Exploring Hf-Ta-O precipitation upon ablation of Hf-Ta-Si-C coating on C/C composites

Mu, Tong; Chen, Chunjin; Fu, Qiangang; Feng, Tao; Hou, Wanbo; Zhang, Jiaping; Sun, Jia; Zhou, Lei

doi:10.1016/j.jeurceramsoc.2022.01.054

Cited by 23 publications

(3 citation statements)

References 32 publications

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“…First, bisulfite ions were neutralized into sulfite upon the addition of KOH (equation ), which then reduced Cu 2+ into Cu + , as the formal potential of the

{\rm{SO}}_4^{2 - }/{\rm{SO}}_3^{2 - }

couple (E° = ‐0.936 V) is far more negative than that of Cu 2+ /Cu + (+0.159 V) (equation ). [ 44 ] The resulting Cu + subsequently reacted with OH − to produce cuprous hydroxide (CuOH) (equation ); and in the presence of select organic ligands, such as acetylene (HCCR) and mercapto (HSR) derivatives, stable CuOH nanostructures were produced, due to the formation of CuOHCC and CuOHS interfacial bonds (equations and ), [ 45 ] as manifested by the apparent color change from blue to bright yellow (Figure S2, Supporting Information). Three samples were prepared using EPA, HC16, and EPT as the protecting ligands, and denoted as CuOH‐EPA, CuOH‐HC16, and CuOH‐EPT, respectively.…”

Section: Resultsmentioning

confidence: 99%

Stable Cuprous Hydroxide Nanostructures by Organic Ligand Functionalization

et al. 2022

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chalcogenides, [5,6] halides, [7,8] and some complicated salts (e.g., Chevreul's salt), [9] which have found diverse applications, such as catalysis, [10,11] sensing, [12,13] energy conversion, [14,15] and optics. [16] Amongst these, cuprous oxide (CuOH) has long been attracting extensive interest. [17,18] Back in the early 1900s, Miller and Gillett observed that when a NaCl solution was electrolyzed with copper working electrodes at low temperatures (below 60 °C), yellow CuOH precipitates were produced. [19,20] Subsequently, several studies were conducted to investigate the characteristic structure and properties of CuOH synthesized via various methods. [21][22][23] Nevertheless, in these early studies, CuOH was mostly in the bulk solid form and structurally metastable, where the yellowish precipitates would rapidly change the color appearance to dark red, signifying the formation of Cu 2 O, upon exposure to the ambient or thermal treatment due to the lack of proper protection from oxidation and/or dehydration. Such structural instability makes it difficult to study the properties and applications of the obtained CuOH. In 2012, Korzhavyi et al. [24] carried out theoretical studies and demonstrated that CuOH could exist in a solid form; yet the metastability led to the formation of a random mixture of various configurations in the crystal structure, such as Cu 2 O and ice VII H 2 O. SorokaCopper compounds have been extensively investigated for diverse applications. However, studies of cuprous hydroxide (CuOH) have been scarce due to structural metastability. Herein, a facile, wet-chemistry procedure is reported for the preparation of stable CuOH nanostructures via deliberate functionalization with select organic ligands, such as acetylene and mercapto derivatives. The resulting nanostructures are found to exhibit a nanoribbon morphology consisting of small nanocrystals embedded within a largely amorphous nanosheet-like scaffold. The acetylene derivatives are found to anchor onto the CuOH forming CuC linkages, whereas CuS interfacial bonds are formed with the mercapto ligands. Effective electronic coupling occurs at the ligand-core interface in the former, in contrast to mostly nonconjugated interfacial bonds in the latter, as manifested in spectroscopic measurements and confirmed in theoretical studies based on first principles calculations. Notably, the acetylene-capped CuOH nanostructures exhibit markedly enhanced photodynamic activity in the inhibition of bacteria growth, as compared to the mercapto-capped counterparts due to a reduced material bandgap and effective photocatalytic generation of reactive oxygen species. Results from this study demonstrate that deliberate structural engineering with select organic ligands is an effective strategy in the stabilization and functionalization of CuOH nanostructures, a critical first step in exploring their diverse applications.

