Fabrication and Oxidation Resistance Property of SiC Coatings on Surface of Graphite by Chemical Liquid Deposition

2011 ◽  
Vol 55-57 ◽  
pp. 82-86
Author(s):  
Yun Hu Zhu ◽  
Hao Ran Geng ◽  
Guang Li Chen
Keyword(s):  
Optimum Condition ◽  
Mass Loss ◽  
Oxidation Resistance ◽  
Deposition Temperature ◽  
Test Results ◽  
Different Temperatures ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition ◽  
Sic Coatings ◽  
Oxidation Behaviors

SiC coatings were fabricated by the Rapid Chemical Liquid Deposition (RCLD) on the surface of graphite, the influence of deposition temperature on the microstructure of SiC coatings was investigated, the oxidation behaviors of SiC coatings at different temperatures were analyzed. The results indicated that the optimum condition for the SiC coatings are at 1150°C, a smooth and dense coating will be obtained, the thickness of the coatings are between 80～120μm. The oxidation resistance test results indicated that after oxidation at 1000°C for 5h, the mass loss of the sample is only 21%.

Oxidation Behaviors of TiB2-TiCX and TiB2-TiCX/15SiC Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 179-183 ◽  
Author(s):  
De Gui Zhu ◽  
Hong Liang Sun ◽  
Yu Shu Wang ◽  
Liang Hui Wang
Keyword(s):  
Oxidation Resistance ◽  
Effective Temperature ◽  
Hot Isostatic Pressing ◽  
Ceramic Composites ◽  
Optical Micrograph ◽  
Different Temperatures ◽  
The Mean ◽  
Mean Time ◽  
Oxidation Behaviors

Fully dense samples of TiB2-TiCX and TiB2-TiCX/15SiC ceramic composites were fabricated by in-situ synthesis under hot isostatic pressing from TiH2, B4C and SiC powders. Their oxidized behaviors at different temperatures were tested. Optical micrograph studies and thermo-gravimetric analyses show that the highest effective temperature of oxidation resistance is 700°C for TiB2-TiCX, and 1100°C for TiB2-TiCX/15SiC. The weight gain of TiB2-TiCX/15SiC below 1100°C is quite low, and it rises up suddenly when the temperature reaches 1200°C. Thus, the highest effective temperature of oxidation resistance is 1100°C for TiB2-TiCX/15SiC. The oxidation dynamic curves of TiB2-TiCX/15SiC ceramics accord with the parabola’s law. The activation energy of TiB2-TiCx/15SiC (189.87kJ.mol-1) is higher than that of TiB2-TiCx (96.44kJ.mol-1). In the oxidation process of TiB2-TiCx/15SiC, TiB2 reacts with oxygen and generates TiO2 and B2O3 at first. A layer of whole homogeneous oxide film cannot be formed, in the mean time, the oxidation of TiC begins. When temperature goes up to 1000°C, TiC phase is totally oxidized. SiC is oxidized to SiO2 at about 900°C, Meanwhile, TiO2 forms denser film than B2O3, which grows and covers the surface of the material, and gives better property of oxidation resistance.

MODIFIED SiC-MoSi2 OXIDATION PROTECTIVE COATING FOR SiC-COATED CARBON/CARBON COMPOSITES THROUGH INFILTRATING LIQUID Si

2011 ◽  
Vol 18 (03n04) ◽  
pp. 109-114 ◽  
Author(s):  
ZHENG-ZHONG ZHANG ◽  
HE-JUN LI ◽  
CHAO MA ◽  
QIAN-GANG FU ◽  
YU-LEI ZHANG ◽  
...  
Keyword(s):  
Phase Composition ◽  
Mass Loss ◽  
Oxidation Resistance ◽  
Protective Coating ◽  
Pack Cementation ◽  
Carbon Composites ◽  
Test Results ◽  
Oxidation Test ◽  
Coated Carbon ◽  
Pack Cementation Process

To improve the oxidation resistance of the SiC-MoSi2 coating prepared by two-step pack cementation, a liquid Si infiltrating method was adopted to modify it. The phase composition and microstructure of the coatings were analyzed by XRD and SEM. The results show that the size and number of the cracks in the modified coating decreased evidently after infiltrating Si . The oxidation test results in air at 1773 K show that the mass loss of the SiC-MoSi2 coating coated carbon/carbon (C/C) composites was up to 1.18% after oxidation for 206 h, while that of the modified coating coated C/C composites was only 0.77% after oxidation for 460 h. The reason is that the cracks formed in the pack cementation process were partly sealed and there were no penetrable cracks in the modified coating. Therefore, there were no direct channels for the oxygen to diffuse into the C/C substrate.

scholarly journals Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol

2020 ◽  
Vol 10 ◽  
pp. 184798042096688
Author(s):  
Galo Cárdenas-Triviño ◽  
Sergio Triviño-Matus
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Colloidal Dispersions ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Chemical Liquid Deposition ◽  
Liquid Deposition

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

Oxidation resistance of nickel-based superalloy Inconel 600 in air at different temperatures

Rare Metals ◽  
2018 ◽  
Author(s):  
Dong-Sheng Li ◽  
Guang Chen ◽  
Dan Li ◽  
Qi Zheng ◽  
Pei Gao ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Inconel 600 ◽  
Nickel Based Superalloy ◽  
Different Temperatures

Oxidation Resistance of HfB2-SiC Coatings for Pro...

