents in a power system, it is imperative to enhance the comprehensive performance of the electrical contacts, which serve as the lynchpin of circuit breakers, so as to improve the breaking capacity of high-voltage circuit breakers. Graphene, as the most prominent two-dimensional carbon material in recent years, has garnered widespread applications across various fields. In this study, graphene-enhanced CuW composites for high-voltage circuit breaker electrical contacts were prepared innovatively using integrated vacuum infiltration technology. The innovative graphene-enhanced CuW composites significantly improved the mechanical, electrical, and ablation resistance properties, and have been successfully applied in the 252 kV/63 kA high-voltage SF6 circuit breakers, achieving 20 times effective consecutive full-capacity short-circuit current breaking. It provides a new route for the development and application of high-performance CuW electrical contacts. Looking ahead, it is planned to extend their application to higher voltage grade high-voltage circuit breakers.

Properties of shape memory polyimide composites with continuous “brick-and-mortar” layered structure: High flame retardancy, ablation resistance, and high mechanical properties

Shape memory polymer (SMP) is a type of smart materials mostly working below 200 ℃, which is difficult to be applied in the ultra-high temperature, even 1000 ℃. Herein, we have prepared shape memory polyimide composites (SMPIC) inspired by nacre “brick-and-mortar” layered structure. The SMPIC has the flame-retardant grade of V0 and the limiting oxygen index of 53.1% when the flame retardants amount is 20%. Besides, it has excellent resistance to high temperature airflow erosion, and the mass ablation ratio is 0.0053 g/s. After rapid thermal processing at 1000 ℃, the mechanical strength is 100 MPa, and the strength retention ratio is 103.3%. Also, the simple actuator can overturn iron blocks that are more than 8 times of its own weight, thus, the smart composite has huge application prospects in the high temperature environment, such as active morphing re-entry parachute, which provides reference for lightweight smart structures.

Improving the ablation resistance of epoxy modified organosilicon resin synergistic modified with B2O3 and ZrSi2

The boron oxide and zirconium silicide synergistic modified epoxy modified organosilicon resin composites were prepared and the ablation resistance properties of the composites were analyzed. With the synergistic effect of boron oxide and zirconium silicide, the properties, such as: the residue yield, hardness, tensile strength and ablation resistance (oxyacetylene ablation and static muffle furnace ablation) of the samples are markedly enhanced. The oxyacetylene linear ablation rate of the modified composite was observed to the minimum (0.04 mm s−1), when the contents of resin, boron oxide and zirconium silicide are 100 g, 50 g, and 150 g, respectively. The skeleton-like compact structure formed in the surface of composites after oxyacetylene ablation, which results in the best ablation resistance.

Development of EPDM composites reinforced by CNTs@SiO2 for thermal protection systems of aerospace propulsion: Significant improvement in oxidation and ablation resistance properties

Carbon Nanotubes (CNTs) reinforced Polymer-Matrix Composites (PMCs) is widely used as insulation materials in thermal protection system of aerospace propulsion. However, CNTs are prone to oxidation and have high thermal conductivities, which makes it difficult to improve the ablation resistance of insulation materials that contain CNTs. SiO2 was encapsulated onto the surface of CNTs (CNTs@SiO2), which were then added to Ethylene Propylene Diene Monomer (EPDM) rubber to prepare the insulation materials. Thermogravimetric analysis and ablation test were used to evaluate the resistance of the insulation materials to thermal oxidation and ablation. Additionally, scanning electron microscopy was performed to analyze their microstructures. Results revealed that the addition of CNTs@SiO2 could visibly reduce the effects of hot corrosion and ablation on insulation materials. The C-CNTs@SiO2-1 formulation had the best ablative resistance. Further, compared with the unencapsulated formulation (C-CNTs-10), the C-CNTs@SiO2-1 formulation reduced the line ablation rate by 51% to 0.0130 mm/s after oxygen-acetylene experiments. Lastly, the ablation mechanism was investigated based on the effects of the CNTs@SiO2 additive on their properties. Thus, the improvement in ablation performance may be attributed to CNTs@SiO2-induced decreases in thermal conductivity, improvement in the hot corrosion resistance in the char layer, and changes in the microstructure.

