SU1638579A1 - Method of preparation of reference substance for high pressure transducers - Google Patents

Abstract

The invention relates to substances used in high-pressure sensors that can be used in chambers for the synthesis of superhard materials, stone-precious raw materials, ceramics, as well as in sintering plates for blade tools and in laboratory practice. The aim of the invention is to create a point pressure sensor based on metal chalcogenides having several precisely fixed phase transitions at certain values of pressure and room temperature with an increased conversion factor of pressure to electrical signal (sensitivity). that the reference substance based on metal chalcogenides (cadmium telluride and lead selenide) is additionally machined by grinding in a ball mill or a mortar, and at given intervals the mixture is removed, its electrical resistance is measured and the grinding is continued until a constant maximum value is reached electrical resistance of the mixture of 2 or 2 table

Description

The invention relates to methods for producing substances used in high pressure sensors used in chambers for the synthesis of superhard materials, stone-precious raw materials, ceramics, etc., as well as in laboratory practice for conducting studies of the condensed phase in a highly compressed state.

The aim of the invention is to increase the sensitivity of the reference substance.

FIG. Figure 1 shows the dependence of the electrical resistance on the pressure of a mixture of cadmium telluride and lead selenium at a ratio of 1 to 10; FIG.

2 is a diagram of an experimental setup for measuring electric-power characteristics of reference substances.

The method for making the reference substance is as follows.

The reference material for high pressure sensors in the form of a mixture of chalcogenide reference materials, having fixed phase transitions at certain pressures and room temperature, was prepared in this way. Polycrystalline powders of two chalcogenides — cadmium telluride and lead selenide — spekO were taken separately.

CA 00

ate VI

YU

pure purity, they were separately poured into a ball mill (or mortar) and subjected to grinding to a particle size of 0.0056 mm or less (a sieve with a cell size of 0.0056 mm). Then, the powders were mixed in a specific ratio and jointly machined in a ball mill (or mortar) until the maximum initial electrical resistance was reached (electrical resistance was measured using control experiments and recorded with a semi-automatic potentiometer P363 / 2).

Example. The reference substance for high-pressure sensors in the form of a mixture of cadmium telluride powders and lead selenide was taken at a ratio of 1:10 (as with this ratio of components, phase transition points are most clearly visible - there is no shunting of one material to others), i.e. 30 and 300 g previously crushed to a particle size of 0.0056 mm and less than the indicated components of the spectral frequency. The purity was determined using an ISP-28 spectrograph, and the particle size was determined with a sieve with a cell size of 0.0056 mm. Weighing was performed on an analytical balance with an accuracy of ± 0.0001 g. The mixture was placed in a thoroughly washed and dried ball mill (ball diameter 12 mm ) and machined. Periodically made control measurements with a sample (initial) pressure of 0.5-1 GPA at the facility (Fig. 2).

The installation comprises a press 1 with support plates 2, block matrix 3, conductors 4, between which sample 5 is placed, a container made of lithographic stone 6, pyrophyllite rings 7, and a signal recording system 8.

In tab. Figure 1 shows the dependence of the electrical resistivity in a mixture of cadmium telluride and lead selenide on the composition.

In tab. Figure 2 shows the dependencies of the electrical resistance on the initial value of the electrical resistance for a component ratio of 1:10.

When the value of the relative electrical resistance (1.2 ± 0.2) ohms was reached, the mechanical treatment was stopped, the contents of the mill were removed, and the mixture

used as a reference material for the production of point-sized pressure sensors with several fixed points on a pressure scale of 3.53 ± 0.07 GPa, 4.23 ± 0.1 GPa, and also 5.97 ± 0.23 GPa. Pressure transducers were manufactured according to an established method — 2-3 mg of substance was pressed into a cardboard disc with a millimeter hole (3-4 mg of powder was poured on the anvil and, on the contrary,

the top of the slide was placed a hole in the cardboard disc, the same amount of powder was poured on top, and with the help of a mandrel the material was pressed into the hole of the disc, unused material

crumbled and reused).

Experiments have shown that due to the mechanical processing of the mixture of components, it is possible to increase the jump in electrical resistivity during a phase transformation in the sensor material from a pressure action of more than 25 times (see Fig. 2) and, as a result, more accurately fix the pressure of the onset of phase transitions in the material sensor, and hence the pressure in the reaction volume of the chamber (apparatus) high pressure.

Claims (1)

The invention of the method of manufacturing a reference substance for high pressure sensors, including the preparation of a mixture of cadmium telluride powders and lead selenide, characterized in that, in order to increase the sensitivity, the mixture is further subjected to rubbing, the mixture is removed at specified time intervals electrical resistance under the influence of the reference pressure and continue to grind to achieve a constant maximum value of the electrical resistance of the mixture Table 1 P, nanometer readings. Fig D table 2 50 SO 150 R eight / FIG. 2