A technique for determining corrosion current density Ⅰ_(corr) and anodic and cathodic Tafel coefficient b_a and b_c based on the data on cathodic polarization curve in weak polarization region was suggested. The influence of pH value and Cl~--eoncentration on the electrochemical behavior of Fe te corrosion process in acid solutions was studied by using this technique, and the results obtained were verified, by the data in strong polarization region. It is shown that OH~- and Cl~- both take part in the anodie dissolution process Of Fe with reaction orders of 1 and 0.5 respectively, and the values of b_a and b_c are 40 mV/decade and 120 mV/deeade respectively. A kinetic model for the anodic dissolution reaction of Fe in Cl~--containing acid solutions was suggested. It is also demonstrated that there is no significant interaction between the influence of pH value and Cl~--concentration on E_(corr) and Ⅰ_(corr).

The dczincification behavior of an (α+β) brass (HPb59-1)in deaerated acidified solution of sodium chloride containing no Cu~+ was investigated by rotating ring-disc electrode. Experimental results show that the collection efficiency of the brass disc-Pt ring electrode changes with time and rotating speed and disc current during anodic dissolution. Thus it can be proved that the dezincification of this (α+β) brass follows the dissolution-redeposition me chanism. According to the linear relationship of(N_(Cu)~0+-N/N-ω), the rate constant of copper redeposition reaction has been calculated to be 2.1×10~(-2) cm/Sec.

The effect of Cr, Ta and inert gas ion implantation on the tarnishing resistance of high purity copper in hydrogen sulphide containing atmospheres has been studied using surface reflectance measurements, coulometrie reduction of surface films, scanning electron microscopy and wavelength dispersive analysis of X-rays. The exposure tests were conducted in air containing different levels of H_2S covering the range 0.006 to 6 VPM at 25℃ and 100％RH. Implantation of Cr and Ta markedly improves the tarnishing resistance of copper, Xe implantation gives a small improvement and Ar implantation has no effect. Coulometric reduction demonstrates that samples implanted with Cr and Ta have thinner tarnish films and that the composition of these films is different from that formed on unimplantedcopper. Seanningeteetron microscopy combined with WDAX analysis indicates that Cr implantation suppresses the formation of metallic sulphides in tarnish films on copper.

The effect of hot corrosion on creep strength of the superalloy GH37 at 700℃ and 850℃ has been studied by comparing the results for both bare specimens and specimens coated with a salt mixture of 25％ NaCl and 75％ Na_2SO_4. Results show that the secondary creep rate increases and that the life of creep rupture and ductility decreases considerably with salt coated specimens. The effect of hot corrosion on creep strength of alloy at 700℃ is much more severe than that at 850℃, although the alloy is nearly unattacked at 700℃ by salt. Direct observation of fracture surface leads us to suggest that for the salt coated specimens the decrease of creep rupture life at 700℃ is due to the reduction, of the crack initiation time, while the reduction of the creep rupture life at 850℃ is due to the acceleration of creep crack growth rate. The creep strength of the alloy can be improved by means of Al-Cr diffusion coating on the specimen.

The effect of carbon on hot corrosion behavior of IN-738 was studied with the fused-salt crucible method. Surfaces of corroded specimens have been examined by means of metallography, X-ray diffraction analysis, EPMA, SEM, etc. It was shown that carbon greatly improved the hot-corrosion resistance of IN-738, especially at about 800℃. When the carbon content was below 0.1％, improvement was most remarkable, between 0.1-0.2％, the effect decreased gradually, and beyond 0.2％, it had no further effect. Two possibilities are suggested to account for the beneficial effect of carbon: retardation of basic fluxing corrosion and promotion of formation of a Cr-rich protective oxide film.

The diffusion process(M_t～t~(1/2) curves)of chemical media in glass fiber einforced plastics(FRP)was investigated by gravimetrie method. With variation in chemical media, environmental temperature and resin content of FRP, four kinds of deviation from Fiek law were observed. The corrosion resistance of FRP in different chemical media bears some relationship to the mode of diffusion and can be roughly estimated from the latter. When the chemical medium and components of FRP have been fixed, the diffusion coefficient and diffusion activation energy can be determined.

The effect of M_(23)C_6 and intermetallic compound x-phase on the stress corrosion cracking behavior of a Cr-Mn-N austenitic stainless steel was studied in 4N NaCl and 45％ MgCl_2 solutions. The results showed that the two precipitates had a pronounced influence on open circuit potential and the time to failure at various applied potentials in 4N NaCl solution while they had little effect in the 45％ MgCl_2 solution. The different effects of these two precipitates in above mentioned solutions were related to different failure mechanisms.

Crystallographic orientation of electrodeposited zinc in five different electrolytes were studied by means of X-ray diffraction technique. According to the relationship between the most close-packed planes and surface of deposit layer, these deposits can be classified into two types, the parallel and the perpendicular. The parallel type of deposits is more preferable for improved corrosion resistance.