JP2012078146A - Differential scanning calorimeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential scanning calorimeter capable of measuring a sample to be measured with high accuracy by accurately controlling a temperature of a furnace body.SOLUTION: A differential scanning calorimeter 1 comprises: a heat-sensitive plate 10 including a metal placement plate 11 having a measured sample placing part 11a for placing the sample to be measured thereon, a reference material placing part 11b for placing the reference material thereon, and outer peripheral edges 11c, 11d; a metal furnace body 20 in which a joint part 22 joining with the outer peripheral edges of the placement plate 11 is formed; a heater 30 wound around the outer periphery of the furnace body 20 for conducting heat to the placement plate 11; and a differential heat flow detector 40 for detecting a temperature difference between the sample to be measured and the reference material and for outputting the detected temperature difference as a heat flow difference signal. In the differential scanning calorimeter 1, a metal 60, which is the same kind of metal as that forming the furnace body 20, is arranged between the heater 30 and the furnace body 20.

Description

  The present invention relates to a differential scanning calorimeter that measures how the physical properties of a sample to be measured change with temperature. In particular, the differential scanning calorific value is measured based on the temperature difference (differential heat) between the sample to be measured and the reference material, when the temperature is changed, and the amount of heat released or absorbed by the sample to be measured compared to the reference material. Regarding the total.

  A differential scanning calorimeter (hereinafter referred to as “DSC”) includes a thermal compensation type DSC (also referred to as “input compensation type DSC”) and a heat flux type DSC (also referred to as “quantitative DTA”). There is. The heat flux type DSC has a constant temperature plate of about 0.2 mm joined to a silver furnace body, and a reference material (a thermally stable material such as alumina) on the upper surface of the heat plate. And the sample to be measured are placed apart. Then, while heating the furnace body, heat is conducted to the reference material and the sample to be measured through the heat sensitive plate at a constant temperature increase rate. At this time, by detecting the temperature difference between the sample to be measured and the reference material, the difference between the heat flow between the furnace body and the sample to be measured and the heat flow between the furnace body and the reference material ( Calorie). Thus, the amount of heat at the time of melting or transition of the sample to be measured is obtained.

In such a heat flux type DSC, heat transfer occurs due to heat conduction between the furnace body and the heat sensitive plate. Therefore, in order to conduct heat to the reference material and the sample to be measured at a constant heating rate, the heat sensitive plate is used. It is important that the outer peripheral edge portion of the steel plate and the joint portion of the furnace body be bonded in a uniform manner. Then, what joined the outer peripheral part of the heat sensitive board and the junction part of the furnace body by spot welding is disclosed (for example, refer patent document 1).
FIG. 2 is a schematic diagram showing a conventional DSC. Fig.2 (a) is a top view which shows DSC, FIG.2 (b) is sectional drawing of the BB line shown to Fig.2 (a). In addition, illustration of the lid | cover 24 is abbreviate | omitted in Fig.2 (a).
The DSC 101 includes a thermal plate 10 having a constantan mounting plate 11, a silver furnace body 20, a sheathed heater 30 wound around the outer periphery of the furnace body 20, and the temperature of the sample S to be measured and the reference material B. A differential heat flow detector 40 that detects the difference and outputs the detected temperature difference as a heat flow difference signal; a temperature control thermocouple 50 that detects the temperature of the furnace body 20 and outputs the detected temperature as a temperature signal; A control unit (not shown).

  The mounting plate 11 made of constantan is a plate-like body having a thickness of about 0.2 mm, and has a shape in which two circles (for example, a diameter of 12 mm) are adjacent when viewed in plan. The circular central portion of one circle becomes the measured sample mounting portion 11a on which the sample holder storing the measured sample S is placed, and the circular central portion of the second circle is the reference substance B. The reference material holder 11b on which the stored reference material holder is placed is formed. An outer peripheral edge portion 11c is formed on the outer periphery of the measured sample mounting portion 11a, and an outer peripheral edge portion 11d is formed on the outer periphery of the reference material mounting portion 11b.

