Dry Corrosion Research Articles

乾食さまざま

乾食さまざま

Influence of ultrasonic vibrations during corrosion of metals

The purpose of this investigation was to make an exploratory study of the effect the introduction of ultrasonic vibrations might have upon the corrosion of metals. Both dry and wet corrosion were studied. The ultrasonic frequency of vibrations used was 20 kHz with power levels up to 30 W/cm2 being introduced into the metals, and power levels up to 0.3 W/cm2 being introduced into the electrolytes. In dry corrosion, at elevated temperature, the introduction of ultrasonic vibrations produced a more dense corrosion film on the surface of the metal. In wet corrosion, it was found that ultrasonic vibrations generally increased the rate of corrosion and attempted to negate cathodic protection of the metal. Potentiostat experiments showed that the introduction of ultrasound substantially increased the flow of current in the system.

A Study of the Diffusion of Oxygen in Alpha‐Zirconium by Means of Nuclear Microanalysis

Polycrystalline zirconium samples were oxidized in pure oxygen under atmospheric pressure at temperatures ranging from 700° to 845°C and for times up to 400 hr. The diffusion of oxygen in the metal, beneath the oxide layer formed, was studied using a direct quantitative method of analysis based on the observation of the nuclear reaction . It was found that at a given temperature the oxygen concentration profiles, referred to the oxidemetal interface, may be superimposed after scaling by a factor . The results may be fitted assuming a concentration independent diffusion coefficient , the oxygen concentration at the oxide‐metal interface being constant and nearly equal to the saturation value, around 30 atom per cent. An activation energy was found for the process. Identical results were obtained in air, showing that, at atmospheric pressure, nitrogen in the air plays a negligible role in the dry corrosion of zirconium.

ANTI‐CORROSION METHODS AND MATERIALS

Studere Corrosion has been described as a transformation process in which a metal passes from its elementary form to a combined condition. It includes wet and dry corrosion; the former requires an aqueous environment and the latter is oxidation. Deterioration of the metal due to physical causes is not called corrosion, but is known as erosion, galling, wear, etc, depending upon the material and the conditions. Corrosion is the result of the metal chemical or an electrochemical reaction with its environment. Sometimes the chemical reaction is accompanied by physical deterioration, as in fretting corrosion. It should be noted here that the term corrosion is only applied to metals; non‐metals rot, crack or erode. Also it should be appreciated that only ferrous metals can ‘rust’, i.e. form hydrous ferric oxides.

Studies on the Dry Corrosion of Contact Surface

Studies on the Dry Corrosion of Contact Surface

ENDURO S-1

Abstract ENDURO S-1 is a chromium type stainless steel providing high strength, toughness and resistance to impact when heat treated. It shows resistance to wet and dry corrosion. It is recommended for steam turbine parts, valves, cutlery, pump components, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-185. Producer or source: Republic Steel Corporation.

On the wet and dry corrosion test of the aluminium alloysfor casting, No. 4 and No. 7

The anti-corrosion property of the aluminium alloy No. 4C for casting, which has good castability and weldability, and excellent air tightness and shock resisting property, is compared in corrosion test, especially in wet and dry corrosion test, with that of the aluminium alloy No. 7B for casting which is known to have the best anti-corrosion property good mechanical properties in aluminium alloys. This study was made for the purpose of confirming the utilization of No. 4C in industrial use. Recently, the usage of aluminium alloys has been drastically increased and the high anti-corrosion properties of the alloys has been getting more desired. No. 7B alloy requires the high level technique in working and has various problems in pratical uses in spite of its good anti-corrosion property, No. 4 alloy was selected to be studied for the purpose of substituting the No. 7 alloy. The characteristics of the alloy in the case of the periodic wet and dry corrosion test was particularly examined. (3%NaCl 0.15%H2O2) solution was used for this test.

Local Cell Action during the Scaling of Metals, I

When a tantalum wire partly covered by silver is exposed to iodine vapor at 174°C, a layer is formed not only on silver but also rapidly along the tantalum surface by virtue of local cell action involving migration of silver ions in and migration of electrons in the tantalum wire and across the layer. The observed rate of sidewise growth of the layer along the tantalum surface is in accord with theoretical calculations. By and large, local cell action may increase the rate of dry corrosion when there are different phases, one of which involves easy flow of ions and another involves easy flow of electrons.

Dry Corrosion Investigated at Pittsburgh Conference

Dry Corrosion Investigated at Pittsburgh Conference

The mechanism of “Dry corrosion”

The mechanism of “Dry corrosion”

The mechanism of the so-called “dry corrosion” of metals

The mechanism of the so-called “dry corrosion” of metals