Carbon/carbon (C/C) composites, have emerged as highly promising high-temperature structural materials for hypersonic vehicles, spacecraft re-entry systems, nuclear energy, and other fields, owing to their excellent comprehensive properties, However, their oxidation susceptibility let them failure under extreme ablation conditions easily. This shortcoming restricts their widespread application in aerospace areas. Although matrix modification or surface coating with silicon-based ceramics or ultra-high-temperature ceramics (UHTCs) can improve their oxidation and ablation resistance to a certain extent, a single protective strategy still has obvious defects and limitations. In recent years, the research focus in this field has gradually shifted from a single protection mode to a multi-scale synergistic method. This method refers to a systematic protection scheme that integrates matrix modification and coating protection. This review is to systematically summarize the most recent major and important advancements in the field of ablation-resistant protection for C/C composites over the past decade, including mainstream synergistic protection methods, the synergistic mechanism of matrix modification and coating technology, as well as interface engineering and integrated fabrication technologies. The correlation between multi-scale structural design and the ablation resistance of materials is analyzed, and theoretical support for the preparation of C/C composites with high-temperature oxidation/ablation resistance is provided. Finally, this review is concluded with the scientific problems and challenges in current research, indicating directions for subsequent studies. This review is of great scientific and industrial significance, as it not only provides theoretical support for elucidating the damage mechanism of materials under extreme environments, but also offers feasible new ideas for the low-cost manufacturing of high-performance complex components, as well as the design and engineering application of next-generation thermal structural materials with high reliability, long service life and intellectualization.
To improve the service stability of carbon fiber reinforced polymer (CFRP) in water environments, corrosive media, and contaminated conditions, this study takes Chenopodium album leaves as a biomimetic prototype and fabricates a biomimetic superhydrophobic surface via h-BN/epoxy spraying, femtosecond laser structuring, and FDTS vapor deposition, constructing a micro–nano hierarchical structure with low surface energy. After orthogonal optimization, the surface exhibits a water contact angle of 160.28° ± 1.5° and a sliding angle of 4.6° ± 1.3°. The surface maintains good wetting stability under temperature variation, acidic/alkaline environments, and mechanical abrasion, while showing low droplet adhesion and excellent self-cleaning ability. Compared with pristine CFRP, the surface exhibits significantly improved wear resistance and corrosion resistance, with the corrosion current density reduced to 23.3
To optimise the process parameters of Electro-Fenton chemical mechanical polishing (EF-CMP) for single-crystal SiC, an L27(313) orthogonal experimental design was implemented to investigate the effects of voltage (A), H2O2 concentration (B), abrasive concentration (C), polishing pressure (D), and selected two-factor interactions on material removal rate (MRR), surface roughness Ra, maximum peak-to-valley roughness (Rt), and total thickness variation (TTV). Quadratic regression models were developed for the four responses, and range analysis, ANOVA, and effect curve analysis were used to identify the dominant factors for each single response. Because the optimal parameter combinations for MRR, Ra, Rt, and TTV were inconsistent, entropy-weighted grey relational analysis (GRA) was further applied to transform the multi-response optimisation problem into a single-objective problem based on the derived grey relational grade (GRG). The regression models showed good predictive ability, with adjusted R2 values of 0.9958, 0.8810, 0.8323, and 0.8416 for MRR, Ra, Rt, and TTV, respectively, and all validation errors were within 20
Systematic experimental investigations were conducted to study fretting corrosion wear of 17-4PH stainless steels aged by different temperatures in a H2SO4 solution (pH = 2) to simulate the sulfuric acid rain condition. The fretting corrosion wear tests under different amplitudes with a fixed normal load were carried out. The fretting coefficient, fretting corrosion wear resistance and failure mechanism under different fretting running regimes were discussed. Results show that fretting corrosion wear volume firstly decreases and then increases with increasing the aging temperature. Regardless of fretting running regimes, the microstructure of sample T2 with BCC Cu-rich precipitates (CRPs) aged at 460℃ has a best fretting corrosion wear resistance, while the lowest is the sample T4 with FCC CRPs. In partial slip regime (PSR), the damage is quite marginal, while in mixed fretting regime (MFR) and gross slip regime (GSR) the failure mechanisms are mainly delamination and ploughing. Moreover, the formation of tribo-oxidation during wear process may be helpful to improve the fretting corrosion wear resistance. Cross-section observations suggest that the tribo-layer without crack can enhance the fretting wear resistance.
Surface-induced thrombosis restricts the clinical safety of blood-contacting devices. Although surface heparinization is a widely commercialized strategy for enhancing hemocompatibility, current methods (e.g., covalent grafting, Layer-by-Layer assembly) suffer from complex procedures or insufficient stability. Herein, we introduce a facile, one-step strategy to construct robust anticoagulant coatings driven by a salt-concentration gradient. By utilizing 4 mol/L NaCl to screen electrostatic interactions between polyethyleneimine (PEI) and heparin, a homogeneous precursor slurry was prepared. During a simple immersion-withdrawal process, rapid salt diffusion at the interface triggers immediate liquid–liquid phase separation, inducing the dense coacervation of polyelectrolyte complexes onto substrates. The resulting coating exhibits exceptional stability via physical entanglement, retaining 73