Further, a plurality of arc-shaped first grooves 11e are formed by an etching method between the measured sample mounting portion 11a and the outer peripheral edge portion 11c. Thereby, the heat flow path for conducting the heat of the sheathed heater 30 from the outer peripheral edge portion 11d to the measured sample mounting portion 11a is long to avoid the first groove 11e.
Further, a plurality of arc-shaped first grooves 11g are formed by an etching method between the reference material placing portion 11b and the outer peripheral edge portion 11d. Thereby, the heat flow path for conducting the heat of the sheathed heater 30 from the outer peripheral edge part 11d to the reference material placing part 11b is long to avoid the first groove 11g.

A chromel plate 12a, which is a disc-shaped body (for example, 7 mm in diameter) having a thickness of about 0.2 mm, is fixed to the lower surface of the measurement sample mounting portion 11a by, for example, spot welding. Further, a chromel / alumel thermocouple 13a is laser welded to the center of the lower surface of the chromel plate 12a.
On the other hand, a chromel plate 12b, which is a disk-like body (for example, 7 mm in diameter) having a thickness of about 0.2 mm, is fixed to the lower surface of the reference material placement surface 11b by, for example, spot welding. Further, a chromel / alumel thermocouple 13b is laser welded to the center of the lower surface of the chromel plate 12b. That is, the thermal plate 10 is composed of the mounting plate 11, the chromel plate 12a, and the chromel plate 12b.

  Although details will be described later, the thermocouple 13a is drawn out of the furnace body 20 through the through hole 21a formed in the furnace body 20, and the thermocouple 13b is formed in the through hole formed in the furnace body 20. It will be pulled out of the furnace body 20 through 21b. Thereby, the chromel plate 12a and the chromel plate 12b output the detected temperature difference between the measured sample S and the reference material B to the outside of the furnace body 20 as a heat flow difference signal via the thermocouple 13a and the thermocouple 13b. ing. That is, the differential heat flow detector 40 is comprised by the mounting board 11, the chromel board 12a, the chromel board 12b, the thermocouple 13a, and the thermocouple 13b.

The silver furnace body 20 has, for example, a cylindrical shape having an inner diameter of 30 mm, an outer diameter of 35 mm, and a height of 20 mm, and an annular joint portion 22 is formed in plan view so as to protrude inward at the lower portion of the inner wall surface. Further, a horizontal rectangular bottom surface 23 is formed in the cylindrical lower portion. The inside of the cylindrical upper part can be sealed with a removable circular lid 24. A through hole 21a for passing the thermocouple 13a and a through hole 21b for passing the thermocouple 13b are formed on the bottom surface 23.
As described above, the outer peripheral edge of the lower surface of the mounting plate 111 is joined to the upper surface of the joint portion 22 by spot welding, the thermocouple 13a passes through the through hole 21a, and the thermocouple 13b passes through the through hole 21b. The heat sensitive plate 10 is arranged so as to pass through.

  The sheathed heater 30 is configured by holding a heating element (for example, nichrome wire) in a metal sheath (for example, stainless steel or NCF600), and filling a gap with a powder of an inorganic insulator (for example, magnesium oxide). is there. The sheathed heater 30 has a circular tube shape with a diameter of 6 mm to 30 mm, and is wound around the outer peripheral surface of the furnace body 20 with the central axis of the furnace body 20 as the central axis. Further, it is connected to the control unit, and is heated based on an output instruction from the control unit. Thereby, the heat of the sheathed heater 30 is conducted with the furnace body 20, the heat sensitive plate 10, the sample S to be measured or the reference material B.

  The temperature control thermocouple 50 is a chromel / alumel thermocouple and is attached to the furnace body 20. And the thermocouple 50 for temperature control converts the temperature of the furnace body 20 into a temperature signal, and outputs it to a control part.

Japanese Patent Laying-Open No. 2005-83763

By the way, in the differential scanning calorimeter 101, the heat of the sheathed heater 30 is conducted to the furnace body 20, the heat sensitive plate 10, the sample S to be measured or the reference material B. It is wound around the outer peripheral surface of the furnace body 20. That is, air exists between the sheathed heater 30 and the furnace body 20. Therefore, it takes time because the heat of the sheathed heater 30 is conducted to the furnace body 20 through the air, and it is difficult to control the temperature of the furnace body 20 by the control unit. As a result, the sample S to be measured may not be accurately analyzed.
SUMMARY OF THE INVENTION The present invention is directed to a differential scanning calorimeter that can accurately measure a sample to be measured by accurately controlling the temperature of a furnace body.

