SU1404915A1 - High-temperature dilatometer - Google Patents

Abstract

The invention relates to devices for high-temperature studies of the physical characteristics of materials. more precisely, to devices for measuring the temperature coefficient of linear expansion (TCLE) in the temperature range 900-1900 ° C. The purpose of the invention is to improve the measurement accuracy during photoelectric recording by eliminating the influence of the holder deviating from the vertical. The device contains a chamber with a support plate on which the sample holder is attached by means of a pipe, an additional local heater located at the base of the suspension tube of the holder, and a balance bar for hanging the holder relative to the vertical, 1 sludge. about (3

Description

The invention relates to a measuring technique and can be used at high temperatures for measuring the differential temperature coefficient of linear expansion (TKPR) of solids with high accuracy for metrological purposes, as well as for research.

The aim of the invention is to improve the measurement accuracy.

The drawing schematically shows a dilatometer for high temperatures.

The dilatometer for high temperatures includes an optical measurement system of elongation mounted on a massive base and rigidly connected to the camera body 1. The optical system contains a radiation source 2, for example an LG-52 helium-neon laser, located at the exit of the laser beam, a cube divider 4, a Fizeau interferometer, comprising two interference plates 5, for example, from single-crystal sapphire with a melting point of 2080 ° C, between which sample 6 is installed with a hole in the center for the passage of rays. The recording system of the interference pattern contains a slit 7 and a photodetector 8 of the PMT type,

The Fizeau interferometer and sample 6 are placed in the internal cavity 9 of the holder 10 of sample 6, made in the form of a massive block, for example, with external dimensions of 60x90 mm, with an internal cavity of 9, dimensions of 2 x 60 mm, made of tantalum and mass. - 6 kg. The holder 10 has a detachable side wall 11 for mounting the sample 6, to the lower part of the holder 10 there is attached a balance bar 12 with an offset center, made, for example, of tungsten rotatably around its axis, designed to facilitate the centering of the system when installing samples into the cavity 9 sample holder 10.

The holder 10 is suspended on a thin tube 13, for example, with a wall thickness of 0.1 mm and a length of 250 mm made of tantalum. The tube 13 is attached to the support plate 14, which is mounted horizontally on the three lugs 15 of the chamber 1 of the dilatometer. At the top of the tube 13 is placed a local heater 16, which is covered

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tube 13 and is designed to create a thermal hinge. Such a design of the holder 10, suspended on the tube, performed the role of a plumb, automatically tends to take a strictly vertical position. The holder 10 is placed inside the main heater 17.

To prepare the dilatometer for operation, the holder 10 is removed from the chamber using a known lifting device, the side wall of the holder 10 is removed, into the cavity of which sample 6 and the interference plates are installed, then the holder 10 is monitored by the balancer relative to the vertical by moving it coincidence of its vertical axis with the axis of the holder passing through the center of gravity.

The fitted holder 10 is installed inside the chamber. The procedure for controlling the alignment of the holder 10 in the working position is carried out using an auxiliary laser (not shown). The beam of the auxiliary laser, which is set vertically strictly with an error of 0.5, is directed to the lower mirror, which is located in the internal cavity of the holder 10 on the polished bottom. Reflect from the mirror, the laser beam enters the control. the point. Then the system is hermetically closed, a vacuum of 6-10 Pa is created, further adjustment is carried out after switching on the local 16 and main 17 heaters, when the softening temperature of the suspension tube 13 is reached. The system can operate in vacuum and in inert gas atmosphere.

The use of the invention eliminates the misalignment of the elongation measurement system during the experiment and reduces the error in elongation measurement, which will increase the accuracy of determining the temperature coefficient of linear expansion in the centigrade temperature range to a value of 1.510 K, which is especially important with photoelectric interference pattern hysteresis.

Claims (1)

The invention of the High-temperature dilatometer, including a system for measuring the elongation of the sample with a through hole. 314049 containing a radiation source, a cube divider, a Fizeau interferometer and a recording device, optically coupled to each other, a chamber with protrusions on the inner surface of the walls, a support plate with a hole in the center, mounted horizontally on the projections, on the inner surface of the walls; Q P (} R is rigidly fixed in the hole of the support plate, the holder, made with the internal cavity for the sample and with a coaxial hole five a support plate with a hole in its upper part, in which the lower end of the suspension tube is rigidly fixed, characterized in that, in order to improve the measurement accuracy, it additionally contains a local heater covering the suspension tube and rigidly fixed at the base of the attachment of the suspension tube to the support plate, and In the lower part of the holder, the balance bar is fixed with the possibility of rotation around its vertical axis.