JPS63255649A - Differential scanning calorimeter - Google Patents

Abstract

PURPOSE:To prevent the lowering in the calorific value detection sensitivity of a detector, by embedding a specimen holder in the recessed cavity of a heat sink to reduce the conduction of heat due to radiation even in a high temp. region. CONSTITUTION:Recessed cavities 2, 3 are provided to the surface of a heat sink 1 and the specimen holder 4 on a specimen side is embedded in the cavity 2 and the specimen holder 5 on a reference substance side is embedded in the cavity 3. A specimen and specimen container 9 are provided in the holder 4 and a reference substance and reference substance container 10 are provided in the holder 5. When the temp. of the heat sink 1 is controlled by a heating oven 11, a heat stream is supplied to the specimen and the reference substance from the heat sink 1 through the specimen holders 4, 5. Therefore, by measuring the voltage between platinum-rhodium 13% wires 6, 7, the temp. difference between the holders 4, 5 can be detected and the lowering in the calorific value detection sensitivity of a detector can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a differential scanning calorimeter (hereinafter abbreviated as DSC).

[Summary of the invention]

The present invention is a heat flux type DSC in a high temperature range (approximately 1000
In order to reduce the decrease in the heat detection sensitivity of the heat flow detector due to the effect of heat transfer by radiation at temperatures near
It consists of a sample holder that almost fits into the concave recess of this heat sink, and a means for controlling the temperature of the heat sink.
Even at low temperatures (near This has achieved the above objectives.

[Conventional technology]

The structure of a conventional DSC of this type is shown in Figure 20 (B-02), and as shown in Figure 3, it has a sample and sample container 59, a reference material and a reference material container 60. The sample holders 54 and 55 on the sample side and the reference material side for installation had a structure in which they protruded in a convex shape with respect to the heat sink 51.

[Problems to be solved by the invention] ■ In the 22-day technology, the sensitivity of the detector for detecting hot stars is lower in the high temperature range (for example, around the melting point of metal indium, 156.6°C) than in the low temperature range (for example, around the melting point of metal indium, 156.6°C). The melting point of 1063°C ζJ
However, in recent years, the disadvantage was that it decreased significantly.

In general, the structure of the calorific value detection system of the Tough overnight bundle type DSC is as shown in the conventional example shown in Fig. 3, which includes a sample holder 54 on the sample side for installing the sample and five sample containers, a reference material and a container 60 for the reference material. A sample holder 55 on the reference material side is installed to connect each sample holder 54, 55 and a temperature-controlled heat sink 51 with an appropriate thermal resistor 52, A temperature difference detector such as a thermocouple (for example, a differential thermocouple 56) is provided in the sample holder 54 to detect the temperature difference between the sample holders 54 and 55.

This detected temperature difference is transmitted from the heat sink 51 through each thermal resistor 52 and each sample holder 54, 55 to the sample and sample container 59, and the base [1! ! Heat conduction is proportional to the difference in heat flow between the substance and the substance container 60.

Figure 4 +a+, (bl) shows the heat flow when measuring a sample with a conventional DSC in a low temperature range (e.g. around the melting point of metallic indium, 156.6°C) and (Figure 4 (a)
)) and when measured in a high temperature range (for example, near the melting point of gold, 1063° C.) (Fig. 4(b)).

In FIG. 4, only the peripheral portion of the sample holder 54 on the sample side of the sample 41 is shown. The periphery of the 1L substance side sample holder 55 is symmetrical to the periphery of the sample holder 54 on the sample side, and the flow of heat conforms to the flow shown in FIG.

In the low temperature range, the heat flow to the sample is mainly due to heat flow 64 from the heat sink due to thermal conduction, or in the high temperature range, in addition to the heat flow 65 from the heat sink due to heat conduction, there is also radiation from the heat sink. There is a large amount of heat flow 66 caused by heat flow and heat flow 67 caused by radiation from the heating furnace wall. This is because, as is well known, the amount of heat transferred by radiation between two objects depends on the difference in the nominal absolute temperature of the two objects to the fourth power. ＼The amount of heat flowing into a part of the sample boulder from the heat sink 51 and the outside world (heating furnace wall 62, etc.), which would not be a problem in the high temperature range (near 156.6°C), This is because the amount is large in the vicinity).

By the way, even if the surface conditions of two objects change and the temperature difference between the two objects does not change, the amount of heat transferred by radiation between these two objects at around 156.6°C is 106
The amount of heat transferred by radiation between these two objects at around 3°C is approximately 304@.

