排序方式: 共有29条查询结果,搜索用时 15 毫秒
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Ashish Ganvir Sainyam Nagar Nicolaie Markocsan Kantesh Balani 《Journal of the European Ceramic Society》2021,41(8):4637-4649
Axial plasma spray is one of the thermal spray techniques to deposit multifunctional advanced coatings. The present work explores the use of this process to deposit thin, continuous, and adherent Ca5 (PO4)3OH (hydroxyapatite, HAp) coatings and characterize its microstructure, phases, hardness and adhesion strength. Three different suspension-deposited HAp coatings were investigated and compared with powder-deposited HAp coating on a Ti6Al4V substrate. The effect of mean solute particle size and solid-loading in the suspension has been explored on the evolution of microstructure, phase content and mechanical properties of axial suspension plasma sprayed (ASPS) coatings. Phase-characterization has shown retention of hydroxyapatite phase and coating crystallinity in the deposited coatings, whereas the adhesion strength of the HAp coating decreased from ~40 MPa to ~13 MPa when bioglass was added to the feedstock material. The lower solid load content and lower mean solute particle size in the suspension were found to be beneficial in achieving porous, rougher, and well-adhering coatings. This work concludes that ASPS can potentially deposit thin HAp coatings (< 50 μm) with high adhesion strength. 相似文献
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Ashish Ganvir Mohit Gupta Nitish Kumar Nicolaie Markocsan 《Ceramics International》2021,47(1):272-283
This paper investigates the influence of suspension characteristics on microstructure and performance of suspensions plasma sprayed (SPS) thermal barrier coatings (TBCs). Five suspensions were produced using various suspension characteristics, namely, type of solvent and solid load content, and the resultant suspensions were utilized to deposit five different TBCs under identical processing conditions. The produced TBCs were evaluated for their performance i.e. thermal conductivity, thermal cyclic fatigue (TCF) and thermal shock (TS) lifetime. This experimental study revealed that the differences in the microstructure of SPS TBCs produced using varied suspensions resulted in a wide-ranging overall TBC performance. All TBCs exhibited thermal conductivity lower than 1 W/(m. K) except water-ethanol mixed suspension produced TBC. The TS lifetime was also affected to a large extent where 10 wt % solid loaded ethanol and 25 wt % solid loaded water suspensions produced TBCs exhibited the highest and the lowest lifetime, respectively. On the contrary, TCF lifetime was not as significantly affected as thermal conductivity and TS lifetime, and all ethanol suspensions showed marginally better TCF lifetime than water and ethanol-water mixed suspensions deposited TBCs. 相似文献
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Ralu Divan Olga V. Makarova Shelby Skoog Roger Narayan Anirudha V. Sumant Cha-Mei Tang Nicolaie Moldovan 《Microsystem Technologies》2014,20(10-11):1797-1802
Nanoporous membranes engineered to mimic natural filtration systems can be used in “smart” implantable drug delivery systems, hemodialysis membranes, bio-artificial organs, and other novel nano-enabled medical devices. Conventional membranes exhibit several limitations, including broad pore size distributions and low pore densities. To overcome these problems, lithographic approaches were used to develop porous silicon, silicon nitride, ultrananocrystalline diamond (UNCD), and polymer film membranes. Here we report processing of high porosity, high-aspect-ratio membranes by two techniques: UNCD fabricated by reactive ion etching after e-beam lithography and epoxy fabricated by interference lithography. 相似文献
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Ioan Vida-Simiti Nicolaie Jumate Gyorgy Thalmaier Niculina Sechel Valentin Moldovan 《Journal of Porous Materials》2012,19(1):21-27
In our preliminary studies the possibility of obtaining sintered porous materials with gradual structure by sedimentation
of metallic powder was demonstrated. In this paper we continued our studies on the influencing factors of the sedimentation
of metallic powders. Irregular and spherical nickel particles were used having a grain size in the 2–90 μm range measured
by the laser scattering particle size analyzer. The particles with irregular shape and larger diameter can sediment faster
than the spherical and the smaller diameter particles. The sedimentation rate is also influenced by the sedimentation medium
and the quantity of the dispersant agent. Deviations from Stokes law was observed in the case of the irregular particles.
