JPH0616015B2 - Thermal analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention precisely measures the sample temperature while heating a relatively small amount (for example, about 0.1 to 100 mg) of the sample, such as a melting point measuring device. The present invention relates to a thermal analyzer.

The invention also relates to a thermally compensated differential scanning calorimeter.

(Prior Art) As an example of a thermal analyzer for measuring the temperature of a small amount of sample while heating it, there is one shown in FIGS. 6 and 7.

In the thermal analyzer having the structure shown in FIG. 6, the heat from the heater 2 is transmitted to the sample 6 through the heat transfer plate 4. A thermocouple 8 as a temperature detector is provided on the heat transfer plate 4 at the position of the sample 6. The heat transfer plate 4 is often made of metal, but there is also a structure in which the heat transfer plate 4 is not provided and the sample 6 is heated by the heater 2 via the air layer. Further, the thermocouple 8 may be directly immersed in the sample 6.

In the thermal analyzer having the structure shown in FIG. 7, the heating furnace 12 is integrally provided below the bottom surface of the sample holder 10. In the heating furnace 12, a heater 16 and a platinum resistor 18 as a temperature detector are embedded in an insulating material 14. Sample holder 10
The sample 20 contained in the container is placed on the upper part of the.

(Problems to be Solved by the Invention) In the thermal analysis device shown in FIG. 6, the heater 2 and the thermocouple 8 are used.
The thermal resistance between the two is large and the response is poor.

In the thermal analyzer shown in FIG. 7, a temperature detector such as a platinum resistor 18 is provided near the heater 16 or integrated with the heater 16. Therefore, it is unknown whether the heater temperature is detected or the sample temperature is detected, and it is necessary to calibrate the thermal analysis device one by one.

Further, for example, when heated at 10 ° C./min with the thermal analyzer shown in FIG. 7, the melting point of indium (In) (156.5 ° C.) may appear about 3 to 4 ° C. higher. This error varies depending on the heating rate, and increases as the heating rate increases.

The present invention provides a thermal analysis device capable of rapidly raising the sample temperature while preventing the heat generated by the heater from being directly transmitted to the temperature detector, and capable of accurately measuring the sample temperature. The purpose is to do.

(Means for Solving Problems) The thermal analysis device of the present invention has a thermal resistance between the first bottom plate and a cylindrical body of a good thermal conductor having an upper opening and having a good opening. It has a second bottom plate of a good heat conductor which is in close contact with the inner side surface of the tubular body through a member at its end face, and the sample is placed on the second bottom plate in a state of being put in a container or directly. A sample holder, a planar heater provided below the first bottom plate in close contact with each other via an electrically insulating member having good thermal conductivity, and attached to the center of the lower surface of the second bottom plate. , The first bottom plate, the electrical insulating member, and the temperature sensor that penetrates through the center of each of the planar heaters and is guided to the outside.

Further, the heat combat device of the present invention is a differential scanning calorimeter, a differential scanning calorimeter, the sample heating means for the reference substance and the sample heating means for sample measurement, respectively the sample holder and The flat heater arranged as described above under the sample holder and the temperature detector arranged as described above.

(Embodiment) FIG. 1 shows an embodiment of the present invention.

Reference numeral 22 is a cylindrical sample holder, and a side wall 24 and a heating member 26 are integrally provided. A bottom plate 30 serving as a bottom surface of the sample holder is inserted above the heating member 26 via a mica 28, and the end surface of the bottom plate 30 and the inside of the sample holder side wall 24 are in close contact with each other.

As the sample holder side wall 24 and the bottom plate 30, a heat resistant metal such as stainless steel or platinum iridium alloy is used.

The thickness of the mica 28 is about 200 to 300 μm, and the thermal resistance is sufficiently large.

The sample 20 placed in a container such as aluminum is placed on the bottom plate 30.

A thermocouple 32 as a temperature detector is joined and attached to the center of the bottom plate 30.

A mica 34, a heater 36, and a mica 38 are inserted in the lower part of the heating member 26 in this order, and further, a disk-shaped portion of a support member 40 in which the tip of the cylinder is expanded in a disk shape is inserted below the mica 34. . These members 34, 36, 38, 40 are fixed by bending the lower part of the sample holder side wall 24 inward.

Mica 28, heating member 26, mica 34, heater 36,
The mica 38 and the support member 40 have a hole in the center,
The thermocouple 32 protected by the insulator 33 is guided to the outside through these holes.