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“…First, bisulfite ions were neutralized into sulfite upon the addition of KOH (equation ), which then reduced Cu 2+ into Cu + , as the formal potential of the

{\rm{SO}}_4^{2 - }/{\rm{SO}}_3^{2 - }

Section: Resultsmentioning

confidence: 99%

Stable Cuprous Hydroxide Nanostructures by Organic Ligand Functionalization

et al. 2022

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“…21 The supramolecular self-assembly is becoming an important component of the toolbox for synthesis of functional organometallic polymers. [32][33][34][35]…”

Section: Discussionmentioning

confidence: 99%

Supramolecular chemistry of organoplatinum(IV) complexes: A syndiotactic polymer with uracil substituents

Nieradko

Puddephatt

2022

Journal of Chemical Research

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The reaction of RCH2X with [PtMe2(DPA)], 1, (DPA = di-2-pyridylamine) has given [PtXMe2(CH2R)(DPA)] by cis oxidative addition to give 2a, when R = 6-uracil, X = Cl, or 3a, when R = CO2H, X = Br, but by a mixture of cis and trans oxidative addition to give 4a/4b when R = 4-C6H4CO2H, X = Br. The unusual cis stereochemistry of oxidative addition is rationalized thermodynamically by the formation of an intramolecular hydrogen bond in 2a and 3a but not 4a, and kinetically by the role of the ligand DPA NH group in hydrogen bonding to halide. Complex 2a in the solid state forms an unusual supramolecular syndiotactic polymer by forming two different intermolecular NH..O=C hydrogen bonds to neighbouring molecules.

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“…Table 3 showcases recent ablation and oxidation properties of C/SiZM composites and provides a summary of both historical and recent ablation research results of C/C-SiC-Z composites. [193] Si-Zr-Mo [199] C/C-SiC-HfC-TaC 2D SiC-coated C/C preform HfC-TaC PC; SAPS oxyacetylene torch 0.35 1.05 × 10 −3 [200] Si-Zr-Ti…”

Section: Ablation Of the C/sizm Compositesmentioning

confidence: 99%

Advances in Ablation or Oxidation Mechanisms and Behaviors of Carbon Fiber-Reinforced Si-Based Composites

et al. 2023

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Composites with excellent thermomechanical and thermochemical properties are urgently needed in the aerospace field, especially for structural applications under high-temperature conditions. Carbon fiber-reinforced Si-based composites are considered the most promising potential high-temperature materials due to their excellent oxidation resistance and ablative behaviors, good structural designability, and excellent mechanical properties. The reinforcement of the relevant composites mainly involves carbon fiber, which possesses good mechanical and temperature resistance abilities. In this paper, the ablation behaviors and mechanisms of related composites are reviewed. For carbon fiber-reinforced pure Si-based composites (C/SiM composites), the anti-ablation mechanism is mainly attributed to the continuous glassy SiO2, which inhibits the damage of the substrate. For C/SiM composite doping with refractory metal compounds, the oxides of Si and refractory metal together protect the main substrate from ablation and oxidation. Moreover, in addition to thermochemical damage, thermophysical and thermomechanical behavior severely destroy the surface coating of the substrate.

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Exploring Hf-Ta-O precipitation upon ablation of Hf-Ta-Si-C coating on C/C composites

Cited by 23 publications

References 32 publications

Stable Cuprous Hydroxide Nanostructures by Organic Ligand Functionalization

Stable Cuprous Hydroxide Nanostructures by Organic Ligand Functionalization

Supramolecular chemistry of organoplatinum(IV) complexes: A syndiotactic polymer with uracil substituents

Advances in Ablation or Oxidation Mechanisms and Behaviors of Carbon Fiber-Reinforced Si-Based Composites

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