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High Temperature Oxidation and Wear Resistance of Y-modified Hot dipping Aluminized Coating on SCH12 Steel

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稀有金属材料与工程 2012年第S1期41卷 231-235页

作者： Fan, X. S. Yang, Z. G. Zhang, C. Tsinghua Univ Dept Mat Sci & Engn State Key Lab New Ceram & Fine Proc Beijing 100084 Peoples R China

Microstructures,high-temperature oxidation and wear resistance of hot dipping Al-Si-Y coating on SCH12 heat resistant cast steel were investigated in this study.The aluminized coating was characterized by scanning electron microscopy(SEM),energy dispersive X-ray spectrometry(EDX)and X-ray diffraction(XRD).The results showed that the coating was composed of the Al-rich outer layer and the intermetallics inner layer.In the Al-rich layer,some Y-rich precipitates and Fe-Al-Si-Cr precipitates could be observed.The intermetallics layer presented three layers induced by the increase of Fe,Cr,Ni content and the corresponding decrease of Al,Si content.The oxidation tests were conducted in still air at 850℃for up to 100 h.After oxidation,a top oxide scale composed of mainlyα-Al2O3,Al5Y3O12 was formed on the steel surface.The intermetallics beneath the oxide scale consisted of mainly FeAl and small amount of Fe2Al5 and Cr3Si phase.The mass gain of the coated and uncoated SCH1steel is 0.45 mg/cm 2 and 0.57 mg/cm 2,respectively.The wear resistance was investigated using a high-temperature pin-on-disc tribometer at 650℃.The wear rate for the coated and uncoated steel is 0.45μm 3 /μm.N and 3.01μm 3 /μm.N,respectively.The high temperature wear tests and oxidation tests results demonstrated that the yttrium-modified aluminized specimen had significantly improved high-temperature wear resistance and equivalent oxidation resistance compared with the original SCH12 specimen.

关键词： hot dipping aluminizing oxidation resistance high-temperature wear resistance

Formation and structure of composite coating of HDA and micro-plasma oxidation on A3 steel

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 310-314页

作者： YU Sheng-xue XIA Yuan CHEN Ling GUAN Yong-jun YAO Mei Department of Environment Science and Chemical Engineering Yanshan University Qinhuangdao 066004 China Institute of Mechanics Chinese Academy of Science Beijing 100080 China Institute of Mechanics Chinese Academy of Science Beijing 100080 China Department of Environment Science and Chemical EngineeringYanshan University Qinhuangdao 066004 China Institute of Mechanics Chinese Academy of Science Beijing 100080 China College of Materials Science and EngineeringYanshan University Qinhuangdao 066004 China

Composite coatings were obtained on A3 steel by hot dipping aluminum(HDA) at 720 ℃ for 6 min and micro-plasma oxidation(MPO) in alkali electrolyte. The surface morphology, element distribution and interface structure of composite coatings were studied by means of XRD, SEM and EDS. The results show that the composite coatings obtained through HDA/MPO on A3 steel consist of four layers. From the surface to the substrate, the layer is loose Al2O3 ceramic, compact Al2O3 ceramic, Al and FeAl intermetallic compound layer in turn. The adhesions among all the layers are strengthened because the ceramic layer formed at the Al surface originally, FeAl intermetallic compound layer and substrate are combined in metallurgical form through mutual diffusion during HDA process.Initial experiment results disclose that the anti-corrosion performance and wear resistance of composite coating are obviously improved through HDA/MPO treatment.

关键词： hot dipping aluminum micro-plasma oxidation composite coating ceramic coating

Crustal structure study based on principal component analysis of receiver functions

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Science China Earth Sciences 2019年第7期62卷 1110-1124页

作者： Jianyong ZHANG Ling CHEN Xu WANG State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau Earth Sciences

