Kyushu University · 재료과학
메하메드 에지자 교수의 연구실은 나노다이아몬드 및 초경성 탄소 복합막을 중심으로 초경성 코팅 재료의 개발에 주력하고 있습니다. 특히 케멘티드 카바이드 기반 공구 재료에 대한 내구성과 경도를 향상시키기 위해 Si, Cr, Al 등 도핑 및 인터레이어를 활용한 표면 개질 기술을 연구하고 있으며, 고온·고압 환경에서의 물성 안정성과 기계적 특성 향상을 목표로 합니다. 고해상도 분석 기법(예: HAXPES)과 기계적 성질 평가를 융합한 다학제적 접근이 특징입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Si and Cr doped ultrananocrystalline diamond/amorphous carbon composite films were deposited on cemented carbide (WC-Co) substrates by using coaxial arc plasma deposition with Si and Cr blended graphite targets. The undoped films deposited at room temperature and a repetition rate of arc discharges of 1 Hz have the maximum hardness of 51 GPa and Young’s modulus of 520 GPa. With increasing substrate temperature and repetition rate, the hardness and modulus are degraded, which might be because the
The increasing global need for freshwater, coupled with the imperative for sustainable and energy-efficient solutions, has fueled interest in solar distillation technologies. Solar stills (SSs) offer a simple, low-cost, and environmentally friendly approach to desalination. However, their performance can be significantly influenced by various factors, including climatic conditions, design parameters, and operational variables. To address these challenges and predict SS performance, machine learn
Hard X-ray photoemission spectroscopy (HAXPES) was employed for the structural evaluation of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) composite films deposited on cemented carbide substrates, at substrate temperatures up to 550 °C by coaxial arc plasma deposition. The results were compared with those of soft X-ray photoemission spectroscopy (SXPES). Since nanocrystalline diamond grains are easily destroyed by argon ion bombardment, the structural evaluation of UNCD/a-C films, wit
Abstract 1 at% Si-doped nanocrystalline diamond/amorphous carbon (NCD/a-C) composite films were deposited on cemented carbide (WC–Co) substrates by coaxial arc plasma deposition. The doping of Si evidently degraded the hardness of films directly deposited on the substrates due to catalytic effects of diffused Co atoms into the films. On the other hand, by employing undoped NCD/a-C buffer layers, the Co diffusion was suppressed and the hardness was enhanced from 42 to 60 GPa. It was found that th
Fused Filament Fabrication (FFF) is a widely adopted additive manufacturing technique, yet its mechanical performance is highly dependent on process parameters, particularly nozzle diameter and printing speed. This study evaluates the influence of these parameters on the tensile behavior of Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA), aiming to determine optimal conditions for enhanced strength. ASTM D638-Type IV specimens were printed using nozzle diameters ranging from 0.05
Super-hard nanodiamond composite (NDC) films, synthesized via cathodic arc plasma deposition on unheated WC − Co substrates, offer an eco-friendly solution for cutting tools. A 100 nm-thick Al-interlayer mitigates Co catalytic effects, improving adhesion and yielding smooth and dense 10 µm-thick films at a deposition rate of 3.3 μm/hr. These grain-boundary-rich nanostructured films, with an impressive 58 GPa hardness attributed to a substantial 70 % C sp3 fraction, prove optimal for hard coating
In response to environmental concerns, there is a growing demand for durable and sustainable mechanical seals, particularly in high-risk industries like chemical, petroleum, and nuclear sectors. This work proposes augmenting the durability and sustainability of silicon carbide (SiC) ceramic seals with the application of a nanodiamond composite (NDC) film through coaxial arc plasma deposition (CAPD) in a vacuum atmosphere. The NDC coating, with a smooth surface roughness of Ra = 60 nm as substrat
Sustainable nanodiamond composite (NDC) films hold promise for high-performance hard coatings thanks to coaxial arc plasma deposition (CAPD). This eco-friendly technique eliminates the need for external heating, chemical reactions, or Co substrate pre-treatment. CAPD boasts lower energy consumption and faster deposition rates, making it a sustainable solution for the growing demand for high-quality, environmentally friendly coatings. This study investigates the influence of discharge energy on t
Cemented carbide (WC−Co) tools suffer from surface abrasion, limiting their performance. This study explores droplet-free tetrahedral amorphous carbon (ta-C) coatings deposited via arc ion plating as a solution. The coatings possess a dense, sp3-rich structure, leading to a remarkable hardness of 60 GPa compared to 37 GPa of WC−Co, and strong adhesion with a critical scratch load of 41 N. Tribological tests confirm their effectiveness. Dry sliding tests show reduced wear and lower CoF (0.123) co
• ANFIS-PSO improved R 2 to 0.989 for yield and cut RMSE by 77 % compared to standard ANFIS. • 30L water volume gave 4.4 L/m 2 /day, a 64.2 % gain over 5L due to better thermal storage. • NSWL-SS raised yield by 58.3 % vs. RSS using stones, wick, and luffa for heat retention. • Energy and exergy efficiencies peaked at 55 % and 6.0 % with passive thermal materials. • PSO reduced MAE by 73 % (energy) and 62.8 % (exergy), boosting ANFIS prediction accuracy. This study addresses the pressing challen
Nanodiamond composite (NDC) films, with a notable hardness of 65 GPa and a substantial thickness of 10 µm, were successfully fabricated on unheated WC−Co substrates using cathodic arc plasma deposition (CAPD) technology. Raman and synchrotron-based structural analysis, comparing NDC films with similarly hard tetrahedral amorphous carbon (ta-C) films and chemical vapor deposition (CVD) diamond, unveiled distinctive features. Visible Raman spectroscopy highlighted NDC's unique nanostructured compo
The Radial-Shear Rolling (RSR) process, commonly utilizing traditional conical rollers, encounters challenges in achieving optimal deformation in high-strength aluminum alloy A2024, vital for aerospace applications due to its exceptional strength-to-weight ratio. This study explores the potential of screw rollers to enhance RSR efficiency for A2024 aluminum, aiming to evaluate their impact on microstructure, mechanical properties, and key deformation parameters (force, temperature) compared to c