Heat-exchanger tubes in fluidized bed combustors (FBCs often suffer from material loss due to combined corrosion and erosion. To further understand the effect of chlorine on in-bed tube wastage, a FBC wastage simulator was used to carry out the study. The later was designed to simulate dense particle impacts on the tube bottoms with well-con- trolled parameters, and has been proven to closely reflect situation found in operation bub- bling FBCs. HCl gas was chosen to be the C1 source and was introduced into the fluidizing air with a dose of 50X Tests were performed at temperatures from ambient to 400'C with samples made of 1018 low carbon steel rods and a bed consisted of commercial SiO sand with average size of 800 pm. The wear profiles after each test was measured using a profilometer. Results showed that the presence of HCl increased the material wastage rates and the rate was significant higher at higher temperatures. The results of microstructural and chemical analysis of the wear surface and corrosion products are also reported. It is concluded that the dominating effect of HCl on the wastage rates is due to an enhanced oxidation and a reduced scale adherence.

The potentials of 23 different metals exposed to Yulin seawater in the south of China for 180 days were measured and the data for various characteristic potentials were dis- cribed. The characters of corrosion potential of metals in tropical seawater was investigated by means 3f potential-time curves. Based on correlative analysis of the potential differences among parallel specimens, potential changes with time and corrosion morphology, the rela- tionship between the potential changes of some metals and localized corrosion stability were investigated.

The oxidation of two iron-based alloys containing 15wt % and 30wt % yttrium as well as pure yttrium has been studied in pure oxygen of 0. 1 MPa. Both alloys formed an external scale containing a mixture of iron and yttrium oxides and double Fe-Y oxides. A re- gion of internal oxidation of yttrium was formed in the alloys. The microstructure of the in- ternal oxidation region followed closely that of the original alloys and there was no any yttri- um depletion in the internal oxidation region. These results are examined by taking into ac- count the limited solubility of yttrium in iron and the presence of intermetallic compounds in the alloy.

A kind of two-step alkaline technology, named as ZH1, to form rare-earth conversion film on LC4 aluminum alloy was developed. The optimum film-forming technolo- gy parameters were obtained by orthogonal method. Corrosion resistance of ZH1 treated LC4 aluminum alloy in chloride solution and its influential factors were investigated by various experimental methods. The experimental results revealed that the resistance against uniform corrosion and pitting of LC4 aluminum alloy after ZH1 treatment was obviously improved. The. rare-earth conversion film retarded both the anodic and cathodic processes. LC4 alu- minum alloy with ZH1 rare-earth conversion film was not sensitive to the changes in C1- con- centration and pH value. LC4 alluminum alloy ,rare-earth conversion film, corrosion resistance

A new method has been developed for ultrasonic hot dip Re-A1 coating basing on flux method. During the hot dip process, ultrasonic vibration plays a role of microalloying and fragment in the coating, the anti-corrosion of the coating is improved remarkably. And this coating also does not influence the fracture strength of the substrate. The kinetics of the coating thickning in the ultrasonic hot dip process has been studied. An optimization criteri- on for anti-corrosion of ultrasonic hot dip Re-A1 coatings is suggested.

Electrochemical impedance spectrum technique was employed to study the cor- rosion behavior of Ni in the molten (Li,K)zC03 at 650'C. It is shown that the electrochemi- cal impedance spectrum for the corrosion of Ni have the characteristics of diffusion-controlled reaction. Ni suffers from fast corrosion, forming a porous oxide scale. A equivalent circuit representing the electrochemical impedance spectrum of Ni is proposed and the parameters in the equivalent circuit are also calculated.

Atmospheric corrosion behavior of cadmium coatings on mild steel has been studied. This atmospheric exposure test lasted about 5. 8 years at four different climate areas (Qingdao, Warming,Jiangjin and Wuhan). The results show that corrosion rate of cadmium coatings in Jiangjin is the highest and in Wanning is the lightest, while the corrosion rate in Wuhan is as well as in Qingdao. The corrosion resistance of cadmium coatings is good in ma- rine atmosphere environment, but it is not suitable to be used in industry polluted atmo- sphere environment. Corrosion rate of non-cyanide cadmium coatings is similar to cyanided ones. It is considered that non-cyanide cadmium coatings can be used for four types of cli- mates instead of cyanide coatings in case of some conditions.

The effects of ion concentration, mineralization degree and other factors in the oil field water on CaC03 scaling tendency have been investigated. Methematic model and cri- terion for scaling tendency have been established. Computer software has been also drown up. The prediction for CaC03 scaling tendency can be made according to the water quality da- ta and calculated scaling index C1 value. The prediction is basically in accordance with the experimental results and in-situ inspected results.

The research of corrosion behavior and cathodic protection of POD919 and LD31 aluminum alloys, for the deep-sea submarine robot was carried out in 3. 5% NaCl solu- tion. The related electrochemical parameters of three types sacrificial anodes have been de- termined by constant current discharge method. The results showed that one kind of zinc al- loy sacrificial anode is suitable to the protection of submarine robot. For the compactness and completeness of the inner structure of the robot, the effects of crevice dimension on ca- thodic protection have been studied also. The results showed that smaller the crevice dimen- sion the shorter the protection distance. Based on the achieved results, the design and regu- lation of the cathodic protection for robot has been suggested.

The investigation and inspection on Stray Current Corrosion during repairing and building ships have been made. The cause for generating stray current being analyzed, the power line distribution map for Stray Current Corrosion is drawn. A propose1 fbr solving the problem is suggested.

A failure analysis of an underground oil pipeline has been made by using in- situ inspection, metallographic examination and mechanical property testing. Analytical re- sults showed that corrosion product contained higher sulphur content and the failure was caused by pitting corrosion.