JP3352075B2 - Heat flux thermal expansion simultaneous measurement element and heat flux thermal expansion simultaneous measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat flux and thermal expansion simultaneous measuring device and a heat flux and thermal expansion simultaneous measuring device.

[0002]

[Prior Art] As a heat flux measuring device, a calorimetry / thermal analysis handbook (Maruzen, 1998), p. 42, DSC, isothermal wall calorimeter, conduction calorimeter and the like. In recent years, the present inventors have developed a heat flux measuring device (K. Tozak) having a temperature resolution on the order of millikelvin.
i et al., Proceedings of International Conferenceo
n Solid-solid Transformations, Kyoto, May 24, 199
9, p1433-1436, Editedby M. Koiwa, K. Otsuka and T.
Miyazaki).

On the other hand, as a thermal expansion measuring device, the basics and applications of thermal analysis, 3rd edition (Realize, 1994), p. 20, a push-rod type thermal dilatometer, a capacitance method (Tetsuya Takeuchi, Solid State Physics, Vol. 33 (1998), p. 9)
96).

[0004]

An attempt has been made to measure, for example, the phase transition point of a BaTiO ₃ single crystal by using the above-mentioned heat flux measuring device. According to such a heat flux measuring device, BaTiO ₃
In the single crystal, thermal anomalies considered to be due to several phase transitions are observed between 129 and 130 ° C. However, measurement of only the heat flux could not verify whether such a phase transition actually occurs in a temperature range of 1 ° C.

When a magnetic change of a paramagnetic substance or an antiferromagnetic substance is measured under a strong magnetic field from the thermal expansion of these substances, since these substances have a weak magnetic field effect, highly accurate detection is possible. Could not do. Even if a weak signal related to thermal expansion or the like can be detected, there is a problem that it cannot be determined whether or not this signal is significant as thermal expansion in the substance.

The above problem arises from the fact that only one of the heat flux and the thermal expansion can be measured for a sample to be measured in one measurement operation. Therefore, it is desired to have an apparatus capable of simultaneously measuring the heat flux and the thermal expansion of the sample to be measured.

An object of the present invention is to provide a novel measuring element and a novel measuring device capable of simultaneously measuring a heat flux and a thermal expansion.

[0008]

In order to achieve the above object,
The present invention provides a metal block having a concave portion on a main surface and having a cavity therein, a metal plate provided on the main surface of the metal block, and a measurement sample provided in the concave portion of the metal block. A thermoelectric element for measuring the heat flux of the metal block, connected in the cavity of the metal block,
A high-frequency introduction cable for introducing high frequency to measure the thermal expansion of the measurement sample,
The present invention relates to a heat flux and thermal expansion simultaneous measurement element.

The heat flux and thermal expansion simultaneous measuring element may include a temperature sensor for monitoring the temperature when measuring the heat flux and thermal expansion of the measurement sample.

The heat flux and thermal expansion simultaneous measuring device of the present invention comprises the heat flux and thermal expansion simultaneous measuring element, a high-frequency oscillation source for generating the high frequency, and the heat flux and thermal expansion simultaneous measurement based on a reflected wave with respect to the high frequency. It is characterized by comprising a measuring element and a calculating means for calculating a resonance frequency for the measuring sample.

The heat flux and thermal expansion simultaneous measuring device may include a heat insulating member provided so as to surround the heat flux and thermal expansion simultaneous measuring element. Hereinafter, the heat flux thermal expansion simultaneous measurement element and the heat flux thermal expansion measurement device of the present invention,
This will be described in detail with reference to a specific example.

[0012]

FIG. 1 is a schematic view showing an example of a heat flux / thermal expansion simultaneous measuring element of the present invention. The heat flux and thermal expansion simultaneous measurement element 10 shown in FIG. 1 includes a metal block 1 having a concave portion 1B in a main surface 1A and a cylindrical hollow portion 1C therein, and a main surface 1A of the metal block 1 on the main surface 1A. A metal plate 2 provided at a small distance so as to cover the entirety of 1A, and a semiconductor material or the like for measuring a heat flux of a measurement sample A provided in a concave portion 1B of a metal block 1. Thermoelement 3.

Further, in order to measure the coefficient of thermal expansion of the measurement sample A, a high-frequency introduction cable 4 composed of a coaxial cable or the like for introducing a high frequency into the element 10 is provided in the cavity 1C of the metal block 1. It is provided so as to be connected. A temperature sensor 5 for monitoring the temperature at the time of measurement is provided inside the metal block 1. When measuring the heat flux and the thermal expansion, the measurement sample A is a metal block 1
Is set on the thermoelectric element 3 in the concave portion 1B.

