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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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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
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Ioan Vida-Simiti Dorel Nemes Nicolaie Jumate Gyorgy Thalmaier Niculina Sechel 《JOM Journal of the Minerals, Metals and Materials Society》2012,64(10):1143-1147
Anodic aluminum oxide (AAO) membranes with highly ordered nanopores serve as ideal templates for the formation of various nanostructured materials. The procedure of the template preparation is based on a two-step self-organized anodization of aluminum. In the current study, AAO templates were fabricated in 0.3?M oxalic acid under the anodizing potential range of 30?C60?V at an electrolyte temperature of ~5°C. The AAO templates were analyzed using scanning electron microscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, and differential thermal analysis. The as obtained layers are amorphous; the mean pore size is between 40?nm and 75?nm and increases with the increase of the anodization potential. Well-defined pores across the whole aluminum template, a pore density of ~1010?pores/cm2, and a tendency to form a porous structure with hexagonal symmetry were observed. 相似文献
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Y. Zhao A. Shinmi X. Zhao P.J. Withers S. Van Boxel N. Markocsan P. Nylen P. Xiao 《Surface & coatings technology》2012
A modified four-point bending test has been employed to investigate the interfacial toughness of atmospheric plasma sprayed (APS) yttria stabilised zirconia (YSZ) thermal barrier coatings (TBCs) after isothermal heat treatments at 1150 °C. The delamination of the TBCs occurred mainly within the TBC, several to tens of microns above the interface between the TBC and bond coat. X-ray diffraction analysis revealed that the TBC was mainly tetragonal in structure with a small amount of the monoclinic phase. The calculated energy release rate increased from ~ 50 J/m− 2 for as-sprayed TBCs to ~ 120 J/m− 2 for the TBCs exposed at 1150 °C for 200 h with a loading phase angle about 42°. This may be attributed to the sintering of the TBC. X-ray micro-tomography was used to track in 3D the evolution of the TBC microstructure non-destructively at a single location as a function of thermal exposure time. This revealed how various types of imperfections develop near the interface after exposure. The 3D interface was reconstructed and showed no significant change in the interfacial roughness after thermal exposure. 相似文献
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Nicolaie Markocsan Mohit Gupta Shrikant Joshi Per Nylén Xin-Hai Li Jan Wigren 《Journal of Thermal Spray Technology》2017,26(6):1104-1114
Liquid feedstock plasma spraying (LFPS) involves deposition of ultrafine droplets of suspensions or solution precursors (typically ranging from nano- to submicron size) and permits production of coatings with unique microstructures that are promising for advanced thermal barrier coating (TBC) applications. This paper reviews the recent progress arising from efforts devoted to development of high-performance TBCs using the LFPS approach. Advancements in both suspension plasma spraying and solution precursor plasma spraying, which constitute the two main variants of LFPS, are presented. Results illustrating the different types of the microstructures that can be realized in LFPS through appropriate process parameter control, model-assisted assessment of influence of coating defects on thermo-mechanical properties and the complex interplay between pore coarsening, sintering and crystallite growth in governing thermal conductivity are summarized. The enhancement in functional performances/lifetime possible in LFPS TBCs with multilayered architectures and by incorporating new pyrochlore chemistries such as gadolinium zirconate, besides the conventional single 8 wt.% yttria-stabilized zirconia insulating ceramic layer, is specifically highlighted. 相似文献
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This study introduces the development of a new experimental setup using an enhanced triaxial tester and a new methodology for the characterization of fine particulate systems in an aerated condition. Tests were performed using the new setup to study the effects of aeration on two different powders: a highly cohesive precompacted powder and a cohesionless powder, the former being microcrystalline cellulose PH-102, mean particle size 90 μm, and the latter alumina powder, mean particle size 100 µm. The degree of aeration was small and it was of the same order of magnitude as the velocities encountered during the entrapment of air in filling and during other handling processes. The superficial velocity for aeration was about three orders of magnitude lower than that required for fluidization. The immediate results have shown that even a small amount of interstitial air has a dramatic effect on the quasi-static strength and an obvious effect on the elastic parameters of the powder. The quasi-static strength of the alumina powder was reduced by about 20%, at a superficial air velocity of 0.02 m/s, whereas the quasi-static strength of microcrystalline cellulose was reduced by about 17%, at a superficial air velocity of 0.009 m/s. The Young's modulus values were reduced by about 13% on average and the bulk modulus values by about 8% on average for microcrystalline cellulose for the air velocity given above.
aerated dry particulate systems elastic parameters compressibility and/or dilatancy boundary failure envelope 相似文献
aerated dry particulate systems elastic parameters compressibility and/or dilatancy boundary failure envelope 相似文献
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Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable of producing highly porous columnar microstructures similar to the conventionally used electron beam–physical vapor deposition. However, lifetime of SPS coatings needs to be improved further to be used in commercial applications. The bondcoat microstructure as well as topcoat–bondcoat interface topography affects the TBC lifetime significantly. The objective of this work was to investigate the influence of different bondcoat deposition processes for SPS topcoats. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial vacuum plasma-sprayed NiCoCrAlY and PtAl diffusion bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue testing. Isothermal heat treatment was performed to study bondcoat oxidation over time. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs. 相似文献