Yu. N. Mikhailovskii

Effect of cathodic polarization on the corrosion cracking rate in pipe steels

Cathodic polarization can both inhibit and promote the growth of corrosion cracks in pipe steels. The promoting effect indicates that corrosion cracking follows the mechanism of hydrogen embrittlement. The critical current of hydrogen penetration across a steel membrane can serve as a criterion for the risk of embrittlement. Critical currents of hydrogen penetration for 14Γ2CAΦ and X70 steels were determined.

Generating Harmonic Oscillations by Corrosion–Electrochemical Systems

The phenomenon of generating harmonic oscillations by systems formed of iron, zinc, copper, and aluminum or magnesium and a 0.5 M sulfuric acid solution under conditions of the spontaneous dissolution of metals is investigated. The corrosion–electrochemical circuit was found to generate resonance oscillations as a master oscillator. The oscillation frequency depends both on the parameters of electronic scheme and the corrosion–electrochemical properties of a system itself. The frequencies studied (f) range from 5 to 50 kHz. The parameters of resonance oscillations are determined by the corrosion–electrochemical characteristics of the electrode used. The technique developed supposedly supplements the electrochemical impedance spectroscopy and provides new prospects in developing the technique of resonance spectrometry.

Field and accelerated tests of contact and volatile inhibitors of atmospheric corrosion with various metals

The results of two-year field (in rural, urban, and marine atmospheres) and accelerated tests of contact and volatile inhibitors with steel, brass, and aluminum and magnesium alloys are reported. The protective values of contact inhibitors (IPKhAN-29a and IPKhAN-50) were found to decrease by 30 to 60% in all of the aforementioned atmospheres in already one year of the tests. In sealed polyethylene bags, metals and alloys retained high corrosion resistance both without and with volatile inhibitors, regardless of the inhibitor’s nature IPKhAN-110 and DAN). The protective value of contact inhibitors only slightly depends on the atmospheric corrosivity, though the latter increased from rural to marine according to the ratio 1∶1.4∶5.7. For the inhibited systems, the results of the field and accelerated tests were shown to correlate.

Estimation of the probability of hydrogen embrittlement of steel pipelines in the operation zones of cathodic stations

A procedure for determination of the probability of hydrogen embrittlement of steel pipes was described. The experience of the application of hydrogen sensors in selected sections of the Tyumentransgaz and Mostransgaz gas mains was generalized.

Determining Metal Corrosion Rates in Electrolytes from Spectra of Harmonic Oscillations Generated by Metal/Electrolyte Interfaces

Spectra of harmonic oscillations emerged from a corrosion-electrochemical generator whose oscillatory circuit is a steel electrode in sulfuric acid or aluminum electrode in alkaline solution are studied. The circuit parameters (the time constant τp and the polarization resistance Rp) determining the rate of metal corrosion are calculated. It is unambiguously shown that the frequency of harmonic oscillations is a quantitative measure of the electrode dissolution current.

Monitoring of the Corrosion State of Underground Pipelines with Corroding Resistors-Transducers

Two types of resistors-transducers were designed to measure the underground corrosion rate of steel with an accuracy of ±10%. The transducers were field tested at the operated Mostransgaz and Tyumentransgaz gas mains.