检索结果-南通市图书馆

Improvement in hot corrosion resistance of dissimilar alloy 825 and AISI 321 CO2-laser weldment by HVOF coating in aggressive salt environment at 900℃

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1536-1550页

作者： S.M.Muthu M.Arivarasu T.Hari Krishna Supriyo Ganguly K.V.Phani Prabhakar Saurav Mohanty School of Mechanical Engineering Vellore Institute of TechnologyVelloreTamil Nadu 632014India Center for Innovative Manufacture Research Vellore Institute of TechnologyVelloreTamil Nadu 632014India Welding Engineering and Laser Processing Centre Cranfield UniversityBedfordUnited Kingdom CLPM International Advanced Research Centre for Powder Metallurgy&New Materials(ARCI)HyderabadIndia Department of Mechanical Engineering North Carolina State UniversityRaleighUSA

This study investigated the hot corrosion performance of a dissimilar weldment of Ni-based superalloy and stainless steel joined by CO2-laser welding and improved by high-velocity oxy-fuel(HVOF)coating in a Na2SO4-60wt%V2O5 environment at 900℃.A dissimilar butt joint of AISI 321 and alloy 825 was fabricated by CO2-laser welding with low heat input after obtaining the optimum welding parameters by bead-on-plate *** metallurgical and mechanical properties of the laser weldment were *** tensile test results indicated the occurrence of fracture in the base metal AISI 321 *** HVOF process was employed to coat Ni-20wt%Cr on the *** evaluate the surface morphology of the corrosion products formed on the uncoated and Ni-20wt%Cr-coated weldments,scanning electron microscopy(SEM)analysis was ***-dispersive spectroscopy(EDS)was used to determine the different elements present on the surface *** existence of oxide phases on the weldments was determined by X-ray diffraction(XRD).The cross sections of the weldments were characterized by SEM with EDS line mapping *** results indicated that the Ni-20wt%Cr-coated weldment exhibited superior hot corrosion resistance due to the development of Cr2O3 and NiCr2O4 protective oxide scales.

关键词： nickel-based superalloy dissimilar welding weldment corrosion high-velocity oxy-fuel coating corrosion kinetics

Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2015年第3期25卷 242-250页

作者： Shengrong Wang Cuiwei Du Xiaogang Li Zhiyong Liu Min Zhu Dawei Zhang corrosion and Protection Center Key Lab of Minstry of Education University of Science and Technology Beijing

The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS), and X-ray diffraction(XRD).The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface. α-Fe OOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorrdecreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy(EIS) are consistent with potentiodynamic polarization tests.

关键词： X70 steel Soil corrosion corrosion kinetics Non-uniform corrosion Pitting corrosion

Mechanistic study of ammonium-induced corrosion of AZ31 magnesium alloy in sulfate solution

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第19期54卷 1-13页

作者： Hui Pan Liwei Wang Yi Lin Feng Ge Kang Zhao Xin Wang Zhongyu Cui College of Electromechanical Engineering Qingdao UniversityQingdao 266071China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

The influence of NH4+ions on the corrosion behavior of AZ31 magnesium alloy was investigated by immersion test,hydrogen evolution,electrochemical methods and morphology *** results demonstrate the acceleration effect of NH4+on corrosion of AZ31 magnesium alloy due to the disruption of protective MgO film in NH4+-containing *** loose and cracked corrosion products of AZ31 magnesium alloy in NH4+-containing solutions are mainly composed of(Mg0.833Al0.167)(OH)2(CO3)0.083·0.75H2O and Mg5(CO3)4(OH)2·*** the NH4+concentration is lower than 0.01 M,knife-cut like corrosion occurs in some active area of the surface due to the partial dissolution of MgO *** the NH4+concentration is increased to 0.1 M,the MgO layer is completely disrupted,resulting in the occurrence of uniform *** cathodic and anodic reactions are accelerated by NH4+ions,while the effect of original pH values on the reaction kinetics can be neglected in NH4+-containing solutions.

关键词： Magnesium alloy Ammonium corrosion kinetics Knife-cut like corrosion

corrosion Behavior of Ferritic/Martensitic Steels CNS-Ⅰ and Modified CNS-Ⅱ in Supercritical Water

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2012年第5期19卷 69-73,36页

作者： YANG Ying YAN Qing-zhi YANG Ya-feng ZHANG Le-fu GE Chang-chun School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Nuclear Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The corrosion behaviors of CNS-I and modified CNS-II were evaluated by exposing to superciritical water （SCW） at 550℃ and 25 MPa with a dissolved oxygen concentration of 200× 10 ^-9 for up to 1 000 h. Detailed corrosion results of these two alloys were provided, including the growth rate of the oxide scales, microstructure of the oxide scales, distribution of phases and alloying elements. The mass gains of CNS-I and modified CNS-II were 609.73 mg/dm2 and 459.42 mg/dm2 , respectively, after exposing to SCW for 1 000 h. A duplex oxide scale with an outer porous magnetite layer and an inner relatively dense magnetite/spinel-mixed layer was identified on CNS-I and modified CNS-II after the test. The oxide scales were rather porous at the beginning of the test but the porosity decreased with increase of the exposure duration. It was found that Fe was enriched in the outer oxide layer, Cr was enriched in the inner oxide layer and O existed at a very high concnetration in the whole oxide scale. Other alloying elements such as Mo, W, Mn were depleted from the outer oxide layer and showed slightly enrichment in the inner oxide layer. The distributution of Ni was different from other elements, it was enriched in the interface bewteen the base metal and the oxide scale and depleted in the outer and inner oxide layers.

关键词： ferritic/martensitic steel supercritical water corrosion kinetics oxide scale morphology and structure