  The differential scanning calorimeter of the present invention, which has been made to solve the above problems, includes a measured sample mounting portion on which a measured sample is mounted, a reference material mounting portion on which a reference material is mounted, and an outer periphery. A heat sensitive plate having a metal mounting plate having a portion, a metal furnace body formed with a joint portion to which the outer peripheral edge portion of the mounting plate is bonded, and conducting heat to the mounting plate. Therefore, a heater wound around the outer periphery of the furnace body and a differential heat flow detector for detecting a temperature difference between the sample to be measured and a reference material and outputting the detected temperature difference as a heat flow difference signal are provided. In the differential scanning calorimeter, a metal of the same type as the metal forming the furnace body is arranged between the heater and the furnace body.

  As described above, according to the differential scanning calorimeter of the present invention, the same type of metal as the metal forming the furnace body is disposed between the heater and the furnace body. It can be managed accurately, and the sample to be measured can be measured with high accuracy.

(Means and effects for solving other problems)
In the differential scanning calorimeter of the present invention, the metal forming the furnace body may be silver.
According to the differential scanning calorimeter of the present invention, since the furnace body is silver, deterioration due to oxidation can be prevented.
Furthermore, in the differential scanning calorimeter of the present invention, the heater may be a sheathed heater.

It is the schematic of DSC which concerns on this invention. It is the schematic of conventional DSC. It is a figure for demonstrating the response time in DSC.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

FIG. 1 is a schematic diagram showing a DSC according to the present invention. Fig.1 (a) is a top view which shows DSC, FIG.1 (b) is sectional drawing of the AA line shown to Fig.1 (a). In addition, illustration of the lid | cover 24 is abbreviate | omitted in Fig.1 (a). In addition, the same reference numerals are given to the same components as the DSC 101 described above.
The DSC 1 includes a thermal plate 10 having a silver mounting plate 11, a silver furnace body 20, a sheathed heater 30 wound around the outer periphery of the furnace body 20, and a temperature difference between the sample S to be measured and the reference material B. And a differential heat flow detector 40 that outputs the detected temperature difference as a heat flow difference signal, a temperature control thermocouple 50 that detects the temperature of the furnace body 20 and outputs the detected temperature as a temperature signal, and control Part (not shown).

In the space between the sheathed heater 30 and the furnace body 20, the same type of metal 60 as the metal forming the furnace body 20 is disposed. That is, there is no air in the space between the sheathed heater 30 and the furnace body 20.
Here, an example of the manufacturing method which arrange | positions the silver 60 which is the same kind of metal as the metal which forms the furnace body 20 between the sheathed heater 30 and the silver furnace body 20 is demonstrated.
Such a manufacturing method includes a preparation step (A) for preparing a silver furnace body 20 and silver clay, and after applying silver clay to the outer peripheral surface of the furnace body 20, a sheathed heater 30 is applied to the outer peripheral surface of the furnace body 20. The winding process (B) which winds and the baking process (C) which bakes silver clay are included.

(A) Preparation Step A silver furnace body 20 and silver clay are prepared.
Silver clay contains silver particles, water, and a binder. In addition, after modeling in the state of clay using silver clay, the moisture is evaporated by drying, and the binder is burned away by baking at a high temperature, so that the final purity is about 99.9% by weight or more. Only silver will remain.

(B) Winding process After applying silver clay to the outer periphery of the furnace body 20 with a thickness of 0.5 mm to 1 mm, the sheathed heater 30 is wound around the outer peripheral surface of the furnace body 20. At this time, silver clay is disposed so that no space is formed between the sheathed heater 30 and the furnace body 20.
(C) Baking process After the silver clay is dried, it is baked at a high temperature (for example, 650 ° C. to 750 ° C.). As a result, a structure in which silver is disposed between the sheathed heater 30 and the furnace body 20 is obtained.

