SU1224692A1 - Apparatus for spectral measurements during electrochemical process flow - Google Patents

Abstract

The invention relates to devices for spectral studies, in particular, gamma-resonance spectroscopy of the surface layers of metallic materials under electrochemical polarization conditions. In the proposed device, in order to increase the reliability of measurements, the porous electrodes under study are placed horizontally, the anode and detector grid are located above Him, the radiation source is installed above the device, and the radiation receiver is below it. 1 il.

Description

11224692

The invention relates to spectroscopy, in particular to gamma-resonance Mössbauer spectroscopy, and can be used in chemical pO1 "metasurgy and metal

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in electrochemistry and to investigate corrosion processes.

The purpose of the invention is to increase the accuracy of spectral measurements and the reliability of information about the chemical and phase composition of the surface of the porous electrode under study.

The drawing shows a diagram of a device for spectral measurements during the course of electrochemical processes with some blocks of a gamma-resonance spectrometer. The device consists of a sealed container, the upper part 1 of which is made of Teflon, and the lower part 2 - of thin glass. The porous electrode 3 under study is mounted horizontally, which minimizes the thickness of the electrolyte layer and drastically reduces the intensity of gamma radiation absorbed by the electrolyte layer 4. Auxiliary electrode 5 is made of platinum wire and separated from the working volume of the device by means of a section. The capillary of the reference electrode 6 is placed in one of the holes of the electrode 3. The tubes for the introduction of 7 and the output of 8 gases are provided in it for purging the gases through the device. In the replaceable sensor element 9, there is an input window 10 made of Plexiglas, aluminum or beryllium, which is at the same time a filter from the X-ray radiation of the 11-Co source moderbauers, which is mounted either directly on the vibrator 13 of the Doppler velocity sensor, or connected to the vibrator using a rod 12. In addition, in detector 9 there are anode of detector 14 and grid electrode 15 for supplying a braking potential. The grid electrode 15 is needed to reduce the background from the walls and select different energies of electrons produced by the absorption of Mössbauer gamma quanta by the studied electrode. For measurement in a dry device, a tube 16 is provided for draining the electrolyte. The drawing also shows the receivers 17 and 18 Mössbauer

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radiation and regulator 19 electrolyte level.

The device works as follows.

An alkali solution, an electrolyte, is poured into the container 2, through which an inert gas is blown to remove dissolved oxygen from the electrolyte. Then the working electrode 3 is subjected to electrochemical i polarization. The phase transformations occurring on the surface of the electrode under study are recorded by measuring the Mössbauz conversion and Auger electrons, respectively, on a Mössbauer spectrometer. In the process of polarization of the electrodes, both in electrochemical and in chemical and corrosion processes, the following spectral measurements can be carried out.

1. Investigation of phase transformations on the surface of samples by scattering Mössbauer gamma quanta (the investigated depths to

20 microns). Measurements are carried out both in the angular scattering mode using filled proportional counters and scattering in geometry 2 using special proportional counters 18 with a through hole through the volume of the counter (in this measurement mode the vibrator 13, the Mössbauer source P and the receiver 18 are used).

2. Measurements in 21G geometry scattered to a depth of 10 µm by recording X-rays

with an energy of 6.3 keV and a transition probability of 0.24 (in this version of the measurements, a vibrator 13, a Mössbauzer source 11 and a detector 9 are used).

3. Measurements to a depth of up to 0.4 µm in the 2TG scattering geometry by registering K-conversion electrons with an energy of 7.3 KeV and a transition probability of 0.63. In this measurement, instead of nitrogen (mode 1) and a mixture of argon with 5% CH (mode 2), a mixture of He + 5% CH is passed through the cell (using a vibrator 13, Mössbauer source and detector 9).

4. Study of phase transformations in even thinner surface layers by filling the entire cell volume with gas (e.g. CHj) at a pressure of 5-10 Torr and using

lower high voltage for the anode of a replaceable sensitive cell - counter for conversion and Auger electrons. The device has a grid electrode 15 on which a variable negative potential is applied, allowing you to increase the signal-to-background ratio and take the energies of the detected electrons. A vibrator 13, a Mössbauer source 11 and a detector 9 are used.

With modes 2–4 (conducting potential-dynamic and potentiostatic studies in situ), the device is also a detector-detector for analyzing the energy distributions of radiation. The electrode under investigation is always at zero potential (ground) and is the cathode of the detector, and the anodic or cathodic polarization is determined by the polarity of the polarization changing. Optimal conditions for each of the examples given are achieved by changing the sensing element. For example, for mode 2, the distance between the anode (a thread with a diameter of 20 µm or a thin light magnesium alloy plate or beryllium) and a cathode (the test sample) is chosen to be about 8 mm or more, and for modes 3 and 4 4 mm.

The proposed device allows; conduct simultaneously electrochemical and spectral measurements of the sample in in situ mode, without allowing the sample to come into contact with air

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ko increases the reliability of information on the chemical and phase structure of the surface layers of the sample. With electrochemical polarization, the porous fine sample is completely in the electrolyte. The device can be used in the study of samples with a natural (not enriched) content of the Mössbauer isotope, which allows the study of chemical transformations on the surface of the samples.

Claims (1)

Claims. A device for spectral measurements during the flow of electrochemical processes, containing a sealed electrolyte tank, equipped with inlet and outlet gas purging tubes, a source and detector of electromagnetic radiation, and the test and auxiliary electrodes embedded in the electrolyte and connected windows for electromagnetic radiation, in which that, in order to improve the accuracy of spectral measurements and the reliability of information about the hyoscale and phase composition on the surface of the About the porous electrode, the device further comprises an anode and a grid electrode located above the electrolyte layer perpendicular to the direction of radiation propagation, the source of which is located above the tank, and the receiver - under the tank. 1.17 Editor I. Casard Compiled by E. Anisimov Tehred I. Veres Projector Corrector M. Demchik Order 1944/43 Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5 Production: 1Water (a firm-polygraphic enterprise, Uzhgorod, Project St., 4