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Carrier Gas Flow Rate (carrier + gas_flow_rate)
Selected AbstractsEffect of Injection Parameters on Velocity and Temperature Distributions of Alumina-Titania In-Flight Particles in Atmospheric Plasma SprayingADVANCED ENGINEERING MATERIALS, Issue 8 2004S. Guessasma Three injection parameters (carrier gas flow rate, injector diameter and injection distance) were correlated to the characteristic distributions in the case of alumina titania in-flight particles. A high speed two color pyrometer was implemented to measure, at the centre of the particle flow, individual in-flight particle characteristics, which were used to build velocity and temperature distributions. Results showed that mean characteristic variations were explained by distribution width flattening and centre shift. These were not significant compared to energetic parameter effects. [source] Nanoparticle formation through solid-fed flame synthesis: Experiment and modelingAICHE JOURNAL, Issue 4 2009W. Widiyastuti Abstract The preparation of silica nanoparticles through solid-fed flame synthesis was investigated experimentally and theoretically. Monodispersed submicrometer- and micrometer-sized silica powders were selected as solid precursors for feeding into a flame reactor. The effects of flame temperature, residence time, and precursor particle size were investigated systematically. Silica nanoparticles were formed by the nucleation, coagulation, and surface growth of the generated silica vapors due to the solid precursor evaporation. Numerical modeling was conducted to describe the mechanism of nanoparticle formation. Evaporation of the initial silica particles was considered in the modeling, accounting for its size evolution. Simultaneous mass transfer modeling due to the silica evaporation was solved in combination with a general dynamics equation solution. The modeling and experimental results were in agreement. Both results showed that the methane flow rate, carrier gas flow rate, and initial particle size influenced the effectiveness of nanoparticle formation in solid-fed flame synthesis. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Spheroidization of Titanium Carbide Powders by Induction Thermal Plasma ProcessingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2001Ya-Li Li Highly spherical particles of titanium carbide (TiC) have been produced by in-flight heat processing of irregularly shaped TiC powders in an aerosol reactor under argon-hydrogen and argon-helium induction thermal plasma. The spherical powders obtained by the plasma treatment consist of unagglomerated and uniform particles with mean diameters between 25 and 28.5 ,m, which is smaller than the original TiC particle mean diameters (29.5 ,m) because of partial evaporation of the particles during the plasma treatment. The spheroidization ratio of the treated TiC powders increases with the increase of hydrogen flow rate in plasma gases and the reduction of powder feeding carrier gas flow rate. Under certain processing conditions, the TiC powders have been completely spheroidized. The morphology and structure of individual spherical particles were examined and their formation mechanism was discussed based on calculation of heat transfer kinetics of the particles in the thermal plasma. [source] Influence of Plasma Spray Parameters on Formation and Morphology of ZrO2,8 wt% Y2O3 DepositsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2001Ahmet Kucuk Spray prints of thermal spray coatings were created on glass slides for air-plasma-sprayed 8-wt%-yttria-partially-stabilized zirconia (YSZ) deposits. The spray parameters such as carrier gas flow rate, standoff distance, and torch power were systematically changed to investigate the influence of these parameters on the YSZ deposit characteristics. The deposit properties such as deposition efficiency (DE), substrate coverage, deposit thickness, and roughness were measured. The deposits sprayed with a 3.5,4.0 L/min carrier gas flow rate at an 80 mm standoff distance exhibited higher values of DE within the range of studied process parameters. The DE increased as much as 25% by varying the carrier gas flow rate from 2.0 to 4.0 L/min. The deposits sprayed at a higher standoff distance and low torch power gave poor deposit characteristics. The deposit characteristics were compared with the in-flight particle parameters and revealed that the deposit characteristics strongly depended on the in-flight particle temperature. Using the in-flight particle properties, the flattening ratio and the splat thickness were calculated. The average size of particles adhering to the substrate was found to drastically change with a change of process conditions, being much less than the average size of the starting powder. [source] Influence of Growth Temperature and Carrier Flux on the Structure and Transport Properties of Highly Oriented CrO2 on Al2O3 (0001),CHEMICAL VAPOR DEPOSITION, Issue 10 2007M. Sousa Abstract In this work we report on the structure and magnetic and electrical transport properties of CrO2 films deposited onto (0001) sapphire by atmospheric pressure (AP)CVD from a CrO3 precursor. Films are grown within a broad range of deposition temperatures, from 320 to 410,°C, and oxygen carrier gas flow rates of 50,500,sccm, showing that it is viable to grow highly oriented a -axis CrO2 films at temperatures as low as 330,°C i.e., 60,70,°C lower than is reported in published data for the same chemical system. Depending on the experimental conditions, growth kinetic regimes dominated either by surface reaction or by mass-transport mechanisms are identified. The growth of a Cr2O3 interfacial layer as an intrinsic feature of the deposition process is studied and discussed. Films synthesized at 330,°C keep the same high quality magnetic and transport properties as those deposited at higher temperatures. [source] | ||||||||||