Improving ablation-resistant properties of novolac epoxy coatings via boric acid or POSS-modified expandable graphite with a PDA bridge

Improving ablation-resistant properties of novolac epoxy coatings via boric acid or POSS-modified expandable graphite with a PDA bridge

High ablation-resistant silicone rubber composites via nanoscale phenolic resin dispersion

High ablation-resistant silicone rubber composites exhibit significant potential for solid rocket engine ablation coating applications. However, the low char yield of silicone rubber restricts its real-world usage. Herein, silicone rubber with nanoscale dispersed Novolac-type phenolic resin particles (novolac-silicone rubber, NSR) is synthesized. The introduction of dynamic urethane bonds is crucial for achieving nanoscale dispersion of the phenolic resin, as it leads to both improved mechanical strength and enhanced char yield. In addition, the NSR-based composite materials demonstrate linear and mass ablation rates of 0.1440 mm/s and 0.0466 g/s, respectively, representing reductions of 44.19 % and 17.81 % compared with their conventional silicone rubber counterparts. Moreover, unlike the traditional physical blending approach, the nanoscale dispersion in this work is achieved by introducing a dihydroxypropyl-terminated silicone oil-novolac phenolic resin block copolymer to the silicone rubber matrix. The enhanced structural compatibility is proven to be pivotal for the improved performance of NSR. This work provides new routes for the synergistic improvement of the ablation resistance and mechanical properties of silicone rubber composites.

Optimized ablation resistance behavior and mechanism of C/SiC composites with high thermal conductive channels

AbstractAimed to enhance the high‐temperature service performance of C/SiC composites in high‐speed aircraft thermal protection system, in this article, pitch‐based carbon fibers were used to construct high thermal conductive channels to improve the heat transfer capability of C/SiC composites. The results revealed that the as‐prepared composites equipped with 4.7 times higher thermal conductivity than that of conventional C/SiC composites. The oxyacetylene flame ablation test confirmed that the constructed high thermal conductive channels, which quickly conducted the heat flow from the ablation center area to other areas is the main reason of as‐prepared composites exhibiting a very impressive ablation resistance property. Briefly, the ablation temperature of the as‐prepared composite surfaces considerably dropped by about 300°C compared with conventional C/SiC composites, while the linear ablation rate and mass ablation rate of the composites are 1.27 μm/s and 0.61 mg/s respectively, which is superior to many recent reports, demonstrating that this article provides a simple but highly effective measure to improve the ablation resistance property of C/SiC composites.

Two birds with one stone: Construction of bifunctional-POSS hybridized boron-silicon ceramicized phenolic composites and its ablation behavior

To further enhance the ablation resistance properties of thermosetting phenolic resin matrix composites, in this work, bifunctional alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized to catalyze the synthesis of boron phenolic resin and provide silicon source to obtain boron-silicon hybrid phenolic resin (BPOSSPR) with excellent ablative resistance. BPOSSPR possesses a low curing activation energy (101.4 kJ/mol) and excellent thermal properties (initial decomposition temperature was 453.0°C and char yield at 1000°C was 72.7%). The mechanical and thermal insulation properties of carbon fiber reinforced BPOSSPR composites (CF/BPOSSPR) and high silica fiber reinforced BPOSSPR composites (HSF/BPOSSPR) are significantly enhanced. The linear ablation rate and mass ablation rate of CF/BPOSSPR are as low as 0.003 mm/s and 0.0354 g/s; those of HSF/BPOSSPR are 0.119 mm/s and 0.0264 g/s. The ablation-resistance mechanism of BPOSSPR composites is mainly due to the formation of ceramic thermal barrier layers under high temperature conditions, such as B2O3, SiO2, borosilicate glass, SiC, which might play an effective role in protecting against heat flow erosion. As a result of these excellent properties, the innovative heat shielding BPOSSPR composites could offer the ability to tolerate harsher environment in future aerospace applications.