The temperature difference detected by the differential thermocouple 56 is proportional to the difference in heat flow 64,65 from the heat sink due to thermal conduction between the sample side and the reference material side. Therefore, the sample side of the total heat flow to the sample and reference material.

The ratio of the heat flow difference detected and converted by the differential thermocouple 56 to the heat flow difference on the reference material side becomes significantly smaller in the high temperature range than in the low temperature range. This means that the sensitivity of the detector for detecting the amount of heat is significantly reduced.

[Means for solving problems]

The present invention was developed to eliminate the above-mentioned drawbacks.
The heat sink is comprised of a heat sink having two concave recesses, a sample holder that fits approximately into the concave recesses of the heat sink, and means for controlling the temperature of the heat sink.

[Effect]

The effect of the above configuration is that the heat sink temperature is controlled in a high temperature range (for example, the melting point of gold is 1063
Even when the temperature is raised to a temperature close to 44 °C, the inflow of heat into a part of the sample boulder is mainly due to heat conduction from the heat sink. Prevents the decrease in heat detection sensitivity in the device.

〔Example〕

FIG. 1 shows a cross-sectional view of an embodiment of a DSC according to the invention. 1 is alumina sink-1-sink, concave 4Je (7)
<Homs 2 and 3 are placed at symmetrical positions on the heat sink surface. A sample holder 4 on the sample side is embedded in the concave depression 2, and a sample holder 5 on the %Yp material side is embedded in the concave depression 3, and each is in contact with the heat sink 1 by a method such as alumina adhesive or implantation. maintains its condition.

Each sample holder is made of platinum on the inside 20 of the sample holder, and a 13% platinum-rhodium alloy on the outside 21 of the sample holder, and the inner and outer parts are integrated by multi-point welding or the like. The bottom surface of each sample holder is coated with platinum-rhodium-13.
% wire 6.7 is welded, and a platinum wire 8 is welded to the platinum part on the inside 20 of each sample holder, and the sample holder 4 on the sample side and the sample holder 5 on the reference material side are connected by this platinum wire 8. Electrical continuity is maintained.

As a result, the electrical system path of the platinum-rhodium 13% wire 6, the sample holder 4 on the sample side, the platinum wire 8, the sample holder 5 on the reference material side, and the platinum-rhodium 13% vA7 form a differential thermocouple. Therefore, by measuring the voltage between platinum-1 codium 13% vA6 and 7, the temperature difference between the sample holder 4 on the sample side and the sample holder 5 on the reference material side can be detected.

A sample and a sample container 9 are placed in the sample holder 4 on the sample side, and a reference substance and a container 1 for the reference substance are placed in the sample holder 5 on the reference material side.
When the temperature of the heat tank 1 is controlled by the heating furnace 11, a heat flow is supplied to the sample and the reference material from the heat sink 1 through each sample holder. The difference in heat flow between the sample side and the reference material side corresponds to the temperature difference measured by the differential thermocouple, and this structure is a well-known structure of a heat flux type DSC.

I) SC shown in this example is used to measure samples in a low temperature range (e.g. around the melting point of indium, 156.6°C) and in a high temperature range (e.g. around the melting point of gold, around 1063°C). Figure 2 shows a comparison of the heat flow in these cases.

In FIG. 2, only the peripheral part of the sample holder 4 on the sample side is shown. The periphery of the reference material side sample holder 5 is the sample side sample holder 4.
It has a symmetrical shape with its surroundings, and the heat flow follows the flow shown in Figure 2.

In the DSC shown in the example, the sample holder 4 is embedded in the concave recess 2 of the heat nok 1, and the sample holder 4 is
Since there are no exposed parts, heat flow due to radiation from the heat sink I and the heating furnace wall 12 does not pose a problem even in a high temperature range as in a low temperature range.

Therefore, the main flow of heat to the sample, whether in the low temperature range or the high temperature range, is the heat flow 14.15 from the heat sink due to thermal conduction. This is detected by the differential thermocouple in the example for the heat flow difference between the sample side and the reference material side of the overall heat flow to the sample and reference material, and the ratio of the converted heat flow difference is in both the low temperature range and the high temperature range. But it shows that there is no big difference.

In other words, in the embodiment, the sensitivity of the detector for detecting the amount of heat does not decrease even in the high temperature range, and measurement is possible.

Furthermore, the structure of the embodiment not only prevents a decrease in heat detection sensitivity in a high temperature range, but also has the following effects.

