Inhibitor Protection Of Steel Research Articles

Inhibitor Protection of Steel Against Corrosion and Scaling Under the Influence of Ultrasound

We study the combined action of reagents and ultrasound on corrosion and scaling under the conditions of operation of water-heating equipment at a temperature of 95 ?? 2???? and under atmospheric pressure. The efficiency of a known agent (oxyethylidene diphosphonic acid) and a ???green??? inhibitor based on the extract of rapeseed oil meal is found in high-hardness water both under the conditions of their individual action and in combination with ultrasonic irradiation of the medium in the subcavitation mode. The scaling (according to the mass increments) and corrosion (by the method of polarization resistance) rate are determined on the same samples. The functional time dependences of the specific scaling and corrosion rates are obtained under the conditions of reagent, ultrasonic, and combined treatment of water. It is shown that ultrasound exerts a negative influence on the antiscale properties of the investigated reagents by decreasing the efficiency of action of the antiscalant. A protective anticorrosion film is formed on the steel surface with time, as follows from the behavior of the corrosion rate, which sharply decreases in the initial period of the tests and then stabilizes on a level of 0.02 mm/yr. It is demonstrated that the complex influence of antiscalants and ultrasound in certain modes of treatment of the medium makes it possible to optimize the formation and preservation of a phase microlayer with antirust properties, which exerts almost no influence on the heat exchange between the metal surface and the heat carrier.

Inhibitor Protection of Steels in Solutions of Sulfuric Acid under High-Temperature Corrosion (up to 200°C)

This article analyzes corrosion of 08Kh18N10T chrome nickel steel in 2 M H2SO4 in wide temperature range t = 0–200°C. Under such conditions, corrosion of metal increases with increase in t and at 200°C reaches 9.7 kg/(m2 h). It is demonstrated that the composition of substituted triazole, IFKhAN-92 inhibitor and KI (mole ratio 1 : 1), makes it possible to protect this steel in 2 M H2SO4 at temperatures up to 140°C, inclusive. A three-component mixture of IFKhAN-92, KI, and hexamethylenetetramine (1 : 1 : 4), is more interesting in this regard, it efficiently inhibits corrosion at t up to 180°C, inclusive, maintaining protection for at least 8 h. The same composition reliably protects low carbon steel, grade 20, in 2 M H2SO4 at temperatures up to 180°C, inclusive; moreover, metal corrosion is decelerated in time.

Application of the Electrochemical Methods in the Diagnostics of the Engineering State of Structural Materials

We study the possibility of application of electrochemical approaches to the analysis of the engineering state of structural metal materials in the stages of design and long-term operation in hydrogenating corrosive media. It is shown that the analysis of the effect of stresses on the intensity of corrosion processes should take into account the nonstationary electrochemical processes of interaction of the metal with the medium, which serves as a basis for the prediction of corrosion resistance, corrosion-fatigue strength, and cavitation resistance. The influence of the operation factors (service time, absorbed hydrogen, contact corrosion, macroscopic galvanic couples, and bioactive media) on the intensity of corrosion and stress-corrosion fracture of steels is investigated. The possibility of application of the methods of stationary or nonstationary electrochemistry to the prediction of the efficiency of protector and inhibitor protection of steels in loaded structures is demonstrated. The efficiency of the use of some electrochemical characteristics in the evaluation of the in-service degradation of the mechanical properties is substantiated.

Inhibitor protection of steels in acid and neutral media by the derivatives of 2-mercaptobenzimidazole

We study the anticorrosion properties of newly synthesized derivatives of 2-mercaptobenzimidazole and the efficiency of their action in compositions based on the wastes of production of ɛ-caprolactam at the Chernihiv “Khimvolokno” Open Joint-Stock Company. A conclusion is made that these compounds can be used as corrosion inhibitors for 20 steel placed in acid and neutral media. The efficiency of application of protective compositions based on the wastes of production of ɛ-caprolactam with admixtures of the derivatives of 2-mercaptobenzimidazole is demonstrated for working media with pH 1–6.5.

Estimation of the efficiency of inhibitor protection of steels against cavitation- erosive fracture

The addition of inhibitors in small concentrations to water must not significantly change the hydrodynamic conditions on a cavitated surface. Therefore, in general, the revealed influence of inhibitors should be considered exclusively as a manifestation of the corrosion factor due to a change in the electrochemical conditions during the process of cavitation-erosive fracture. In the process of cavitation-erosive fracture of structural steels in water, if the influence of the corrosion factor is predominant, then one can considerably improve the workability of these steels by using highly efficient inhibitors. The method for estimation of the efficiency of the inhibitor protection against corrosion fatigue fracture proposed earlier in [1] can also be useful for cavitation-erosive fracture. Common symptoms concerning an increase in the resistance to corrosion mechanical fracture of both types by means of the inhibitor protection testify to the similarity of mechanisms of the influence of the medium on the initiation and growth of short fatigue cracks. This specific feature can be used in practice to increase the durability of structural elements under conditions of cyclic loading and cavitation.

A method of evaluation of the effectiveness of inhibitor protection of steels from stress-corrosion failure

A method of evaluation of the effectiveness of inhibitor protection of steels from stress-corrosion failure

Influence of metallurgical and technological heredity on the efficiency of inhibitor protection of steel

The use of inhibitor protection (taking metallurgical and technological heredity of steel into account) opens up broad possibilities of deliberately changing the quality of the surface layer, of producing optimal physical, mechanical, and electrochemical properties of the metal; this is particularly important when steel components operate in aggressive media.

Inhibitor protection of steel from corrosion and corrosion-mechanical failure in hydrochloric acid washing solutions

Inhibitor protection of steel from corrosion and corrosion-mechanical failure in hydrochloric acid washing solutions

Effect of halide anions on the effectiveness of the inhibitor protection of steel during low-cycle corrosion fatigue in acidic media

Effect of halide anions on the effectiveness of the inhibitor protection of steel during low-cycle corrosion fatigue in acidic media