Fiber-reinforced alumina-carbon core-shell aerogel composite with heat-induced gradient structure for thermal protection up to 1800 °C

High performance thermal insulation materials are urgently demanded for hypersonic spacecraft. Aerogels are considered as promising candidates owing to their low density and low thermal conductivity. However, some deficiencies, such as the unsatisfactory high-temperature thermal insulation properties and the non-exfoliation-resistant particle porous structure of ceramic aerogels, the ease of oxidation and large carbonization shrinkage of carbon aerogels, remain great challenges for their further applications in high-temperature aerobic ablation environments. Here, we report a multiscale fiber-reinforced Al2O3-carbon core–shell aerogel composites with low density (0.23–0.31 g·cm−3), excellent mechanical properties (4.89 MPa at 10% strain) and ultra-low carbonization shrinkage (as low as 1.33%). Benefiting from the synergistic effect of in situ nano-doped light-shading carbon layers, porous Al2O3 ceramic rod skeleton and oriented fibers, the composites demonstrate an extremely low high-temperature thermal conductivity (0.055 W·m−1·K−1 at 1200 °C) that is far superior to those of existing high-temperature insulating aerogel composites. In addition, the unique heat-induced gradient structure also confers outstanding thermal protection properties to the composite at 1800 °C with a liner ablation rate of 6.44 μm·s-1and a mass loss rate of 0.167 mg·s−1. This work not only opens a new path for the preparation of thermal superinsulating materials used for spacecraft, but also provides a simple solution to the difficulty of compatibility between low-density insulating porous skeleton and ablation-resistant tough structures, thereby enabling thermal insulation materials to possess desired ablation-resistant properties.

THE INFLUENCE OF FRACTAL DIMENSION OF OXIDE LAYER ON PASSIVE OXIDATION OF THE C/SiC COMPOSITE

The C/SiC composite is a promising material for ablation-resistant thermal protection in near-space hypersonic environments. The formation of an SiO2 oxide layer through passive oxidation on the surface of the composite is a significant factor influencing its performance. It is essential to accurately predict the thickness of the SiO2 oxide layer and the recession and mass loss of the C/SiC composite during passive oxidation. The SiO2 oxide layer is a typical porous media exhibiting self-similarity and thus fractal theory can be applied to establish the relation between the oxygen flow rate and microstructural parameters of the oxide layer. The Weierstrass–Mandelbrot (WM) function is employed to simulate the rough interfaces between the SiO2 oxide layer and the C/SiC composite to evaluate the influence of the fractal dimensions of the oxide layer on the performance of thermal protection of the C/SiC composite. The results show that the C/SiC composite exhibits improved thermal protection performance when accompanied by a lower tortuosity fractal dimension and a higher pore area fractal dimension of the oxide layer. Conversely, the composite demonstrates enhanced ablation resistance with a higher tortuosity fractal dimension and a lower pore area fractal dimension of the oxide layer. The predictions of the calculation model show good agreement with the experimental data and demonstrate the critical influence of microstructural parameters of the oxide layer on passive oxidation of the composite, providing practical implications for designing materials with desired thermal protection or ablation resistance properties.

Excellent ablation resistance and reusability of silicon carbide fiber reinforced silicon carbide composite in dissociated air plasmas

This work explores the potentials of SiC fiber reinforced SiC matrix composites (SiCf/SiC) with SiC coating to resist aerodynamic ablations for thermal protection purpose. A plasma wind tunnel is employed to evaluate their anti-ablation property in dissociated air plasmas. The results suggest a critical ablation temperature of SiC coated SiCf/SiC, ≈ 1910 °C, which is the highest ever reported in literatures. Benefited by ‘all-SiC’ microstructures and relative flat ablated surfaces, the SiCf/SiC is still ablation-resistant up to ≈ 1820 °C after the occurrence of ablation. This implies an excellent ablation resistance and reusability property of SiCf/SiC, which surpasses that of traditional carbon fiber reinforced composites. Finally, an ablation mechanism dominated by surface characteristic is proposed. For the SiC coated SiCf/SiC, ablation is prone to take place at surface cracks formed by thermal mismatch; while for the ablated SiCf/SiC, ablation is triggered at the exposed fiber bundles which is over-heated in the plasmas.

