SU866458A1 - Method of determining melting rate of magnesium alloys - Google Patents

Description

The invention relates to reactor metallurgy and can be used, for example, to study the corrosion of the claddings of fuel rods made of magnesium alloys.

A known method for determining the corrosion * growth rate [1].

There is also a method of determining the corrosion rate by the loss of metal in oxide films [2].

^{u l} 10

The disadvantage of this method is that the corrosion of magnesium alloys in diphenyl smvsi occurs mainly under the influence of water, which is present in the diphenyl mixture in the amount of -v 0.02 wt.% Under normal conditions. In the process of corrosion, an oxide film forms on the metal surface, which, not having sufficient strength, partially fades away. This leads to irreproducible ™ experimental data from corrosive samples. Therefore, before weighing these samples, they remove the oxide film from them mechanically or chemically. The thickness of the removal of the oxide film depends on the experimenter's experience and significantly affects the accuracy of measuring the corrosion rate.

The purpose of the invention is the acceleration of corrosion assessment.

This goal is achieved by the fact that in the known method for determining the corrosion rate by the loss of metal in oxide films, the amount of water is measured in the diphenyl mixture after irradiation, the rate of corrosion is determined by the loss value of which.

The water content during irradiation of the diphenyl mixture to I0 ^ rad in the temperature range from 20-200 C in the absence of corrosive surfaces does not change. Thus, the decrease in water in the diphenyl mixture can serve as a measure of the degree of corrosion that occurs in accordance with the reaction

Mg + H10 -9 MdO

By measuring the loss of water in the diphenyl mixture in which the magnesium samples were placed during the tests, calculate the muda.

V =

100 where M, can be the corrosion rate according to forη -; - · g— I ^{4 m} n _g о st - mass of diphenyl mixture (g);

1¾ and the percentage of water in the diphenyl mixture before and after the experiment, respectively (wt.%);

- molecular weight of water (g);

- atomic weight of magnesium (g);

- total surface area of the samples (m);

- the duration of the experiment (h).

^M ido

866458 4th formula. In parallel, it was determined by the weight method. A matching result was obtained.

It is important to note that, in contrast to irradiated samples, samples of the diphenyl mixture taken from the ampoule have low activity, since the composition of the diphenyl mixture includes C, H, O, having a short half-life (l / 1 min).

Using the proposed method for determining the corrosion rate can reduce the time of measuring the corrosion rate to several hours, in the case of using the weight method this time is several weeks, months and reduce the radiation hazard during measurements.

t

This method was implemented as follows.

Claims (2)

The invention relates to reactor metal metallurgy and can be used, for example, to study the corrosion of fuel rod cladding made from magnesium alloys. A known method for determining the corrosion rate is l. There is also known a method for determining the corrosion rate by metal loss in oxide films 2. The disadvantage of this method is that corrosion of magnesium alloys in diphenyl smvsi occurs mainly under the influence of water, which is present in the diphenyl mixture in the amount of l / 0.02 wt.% under normal conditions. During the corrosion process, an oxide film is formed on the surface of the metal that does not have sufficient strength and partially peels off. This leads to the irreproducibility of experienced dunks of corrosive samples. Therefore, by over-weighing these samples from these si-rm, the oxide film is mechanical or chemical. The thickness of the removal of the oxide film depends on the experimenter's experience and significantly affects the accuracy of measuring the corrosion rate. The purpose of the invention is to accelerate the evaluation of corrosion. This goal is achieved by the fact that in the lime method of determining the corrosion rate by the metal loss in the oxide film, the amount of water in the diphenyl mixture after irradiation is measured, the corrosion rate is determined by the magnitude of the decrease. The water content during irradiation of the diphenyl mixture to 1 O rad in the range of temperatures from 20-200 ° C in the absence of corrosive surfaces does not change. Thus, the loss of water in a diphenyl mixture can serve as a measure of the degree of corrosion that occurs in accordance with the Md + HiO - MgO reaction. By measuring the loss of water in the diphenyl mixture that contained magnesium samples during the tests, it is possible to calculate the corrosion rate by form. and - (d-r V VDR. - 100 St where M is the mass of the diphenyl mixture (g); 1C J and Cjj is the npo4eHfth water content of the diphenyl mixture before and after the experiment, respectively (wt.%) 5 is the molecular weight of water (g); -atomic weight of magnesium (g); -summary surface area of samples (m t - test duration (h) The tribute method was implemented as follows. Ten samples from magnesium alloy MB in the form of rectangular plates with a total surface cm were placed in an ampoule with a known (l40 g) amount of diphenyl mixture. The ampoule was lowered into the channel of the hydrofluoric reactor at m about 500 for which the dose of nJ radiation absorbed in the diphenyl mixture was rad.At the end of the irradiation from the ampoule, a sample of the difecyl CMecHC / vS (g) sample was collected, which was analyzed for water content by one of the known methods. The corrosion rate was calculated according to the formula 84. Parallel to this, it was determined by the weighting method. It is important to note that, unlike irradiated samples, samples of a diphenyl mixture taken from an ampoule have low activity, since C, H, O are part of the diphenyl mixture. having a short half-life (l / 1 min). Using the proposed method of determining the rate: corrosion allows reducing the time of measuring the corrosion rate to several hours; DETAILED DESCRIPTION OF THE INVENTION Method for determining the rate of corrosion of magnesium alloys by metal loss into oxide films, characterized in that, in order to accelerate the evaluation of corrosion, the amount of water in the diphenyl mixture after irradiation is measured, the rate of which is determined by the amount of kill. Sources of information taken into account in the examination 1. USSR author's certificate number 528395, class. 01 N 17/00, 1978. 2.Bakhvalov G.T., Turkhovska L.V. Corrosion and protection of metals, M., 1959, p. 97-104 (prototype).