The Influence of Diamond Addition to Ni-Al Powder on Oxidation Behavior of Ni-Al During Plasma Spraying for High Performance Oxide-Free Ni-Al Intermetallic Coating

2021 ◽  
Author(s):  
Li Zhang ◽  
Di Wang ◽  
Xian-Jin Liao ◽  
Xiao-Tao Luo ◽  
Chang-Jiu Li
Keyword(s):  
Oxygen Content ◽  
High Performance ◽  
Thermal Spraying ◽  
Low Oxygen ◽  
Mechanically Alloyed ◽  
Intermetallic Coating ◽  
Novel Approach ◽  
Ultrahigh Temperature ◽  
Diamond Powders ◽  
Plasma Sprayed

Abstract Ni-Al intermetallics have excellent corrosion and oxidation resistance, but their use in thermal spraying has been limited due to issues with in-flight oxidation. In this study, a novel approach is proposed to remove oxide from Ni-Al droplets in-flight by adding a deoxidizer (diamond) to the feedstock powder. A mixture of nickel, aluminum, and diamond powders was mechanically alloyed using a combination of cryogenic and planetary ball milling. The resulting Ni/Al/diamond composite powder was then plasma sprayed via the APS process, forming Ni-Al coatings on Inconel 738 substrates. Phase composition, microstructure, porosity, and microhardness of the coatings were characterized by X-ray diffraction, scanning electron microscopy, image analysis, and hardness testing, respectively. Oxygen content measurements showed that the coatings contained significantly less oxygen than coatings made from ordinary Ni/Al powders. In-flight particle temperatures were also measured and found to be higher than 2300 °C. The low oxygen content in the coatings is attributed to the in-situ deoxidizing effect of ultrahigh temperature droplets which are also oxide-free.

High Performance Magnets - Microstructure and Coercivity

1999 ◽  
Vol 577 ◽  
Author(s):  
J. Fidler ◽  
S. Sasaki ◽  
E. Estevez-Rams
Keyword(s):  
Energy Density ◽  
Oxygen Content ◽  
Coercive Field ◽  
High Performance ◽  
Magnetic Energy ◽  
Low Oxygen ◽  
Critical Temperatures ◽  
High Oxygen Content ◽  
Magnetic Energy Density ◽  
Strip Cast

ABSTRACTThe importance of newly developed permanent magnetic materials in many electro-, magnetomechanical and electronic applications can be attributed to the drastic improvement of the magnetic energy density product and coercive field. A systematic study has been undertaken in order to determine the influence of oxygen content on microstructure and coercivity of high remanence Nd2Fe14B based sintered magnets. The energy density product >400 kJ/m3 (50 MGOe) and the coercive field of 800 kA/m were obtained after a combination of rubber isostatic and transverse die pressing methods. Magnets of the composition Nd151−xFe78+xB6Cu0.03A10.7 [x= 0-2.5] were prepared using strip cast materials. The high oxygen content of the magnets was gradually decreased from values of 4000-6000 ppm to a value < 1000 ppm. Abnormal grain growth (AGG) of the 2:14:1 grains occurred preferentially in magnets with low oxygen content, thus the squareness of the demagnetisation curve drastically decreased. The oxygen content strongly affects the AGG and the magnets with higher oxygen content have the higher critical temperatures at which the AGG occurs. On the other hand, isotropic magnets tend to have the lower critical temperatures than anisotropic magnets by 10-20°C. In the second part of the paper examples of the influence of intergranular phases, grain size and grain shape observed by TEM on coercivity of sintered and melt-spun Nd-Fe-B magnets are compared.

Fe-Sn Intermetallics Synthesized via Mechanical Alloying-Sintering and Mechanical Alloying-Thermal Spraying

2015 ◽  
Vol 659 ◽  
pp. 329-334
Author(s):  
Pinya Meesa-Ard ◽  
Vitoon Uthaisangsuk ◽  
Nattaya Tosangthum ◽  
Panadda Sheppard ◽  
Pongsak Wila ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Thermal Spraying ◽  
Argon Atmosphere ◽  
Mechanically Alloyed ◽  
Porous Coatings ◽  
Fe Powder ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Plasma Sprayed ◽  
Sintered Materials

Iron (Fe)-tin (Sn) intermetallics were synthesized by using two different routes. These two routes had a common synthesis step, in which Fe powder (19 wt. %) was mechanically alloyed with Sn powder (81 wt. %) for 25 h under argon atmosphere. The mechanically alloyed powders were then treated with different heating routes. In the first route, the compacts of the mechanically alloyed powders were sintered at different temperatures for different times. It was found that the FeSn2 content increased with increasing temperature and time. There were small traces of Fe, Sn and FeSn found in the sintered materials. In the second route, the mechanically alloyed powders were plasma-sprayed using different currents of 300, 400 and 500 A. It was found that the porous coatings produced by plasma sprayng consisted of mixed Fe, Sn, FeSn2, SnO, FeO and Fe3O4 for all employed currents.