In the transfer of heat by thermal conduction, if the thermal resistance between two points in the transfer path is determined, the heat flow between these two points is uniquely determined by the temperature difference between these two points.

On the other hand, the amount of heat transferred between two objects by radiation depends on the difference in the fourth power of the absolute temperature of each object, and also on the surface condition (surface area and radiation coefficient at the surface) of each object. In other words, the amount of heat transferred by radiation is the amount of heat transferred. When the temperature of two objects changes, or the shape or surface color of each object changes, a large change occurs.

In the case of a DSC with a conventional structure, a large amount of heat flows into the sample holder due to radiation during measurements in a high temperature range. (Heat tank surface thickness) 11 = 8 - Thickness (changes) due to changes in temperature and surface condition of the furnace wall surface, etc. Therefore, the heat flow difference detected and converted by a differential thermocouple is also affected by changes in the amount of heat inflow due to radiation. Since the amount of heat varies, it is virtually impossible to quantify the amount of heat in such a high temperature range due to lack of reproducibility.

On the other hand, in the DSC of the embodiment, even in the high temperature range, the amount of heat inflow by radiation itself is small as in the low temperature range, so it is possible to quantify the amount of heat even in the high temperature range, where it is impossible to quantify the amount of heat with the conventional DSC.

In addition, in the heat flow of the embodiment shown in FIG. 2 and the heat flow of the conventional example shown in FIG. Although not shown, this can be prevented by covering the sample and sample container with a radiation shielding cover made of a material with low emissivity such as platinum. Needless to say.

In addition, in the example, the sample holder used was a welded body of platinum and platinum/rhodium 13% wire gold, or basically a structure in which it fits into a concave hole in the heat sink to establish thermal contact with the heat sink. A similar effect can be obtained by using a material with relatively good thermal conductivity. Furthermore, it goes without saying that a differential thermocouple or the like for detecting temperature differences may be installed at a fixed position between the surface of the sample holder and the heat sink.

As long as the heat sink is made of a material with good thermal conductivity, it can be selected according to the temperature range to be measured. In addition, in the embodiment, a heating furnace wrapped around a heater was used as a means for controlling the temperature of the heat sink, but any means that can control the temperature of the heat sink, such as wrapping a heater directly around the heat sink, may be used, and if an appropriate method is selected. good.

〔Effect of the invention〕

As described above, according to the present invention, the sample holder of the heat flow detection system of the DSC is embedded in the concave recess of the heat sink, and the exposed area of the sample holder surface is reduced. Even when the melting point is around 1063°C, the heat transfer due to radiation can be reduced, suppressing the decrease in the heat detection sensitivity of the detector, and increasing the influence of changes in heat transfer due to conventional radiation (because it is affected by It also has the effect of being able to quantify the amount of heat even in a high temperature range (for example, a temperature range exceeding the melting point of gold, 1063°C), which has not been possible to quantify.This greatly expands the range of applications of DSC measurement.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of the present invention, Figure 2 (A)
, (B) is a cross-sectional view showing the flow of heat when a sample is measured with the DSC of the embodiment, FIG. 3 is a cross-sectional view of the conventional example, and FIG. 4 ta1. fbl is a cross-sectional view showing the flow of heat when a sample is measured with a conventional DSC. ■...Heat sink 2...Concave depression 3...Concave depression 4...Sample side sample holder 5...Reference material side sample holder 6...Platinum-rhodium 13% wire 7... Platinum-rhodium 13% wire 8...Platinum wire 9...Sample and sample container 10...Reference material and reference material container 11...Heating furnace 12...Heating furnace wall 13...Heater 14 ... Heat flow from the heat sink 15 ... Heat flow from the heat sink 20 ... Inside the sample holder (
platinum) 21... Sample holder outside (platinum-rhodium 13% alloy) 51... Heat sink 52... Thermal resistor 54... Sample side sample holder 55... Reference material side sample holder 56... Differential thermocouple 59...Sample and sample container 60...Reference material and reference material container 61...Heating furnace 62...Heating furnace wall 64...Heat flow from heat sink 65...Heat I. Flow of heat from the sink 66... Flow of heat due to radiation from the heat sink 67... Flow of heat due to radiation from the heating furnace wall Applicant: Seiko Electronics Co., Ltd.
− Punishment ψ Healing Spinning Rebellion

Claims (1)

[Claims] A differential scanning calorimeter comprising: a heat sink having two or more concave recesses; a sample holder that fits approximately into the concave recesses of the heat sink; and means for controlling the temperature of the heat sink.