2005 ◽  
Author(s):  
P. Lespade ◽  
N. Richet ◽  
P. Goursat
Keyword(s):  
Oxidation Resistance ◽  
Sic Coatings

Oxidation Behaviors of Pure Ti Thermal Plasma Spray Coated Mo-Si-B Alloys

2011 ◽  
Vol 695 ◽  
pp. 365-368 ◽  
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Air Atmosphere ◽  
Elemental Component ◽  
Ti Powder ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. The unstable MoO3 phase is naturally produced when the alloys were exposed at low and /or high temperature in an air atmosphere. In order to resolve the poor oxidation resistance of the alloy system, several attempts have been made via surface coatings and/or component additions. In this study, the oxidation behaviors of the Ti powder thermal spray coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of precursor Ti coatings on Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the Ti powder was tightly bonded and reacted with the surface of the substrate, and TiO2 layer was formed at the outer surface of the coated Ti layer as a result of oxidation exposure. The oxidation behaviors of pure elemental component coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

scholarly journals Residual Oxygen Effects on the Properties of MoS2 Thin Films Deposited at Different Temperatures by Magnetron Sputtering

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1183
Author(s):  
Peiyu Wang ◽  
Xin Wang ◽  
Fengyin Tan ◽  
Ronghua Zhang
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Deposition Rate ◽  
Deposition Temperature ◽  
Energy Dispersive Spectrometer ◽  
Rf Magnetron Sputtering ◽  
Glass Substrates ◽  
Different Temperatures ◽  
Oxygen Atoms

Molybdenum disulfide (MoS2) thin films were deposited at different temperatures (150 °C, 225 °C, 300 °C, 375 °C, and 450 °C) on quartz glass substrates and silicon substrates using the RF magnetron sputtering method. The influence of deposition temperature on the structural, optical, electrical properties and deposition rate of the obtained thin films was investigated by X-ray diffraction (XRD), Energy Dispersive Spectrometer (EDS), Raman, absorption and transmission spectroscopies, a resistivity-measuring instrument with the four-probe method, and a step profiler. It was found that the MoS2 thin films deposited at the temperatures of 150 °C, 225 °C, and 300 °C were of polycrystalline with a (101) preferred orientation. With increasing deposition temperatures from 150 °C to 300 °C, the crystallization quality of the MoS2 thin films was improved, the Raman vibrational modes were strengthened, the deposition rate decreased, and the optical transmission and bandgap increased. When the deposition temperature increased to above 375 °C, the molecular atoms were partially combined with oxygen atoms to form MoO3 thin film, which caused significant changes in the structural, optical, and electrical properties of the obtained thin films. Therefore, it was necessary to control the deposition temperature and reduce the contamination of oxygen atoms throughout the magnetron sputtering process.

A System of Selective Non Catalytic Reduction of NOx for Diesel Engine

2011 ◽  
Vol 201-203 ◽  
pp. 643-646 ◽  
Author(s):  
Bo Yan Xu ◽  
Hai Ying Tian ◽  
Jie Yang ◽  
De Zhi Sun ◽  
Shao Li Cai
Keyword(s):  
Catalytic Reduction ◽  
Three Dimensional ◽  
Exhaust Gas ◽  
Test Results ◽  
Practical Application ◽  
Three Dimensional Model ◽  
Reduction Efficiency ◽  
Different Temperatures ◽  
Reduction Of Nox ◽  
Good Agreement

SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.

Optimal Physical Pretreatment Conditions for the Release of Carbohydrate and Protein from Dairy Manure

2013 ◽  
Vol 291-294 ◽  
pp. 383-389
Author(s):  
Jian Ping Sun ◽  
Jun Zhu
Keyword(s):  
Particle Size ◽  
Experimental Design ◽  
Optimum Condition ◽  
Reaction Temperature ◽  
Organic Materials ◽  
Dairy Manure ◽  
Physical Factors ◽  
Test Results ◽  
Release Rates ◽  
Pretreatment Conditions

Various physical factors including particle size, pH, temperature and so on may influence the release of organic materials from dry dairy manure. The effect of these factors on release of protein and carbohydrate was investigated in this study using Box-Behnken Experimental Design with three factors (particle size, temperature and pH) at three levels. Test results suggested that particle size of 0.15-0.25 mm accounted for almost half of the dry manure particles and the optimum condition for release of protein and carbohydrate were pH 2, particle size 1.0-1.4 mm under reaction temperature of 90 oC, under which the protein and carbohydrate release rates could reach 1570.57 and 2813.29 mg l-1, respectively. The degree to which these factors affected organics release was in the order from high to low of temperature > particle size > pH.

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