The gradual structure is influenced by the sintering regime and the powders characteristics too. The obtained structures were
characterized by scanning electron microscopy and mercury porosimetry. The permeability and the filtration fineness were also
determined. 相似文献
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Ioan Vida-Simiti Nicolaie Jumate Valentin Moldovan Gyorgy Thalmaier Niculina Sechel 《材料科学技术学报》2012,28(4):362-366
Asymmetric membranes present better separation and service characteristics than the symmetric ones. In our preliminary studies the possibility of obtaining sintered porous materials with gradual structure by sedimentation of metallic and ceramic powders was demonstrated. Zirconium silicate (ZrSiO4) particles were used for the manufacturing of the porous supports, and mullite powder was deposited by sedimentation in order to achieve the active layer with pores size gradient. The used powders and the obtained structures were characterized by laser scattering particle size analyzer, scanning electron microscopy and mercury porosimetry. The permeability and the filtration fineness of the structures were also determined. By using a thin active layer made of small particles deposited onto a macro-porous support, one can achieve membranes with high flow rates and filtration fineness in the microfiltration area. 相似文献
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Nicholas Curry Nicolaie Markocsan Lars Östergren Xin-Hai Li Mitch Dorfman 《Journal of Thermal Spray Technology》2013,22(6):864-872
The aim of this study was the further development of dysprosia-stabilized zirconia coatings for gas turbine applications. The target for these coatings was a longer lifetime and higher insulating performance compared to today’s industrial standard thermal barrier coating. Two morphologies of ceramic top coat were studied: one using a dual-layer system and the second using a polymer to generate porosity. Evaluations were carried out using a laser flash technique to measure thermal properties. Lifetime testing was conducted using thermo-cyclic fatigue testing. Microstructure was assessed with SEM and Image analysis was used to characterize porosity content. The results show that coatings with an engineered microstructure give performance twice that of the present reference coating. 相似文献
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G. Furtos M. Tomoaia-Cotisel C. Garbo M. Şenilă N. Jumate I. Vida-Simiti 《Particulate Science and Technology》2013,31(4):392-398
Although total joint replacement surgery has become common in recent years, problems due to bacterial infection remain a significant complication following this procedure. One approach in our study was to obtain a self-cured bone cement based on hydroxyapatite with nanosilver (Hap-Ag) and ZrO2 and polymer matrix based on 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane/triethyleneglycol dimethacrylate. New materials were tested for: in vitro silver release, compressive strength (CS), compressive modulus (CM), and radiopacity. In vitro silver release increased in time and depended of silver content in cement. The highest silver release was registered for the cement with 1.26 wt% silver content. The results reveal that the CS for bone cement was between 133.37 and 146.70 MPa and CM was between 1.68 and 1.82 GPa (p > 0.05). A slow increasing of CM was registered for samples with 1.5/1 powder/liquid ratio. Addition of nanosilver and ZrO2 increased radiopacity of experimental bone cement. 相似文献
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Armelle Vardelle Christian Moreau Jun Akedo Hossein Ashrafizadeh Christopher C. Berndt Jörg Oberste Berghaus Maher Boulos Jeffrey Brogan Athanasios C. Bourtsalas Ali Dolatabadi Mitchell Dorfman Timothy J. Eden Pierre Fauchais Gary Fisher Frank Gaertner Malko Gindrat Rudolf Henne Margaret Hyland Eric Irissou Eric H. Jordan Khiam Aik Khor Andreas Killinger Yuk-Chiu Lau Chang-Jiu Li Li Li Jon Longtin Nicolaie Markocsan Patrick J. Masset Jiri Matejicek Georg Mauer André McDonald Javad Mostaghimi Sanjay Sampath Günter Schiller Kentaro Shinoda Mark F. Smith Asif Ansar Syed Nickolas J. Themelis Filofteia-Laura Toma Juan Pablo Trelles Robert Vassen Petri Vuoristo 《Journal of Thermal Spray Technology》2016,25(8):1376-1440
Considerable progress has been made over the last decades in thermal spray technologies, practices and applications. However, like other technologies, they have to continuously evolve to meet new problems and market requirements. This article aims to identify the current challenges limiting the evolution of these technologies and to propose research directions and priorities to meet these challenges. It was prepared on the basis of a collection of short articles written by experts in thermal spray who were asked to present a snapshot of the current state of their specific field, give their views on current challenges faced by the field and provide some guidance as to the R&D required to meet these challenges. The article is divided in three sections that deal with the emerging thermal spray processes, coating properties and function, and biomedical, electronic, aerospace and energy generation applications. 相似文献
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Owen Loh Robert Lam Mark Chen Nicolaie Moldovan Houjin Huang Dean Ho Horacio D. Espinosa 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(14):1667-1674
Nanodiamonds are rapidly emerging as promising carriers for next‐generation therapeutics and drug delivery. However, developing future nanoscale devices and arrays that harness these nanoparticles will require unrealized spatial control. Furthermore, single‐cell in vitro transfection methods lack an instrument that simultaneously offers the advantages of having nanoscale dimensions and control and continuous delivery via microfluidic components. To address this, two modes of controlled delivery of functionalized diamond nanoparticles are demonstrated using a broadly applicable nanofountain probe, a tool for direct‐write nanopatterning with sub‐100‐nm resolution and direct in vitro single‐cell injection. This study demonstrates the versatility of the nanofountain probe as a tool for high‐fidelity delivery of functionalized nanodiamonds and other agents in nanomanufacturing and single‐cell biological studies. These initial demonstrations of controlled delivery open the door to future studies examining the nanofountain probe's potential in delivering specific doses of DNA, viruses, and other therapeutically relevant biomolecules. 相似文献