SU757909A1 - Method and device for preparing tablet for roentgenographic investigating of materials under high pressure by bridjemen's technique of anvils - Google Patents

Description

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The invention relates to the field of measurement technology, mainly to the study of substances under high quasi-hydrostatic pressure.

Known widely used for ³ studies of substances under high pressure method anvil Bridgman.

The closest in technical essence and the achieved result is a method and device for its * 'implementation, which consists in pressing a sample of powder, for example, "amorphous" boron, with a punch in the matrix, making a central hole along the axis of the tablet for placing about-K samples of the material under investigation and Installing the tablet on the surface of the working anvil [2}.

The disadvantage of this method is21 large labor intensity and duration of manufacturing tablets. This disadvantage is associated with the difficulty of drilling the central hole with a small diameter, approaching in size to * the particle size of the pressed powder. In addition, the high abrasiveness of the powder requires the use of special tools for drilling. Factor

- tablet manufacturing speed has 31

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important importance, especially when radiographing substances with a small thickness of half the weakening, when the selection of the optimal tablet size and method of placing the sample in its channel is associated with the breakdown of a larger number of tablets.

The difficulty of ensuring good reproducibility of the measurement results is due to the fact that, due to the poor press characteristics of an “amorphous” boron, when drilling the central hole in the tablet, its wall collapses, coaxiality with the anvil is lost. Therefore, the sample placed in the hole enters the zone of non-uniform pressure and is displaced relative to the axis of the x-ray beam (the device is unmasked). Since the collapse is not systematic, the reproducibility of re-emulsions is low.

The aim of the present invention is to eliminate the above disadvantages, namely:, reducing the time for the manufacture of tablets and improving the reproducibility of measurement results.

The method is implemented due to the fact

what's the center hole in the tablet

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performed by pre-pressing along the axis of the tablet wire, the diameter of which is equal to the diameter of the hole, and subsequent removal of the wire, and the tablet with the test specimen is glued to the working surface of the anvil. ⁵

The purpose of the invention in the device is due to the installation in the cavity of the matrix 'anvil, made with a vertical axial channel, and the punch is made with a vertical ^υ

an axial channel coaxial with the matrix channel, the diameter of the channels of the anvil and the punch being equal to the diameter of the central hole of the tablet, and the outer diameter of the punch being equal to the outer diameter of the tablet, with through holes in the walls of the matrix.

The method is implemented due to the fact that before pressing the tablets in 20

matrix in the holes along the axes of the punch and the molding anvil set the wire, the diameter of which is equal to the diameter of the central hole, which remains in the tablet after removing the wire from the matrix, and the diameter of the punch is equal to the outer diameter of the tablet. Remove the molding anvil.

A sample of the material under investigation is placed in the hole of the tablet and compacted with a pressure of the desired size, compressing the tablet in the matrix between the punch and the working anvil removed from the high-pressure apparatus equal in diameter to the molding anvil. The working anvil is removed. The formed tablet is put forward at the end of the punch in the lower part of the matrix, moistened the end of the working anvil with glue and introduced into the matrix before contact with the end of the tablet, remove the worker at-40 with an installed tablet from the matrix in which the through holes are made.

The drawing shows the device with which this method is implemented.

The device consists of a matrix 1, a molding anvil 2, a punch 3 made of beryllium bronze, and a steel wire 4.

The device works as follows.

For the manufacture of tablets 5 anvil molding 2 is inserted into the lower part of the matrix 1. Through the axial hole ⁵⁵ in cial ^- forming wire passes the anvil 4. The channel in the upper part of the die is filled with powder "amorphous" boron weight of the determinant 60 which is the initial height of the tablet , and is compressed by the Punch 3, into the axial channel of which the upper end of the wire 4 is passed, by an effort on the basis of 2000 kg per 1 s & L of the base of the punch (,

Sona. After removing the load, the wire 4 is aged and the forming anvil is removed. This opens the lower base of the tablet 5 with a channel into which the sample under study is placed (not shown in the drawing). To seal the sample in the channel, the tablet is compressed again, but instead of the molding anvil, the working anvil directly extracted from the high-pressure apparatus is used directly. The external dimensions (height, diameter, etc.) of the molding and working anvils coincide, but the working anvil is made without an axial channel. After re-compression, the anvil is removed from the bottom of the die, where the tablet is squeezed by lightly pressing the punch. Due to the adhesion forces, the tablet is held at the lower end of the punch after it leaves the lower part of the die.

To install the tablet on the anvil, the flat surface of the anvil is moistened with a weak solution of organic glue, and the anvil itself is slowly injected into the lower part of the matrix until it touches the tablet. Since the adhesive force of the tablet with the surface of the anvil moistened with glue is greater than with the punch, the tablet remains on the anvil after it is removed from the matrix.

Tablets made by the method described above were used for X-ray examination of chromium telluride. The tablets had an initial height of 0.8 - 1.2 mm, an outer diameter of 2 mm, a channel diameter of 0.15 mm. The coaxiality of the canal of the tablet with the anvil is not worse than 0.02 mm. It took 4-6 minutes to make a tablet, including placing a sample in it. The measurement results were highly reproducible.

Claims (4)

Claim. . 1. A method for preparing a pill for a diffraction study - high pressure materials using the Bridgman anvil method, which consists in pressing a sample of powder, for example, "amorphous" boron, with a punch in the matrix, forming a central hole along the tablet and then installing the tablet on the working surface of the anvil, which differs the fact that, in order to reduce the time for its manufacture and increase the reproducibility of the measurement results, the central hole in the tablet is performed by pre-pressing and along the axis of the tablet wire, the diameter of which is equal to the diameter of the hole and the subsequent 5 757909 6 * remove the wire, and the tablet with the test sample is glued to the working surface of the anvil. 2. A device for implementing the method of π. 1 comprising a matrix with an anvil and a punch installed therein, characterized in that the anvil is installed in the cavity of the matrix and is made with a vertical axial channel, and the punch is made with a vertical axial channel coaxial with the matrix channel, the diameter of the channels of the anvil and the punch being equal to the diameter the center hole of the tablet, and the outer the diameter of the punch is equal to the outer diameter of the tablet. 3. The device according to p. 2, characterized in that, in order to provide visual observation 5 for removing the tablet in the walls, the matrix is made through holes.