The behavior of anodie dissolution of brass(Cu37Zn)was investigated in 1N Na_2SO_4 and 0.5N NaCl solutions with rotating ring-disc electrode. Partial anodic current densities of zinc and copper dissolution(i_(Zn) and i_(Cn)) of brass were measured respectively. Experimental results show that dezincification of Cu37Zn takes place in above mentioned media during anodic dissolution. Calculated dezincification factor of Cu37Zn Varies with electrode potential in 1N Na_2SO_4 solution. However, this factor does not vary significantly with electrode potential in 0.5N NaCl solution. By extrapolation of the partial polarization curves of copper and zinc for Cu37Zn, partial corros on current densities of zinc and copper have been calculated as follows: i_(corr)(Cu) i_(corr)(Zn) 1N Na_2SO-4 3×10~(-5)μA/cm~2 0.089μA/cm~2 0.5N NaCl 1.6μA/cm~2 3.6μA/cm~2 Experimental results also show that the rate of anodie dissolution of brass is mass-diffusion-controlled in both investigated media.

Fracture mechanism of austenitic stainless steels used in H_2S-H-2O system has been investigated by means of X-ray analysis, scanning electron microscopy and transmission electron microscopy. It is shown that the hydrogen produced by chemical reaction is the main cause of failure. The observation upon the film sample indicates that a lot of dislocations and stacking faults have been formed before the formation of the martensite induced by hydrogen. The "DECOHESION" caused by hydrogen has been regarded to be responsible for aforementioned phenomena in such steels.

The effect of the stress state on the apparent yield stress, which is the external stress required to cause the local macroscopic plastic deformaton, is investigated with combined type(Ⅰ+Ⅲ)specimen. The possibility of hydrogen embrittlement, i. e. hydrogen induced cracking of the type Ⅲ specimen is investigated. The results show that the apparent torsional yield stress of the severely charged type Ⅲ specimens does not decrease, and then the hydrogen induced delayed crackingand fracture cannot occur on the original crack plane. For combined type (Ⅰ+Ⅲ)specimen, the apparent torsional yield stress can be decreased only when K_1 is so large that hydrogen induced delayed plastic deformation can occur under the action of K_1 itself. For the charged type Ⅲ crack or notch specimen, the hydrogen induced delayed cracking can occur on the plane inclined at an angle of 135°(or -45°) to the original crack plane when a large enough torque is sustained for a long time. This delayed failure is a typical intergranular fracture. The plane shear fracture can be obtained on the original crack if the charged type Ⅲ specimen is twisted to fracture immediately. For uncharged or outgassing type Ⅲ specimen, no delayed cracking and failure occurs even if a maximum torque is sustained for a long time. The interactive energy between the stress field of type Ⅲ crack and the strain field of hydrogen atom is calculated. The result shows that the interactive energy has a minimum value on the plane inclined at an angle of 135° (or-45°) to the original crack plane. Therefore, atomic hydrogen will diffuse to and enrich into these planes. The hydrogen induced delayed cracking and fracture will occur on the plane inclined at an angle of 135° to the original crack plane when the hydrogen concentration on the plane reaches a critical value.

Through the observation of fracture morphology by electronfractography, it is shown that the fracture moprhology of steels is not governed by a single mechanism, but is strongly dependent upon interaction between stress, medium and steel. According to the corrosive action of medium to steel, there are observed the following cases: a)corrgsion is weak or absent, only striation is observed; b)when corrosion is strong, then it can be further divided into five cases: ⅰ)with general corrosion, attacked and widened striation is observed; ⅱ)with pitting corrosion, the pit was only a source of crack; ⅲ) with intergranular corrosion, characteristic intergranular corrosion striation can be observed; ⅳ) when the specimen, is sensitive to stress corrosion crac king (SCC) and K_(Imax)>K_(ISCC), the characteristic fracture morphology of SCC is. observed; ⅴ) when the specimen is sensitve to hydrogen embrittlement (HE)., characteristic HE morphology is observed, As there are several different kinds of CF mechanism, it is improper to explain all CF phenomena by one model of CF such as the superposition model or process competition model.

In this paper, we propose a method to investigate the AC corrosion on the basis of the effect of electric field combination with that of electrochemistry. Under the effect of strong yet swiftly changing electric field, the electrochemical process of corrosion has changed essentially, and the intensity of electric field is an important physical parameter. After measurement and analysis of the interfering voltage, potential gradient, the point current density, the weight-loss increases with average current density, and the depth of penetration increases with the interfering voltage. Based on experimental results the authors have proposed safety limits of voltage on prevention of corrosion.

This paper covers a study of the stability of corrosion products on low alloy steels after leaving sea water. When taken from the sea, the samples are de-watered in alcohol, dried in cold air and coated for sealing with epoxy resin.Then the samples are packed with antirust paper and kept in a desiccator. Then the scales are taken off the steel samples in an argon cabinet and are immediately put into a test tube filled with argon. Part of the rust scale is then transferred into a sample box made of organic glass sealed leakproof and is ready for Mossbauer spectrum analysis. In this way the decomposition of extremely unstable Fe(OH)_2 can be avoided. Once the scale is exposed to the air, Fe(OH)_2 will decompose, while other physical phases will remain unchanged for a relatively long time. Any changes in physical phases will be shown from the results of Mossbauer spectrum analysis.

A silver/silver chloride reference electrode for use in molten salts is described. Since a commercial porcelain tube conductive to codium and potassium tons is used as the diaphragm, the junction potential between the liquid salts and solid porcelain membrane is definite. The tubular type of construction helps to protect the silver chloride inside the tube from mixing with and contamination by salts outside the tube. The porcelain tubes are industrial products of our country. Experimental results show that the electrode is stable, reproducible and reversible in the temperature range between 700 and 900℃. No significant membrane asymmetric potential is found in comparing two porcelain tubes of different composition. The main advantage of the silver/silver chloride with porcelain diaphragm over the conventional reference electrode with glass diaphragm is that it can be used at higher temperature up to 900℃.

A mixed liquid of diethylene glycol and water can be satisfactorily used in hydraulic system for all weather conditions. The galvanic corrosion of multiple contacting metals is tested for practical hydraulic system by contact corrosion test, high temperature refluxing contact corrosion test as well as by the determination of corrosion potentials of steel and Al-bronze couple. The composition of inhibitors for use in anti-corrosion hydraulic system is selected. This inhibited liquid gives good corrosion protection to steel, copper, brass, Al-bronze, zinc, aluminium, black enamelled steel as well as steel plated with chromium and can be safely used in pure hydraulic system. It has passed service tests of 23 months duration in practical hydraulic system with satisfactory corrosion protection to all above mentioned metals.