Oxygen Effects in Mechanically Alloyed Si80 Ge20 Doped with GaP and P

1991 ◽  
Vol 234 ◽  
Author(s):  
B. A. Cook ◽  
J. L. Harringa ◽  
B. J. Beaudry
Keyword(s):  
Thermal Conductivity ◽  
Oxygen Content ◽  
Carrier Mobility ◽  
High Mobility ◽  
Fused Silica ◽  
High Oxygen ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Mechanically Alloyed ◽  
Oxygen Effects

ABSTRACTA neutron activation study was performed to follow the total oxygen content during the preparation sequence of mechanically alloyed Si-20 at.% Ge n-type alloys using both elemental powders and chunk starting materials. The Si-20 at. % Ge alloys were doped with 1.6 at. % GaP and 3.4.at. % P and the total oxygen concentration was measured in the starting materials, after six hours of mechanical alloying in a helium environment, after hot pressing, and after a short 1100°C soak in fused silica ampoules. The alloys containing high oxygen levels showed low carrier mobility and low thermal conductivity whereas those containing low oxygen showed high mobility and thermal conductivity. The microstructure, as observed by optical metallography and SEM, was found to differ greatly with oxygen content as the low oxygen alloys showed relatively large, well defined grains and the high oxygen alloys showed evidence of poor sintering and limited grain growth.

scholarly journals Human emotion modeling (HEM): an interface for IoT systems

2021 ◽  
Author(s):  
Mohammed R. Elkobaisi ◽  
Fadi Al Machot
Keyword(s):  
Assisted Living ◽  
High Performance ◽  
Modeling Language ◽  
Emotional States ◽  
Human Emotion ◽  
Care Givers ◽  
Novel Approach ◽  
Domain Specific Modeling ◽  
Increasing Demand ◽  
Human Support

AbstractThe use of IoT-based Emotion Recognition (ER) systems is in increasing demand in many domains such as active and assisted living (AAL), health care and industry. Combining the emotion and the context in a unified system could enhance the human support scope, but it is currently a challenging task due to the lack of a common interface that is capable to provide such a combination. In this sense, we aim at providing a novel approach based on a modeling language that can be used even by care-givers or non-experts to model human emotion w.r.t. context for human support services. The proposed modeling approach is based on Domain-Specific Modeling Language (DSML) which helps to integrate different IoT data sources in AAL environment. Consequently, it provides a conceptual support level related to the current emotional states of the observed subject. For the evaluation, we show the evaluation of the well-validated System Usability Score (SUS) to prove that the proposed modeling language achieves high performance in terms of usability and learn-ability metrics. Furthermore, we evaluate the performance at runtime of the model instantiation by measuring the execution time using well-known IoT services.

scholarly journals Tracking by Deblatting

2021 ◽  
Author(s):  
Denys Rozumnyi ◽  
Jan Kotera ◽  
Filip Šroubek ◽  
Jiří Matas
Keyword(s):  
High Speed ◽  
High Performance ◽  
Motion Blur ◽  
Velocity Estimation ◽  
High Speed Camera ◽  
Trajectory Function ◽  
Novel Approach ◽  
Blind Deblurring ◽  
Object Trajectories ◽  
Complex Trajectories

AbstractObjects moving at high speed along complex trajectories often appear in videos, especially videos of sports. Such objects travel a considerable distance during exposure time of a single frame, and therefore, their position in the frame is not well defined. They appear as semi-transparent streaks due to the motion blur and cannot be reliably tracked by general trackers. We propose a novel approach called Tracking by Deblatting based on the observation that motion blur is directly related to the intra-frame trajectory of an object. Blur is estimated by solving two intertwined inverse problems, blind deblurring and image matting, which we call deblatting. By postprocessing, non-causal Tracking by Deblatting estimates continuous, complete, and accurate object trajectories for the whole sequence. Tracked objects are precisely localized with higher temporal resolution than by conventional trackers. Energy minimization by dynamic programming is used to detect abrupt changes of motion, called bounces. High-order polynomials are then fitted to smooth trajectory segments between bounces. The output is a continuous trajectory function that assigns location for every real-valued time stamp from zero to the number of frames. The proposed algorithm was evaluated on a newly created dataset of videos from a high-speed camera using a novel Trajectory-IoU metric that generalizes the traditional Intersection over Union and measures the accuracy of the intra-frame trajectory. The proposed method outperforms the baselines both in recall and trajectory accuracy. Additionally, we show that from the trajectory function precise physical calculations are possible, such as radius, gravity, and sub-frame object velocity. Velocity estimation is compared to the high-speed camera measurements and radars. Results show high performance of the proposed method in terms of Trajectory-IoU, recall, and velocity estimation.

Novel approach for simple fabrication of high-performance InP-switch matrix based on laser-amplifier gates

1996 ◽  
Vol 8 (9) ◽  
pp. 1178-1180 ◽  
Author(s):  
F. Dorgeuille ◽  
B. Mersali ◽  
M. Feuillade ◽  
S. Sainson ◽  
S. Slempkes ◽  
...  
Keyword(s):  
High Performance ◽  
Laser Amplifier ◽  
Novel Approach
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