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Effect of the Oxidation Time on Properties of Ceramic Coatings Produced on Ti-6Al-4V by Micro-Arc Oxidation 被引量:3
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作者 Zhaohua JIANG, Xuetong SUN, Yanping LI, Fuping WANG and Yandong LU Department of Applied Chemistry, Harbin Institute of Technology, Harbin 150001, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第2期281-284,共4页
Ceramic coatings were prepared on Ti-6AI-4V alloy using ac micro-arc oxidation (MAO) in silicate-hypophosphate solution. Growth regularity and formation mechanism of ceramic coatings were discussed. It was found that ... Ceramic coatings were prepared on Ti-6AI-4V alloy using ac micro-arc oxidation (MAO) in silicate-hypophosphate solution. Growth regularity and formation mechanism of ceramic coatings were discussed. It was found that during the first stage the growth rate of coatings toward the external surface was larger than that toward substrate and then the coating began to grow mainly towards Ti alloy. When the total coating thickness reaches a certain value, it would no longer increase. In addition, the variations of the composition and microstructure of ceramic coatings according to the depositing time were also investigated with X-ray diffraction (XRD) and scanning electron microscope (SEM). The amount of rutile TiO2 gradually increased, whereas the amounts of the anatase TiO2 and amorphous phases first increased and then decreased slightly. 展开更多
关键词 Titanium alloy Ceramic coating Oxidation time Thickness
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Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions 被引量:1
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作者 马嘉璧 吴晓楠 +2 位作者 赵艳霞 丁迅雷 何圣贵 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期133-137,I0001,共6页
The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H... The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules. 展开更多
关键词 time of flight mass spectrometry Zirconium oxide cluster anion Reactivity Density functional theory Hydrogen atom abstraction
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ANTIOXIDANT DEPLETION AND OIT VALUES OF HIGH IMPACT PP STRANDS
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作者 Werner W.Müller Ines Jakob +1 位作者 Chunshan Li Renate Tatzky-Gerth 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第3期435-445,共11页
The service life of a polyolefin product depends to large extent on the type and amount of the antioxidants added. During the manufacturing,storage and use of the product the antioxidants are depleted by physical proc... The service life of a polyolefin product depends to large extent on the type and amount of the antioxidants added. During the manufacturing,storage and use of the product the antioxidants are depleted by physical processes and chemical degradation,and this impairs its long-term performance.The initial and in-use oxidation stability is often characterized and monitored by the measurement of the oxidative induction time(OIT),and service life predictions are based on the rate of decrease of the OIT value.To study the correlation between the OIT value and the actual antioxidant concentration,eight random arrays of high-impact polypropylene(PP)strands stabilized using six different antioxidant packages(composed of Irgafos 168,Irganox 1010 and 1330,Chimassorb 944)were immersed in hot water(80℃and 90℃)and oven aged in air (80℃)for more than two years,and the change of OIT values and antioxidant concentrations was measured.For phosphitic and phenolic stabilizers water immersion is generally a more critical aging condition than oven aging in air,while for the hindered amine stabilizers(HAS)the opposite was observed.As expected,a linear correlation between OIT values and concentrations was found for the'classical'package of phosphitic and phenolic stabilizers.In the case of Irganox 1330,the change of the OIT values during aging was considerably slower than the change of concentration.Even when zero concentration was reached according to the vanishing peak height in the chromatogram,a considerable OIT value was still measurable.This may be due to unidentified degradation products of Irganox 1330 which still act as antioxidants in the long run.Addition of HAS(Chimassorb 944)seems to enhance the initial OIT of stabilized phenolic samples and the long-term effectiveness of the phenolic stabilization under air oven aging conditions.However,the marked long-term effectiveness of the HAS itself and the slow change with time of the concentration were not detectable by OIT measurements above the PP melting point of about 170℃. 展开更多
关键词 POLYPROPYLENE STABILIZERS Oxidative resistance Antioxidant depletion Oxidative induction time
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The Timing of the Palaeoproterozoic Great Oxidation Event using Dykes,Sills and Bolcanics of the Ongeluk Large Igneous Province,Kaapvaal Craton
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作者 Ashley P.GUMSLEY Kevin R.CHAMBERLAIN +5 位作者 Wouter BLEEKER Ulf SODERLUND Michiel O.DE KOCK Tobias C.KAMPMANN Emilie R.LARSSON Andrey BEKKER 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期67-68,共2页
The Neoarchaean to Palaeoproterozoic Transvaal Supergroup of the Kaapvaal Craton,southern Africa,is one of the best-preserved and most complete stratigraphic records across a critical in juncture in the Earth’s history.
关键词 Sills and Bolcanics of the Ongeluk Large Igneous Province The Timing of the Palaeoproterozoic Great Oxidation Event using Dykes GOE
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