Abstract: The corrosion behaviour of CuZnAl shape memory alloy in physiological saline solutions has been investigated with immersion test and electrochemical measurement techniques. The results showed that the corrosion form of shape memory alloy was dezincification mechanism. The corrosion resistance of CuZnAl shape memory alloy was such better than annealed CuZnAl alloy. It is mainly related with the martensite phase which has the effects of shape memory and superelasticity improved electochemical behaviour in surface of alloy and increased passivation ability.Thus supressed anodic active dissolution.
Abstract: High energy density plasma technique(HEDP) was applied to surface treatment of Fe3Al. A micro-crystalline layer with grain sizes between 10 and 100nm was obtained. Isothermal oxidation at 1000℃ in air for cast Fe3Al before and after micro-crystallizing was studied. The results showed that for the micro-crystalline Fe3Al,(1) a micro-crystalline oxide scale formed during oxidation;(2) the plasticity and adhesion of oxide scale was remarkably improved;(3) the oxidation rate was decreased;(4) the oxidation kinetics obeyed the forth power equation law.
Abstract: The effect of surface roughness on nucleation and growth of metastable pitting on amorphous NiCrFeSiB alloy was studied using potentiostatic and potentiodynamic polarization tests.Nucleation of metastable pits on the alloy was significantly facilitated by rougher surface. Both the growth rate parameters and the peak currents of metastable pits follow log-normal distribution. Rougher surface also promoted the growth of metastable pits, and lead to a wider distribution of the growth rates.
Abstract: Zn-SiO2 composite samples have been produced by a high-speed plating equipment.The crystallographic structrue、structrue fault and surface morphology were analysed by XRD,SEM,TEM.The reasons that Zn-SiO2 composite has better anti-corrosion properties than pure Zn deposite are explained.
Abstract: The main reason for corrosion of oil pipelines in Qinghai oil field has been studied. High concentration of Cl-,salts, high mineral degree are main factors to influence the corrosion of pipelines. Bacteria also assist corrosion. Localized corrosion induced by Cl- and bacteria was accelerated.Simultaneously the pipelines also suffer from SCC induced by H2S. The pipeline steel could possibly leak by pitting or abrupt fracture by stress corrosion.
Abstract: The influence of water chemistry factors on corrosion of oil pipeline steel in simulated water has been studied by electrochemical method,including discharging of oxygen by Na2SO3,dissolved oxygen,concentration of Cl- and temperature.The critical values of dissolved oxygen, Cl- concentration and temperature below which corrosion rate will not exceed the confined value of Standard SY5329-88 have been obtained.
Abstract: The effect of plasma arc remelting treatment on the microstructure and wear resistance of overlay is investigated and discussed.With plasma are remelting process, a remelting-chilling layer formed on the overlay surface.In the layer,the matrix structure transormed from γ-Ni to Cr0.7Fe0.36Ni2.90,and fine crystallite grains were obtained. Both abrasive and adhesive wear resistance were maised by plasma the remelting process.
Abstract: The solution chemistry in cuneiform crevice of 316L stainless steel was studied in 3.5%NaCl at room temperature.The Cl-was concentrated and PH value decreased in the cuneiform crevice with two sizes of crevice opening. When the crevice opening is 1.36mm,the Cl-concentration increased and PH value decreased with time and the distrance from the opening. The highest Cl-concentration is 1.6mol/l and the lowest PH value is 5.01.When the opening is 0.22mm, the highest Cl- is 1.1 mol/l and the lowest PH value is 3.1.The very low PH value in the crevice was formed by the hydrolysis of dissolving metal ions and Cl-. The chloride can be very concentrated in the crevice. even be saturated.
Abstract: Aluminum-chromium diffusion coatings on pure nickel substrate were formed by two-step pack cementation process. It was found that existed many voids in the coatings which were formed by first aluminizing and then chromizing. It could be understood that aluminum in the coatings reacted with HCL gas decomposed from activator NH4CL and formed ACL3,which evaporated and resulted in formation of the voids.Oxidation resistance of Al-Cr coating with these voids was reduced signigicantly.