FIG. 2 is a schematic diagram showing an example of the heat flux thermal expansion measuring device of the present invention. The heat flux / thermal expansion measuring device 30 shown in FIG. 2 includes a high-frequency oscillation source (not shown) for generating the high frequency, and a not-shown calculation for calculating the resonance frequency of the heat flux / thermal expansion simultaneous measurement element from the reflected wave for the high frequency Means.

Further, the heat flux and thermal expansion simultaneous measuring device 30 shown in FIG. 2 has a heat insulating member 20 provided so as to surround the heat flux and thermal expansion measuring element 10. Thereby, when measuring the measurement sample A, the influence of external heat disturbance can be prevented, and the temperature inside the heat flux thermal expansion measurement element can be kept extremely uniform. Therefore, the heat flux and the thermal expansion of the measurement sample A can be measured with extremely high accuracy.

The heat insulating member 20 is a heat flux thermal expansion measuring element 1
A metal pedestal 11 for mounting and fixing the inner metal shield 0, an inner metal shield 12, an outer metal shield 13, and a heat insulating material 14 provided between the inner metal shield 12 and the outer metal shield 13. I have.

Further, the heat flux thermal expansion measuring device 30 is provided with a heater 15 for heating the heat flux thermal expansion measuring element 10 to a suitable temperature so as to surround the outer metal shield 13. A temperature sensor 16 for controlling the degree of heating by the heater 15 is provided. Similarly, a thermo module 17 for heating the heat flux thermal expansion measurement element 10 to an appropriate temperature and a temperature sensor 18 for controlling the same are provided below the heat flux thermal expansion measurement element 10 via a metal spacer 19. I have. By heating the heat flux thermal expansion measurement element 10 using such a heating means, the measurement sample A can be indirectly heated to a predetermined temperature, and can be used for measurement of heat flux and thermal expansion. become.

In the heat flux thermal expansion measuring device 30 shown in FIG. 2, the heating of the heat flux thermal expansion measuring element 10 is roughly controlled by the heater 15 and the temperature sensor 16, and the heat flux thermal expansion measuring element by the thermo module 17 and the temperature sensor 18. Fine control of heating for 10 is performed.

The measurement of the heat flux and the thermal expansion in the case of using the heat flux thermal expansion measuring element and the heat flux thermal expansion measuring device as described above is performed as follows. Heat flux measurement is
After heating the heat flux thermal expansion measurement element 10 to a predetermined temperature by the heater 15 and the temperature sensor 16, and the thermo module 17 and the temperature sensor 18, the amount of heat flowing into the thermoelectric element 3 from the measurement sample A at each temperature is This is performed by reading as a voltage output change in the thermoelectric element 3. The reading of the voltage output change is performed by a digital voltmeter (not shown) or the like.

The temperature of the element 10 is monitored by a temperature sensor 7. Most of the heat flux thermal expansion measuring element 10 shown in FIG. 1 is made of a metal material as described above, and has extremely excellent thermal conductivity. Therefore, the temperature of the element 10 measured by the temperature sensor 7 is
Temperature.

The thermal expansion is measured by heating the heat flux thermal expansion measuring element 10 as described above, and then applying a high frequency of various frequencies from a high frequency oscillator (not shown) to the high frequency introducing cable 4.
From the device 10. Then, the reflected waves with respect to these high frequencies are taken out through the high-frequency introduction cable 4,
The resonance frequency f is derived by analyzing with a processing means (not shown) such as a network analyzer. After deriving the resonance frequency, arithmetic processing is performed based on the following equation (1).

Δh = Δh ₁ + Δh ₂ = {ε ₀ S / (4π ² L)} (2f ₀ Δf + Δf ² ) (1)

Here, Δh ₁ and Δh ₂ represent the thermal expansion of the measurement sample A and the thermal expansion of the thermoelectric element 3, respectively. Also,
ε ₀ is the dielectric constant of air. S is an area of a central portion 1D of the main surface 1A of the metal block 1 which is opposed to the metal plate 2. L is a constant (inductance) of the entire circuit including the heat flux / thermal expansion simultaneous measuring element 10, the high frequency oscillation source, and the arithmetic processing means. Further, f ₀ represents the resonance frequency at the reference temperature, and Δf represents an increase in the resonance frequency with a rise in temperature, where the relationship Δf = f−f ₀ holds.

Here, the term Δf ^{2 in} the equation (1) is usually 2
Since it is smaller than f ₀ Δf, it can be ignored,
(1) can be approximated by the following equation.

HΔ = Δh ₁ + Δh ₂ = f ₀ Δfε ₀ S / (2π ² L) (2)

In equation (2), ε₀S is heat flux thermal expansion
It is a constant determined by the configuration of the simultaneous measurement element 10.
You. Also, f₀The shape of the element 10, the measurement sample and
Constant uniquely determined by the shape of thermoelectric element
It is. For the circuit constant L, the amount of thermal expansion and the resonance frequency
By performing calibration using two types of substances whose
You can ask. In other words, calibration using each substance
From Δh₁And Δf and Δh_TwoAnd Δf
Can be At this time, ε ₀S and f₀Is known, so
The circuit constant L can be obtained by using the equation (2).

