NIU Yan
,
F.GESMUNDO
,
WU Weitao
,
ZENG Chaoliu
,
F.VIANI
,
(State Key Laboratory for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang.110015
,
China)(Istituto di Chimica
,
Facolta'di Ingegneria
,
Universita'di Genova
,
Fiera del Mare
,
Pad.D
,
16129 Genova
,
Italy)Manuscript received 3 July 1995
金属学报(英文版)
The corrosion properties of a Co-15wt% Y alloy were studied in H_2-H_2S mixtures under a sulfur pressure of 10-3 Pa at 600-800℃ and of 10-2 Pa at 800℃ to examine the effect of Y on the resistance of pure cobalt to sulfur attack at high temperatures.The alloy is nearly single-phase.containing mostly the intermetallic compound Co17Y2 plus a little amount of the solid solution of Y in cobalt.At 600-700℃ and at 800℃ under 10-2 Pa of S2 the alloy forms multi-layered scales consisting of an outer region of pure cobalt sulfide,an intermediate region of a mixture of the sulfides of the two metals and finally an innermost layer of a mixture of yttrium sulfide with metal cobalt.At 800℃ under 10-3Pa of S2,below the dissociation pressure of cobalt sulfide, the alloy forms only a single layer composed of a mixture of metallic cobalt with yttrium sulfide.Pure Y produces only the oxysulfide Y2O2S, as a result of the good stability of this compound and of the presence of some impurities in the gas mixtures used The corrosion kinetics is generally rather complex and irregular except al 800℃under 10-3 Pa of S2.The addition of yttrium always reduces the sulfidation rate of cobalt, even though the formation of a continuous protective external layer of yttrium sulfide is never achieved.The internal sulfidation of Y in Co-15% Y is not associated with a depletion of Y in the alloy.This kind of diffusionless internal attack is typical of alloys with a very small solubility of the most reactive component Y in the base metal A.which restricts severely the Y flux from the alloy towards the alloy-scale interface.
关键词:
:cobalt-yttrium alloy
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WU Weitao ZHANG Jianqing ZENG Chaoliu NIU Yan SHEN Weiliang Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China Professor
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Hot corrosion of intermetallic compound Ni_3Al-0.2B was studied by electrochemical techniques combined with physical analyses.It was found that hot corrosion resistance of Ni_3Al-0.2B is rather inferior.Sulfidation-oxidation is responsible for the accelerated corrosion.The addition of 6at.-% Cr and 0.5at.-% Zr to Ni_3Al-0.2B may accelerate its corrosion.
关键词:
Ni_3Al-0.2B
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HAN Enhou HAN KYumei ZHENG Yuli KE Wei Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China postdoctoral
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Based on theoretical analysis about local strain,strain rate and dissolving rate at crack tip, the corrosion fatigue crack growth rate of steels ZG20SiMn and SM50B-Zc in fresh water and 3.5% NaCl solution were measured experimentally,and the PH and electrode potential within crack were also measured continuously along with crack propagating.It showed that the increase of crack growth rate,caused by both decreasing frequency and raising stress ratio,was mainly accelerated by hydrogen embrittlement.
关键词:
corrosion fatigue
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LIU Dacheng WANG Fuhui CAO Chunan LOU Hanyi Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China Wang Fuhui
,
Laboratory of Electrochemistry
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
A series of single bcc,bcc plus fcc duplex and single fcc microcrystalline coatings of 1Cr18Ni9Ti stainless steel were prepared by using sputtering technique.The resistance against pitting corrosion was studied by measurements of pitting corrosion potentials and electrochemical noise during initiation of corrosion pits.The results show that the sputtered coatings with single bcc phase or single fcc structure are more resistant to pitting corrosion than those with bcc plus fcc duplex phase structure.
关键词:
1Cr18Ni9Ti stainless steel
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WANG Zhengfu ZHU Ziyong KE Wei Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
ChinaZHANG Yun HU Zhuangqi Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
Studies were made of the influence of aging conditions and applied potentials on the stress corrosion carcking(SCC)susceptibility for an Al-Li-Cu-Mg alloy by slow strain rate technique.The relationship between the relative hydrogen content on specimen surface,the applied potentials and elapsed time has also been examined.The SCC susceptibility was found to be dependent on aging conditions in which the peak aged condition gave the worst SCC resistance and the natural aged condition had the best one. The SCC susceptibility and surface hydrogen content relates to the applied potentials. The anodic potentials increase SCC susceptibility,while the cathodic ones below the critical potential accelerate SCC.It is considered that both the anodic dissolution and
关键词:
Al-Li alloy
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F.Gesmundo F.Viani Instituto di Chimica
,
Facolta di Ingegneria
,
Universita di Genova
,
Genova
,
16129
,
ItalyY.NIU Corrosion Science Lab.
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英）
The corrosion of alloys based on Fe,Co and Ni containing 15 and 30 wt-% Nb was studied at 700℃ in H_2-H_2S mixtures providing 10~(-8) atm S_2.The Fe and Co-based alloys formed duplex scales with an outer layer of pure base-metal sulphide and an inner layer containing both metals.The Nb addi- tions were not able to produce exclusive Nb sulphidation but yielded a significant decrease of the corrosion rates for both types of alloys with respect to the pure metals even though they were still much higher than that of pure Nb.The Ni-base alloys corroded rapidly forming a single complex scale layer,mainly due to the appearance of a liquid Ni-S solution.
关键词:
niobium
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WANG Fuhui
,
LOU Hanyi
,
WU Weitao Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China research assistant
,
Institute of Corrosion and Protection of Metats
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The influence of defects on the oxidation, hot corrosion and thermal shock properties of sputtered Co-30Cr-6Al-0.5Y coatings was investigated.The results indicated that the nodular defects reduced the properties of the coatings.For the oxidation,the nodular defects resulted in the severe internal oxidation of aluminium,as a result,the pure alu mina scale could not form at very high temperature such as at 1 100℃.For the hot corrosion,the nodular defects served as the short-path for the diffusion of sulfur into the coating and the substrate,and caused the sulfidation,of the specimen.Moreover,the nodular defects became the crack source during the thermal shock test and decreased the thermal shock resistance.
关键词:
CoCrAlY coating
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LIU Changqing
,
LI Meishuan
,
JIN Zhujing
,
WU Weitao Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China research assistant
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The cantilever bending test,particularly monitored by an acoustic emission technique, was adopted to measure the tensile and interfacial adhesive strengths of the HCD ion plated fine TiN film on pure Ti substrate.The behaviors of film damaging were found to be characterized by:an internal tensile stress which exceeded its tensile strength for TiN facing upward,and a shearing stress along film substrate interface which exceeded its adhesive strength for TiN facing downward.The measured tensile and adhcsive strengths are 603 and 242 MPa respectively.
关键词:
tensile strength
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