SU1370528A1 - Apparatus for determining rate of corrosion of material specimens - Google Patents

Abstract

The invention relates to a testing technique and can be used to determine the corrosion rate of samples of materials. The aim of the invention is to improve the accuracy of determination by providing a constant oxygen content in the chamber. A chamber 3 placed in a thermostat 2 is filled with an aggressive medium and a sample 8 is placed into it. The aggressive medium is moved by means of systems 4 and 5 of its supply and circulation. As sample 8 corrodes, the amount of oxygen in chamber 3 decreases and the pressure in it drops. At the same time, the level of electrolyte in the anode 10 rises and the electrolyte interacts with the working surface 16 of the anode 10 to release oxygen. As soon as the amount of oxygen increases the pressure in chamber 3 B1, the pressure in tank 14, the level of electrolyte in the electrolyzer 9 decreases and oxygen ceases to be released. The cathode 11 of the electrolyzer is located outside the thermostat and is connected to the anode 10 through a valve 12 with a valve 13 of electrically conductive material. The anode 10 and cathode 11 are connected to a coulometer, which fixes the amount of electricity to produce oxygen consumed during corrosion, which is used to determine the corrosion rate. 1 il. (L

Description

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The invention relates to test equipment and can be used to determine the corrosion rate of samples of materials.

The aim of the invention is to improve the accuracy of determination by providing a constant oxygen content in the chamber.

The drawing shows a diagram of the proposed device.

The device contains a base 1, a thermostat 2 placed on it, a test chamber 3 installed in the thermostat 2 and a supply system 4 connected to the chamber and a corrosive medium circulation system 5 with a magnetic drive 6. In the chamber 3 there is a holder 7 of the test sample 8. With the chamber 3, an electrolyzer 9 is connected with an anode 10 located in a thermostat 2 perpendicular to the base 1 and a cathode 11 located outside a thermostat 2. Between the anode 10 and the cathode 11 a valve 12 with a valve 13 of electrically conductive material is located. The thermostat 2 contains a tank 14, the volume of which corresponds to the volume of the chamber 3. The tank 14 is connected to the electrolyzer 9 with a pipe 15 across the working surface 16 of the anode 10 The electrolyzer 9 is filled with a conductive 20% NaOH solution. Anode 10 and cathode 11 are connected to a coulometer (not shown).

The device works as follows.

Before starting the measurements, the aggressive medium is poured into the chamber 3, the chamber 3 and the medium are saturated with aggressive gas and thermostatic. The electrolyzer 9 is filled with electrolyte (20% NaOH solution) so that its level touches the working surface 16 of the platinum anode 10. The cathode 11, which can be made of nickel, is in a vessel with electrolyte (20% NaOH) beyond the outer wall of the thermostat housing 2, and communicates with the anode 10 through a valve 12 with a valve 13 and an electrically conductive material. Anode 10 and zhodod 11 are connected to a direct current source connected to a coulometer (not shown). Sample 8 is placed in chamber 3, the corrosive medium is fed through system 4 and 5 to sample 8. During the corrosion process, oxygen is consumed, the liquid level in part

the anode 10 of the electrolyzer 9 rises and the solution in the electrolyzer 9 contacts the working surface 16 of the anode 10. The circuit closes and oxygen is released at the anode 10. Since oxygen is released at the anode 10 at a rate exceeding its absorption rate as a result of corrosion, after some time (2-3 minutes) the pressure in chamber 3 rises and the level of the solution in the electrolyzer 9 drops below the working surface 16 of the anode 10, the contact between

the anode 10 and the cathode 11 is interrupted and the release of oxygen is stopped. The continuous corrosion process of sample 8 is accompanied by the consumption of oxygen in chamber 3, the anode 10

again comes in contact with the solution and the electrolytic oxygen evolution is resumed. As a result, the amount of oxygen released during electrolysis is equal to

the amount of oxygen consumed in the corrosion process.

The amount of electricity (Q) spent on the allocation of oxygen consumed during corrosion is continuous

measured by a coulometer with automatic recording of results on a digital printing device. From the dependence of the change in Q over time, the corrosion rate (ic.) Per surface unit (S) i liq / & t-S, A / cm is calculated.

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formula of invention

A device for determining the corrosion rate of samples of materials, comprising a base, a thermostat placed on it with a sample chamber installed in it, connected to a chamber of the supply and circulation system of the corrosive medium and an electrolyzer with an anode and cathode, in order to increase accuracy of determination due to the provision of a constant oxygen content in the chamber, it is equipped with a sealed container installed in the thermostat and communicated with the electrolyzer, corresponding to the chamber volume, placed in an electrolytic cell between an anode and cathode

a valve with a valve of electrically conductive material, and the working surface of the anode is displaced relative to the place of communication of the container with the electrolyzer towards the base.

Claims (1)

SUMMARY OF THE INVENTION A device for determining the corrosion rate of samples of materials, containing a base, a thermostat placed on it with a test chamber for samples installed in it, connected to a camera of a system for supplying and circulating aggressive media and an electrolyte with anode and cathode, characterized in that, with In order to increase the accuracy of determination by ensuring the constancy of the oxygen content in the chamber, it is equipped with a sealed capacity installed in the thermostat and in communication with the electrolyzer, corresponding to conductive chamber volume, and placed in an electrolytic cell between an anode and a cathode 55 with a valve cock of an electrically conductive material and the working surface of the anode is offset relative to the location message from the electrolyzer container towards the base.