  As described above, according to DSC 1, since silver, which is the same type of metal 60 as the metal forming the furnace body 20, is disposed between the sheathed heater 30 and the furnace body 20, the furnace body 20. By accurately controlling the temperature, the sample S to be measured can be measured with high accuracy.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<Example 1> Silver clay (A) preparation step A furnace 20 having a silver cylindrical shape with an inner diameter of 30 mm, an outer diameter of 35 mm, and a height of 20 mm is prepared, and silver clay containing silver particles, water, and a binder (Aida A product name “Art Clay Silver 650” manufactured by Chemical Industry Co., Ltd.) was prepared.
(B) Winding process After applying silver clay to the outer peripheral surface of the furnace body 20 with a thickness of 5 mm, a tubular sheathed heater 30 having a diameter of 1 mm was wound around the outer peripheral surface of the furnace body 20.
(C) Baking process After the silver clay was dried, the DSC according to Example 1 was obtained by baking at 700 ° C.

Comparative Example 1 Graphite Sheet (A) Preparation Step A furnace body 20 having a silver cylindrical shape with an inner diameter of 30 mm, an outer diameter of 35 mm, and a height of 20 mm was prepared, and a graphite sheet having a thickness of 0.4 mm was prepared.
(B) Winding Step After winding a graphite sheet around the outer peripheral surface of the furnace body 20, a DSC according to Comparative Example 1 is obtained by winding a tubular sheathed heater 30 having a diameter of 1 mm around the outer peripheral surface of the furnace body 20. It was.

<Comparative Example 2> Boron nitride (BN) powder A DSC according to Comparative Example 2 was obtained in the same manner as in Example 1 except that boron nitride (BN) powder was used instead of silver clay in Example 1. .

<Comparative example 3> Metal putty (SUS blend)
A DSC according to Comparative Example 3 was obtained in the same manner as in Example 1 except that metal putty was used instead of silver clay in Example 1.

<Comparative example 4> Heat transfer cement DSC which concerns on the comparative example 4 was obtained like Example 1 except having used the heat transfer cement instead of the silver clay in Example 1. FIG.

<Evaluation> Measurement of response time In the DSCs according to Example 1 and Comparative Examples 1 to 4, the sheathed heater 30 was heated at 10 ° C./min and controlled to be turned off when the temperature reached 150 ° C. Then, each response time was measured with the time from when the sheathed heater 30 was turned off to when the temperature adjusting thermocouple 50 reached 150 ° C. as the response time. The results are shown in Table 1. In addition, FIG. 3 is a figure for demonstrating the response time in DSC.

<Evaluation> Durability In the DSCs according to Example 1 and Comparative Examples 1 to 4, the sheathed heater 30 is heated at 10 ° C./min and controlled to be turned off when the temperature reaches 700 ° C. Repeated times. Then, in each appearance, “whether it was oxidized” or “whether it was peeled off” was observed. The results are shown in Table 1. If there is no problem, “◯” is indicated. If there is a problem, “X” is indicated.

  As shown in Table 1, the response time of the DSC according to Example 1 was the shortest. Furthermore, the DSC according to Example 1 did not oxidize or peel off.

  The present invention can be used in a differential scanning calorimeter that measures how the physical properties of a sample to be measured change with temperature.

1: Differential scanning calorimeter 10: Thermal plate 11: Placement plate 11a: Measurement sample placement portion 11b: Reference material placement portion 11c, 11d: Outer peripheral edge portion 20: Furnace body 22: Joint portion 30: Seed heater 40 : Differential heat flow detector 60: Metal

Claims (3)

A thermosensitive plate having a metal mounting plate having a measured sample mounting portion on which the measured sample is mounted, a reference material mounting portion on which the reference material is mounted, and an outer peripheral edge;
A metal furnace body formed with a joint portion to which the outer peripheral edge portion of the mounting plate is joined;
In order to conduct heat to the mounting plate, the heater wound around the outer periphery of the furnace body,
A differential scanning calorimeter comprising a differential heat flow detector for detecting a temperature difference between the sample to be measured and a reference material and outputting the detected temperature difference as a heat flow difference signal,
A differential scanning calorimeter, wherein the same type of metal as the metal forming the furnace body is disposed between the heater and the furnace body.   The differential scanning calorimeter according to claim 1, wherein the metal forming the furnace body is silver.   The differential scanning calorimeter according to claim 1, wherein the heater is a sheathed heater.

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