Anzhe Wang,Ping Hu,Xinyuan Zhao,Zhizhi Wang,Cong Zhang,Yongzheng Wang
Although important, fracture strength in structural ceramics remains difficult to predict due to the inherent micropores, and there is a tremendous need for more precise modelling of pore-like flaw-strength relationship. In this study, classical crack problems were successfully transformed into pore-like flaw-strength models by adding a reasonable stress correction factor proposed by Gomez. Based on the accurate fracture toughness measurement and the precise laser introduction of flaws vs strength tests, the optimized Sato-Takahashi model, which is suitable for any cross-sectional shapes and sharpness flaws, was found to have fairly good prediction for fracture strength in five typical structural ceramics. The experimental error at very small-sized flaws was analyzed from the aspects of the critical flaw size and the inherent flaw size detected by nano-CT. Overall, the simple and user-friendly optimized Sato-Takahashi model could pave the way for quantitative assessments of reliability and failure causes for fine ceramics.
Wei Chai,Chijia Wang,Haonan Liu,Yapeng Gao,Shun Zhang,Minghua Xin,Ruitao Wang,Zhanjian Liu,Huaiyuan Wang
Epoxy resins often develop microporous defects during curing, compromising their barrier properties. This study addresses this issue through the synthesis of a multifunctional mica-based filler (AUFBTM) by in situ growth of TiO 2 on mica via sol-gel method, followed by reduction to black TiO 2 , fluorination, and photocatalytic citric acid modification. The resulting filler features a unique ‘hydrophobic protection-interfacial anchoring-chemical crosslinking’ triple-functional structure. When incorporated into epoxy resin, the EP/AUFBTM coating exhibits significant performance improvements: an 18.7 % reduction in wear mass and outstanding corrosion resistance with a maintained impedance modulus of 2.49 × 10 10 Ω·cm² after CO 2 exposure-three orders of magnitude higher than the unmodified coating (20 % TM) and one order of magnitude higher than the fluorinated modified coating (20 % FBTM). These performance improvements result from the following synergistic effects: the fluorine groups on the filler give the coating excellent shielding properties, while the hydroxyl groups on the surface realize effective interfacial anchoring between the filler and the resin system, and finally, the chemical cross-linking between the carboxyl groups and the resin system builds a stable and dense three-dimensional crosslinking network system in the coating, which effectively improves the densification and interfacial bonding strength of the coating. This study not only provides novel insights into the design of amphiphilic conversion fillers but also advances the application of mica in long-term corrosion protection coatings.
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