By performing such a calibration, ε ₀ S, f ₀ and L in the equation (2) are all known. Therefore, by performing the above-mentioned operation, the resonance frequency increment Δ
The thermal expansion amount Δh can be obtained from f. By previously obtained the relation between the thermal expansion amounts Delta] h ₂ of the thermoelectric elements 3 and increment Δf of the resonance frequency can be derived only thermal expansion amount Delta] h ₁ of the measurement sample A.

FIG. 3 is a view showing Ba using the heat flux and thermal expansion simultaneous measuring device and the heat flux and thermal expansion simultaneous measuring device of the present invention.
4 is a graph showing the results of measuring the heat flux and the amount of thermal expansion of TiO ₃ . As is clear from FIG.
Heat flux anomalies and thermal expansion anomalies, probably due to several phase transitions during ° C., have been observed at the same temperature. Such high-resolution heat flux abnormality and thermal expansion abnormality cannot be obtained by the conventional measuring device.

As described above, the present invention has been described in detail based on the embodiments of the present invention with reference to specific examples. However, the present invention is not limited to the above-described contents, and may be implemented in any form without departing from the scope of the present invention. Deformation and modification are possible.

[0030]

As described above, according to the heat flux and thermal expansion simultaneous measuring device and the heat flux and thermal expansion simultaneous measuring device of the present invention, heat flux and thermal expansion can be measured simultaneously. Therefore, by using the measurement data based on the heat flux and the thermal expansion so as to complement each other, it is possible to accurately measure a change in the physical characteristics of the sample.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a heat flow rate and thermal expansion simultaneous measurement element of the present invention.

FIG. 2 is a diagram showing an example of a heat flow rate and thermal expansion simultaneous measurement device of the present invention.

FIG. 3 shows BaTiO ₃ measured using the simultaneous thermal flow rate thermal expansion measurement element and the thermal current rate thermal expansion simultaneous measurement apparatus of the present invention.
4 is a graph showing measurement data of a heat flow rate and a coefficient of thermal expansion of the sample.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Metal block 2 Metal plate 3 Thermoelectric element 4 High frequency introduction cable 5 Temperature sensor 10 Heat flow velocity thermal expansion simultaneous measurement element 11 Pedestal 12 Inner metal shield 13 Outer metal shield 14 Insulation material 15 Heater 16 Temperature sensor 17 Thermo module 18 Temperature sensor 19 Metal spacer Reference Signs List 20 Insulation member 30 Simultaneous measurement device for thermal velocity and thermal expansion

Continuing from the front page (72) Inventor Hideaki Inaba 1-33 Yayoimachi, Inage-ku, Chiba-shi, Chiba Prefecture Within the Faculty of Education (72) Inventor Tsunehisa Kimura 1-1, Minami-Osawa, Hachioji-shi, Tokyo Within the Faculty of Engineering, Tokyo Metropolitan University (56) References JP-A-52-114389 (JP, A) JP-A-3-176652 (JP, A) JP-A-6-43041 (JP, A) JP-A-5-318141 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) G01N 25/18 G01K 1/14 G01K 13/12 G01N 25/02 G01N 25/16 JICST file (JOIS)

Claims (4)

(57) [Claims] A metal block having a concave portion on a main surface and a hollow portion inside; a metal plate provided on the main surface of the metal block so as to cover the entire main surface; A thermoelectric element for measuring a heat flux of a measurement sample provided in the concave portion of the metal block, and a high frequency for measuring a thermal expansion of the measurement sample connected to the cavity of the metal block, for introducing a high frequency. A heat flux / thermal expansion simultaneous measurement element, characterized by comprising: 2. The heat-flux thermal expansion device according to claim 1, wherein the heat-flux / thermal-expansion simultaneous measuring element includes a temperature sensor for monitoring the temperature when measuring the heat flux and the thermal expansion of the measurement sample. Simultaneous measurement element. 3. The simultaneous measurement element for heat flux and thermal expansion according to claim 1 or 2, a high-frequency oscillation source for generating the high frequency, the simultaneous measurement element for heat flux and thermal expansion based on a reflected wave with respect to the high frequency, and the measurement sample. Computing means for computing the resonance frequency for
Simultaneous measurement of heat flux and thermal expansion. 4. The heat flux and thermal expansion simultaneous measuring device according to claim 3, wherein the heat flux and thermal expansion simultaneous measuring device includes a heat insulating member provided so as to surround the heat flux and thermal expansion simultaneous measuring element. .