The effects of MnC1, spraying and C1 ion implantation on the isothermal oxida- tion of TiAl alloy at 950°C have been studied. The oxide scale on TiAl was a mixture of TiO, and Al,03 grains. The oxidation rate was decreased by 4 orders of magnitude after a little amount of MnCl, was sprayed on TiA1. The scale on MnCl, sprayed TiAl mainly consisted of Al,03.' The reason lay in that titanium in the alloy reacted with C1 at the beginning of oxida- tion to form titanium chloride which vaporized from alloy surface. A layer of compact A1,03 scale was formed on the surface of the alloy and prevented the outward diffusion of Ti in the alloy . Ion implantation doses of 1X 10". 1X 10'7Cl-/cmz decreased the oxidation rate appar- ently in the initial period of oxidation and prevented the formation of TiO,. But the amount of TiO2 in the scale increased with increasing oxidation time. Besides A1,03, a little amount of TiO, was also formed on Clbimplanted TiAl at the beginning of oxidation and thus sup- pressed the formation of acompact A1,O3 scale.

The optimization of anode location along pipe line was wxplored.According to the theory of electric field of stable currents, the following functions were studied: (A) the influence of anode location on the anodic resistance (medium circuit resistance ) and on the potential of the jumction field and on the potential distribution along the pipe. Based point to anode cable; (B) the influence of anode location on the anode electric field and on the potential distribution along the pipe line. Based on the ratio of components composing cathodic protection potential system, the anode distance (from 0 to )were divided into three regions. The optimization of anode distance in short range region and in long range region was discussed in details.

The changes of specific energy consumption, material losses, friction coeffi- cient and dynamic hardness of Ti6A14V during corrosive wear process in 0. 5 mol/L H2S04 solution at different potentials and in air were investigated using a pendulum scratching appa- ratus, the hydrogen contents in scratching tracks was measured with SIMS, and the mor- phologies of scratching tracks were observed by SEM. The results showed that the wear pro- cess induced the hydrogen concentrating at wear subsurface, which decreased the energy con- sumption per unit volume of material loss and facilitated the nucleation and propagation of the surface cracks.

The effect of addition of 7. 02%-11. 98% nickel on crevice corrosion be- haviour of Type 304 stainless steel has been investigated with immersion test and electro- chemical measurement techniques in 0. 3%NaCl solution. The results showed that the addi- tion of nickel increased the repassivation potential for crevice corrosion (ER), decreased the product of number of sites attacked, N and average value of maximum depth, D(NXD) and prevented the active dissolution, improving the resistance to crevice corrosion for Type 304 stainless steel. The AES and XPS analysis indicated that nickel was rich in surface film and transition zone, also existed as NiO in film. The joint effect of chromium and nickel im- proved electrochemical behavior and the stability of film.

Corrosion behaviors of LYll Aluminum Alloy and H62 brass in soils were studied. The results showed that the corrosion of LYll and H62 depended on the type of soils and the soil texture. There was severe corrosion in heterogeneous alkaline soil, while only light corrosion in homogeneous neutral clay and acid clay.

Static corrosion rate and corrosive wear loss of AISI304 stainless steel have been examined in 1mol/L H,SO, solution with different contents of C1-. Specific energy con- sumption and the relationship betweem scratch length and energy consumption in above con- dition have been measured using single pendulum scratch device. Experimental results showed that the existence of C1- enhanced the corrosion and corrosion wear for 304 steel and with increasing C1- ,specific energy consumption of material surface decreased. It was sug- gested that the enhancement of corrosive wear of 304 steel would be the environmental em- brittlement resulting from C1-. corrosive wear, specific consumed energy, pendulum scratching

The EIS of rebars in concrete without chloride ion and with 0. 8mol/L chloride ion were measured. The effects of time and composition of concrete on the characteristics of EIS of rebars were studied. When a straight line, which meant diffusion control, appeared on the EIS, the rebar in concrecte began to corrode. The characteristics of EIS of rebars in concrete were different from those of rebars in simulated pore solutions. There were capaci- tive loops, which indicated the existence of sedimentary film of Ca(OH),, in high frequency range. The corresponding equivalent circuits were proposed respectively, which could inter- pret the corrosion mechanism of rebnrs in concrete.

The effects of the heat treatment and coating hardness on the adhesion of elec- troless nickel coatings, Nip and NIB, have been evaluated by the scraping method. It was found that the adhesion of the electroless nickel coatings (Nip and NIB) was intensely affect- ed by the heat treatment. The highest adhesion was obtained after the heat treatment at 200'C 1 h, and then the adhesion rapidly decreased with increasing the heat treatment tem- perature. It was also found that the adhesions was mainly related to the chemical composi- tions. microstructures and internal stresses of the electroless nickel coatings. The coatings with the amorphous microstructures and low internal stresses usually have a higher adhe- sion, comparing to the coatings with crystalline structures.

This paper reports the research and development' of a Fiber Optics Corrosion Sensor (FOCS) fabricated by electroplating a corrosion sensing film onto an optic fiber core. The structure of film electroplated in an Iron ( 1 ) sulfate electrolyte containing a small amounts of citric acid and L-ascorbic acid was studied by X-ray diffraction and burning gas capacity method. The electrochemical corrosion test and chemical corrosion test were used to evaluate the sensing ability of the Fe-C alloy film. The initial results showed : (1) the peak potential of scanning process was in accord with the potential for the largest changing speed of output power in 3.5SNaCl solution; (2) the time taken to rise td maximum output power for FOCS was shortened with increasing the concentration of nitric acid; (3) the responding time was prolonged by almost 3 times, compared with that for non-passivated film. 'The re- sults demonstrated the feasibility of using optical fiber corrosion sensors for monitoring ror- rosion of steel in civil structures.

For in-situ, instantaneous and non-destructive inspection of the concentration distribution of hydrogen atoms in the multi-layer wall of hydrogenation reactor operating at high temperatures and pressures, a new probe technique was developed as a substitution for conventional methods. In the paper, technical consideration, structure and characteristics of the technique are presented. In addition, the prospect for other application of the technique is also discussed.

In recent years, the hot-dipping process has been playing more and more im- portant role for aluminum coating of steels, Since its production equipnient is simple and products have better mechanical and anti-corrosion properties. The hot-dip aluminized steel product can extensively be used in various engineering fields. In the paper, the structure ,in-trinsic properties, application and development tendency at home and abroad of hot-dip alu- minized steel are reviewed.

The leakage of a steam sampling tube made of lCrl8NiSTi stainless steel in a power plant was analyzed using optical microscope ,SEM ,X-Ray and chemical analysis. The results showed that the loading stress during service at high temperatures and the axial ten- sile stress due to the resistence to the contraction of the tube during cooling and trace ele- ment of C1-lead to the SCC of the tube.

The local corrosion of the fire side of waterwall tubes in a coal-fired boiler of a power plant was analysed. The results of electronic probe microanalysis, energy dispersion spectrometer and X-ray diffraction analysis showed that the fire side of waterwall tubes was covered by corrosion products of iron oxide and iron sulfide and sulfur element content was over 20% (wt. ) in maximum. The fire-side corrosion was mainly caused by sulfur corrosion at high temperatures when incompleted fuel combusion occurred.