Study on the mechanism of ultra-high temperature ablation of ZrB2–SiC–TaSi2 coatings by low-pressure plasma spraying on the C/C composites

To improve the high-temperature oxidation resistance of C/C composites, ZrB2–SiC (ZS) and ZrB2–SiC–TaSi2 (ZST) ultra-high temperature ceramics coatings were prepared on their surfaces using induction plasma spheroidization and low-pressure plasma spraying (LPPS). Ablation behaviors of the ZS and ZST coatings were evaluated at 1800°C, 2000°C, and 2200°C using the oxyacetylene flame, we found that the ZS coatings had good ablation resistance at 1800°C, but rapidly failed at 2000°C. Whereas, the ZST coating always performed good oxidation and ablation resistance at even 2000°C with a mass ablation rate of 4.68 × 10-5 g/s and a linear ablation rate of -1.63 × 10-5 mm s-1. The enhancement of the high temperature ablation resistance property was attributed to the introduction of the TaSi2, which improved the density of the coatings prepared by LPPS, reduced the volatilization of the glassy phase at high temperature, and enabled ZrO2 to form a dense oxide layer.

Ablation resistance and mechanical properties of ZrB2 reinforced magnesium phosphate cement composite

In this study, the ablation and mechanical properties of magnesium phosphate cement (MPC) were enhanced by adding ZrB2. The effects of ZrB2 on the microstructure, compressive strength, ablation, and heat insulation performances of MPC were studied. ZrB2 creates nanocrystals in the microstructure of the composites; the compressive strength reaches 25 MPa, the density is improved, and the surface temperature decreases to approximately 100 °C. After ablation for 60 s under an oxyacetylene flame at approximately 2100 °C, the mass and line ablation rates of a 15 mm-thick composite are −20.3 mg/s and 8.5 µm/s, respectively, and the backside temperature is 140 °C. Microstructural observations and thermodynamic calculations suggest that the high thermal conductivity of the ZrB2 additive and the evaporation of boron-containing oxides are key to reducing the surface temperature.

Zirconium chelated hybrid phenolic resin with enhanced thermal and ablation resistance properties for thermal insulation composites

To enhance the ablation resistance of phenolic-based composites, Zr4+ was coordinated with Ph-O- of phenolic resin (PR) to obtain the Zr chelated hybrid PR (ZrPR), which reduces the Ph-OH content of PR and provides metal-organic chelated point for the cured system, ensuring higher thermal stability of PR. The initial decomposition temperature and thermal residual rate at 1000°C of ZrPR was increased from 305.0°C to 57.6% to 405.2°C and 65.5%. Carbon fiber (CF) reinforced ZrPR (CF/ZrPR) composites had flexural and interlaminar shear strengths of 496.0 and 34.0 MPa, 20.2 and 33.3% greater than unmodified composites (CF/PR). Thermal conductivity, linear and mass ablation rate of CF/ZrPR composites were 1.198 W/(m·k), 0.023 mm/s and 0.0607 g/s, respectively, which were 16.7, 50.0 and 10.6% lower than CF/PR composites. The surface ceramic layer with ZrO2 and ZrC phase composition formed from ZrPR in extreme heat can produce an insulating effect to shield the inner material from catastrophic ablation. This research might lead to the development of new and more practical ablation resistant composites for aerospace applications.

Improving ablation resistant properties of epoxy-silicone rubber composites via boron catalyzed graphitization and ceramization

Improving ablation resistant properties of epoxy-silicone rubber composites via boron catalyzed graphitization and ceramization

Comparative research on cyclic ablation behavior of C/C-ZrC-SiC and C/C-ZrC composites at temperatures above 2000 °C

The cyclic and single ablation behavior of C/C-ZrC-SiC and C/C-ZrC composites prepared by reactive melt infiltration were studied. The ablation resistance properties of cyclic ablation of 30 s × 4 and single ablation of 120 s was similar to that of 60 s × 4 and 240 s. The oxidation of the matrix and the peeling content of oxides are aggravated with the increased cyclic ablation numbers. Under the cyclic ablation mode, C/C-ZrC-SiC composites showed lower mass loss than C/C-ZrC composites. At the single ablation of 240 s, C/C-ZrC-SiC composites showed desirable ablation resistance owing to the formation of an effective heat/oxygen protection layer on the ablated surface.