出版者・発行元：Journal of Thermal Spray Technology  

This study primarily demonstrates the feasibility of using aerosol deposition to produce thin GaN coatings through systematic investigation. To date, the roles of particle size and powder morphology in the consolidation of ceramic particles during aerosol deposition remain unclear. To enhance understanding of this process, two GaN powders, one coarse agglomerated and the other a fine monolithic powder, were deposited under various process conditions. The findings revealed that fine GaN powder is more effective in forming denser coating layers as compared to agglomerated GaN powder. Furthermore, the use of helium gas at higher pressures was observed to enhance coating formation in comparison with nitrogen gas. This study not only validates the potential of aerosol deposition for forming thin GaN coatings but also contributes to our understanding of the critical role that particle sizes play in the aerosol deposition process.

DOI： 10.1007/s11666-025-01951-3

Open Access

Web of Science

Scopus

出版者・発行元：Applied Surface Science  

Carbon/carbon (C/C) composites have shown great scope as thermal structural materials in the aerospace industry. However, the material is restricted from being applied in oxygen-containing airflow with high temperatures and high mechanical stress due to high-temperature oxidation. In this study, the ZrB<inf>2</inf>-SiC-La<inf>2</inf>O<inf>3</inf> coatings with different La<inf>2</inf>O<inf>3</inf> contents were prepared on the surface of SiC-coated C/C composites by atmospheric plasma spraying technology. Focusing on the phase and morphology evolution, the oxidation behavior of the composite coatings at 1500 °C for 10 h was studied, which will guide the future application of ultra-high temperature ceramics coatings on C/C composites. The results showed that the composite coating with 10 wt% La<inf>2</inf>O<inf>3</inf> displayed better oxidation resistance. The morphology of the coating after oxidation showed that La atoms partly substitute Zr atoms to form the high-temperature stable phase (La<inf>0.1</inf>Zr<inf>0.9</inf>)O<inf>1.95</inf> and Zr(La)-O-C compounds. These phases not only restrained the ZrO<inf>2</inf> phase transformation but also formed a dense barrier with the uniformly distributed molten phase to resist oxygen erosion, providing effective high-temperature protection for C/C composites. Nevertheless, the excessive addition of La<inf>2</inf>O<inf>3</inf> destroyed the viscosity of the melt phase, which further reduced the high-temperature stability of the oxide layer.

DOI： 10.1016/j.apsusc.2024.162047

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.matdes.2024.113568

Open Access

出版者・発行元：Journal of Advanced Joining Processes  

Achieving strong direct joining between steel and polymers through mechanical interlocking is crucial for developing multi-material structures, particularly in the automotive and aerospace industries. This study synthesized micro-scale structures on a pure Fe substrate (simulating interstitial-free (IF) steel) for mechanical interlocking with thermoplastic parts. Numerous submillimeter-scale Fe/TiB<inf>2</inf> composite particles were in-situ synthesized by laser scanning on the Fe-Ti-B powder mixture and well-bonded with the Fe substrate. The effects of powder composition (TiB<inf>2</inf> volume fraction) on the morphology, microstructure, and joint strength with PA6 were investigated. A TiB<inf>2</inf> volume fraction over 60 % was essential for the formation of the composite particles promoted by a TiB<inf>2</inf> skeletal structure. Higher TiB<inf>2</inf> volume fractions increased the area fraction of the composite particles and decreased the bonding ratio (adhesive) of the particles with the substrate due to poor adhesiveness at the edge of the laser-scanning line. A wider high-temperature region was generated at a higher TiB<inf>2</inf> volume fraction, suggesting that the reaction heat to form TiB<inf>2</inf> assisted the bonding of the particles with the substrate at the edge of the laser scanning line. The Fe/PA6 joint strength increased to approximately 30 MPa with increasing the TiB<inf>2</inf> volume fraction to 100 % and showed a linear correlation with the product of particle area fraction and bonding ratio. A higher TiB<inf>2</inf> volume fraction was preferable for enhancing the joint strength via the micro-scale structures synthesized by laser scanning on the Fe-Ti-B powder mixture. A combination of the micro-structuring process using a high fraction of TiB<inf>2</inf> with advanced joining technologies will contribute to manufacturing high-strength Fe/polymer hybrid parts.

DOI： 10.1016/j.jajp.2024.100249

Open Access

Web of Science

Scopus

出版者・発行元：Surface and Coatings Technology  

To improve the oxidation resistance of carbon/carbon composites in high-temperature environments, the monolayer SiC and ZrB<inf>2</inf>-SiC-Y<inf>2</inf>O<inf>3</inf> coatings and bilayer ZrB<inf>2</inf>-SiC-Y<inf>2</inf>O<inf>3</inf>/SiC coatings were prepared on carbon/carbon composites by atmospheric plasma spray technique. The chemical composition, morphology, and microstructure of the coating were characterized by XPS, SEM, XRD, and TEM. The oxidation behavior of each layer was evaluated at 1723 K for 10 h in the air. The result showed that the bilayer coating could effectively prevent the degradation of the C/C substrates. After 10 h oxidation, its mass loss was only 1.39 % compared to 15.27 % for the monolayer ZrB<inf>2</inf>-SiC-Y<inf>2</inf>O<inf>3</inf>-coated sample and 8.77 % for the SiC-coated sample. Based on XRD pattern results and microstructure observations, the failure mechanism of the monolayer SiC coating was mainly attributed to the evaporation of SiO<inf>2</inf> at elevated temperatures. The coefficient of thermal expansion (CTE) mismatch between the substrate and coating was the main reason for the spallation of the monolayer ZrB<inf>2</inf>-SiC-Y<inf>2</inf>O<inf>3</inf> coating. For the bilayer coating, the inner layer of SiC was responsible for the superior because it blocked the inward diffusion of oxygen and was used as a transition layer to reduce thermal stress, which made the coating more durable. Meanwhile, the amorphous-nanocrystalline composite structure is believed to be able to reduce the evaporation rate of SiO<inf>2</inf> and prevent the inner diffusion of oxygen.

DOI： 10.1016/j.surfcoat.2024.131007

Web of Science

Scopus

開催年月日： 2025年8月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：Suzhou   国名：中華人民共和国  

開催年月日： 2024年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Singapore   国名：シンガポール共和国  

開催年月日： 2024年6月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Wuzhen  

開催年月日： 2025年8月

記述言語：英語   会議種別：口頭発表（一般）  

開催年月日： 2025年8月

記述言語：英語   会議種別：口頭発表（一般）