The receiver function(RF) technique is an effective method for studying crustal structure. For a single station, the average 1-D crustal structure is usually derived by stacking the radial RFs from all back-azimuths, whereas structural variations(such as dipping discontinuities or anisotropy) can be constrained through analysis of waveform dependence on the backazimuth of both the radial and tangential RFs. However, it is often difficult to directly extract information about structural variations from the waveform of RF, due to the common presence of noise in real data. In this study, we proposed a new method to derive structural variation information for individual stations by applying principal component analysis(PCA) to RFs sorted by back-azimuth. In this method(termed as RF-PCA), a set of principal components(PCs), which are uncorrelated with each other and reflect different characteristics of the RF data, were extracted and utilized separately to reconstruct new RFs. Synthetic tests show that the first PC of the radial RFs contains the average structural information of the crust beneath the corresponding station, and the second PC of the radial RFs and the first PC of the tangential RFs both reflect the variations of the crustal structure. Our synthetic modeling results indicate that the new RF-PCA method is valid for a variety of synthetic models with intra-crustal dipping discontinuities and/or anisotropy. We applied this method to the real data from a broadband temporary seismic station(s233) in the central part of the Sichuan Basin. The results suggest that the RF data can be best explained by the presence of two nearly parallel dipping discontinuities within the crust. Combining with previous logging data, seismic exploration and deep sounding observations, we interpret the shallow dipping discontinuity as the top boundary of the Precambrian crystalline basement of the Sichuan Basin and the deep one corresponding to the Conrad interface between the upper and lower crust, consistent with the geological f

关键词： Principal component analysis Receiver function Crustal structure dipping discontinuity Anisotropy Sichuan Basin

ZrB_2 particles reinforced glass coating for oxidation protection of carbon/carbon composites

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Journal of Advanced Ceramics 2019年第1期8卷 102-111页

作者： Cuiyan LI Guibiao LI Haibo OUYANG Jing LU School of Materials Science & Engineering Shaanxi University of Science & Technology

A dense ZrB_2 particles reinforced glass(ZrB_2/SiO_2) coating was prepared on the SiC coated carbon/carbon composites by a facile sol-dipping approach. The prepared ZrB2/SiO2 coating could protect the composites from being oxidized for 160 h at 1773 K with a weight loss of 6.9 mg/cm^2. The flexural strength retention ratio of the ZrB_2/SiO_2 coated composites is 87% after oxidation for 160 h at1773 K. The continuous SiO_2 glass layer embedded with the submicron ZrSiO_4 particles was formed during oxidation. This was helpful to lower the diffusion rate of oxygen and improve the stability of SiO_2 glass film, thus improving the oxidation resistance of the coated samples. After thermal cycles between 1773 K and room temperature for 15 times, penetrated cracks formed in the coating. The weight loss of the ZrB_2/SiO_2 coated sample presented linear relationship, and the final weight loss per unit area was 6.35 mg/cm^2. The generation of the penetrative cracks and the debonded coating interface resulted in the failure of the ZrB_2/SiO_2 coating.

关键词： ZrB2/SiO2 coating silica sol dipping oxidation resistance

Response of Solenopsis invicta （Hymenoptera： Formicidae） to potassium oleate water solution

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Insect Science 2010年第2期17卷 121-128页

作者： Jian Chen Han-Wu Shang Xixuan Jin Biological Control of Pests Research Unit Agricultural Research Service U.S. Department of Agriculture Stoneville Mississippi USA College of Life Sciences China Jiliang University Hangzhou China

In contrast to floating on the surface of distilled water, ants were immediately submerged after being placed in the potassium oleate （PO） water solution, which led to immobilization within minutes. However, some workers survived after being immersed in 0.03% PO water solution at 25℃ for up to 640 rnin. Elevated temperature of the PO water solution is needed to kill ants within a shorter time frame. At 50℃ and 0.13% PO concentration, total mortality was achieved with 10-min immersion for all ants, including brood and adult ants. Soil has a negative effect on the effectiveness of potassium oleate; however, such negative effect can be overcome by increasing either treatment temperature or duration of the treatment. In addition to immobilizing and lethal effect, PO repels ants. PO may have the potential to be incorporated into immersion treatment for the quarantine of imported fire ants to reduce the use of synthetic contact insecticides.

