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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null
,
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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
,
null
,
null
,
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ZHANG Lixin NING Hua Laboratory of Corrosion Science
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica.Shenyang
,
ChinaZHOU Jing LI Liguang Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Professor
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The relations between the non-equilibrium segregation process of P and the change of the texture in Fe-P alloys have been studied by analytical electron microscope and orientation distribution function.It was shown that P segregated preferentialy on the{110}slip planes, the P segregation structures with repeating cycle a=1.582 nm form at 450℃.<001>// ND direction abated.<111>//ND direction heightened.And{111}<110>has a tendancy to transform into{111}<143>texture in recovering process.{111}<143>direction trans- forms into{111}<112>direction after recrystalizing.A model to describe the effects of non-equilibrium segregation structures of P on orientation change was proposed and em- ployed to interpret the experiment results.
关键词:
Fe-P Alloy
,
null
,
null
,
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LI Hiaogang
,
MENG Qinghai
,
CHEN Hua
,
CHEN Jinwei
,
YAO Zhiming
,
KE Wei(State Key Laboratory of Corrosion Science
,
Institute of Corrosion and Protection of Metals
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Fushun Petroleum Institute
,
Fushun 113001
,
China)
金属学报(英文版)
Hydrogen attack occurred in low carbon steel and steel 25CrMo which had been exposed in hydrogen under 18MPa at 450 and 500℃ for 240,480 and 720 h.The methane bubbles and microcracks grow along grain boundaries.The degree of hydrogen attack increases with increasing exposure time and temperature.Magnetic acoustic emission(MAE) was used to detect the degree of hydrogen attack.The results show that the characteristics of MAE for samples of low carbon steel and steel 15CrMo with hydrogen attack have changed obviously comparing to the samples without hydrogen attack,and the MAE signals was sensitive to the degree of hydrogen attack at the last stage of hydrogen attack.The magnetic detection way,as a new method of nonrestrictive testing of hydrogen attack,can be used to detect the hydrogen attack in practice.
关键词:
:magnetic acoustic emission
,
null
,
null
,
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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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null
,
null
,
null
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 Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
An investigation was carried out of the resistance to cyclic oxidation of the as-cast normal-grained Co-30Cr-5Al alloy substrate at 1000℃ in air together with its sputtered coating of microcrystallized CoCrAl alloy grains sized less than 0.5μm.Acoustie emissi on counts showed that the initially formed Al_2O_3 scale on the bare alloy substrate cracked and spalled severely off after only one or two cycles on cooling and then the worse protective layer of Cr_2O_3 and CoCr_2O_4 spinel occurred on surface.While such substrate coated with sputtered microcrystallized CoCrAl alloy film was not damaged under oxidation even through 100 cycles at 1000℃.In comparison with the normal-grained alloy,the microcrystallized al- loy,coating of similar constitution exhibite excellent resistance to oxide spalling on surface.
关键词:
microcrystallized CoCrAl coating
,
null
,
null
HUANG Yanliang CAO Chu'nan LIN Haichao LU Ming Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China Ph D student
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
It is verified that stainless steel AISI 321 is in the active anodic dissolution state in 0.5 mol/L HCll+0.5 mol/L NaCl solution at 55℃.The SCC of the steel in the solution can not be reasonably explained by passive film rupture-nepasivation theory and by hydrogen embrittlement theory.There are evidences that the fracture stress at the tip of the cracks is reduced by anodic dissolution due to its role in relieving strain hardening layer at crack tip.
关键词:
stress corrosion cracking
,
null
,
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WANG Fuhui LOU Hanyi WU Weitao Corrosion Science Laboratory
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China associate professor
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
Effect of a sputtered Co-30Cr-5Al microcrystalline coating on oxidation resistance of intermetallic compound TiAl and oxidation behavior of the bare TiAl were investigated at 900—1000℃ in static air.The oxidation kinetics for the TiAl alloy seems to approximately follow a linear rate law.Poor oxidation resistance of TiAl is due to the formation of the mixed Al_2O_3+TiO_2 scale which is loosely packed and easily spalled off.but not of dense and adherent pure Al_2O_3.A sputtered Co-30Cr-5Al coating,30 μm thickness,can remarkably improve the oxidation resistance of TiAl owing to the formation of adherent Al_2O_3 protective scale.However,many Kirkendall voids were formed between coating and substrate.
关键词:
CoCrAl microcrystalline coating
,
null
,
null
,
null
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
,
null
,
null
,
null
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null
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J.L. Li 1
,
2)
,
K.F. Wong 3) and G.H. Zhu 3) 1) Fushun Petroleum Institute
,
Fushun 113001
,
China 2) State Key Laboratory for Corrosion and Protection of Metal
,
Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China 3) Zhejiang University
,
Hangzhou 310027
,
China
金属学报(英文版)
This paper integrates the characteristic of structure design and manufacture and maintenance for Chinese flat steel band wound pressure vessel(UCWPV) with the problems existing in current in service high temperature and pressure vessel exposed to hydrogen. In view of economy and safety it is suggested that it be practicable for UCWPV to act as reactors for platreating, hydrogenating, and catforming. UCWPV has not only potential advantages, but also removes shortages present in in-service reactors for hydrogen.
关键词:
design
,
null
,
null
