Abstract: Polarization behaviour of electroless amorphous Ni-P alloy coatings have been investigated in 1mol/1 NaOH solution using potentiodynamic method, and surface films at different potentials have been analysed on the basis of XPS method. Results indicate:the anodic dissolution current does not decrease with the increase of P content in the Ni-P alloy, even though there exists H2PO2- and PO4- on the surface film, anodic dissolution of alloys has not been inhibited effectively. The intense hydrolization of P may be the cause of making the dissolution current of Ni-P alloy higher than that of Ni.
Abstract: The sub-lattice model proposed by Bjorn Uhrenius, which was used to describe thermodynamic properties of Fe-C-based ternary systems, has been extended and applied to Fe-C-bssed quaternary alloy systems with the Gibbs energy expressions also being given. The phase equilibria between austenite and carbide in Fe-Cr-Ni-C quaternary system have been calculated based on the calculation of thermodynamic equilibria in Fe-Cr-C ternary system done by Bjorn Uhrenius, in combination of the interaction parameters in Cr-Ni binary system given by Nishizawa.
Abstract: The superposition of pulsed current on the electroless reaction is referred to the pulsed electroless plating. The effects of pulsed parameters (pulsed current desities and duty cycles) and temperatures on the compositions and performances of deposits and the depositing rates are investigated. The results showed that the depositing rates are accelerated by pulsed current without any great loss in the properties of the Ni-P deposit. In addition, the enhancement of the chemical reaction for electroless nickel deposition by pulsed current is found.
Abstract: The results of a study of the effect of increasing carbon concentration on the crystalline-to-amorphous transition and corrosion resistance in high rate sputter-deposited 304ss-carbon alloys are reported. Charaterization using X-ray diffraction, transmission electron microscopy and auger electron microprobe analysis showed that the amorphous state was formed at carbon concentration greater than 6.2wt%.
Abstract: High temperature corrosion behaviors of alloy Co-30Cr, Co-30Cr-4A1 and Co-25Cr-loNi-4Al-5Ta-0.5Y has been studied at the presence of Na2SO4-K2SO4 salts mixture. The experimental results showed the internal sulfidation-internal oxidation to be the major mode of attack. Much severe attack is found in alloy Co-30Cr, and sulfide rich in Cr developed deep in the alloy matrix. Fine inner oxide precipitates rich in Al is found in alloy Co-30Cr-4Al, and sulfur penetration is detected by S radioisotope method. Little inner oxide precipitates rich in Al is found in alloy associated with Co-25Cr-10Ni-4Al-5Ta-0.5Y.
Abstract: The compositive plating technique is first applied to the circle pattern circuit. The new plating system consists of dark nickel, Ni-Al2O3 compositive plating and acid pulse gold plating. After application of the new plating system, the break tendency of the external leads of the shells can be decreased remarkably. On the basis of intermediate experiments for batch process, the technological factors suitable for practical process are found out. A new experimental method for evaluation of the corrosion resistance of external leads of the shells is first established by authors.
Abstract: The stress corrosion cracking (SCC) behaviour of low alloy steel in nitrate aqueous solution was investigated. The effect of temperature, medium concentration and potential on various corrosion types and thier intensities was determined. The temperature-concentration-potential SCC diagram was established. The down critical potential and sensibility zone of SCC was ascertained. The applicability of cathcdic protection was discussed.
Abstract: The sulfidation kinetics of Fe25Cr20Ni2.4Si were carried out at H2S-H2 atmospheres by means of continuously-weighing device and non-conti-nuously 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 predominante diffusion of metals. The subscale grow is controlled by the inward diffusion of sulfur.
Abstract: The pitting behavior of passive 304 stainless steel in pH8.4, H3BO3 (0.2mol/l)-Na2B4O7 (0.05mol/l) and pH9.2, Na2B4O7 (0.05mol/l) solutions containing chlorion has been investigated using impedance technique. The possible reaction mechanism as well as the corresponding equivalent circuit model is presented. It is proposed that an intermediate complex (MOHCl) and its further adsorbed product (MOHCl-Cln-)ads will form during pit initiation and propagation stages.
Abstract: Sulfidation-oxidation behaviors of Ni16Cr, Nil6Cr3Ti, Ni16Cr 2Nb alloys have been studied at 700℃ in O2-10% (SO2+SO3). Corrosion products are observed and examined with X-ray diffraction and SEM. Under experimental condition, containing SO3 corrosion rate of Ni16Cr alloy is rapider. Nb has little effect on degradation of alloy. When alloy containes Al or Ti, the oxidation rate of these alloys is slower. Products of corrosion consist of two layers; external layer (NiO + Ni3S2) mixture and internal layer sulfids and oxides containing all test alloying elements.
Abstract: Aluminium sheet of commercial purity was anodized and electro-lytically coloured in nickel base solution, forming light/thermal conversion coatings. It was found that the colouring of films formed in sulphuric acid was more difficult, if not impossible, as compared with films formed in phosphoric acid. Morphology observations, using ultramicrotomy allied with transmission electronmicroscopy, suggest that the easiness of colouring is related to the diameter of the pore base, independent of the pore size in the surface layer of the film. Good solar energy absorbtive anodic films were obtained by anodizing in phosphoric acid and electrolytically colouring, with absorbance α=0.93 at λ<2.5μm and emittance ε=0.26 at λ>2.5μm.
Abstract: Based on catenary model, a new experimental method for growth stress measurement was reported. The advantage of this method consists in the fact that neither a protective layer nor creep properties are necessary and that question about clastic or plastic deformation can be avoided.
Abstract: It was found that barrier anodic film can be formed on aluminium in (NH4)2MoS4 aqueous solution. Ultramicrotomed sectioning allied with analytical TEM and ion implantation of xenon marker techniques were employed to investigate the morphology, chemical composition of the film and to measure the ion migration during anodizing. Species characterizing the electrolyte (Mo) was not detected in the film section with EDAX analysis. It was found that film growth proceeds at both the alumium/film and the film/electrolyte interfaces. The apparent migration ratio of aluminium ions is 0.44 when the anodizing current density is 1.0mA/cm2.
Abstract: Collected-microelectrode system is a newly developed corrosion electrochemical tool. The main advantage of it is that it may measure transient potential distribution of a corroding sample surface, this is important for the research of localized corrosion. In this paper, the designing, preparation and the problems that might be encountered in its application are discussed.
Abstract: In this paper, the structures similar to those of different zonesin the Heat-Affected Zone (HAZ) of actural welding were obtained in the fatigue specimens with the thermal-simulated technique; the experiments on fatigue life and crack propagation were carried out with the specimens. Through the corrosion fatigue behavior of the different zones in HAZ investigated, the effect of welding process on the corrosion fatigue properties of CF-60 steel was studied. It was found that welding could reduce the corrosion fatigue properties of CF-60 steel because the fatigue properties of the Imcomplete Recrystal Zone (IRZ) in HAZ were worse than those of matrix and the other zones. One of the main reasons that resulted in the case was that the anti-corrosin of IRZ was worst in the welded joint region.
Abstract: The environment and architecture of Application Softwares of Atmospheric Corrosion Database for Materials (ASACDM) which in implemented on the computer IBM/PC-XT are described. And in detail the program in the application of ASACDM are stated. The advantage of this ASACDM system iIs convenient to operate and easy to master. Its use will have more important significance for national atmospheric corrosion test station to do management in a scientific way.
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