关键词： dipping immersion treatment quarantine soap surfactant

Dielectric properties of porous SiC/Si3N4 ceramics by polysilazane immersion-pyrolysis

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Progress in Natural Science:Materials International 2019年第2期29卷 184-189页

作者： Xiao Lin Hongyu Gong Yujun Zhang Jianqiang Bi Yurun Feng Yu Liu Shan Wang Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials of Ministry of Education Shandong University Key Laboratory of Special Functional Aggregated Materials Ministry of Education Shandong University

The SiC nanotubes were synthesized on porous Si3N4matrix by polysilazane immersion-pyrolysis. The β-SiC and free C contents increased with the increasing dipping times, which cause some clear vibration and loss peaks of the dielectric constant patterns emerged at around 12.9 GHz and 14.7 GHz in the samples of 20 wt% and 30 wt%benzoic acid, respectively. The reflectivity of the obtained ceramics were -7 dB ～-10 dB from the frequency of 8 GHz–18 GHz, which means that the amount of 80%–90% electromagnetic wave could be attenuated. The ceramics containing 40 wt% benzoic acid showed the high loss, low reflectivity and a wide absorbing band,indicating the high absorbing efficiency and good dielectric properties.

关键词： SiC Si3N4 dipping Dielectric properties

The upper mantle structure of the Tibetan Plateau and its implication for the continent-continent collision

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Science China Earth Sciences 2005年第8期48卷 1158-1164页

作者： WU Qingju1, ZENG Rongsheng1 & ZHAO Wenjin2 1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China 2. Institute of Geology, China Academy of Geological Sciences, Beijing 100037, China Institute of Geophysics China Earthquake Administration Beijing China Institute of Geology China Academy of Geological Sciences Beijing China

The upper mantle structures of Himalayas-Tibet have been obtained from the mi-gration of receiver functions of the teleseismic events recorded by INDEPTH-III. The result of migration imaging shows a dipping interface subducting northward from the depth of 100 km to the 410-km discontinuity underneath southern Tibet. It indicates that the lithospheric mantle of the Indian continent had been detached from the crust and deeply subducted to the upper mantle of Eurasia during the Indo-Eurasian collision. This kind of continent-continent collision process is fundamentally different from the oceanic collision.

关键词： Tibetan Plateau, receiver function, upper mantle structures, Indo-Eurasian collision, dipping interface.

Electrochemical tests on zincating solution with zinc sulfate and zinc oxide

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中国有色金属学会会刊：英文版 2005年第S2期15卷 231-235页

作者：黄晓梅李宁蒋丽敏黎德育 Department of Applied Chemistry Harbin Institute of Technology Harbin 150001 China

In order to find out a multi-metal zincate solution to get good micromorphology and fine adhesion of coatings, sulfate zincate and zinc oxide zincate with different chelating agents combinations, of which there are 8 solutions are designed. CHI630 electrochemical test system is applied to measure the φ—t curves of zincate process and Tafle curves of zincated plates in 3.5% NaCl medium. The analyzed results show that when molar ratio of sodium hydroxide to zinc ions is constant, the better chelating agents combination for multi-metal zincation solution is the combination of sodium potassium tartrate and sodium citrate in zinc oxide solution, from which zinc alloy is high in potential and perfect in corrosion resistance. After the second zincate immersion for 60s, the immersion potential is -1.606V(vs SCE). The corrosion current density is 6.612, J_ corr/(A·cm -2); and the corrosion potential is -1.381, φ_ corr(I=0)/V.

关键词： high silicon aluminum alloy multi-metal zincating solution dipping time dipping active potential Tafle curve

Drug Loading on Microneedles

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Advances in Chemical Engineering and Science 2019年第2期9卷 204-222页

作者： Meng-Hsuan Hsiao Hsiu-Feng Ye Ta-Jo Liu Jane Wang Department of Chemical Engineering National Tsing Hua University Taiwan

An experimental study was carried out to investigate the amount of drugs loaded on microneedles. The microneedles were made with poly (lactic acid). Aqueous poly (vinyl alcohol) solutions were prepared as drug solutions. Two drug loading approaches, i.e., dropping and dipping, were examined. It was found that capillary number is the only relevant dimensionless group for the two methods. For the dropping approach, dried drugs will spread near the bottom of a microneedle patch provided the surface tension is low. As for the dipping approach, both a single microneedle and an array of nine microneedles were examined. For a single microneedle, high capillary rises before pulling and pulling speed are two key factors to increase the drug loading volume. For an array of microneedles, the effect of capillary rise owing to the interaction between microneedles would increase the drug loading volume several times higher than a single microneedle of the same dimension.

关键词： Microneedle Drug Loading Dropping dipping Capillary Number Capillary Rise