Abstract: The mechanism of electrodeposition of Cu/Ni multilayer thin films from citrate salt electrolyte has been studied by means of potentodynamic sweep, cyclic voltammetry sweep and AC impendence.The results indicated that the copper deposition is mass transfer controlled process and nickel deposition is related to the absorbed intermediate species such as Ni(OH)ads. The nickel ions first form Ni(OH)ads,then was deoxygenated to nickel on the electrode surface.
Abstract: The oxidiation behavior of nickel in molten (Li0.62,K0.38)2CO3 has been investigated by means of cyclic voltammetry and X-ray diffraction and X-ray photoelectron spectroscopy.
Abstract: Anodizing technology for aluminium magnetic films were investigated. The image, size, thickness and the distribution of elements in aluminium magnetic films were analyzed by using SEM, ESCA and RBS. Also, the rectangle rations of the films were measured in our study.
Abstract: Electrchemical anodic oxidation method were used to systhesize a novel graphite intercalation compounds——NH4NO3-GICs,and its microstructure has also been studied.
Abstract: The dependence of structure stability of electrodepositing amorphous Cr-C and Ni-P films on their components have been researched by action of high accelerated voltage electronic cluster. It was shown that, when temperature was far lower than crystalline temperature, the lower the content of submetallic element in films,the bigger the extent to crystallize.
Abstract: The sulfidation kinetics of Fe25Cr20Ni were cairied out at H2S-H2 atmospheres by means of continuously-weighing device and non-continuously weighing device. Sulfidation kinetics curves of the alloy obeys parabolic law.The composition and morphology of sulfide scales were also studied. All sulfide scales consist of two surface layers in addition to subscale. Two surface layers are controlled by predominant diffusion of metals. The subscale growth is controlled by the inward diffusion of suffur.
Abstract: The structure and properties of electroless Ni-P amorphous alloy under the simulated welding condition by changing the temperature and time of heat treatment were investigated.It has been shown that the crystallization of Ni-P alloy would not accur when time of heat treatment is shorter than 60 seconds.(beside 1000℃,60s),but the hardness of the alloy increases obviously.Under the condition of heat treament with shorter time,the handness of the alloy reaches the maximum when the temperature of heat treatment is 700℃.
Abstract: The high-temperature resistance oxidate and the hardness after heat treatment on amorphous Ni-W, Ni-W-B alloys deposite were studied.It was shown that high-temperature resistance oxidate of amorphous alloys deposite is mainly dependent on W and B concentration.
Abstract: Possibility and feasibility of cathodic protection(CP) on the rusted cast iron with thick rust layer and the optimum parameter of protection were studied. The results showed that it was feasible to protect rusted cast iron by cathodic protection technique.The optimum protection potential was between-900 mV and -1000 mV(SCE) under the present condition.If protection potential was more negative than-1100mV (SCE),the protection efficiency would dramatically drop.
Abstract: The management and consultant system of atmospheric corrosion data of protection coatings for metal have the advantage of convenience, promotion and easy leanring.With the help of dialogue between man and computer, the data can be added,modified, deleted, scaned, indexed and sorted. Users can also inguire conveniently out the corrosion data of the protection coating in different areas of the whole country and reference materials about the coating.The system has been developed on an IBM/PC computer. The soft work enviroment of the system is the chinese relatinoship database management system-Foxbase+2.1.
Abstract: The change on the structures of Ni-P alloy coating with different amount of RE in the solution has been investigated.X-ray and TEM analysis showed the ratio of amorphism structure in the coating can be improved obviously with a certain amount of RE in the bath.And its changing law was the same as the changing law of the coating corrosion resistance.The probable mechanism was also discussed.
Abstract: The effects of the Rare Earths(RE) on the corrosion resistance and structure of the electro brush-plating Ni-P alloy coating have been investigated. The results obtained from the immersion test and the polarization curves showed that the corrosion resistance of the coating could be improved obviously with a certain amount of RE in the bath. The X-ray,TEM, EDS composition analysis showed that the RE could improved the amorphism of the Ni-P alloy coating. And the probable mechanism of the RE to improve the amorphism has been proposed.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