The thickness of the mica 34 provided on the bend of the heater 36 and the heating member 26 is about 20 to 30 μm, and this thickness is the mica 38 provided on the bend of the heater 36 and the support member 40.
The thickness of the heater 3 (about 200 μm)
The heat generated in 6 can be efficiently used for heating the sample.

A thin film heater having a thickness of about 15 μm is used as the heater 36, and is insulated by the mica 34 and 38.

The sample holder that doubles as a heating furnace has an outer diameter D of about 7 mm.
It is possible to fabricate mm and height H to about 4 mm.
With such a small size, sample heating at 100 ° C./degree is also possible.

In this embodiment, most of the heat generated by the heater 36 flows to the heating member 26. Then, the heating member 26 and the bottom plate 30
Since the thick mica 28 is interposed between the heating members 2
Most of the heat from 6 flows through the metal portion of the sample holder 22, flows from the sample holder side wall 24 toward the center of the bottom plate 30 as shown by the arrow, and reaches the thermocouple 32. At this time, since the sample 20 is on the bottom plate 30, heat is exchanged between the bottom plate 30 and the sample 20, and at the thermocouple 32, the temperature of the sample 20 and the temperature of the bottom plate 30 are almost equilibrium. .

According to this example, the temperature error of the melting point of indium was within about 0.3 ° C. in the temperature rising rate range of 1 to 20 ° C./min.

If the temperature range is below 400 ° C, mica 28, 34,
Instead of 38, a heat resistant resin such as polyimide can be used. However, mica is preferred when heating to 500-600 ° C.

FIG. 2 shows an exploded perspective view of the embodiment shown in FIG. 1 and the manufacturing method thereof will be described.

The sample holder body 22 is shaped such that the lower portion of the side wall 24 is cut as shown in the figure.

From above the sample holder body 22, the mica 28 is inserted inside the side wall 24, and the bottom plate 30 to which the thermocouple 32 is joined is press-fitted onto the mica 28. From below the sample holder 22, a mica 34, a heater 36, a mica 38, and a support member 40.
Are inserted in this order, and the lower portion of the side wall 24 is bent inward. The lead wires 37a and 37b of the heater 36 are taken out from the cut portion of the side wall 24 to the outside.

FIG. 3 shows a second embodiment of the present invention.

Comparing the embodiment shown in FIG. 1, the mica 34 as an insulating material interposed between the heater 36 and the heating member 26 in the heating furnace is replaced with a ceramic coating 42 containing alumina as a main component in this embodiment. The difference is that. The other structure is the same as that of the embodiment shown in FIG. However,
Illustration of the insulator of the thermocouple 32 is omitted.

The thickness of the ceramic coating 42 is preferably as thin as it is thermally, but if it is thin, the electrical insulating property deteriorates.
About 50 μm is suitable.

The ceramic coating 42 is electrically insulating up to 500 to 600 ° C. and has a higher thermal conductivity than mica. Also,
Since the thickness can be made uniform and an air layer does not enter like mica, it is easy to make a product with uniform characteristics.

The ceramic coating 42 is applied to the heating member 26.
To form the back surface of the heating member 26, as shown in FIG. 2, the back surface of the heating member 26 may be ceramic-coated and lapped while the lower portion of the side wall 24 of the sample holder 22 is straight.

In the embodiment of FIG. 3, mica 28 and 38 are used between the heating member 26 and the bottom plate 30 and between the heater 36 and the support member 40, as in the embodiment of FIG. This not only reduces the heat loss, but also absorbs the difference in thermal expansion between the members due to the temperature cycle and the slight undulations of the ceramic coating, and also serves as a cushioning material for uniformly pressing the heater 36 against the heating member 26. ing.

When the embodiment of FIG. 3 is used, both the baseline and noise level are improved by a factor of 2 to 3 over the embodiment of FIG.

FIG. 4 shows a third embodiment of the present invention.

Compared to the embodiment of FIG. 3, a ceramic coating 44 is also applied to the bottom surface of the bottom plate 30, and thermocouples 46 and 48 are provided between the ceramic coating 44 and the mica 28.
The difference is that the thermocouples 32, 46 and 48 are electrically connected to form a thermopile to increase the side temperature sensitivity. The other structure is the same as that of FIG. Fourth
Also in the figure, the insulators of the thermocouples 32, 46 and 48 are not shown.

FIG. 5 shows an embodiment of the thermal compensation type differential scanning calorimeter of the present invention.

Reference numerals 50a and 50b denote sample holders integrated with a heating furnace, both of which are shown in FIG.

A reference substance 52 is placed on the sample holder 50a, and a measurement sample 54 is placed on the sample holder 50b.

The sample holders 50a and 50b are respectively provided with the support members 40.
It is integrally fixed to the support member 56 by a and 40b.

Chromel alumel is used as the thermocouples 32a and 32b. The chromel wires (C) of both thermocouples 32a and 32b are commonly connected, and the alumel wire (A) of each thermocouple 32a and 32b is connected to each input of the amplifier 58. As a result, both sample holders 50a,
The temperature difference ΔT of 50b is input.

The temperature of each sample holder 50a, 50b can be measured by each thermocouple 32a, 32b.

Reference numeral 60 denotes a power amplifier / switching circuit, which is a heater 36a, 36b of a heating furnace for both sample holders 50a, 50b.
Of the heaters 36a and 36b such that the output signal of the amplifier 58 is input and the depth of the input of the amplifier 58 is 0, that is, the temperature difference Δ = 0.
Control the amount of electricity supplied to.

In the differential scanning calorimeter of FIG. 5, the sample holder 50a,
As 50b, the one shown in FIG. 1 or the one shown in FIG. 4 may be used.

(Effect of the Invention) In the present invention, the sample holder and the heating furnace are integrated,
A temperature detector is connected to the center of the bottom of the sample holder to transfer heat from the heating furnace from the side wall of the sample holder to the bottom, improving the side temperature accuracy and precisely controlling the sample temperature according to a fixed program. become able to.

Further, in the present invention, the side temperature accuracy does not largely depend on the temperature rise. Therefore, when the melting point is simply measured, precise control of the heating rate becomes unnecessary.

Further, according to the present invention, the sample holder and the heating furnace can be integrated into a small size, and can be heated at a high speed, for example, heating up to about 500 ° C. at a heating rate of about 100 ° C./min. .

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same embodiment, FIGS. 3 and 4 are sectional views showing other embodiments, and FIG. FIG. 6 is a schematic sectional view showing an embodiment of a differential scanning calorimeter of the present invention, and FIGS. 6 and 7 are sectional views showing an example of a conventional thermal analyzer. 22 ... Sample holder, 24 ... Sample holder side wall, 26 ... Heating member, 28, 34, 38 ... Mica, 36 ... Heater, 42, 44 ... Ceramic coating, 50a, 50b ... Sample holder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Actual public 39-23983 (JP, Y1) Actual public 40-9111 (JP, Y1) Actual public 44-4400 (JP, Y1)

Claims (4)

[Claims] 1. A cylindrical body of a good heat conductor having a first bottom plate and opening upward, and a heat resistance member is provided between the first bottom plate and the inner surface of the cylindrical body. And a sample holder on which the sample is placed directly in a container placed on the second bottom plate, and a second bottom plate made of a good heat conductor that is in close contact with the first bottom plate. A planar heater provided in close contact with a heat conductive electrical insulating member and a central bottom surface of the second bottom plate, the thermal resistance member, the first bottom plate, the electrical insulating member and the A thermal analysis device, comprising: a temperature detector that penetrates the center of each of the planar heaters and is guided to the outside. 2. The thermal analysis device according to claim 1, wherein mica is used as the thermal resistance member and the electrical insulating member. 3. The thermal analysis apparatus according to claim 1, wherein a ceramic coating is used as a part of the thermal resistance member and the electrical insulation member. 4. A differential scanning calorimeter, wherein a sample heating means for a reference substance and a sample heating means for measuring a sample are provided in a cylindrical body of a good heat conductor having a first bottom plate and opening upward. A second bottom plate made of a good heat conductor is provided between the first bottom plate and the inner surface of the cylindrical body with a heat resistance member interposed therebetween, and the second bottom plate is made of a good heat conductor, and the sample is placed on the second bottom plate. A sample holder that is placed in a container or placed directly, a planar heater that is provided below the first bottom plate and in close contact therewith via an electrically insulating member having good thermal conductivity, and the second heater A temperature detector attached to the center of the lower surface of the bottom plate and led to the outside through the respective centers of the thermal resistance member, the first bottom plate, the electric insulating member, and the planar heater;
A thermal analysis device comprising: