Thermomechanical Analysis Device

Abstract

To provide a thermomechanical analyzer with improved measurement accuracy when using a sample stage. [Solution] A thermomechanical analyzer 1 comprises a sample stage 15 on which a sample S is placed, a sample tube 11 on which the sample stage is placed and which is fixed to the measurement system, a probe 10 extending in the axial direction L with one end of itself in direct or indirect contact with the sample and applying a load to the sample, and heating furnaces 12a, 12b for heating the sample, wherein the sample stage and the sample tube are provided with engaging parts 11s, 15E, respectively, which engage with each other to position the sample stage.

Description

Technical Field

[0001] The present invention relates to a thermomechanical analyzer for measuring the thermal behavior of a sample.

Background Art

[0002] Conventionally, as a method for evaluating the temperature characteristics of a sample, there has been a method called thermal analysis in which the sample is heated and the thermal behavior (physical change) of the measurement sample accompanying the temperature change is measured. Thermal analysis is defined in JIS K 0129:2005 "General Rules for Thermal Analysis", and all methods for measuring the physical properties of a measurement sample when the temperature of the temperature is programmed are regarded as thermal analysis. Commonly used thermal analysis includes (1) differential thermal analysis (DTA) for detecting temperature (temperature difference), (2) differential scanning calorimetry (DSC) for detecting heat flow difference, (3) thermogravimetry (TG) for detecting mass (weight change), (4) thermomechanical analysis (TMA) for detecting mechanical properties, and (5) dynamic viscoelasticity measurement (DMA).

[0003] Among these, thermomechanical analysis (TMA) applies a load to the sample with a probe and detects the shape change of the sample at that time as the displacement of the probe (see, for example, Patent Documents 1 and 2). Thereby, the elastic modulus and expansion rate of the sample can be measured as functions of temperature or time. Here, a thermomechanical analyzer (TMA) includes a sample tube (reference tube) fixed to the measurement system, and the sample is placed directly or indirectly on this sample tube via a sample stage. Then, by bringing the probe into contact with the sample, a load is applied to the sample and various measurements are performed.

[0004] This sample tube (reference tube) usually has a cylindrical shape, and in a state where the sample is held inside or on top of itself, the expansion / compression and needle penetration measurement modes can be performed by pressing the sample with a probe. Furthermore, as described in Patent Document 2, the opening 11k shown in Figure 3 may be provided on the side of the sample tube 11, or a slit 11s may be provided on the bottom surface of the sample tube 11. Then, the chuck 4b can be locked into the slit 11s, and the film-like sample S2 can be clamped between the chucks 4a and 4b to perform tensile measurement. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 2909922 [Patent Document 2] Patent No. 3370620 [Overview of the project] [Problems that the invention aims to solve]

[0006] Incidentally, as described in Patent Document 1, a sample stage is sometimes placed on the sample tube, and the sample is placed on the sample stage. By placing the sample in the sample tube via the sample stage, the sample tube and the sample do not come into direct contact, thus suppressing contamination of the sample tube. However, the sample stage may move when the sample is placed, when the sample tube is moved up and down after the sample is placed, or even slight vibrations when closing the heating furnace surrounding the sample tube may cause the sample stage to move, potentially reducing measurement accuracy.

[0007] This invention was made to solve the above-mentioned problems and aims to provide a thermomechanical analyzer with improved measurement accuracy when using a sample stage. [Means for solving the problem]

[0008] To achieve the above objective, the thermomechanical analyzer of the present invention comprises a sample stage on which a sample is placed, a sample tube on which the sample stage is placed and fixed to a measurement system, a probe extending in the axial direction with one end of itself in direct or indirect contact with the sample and applying a load to the sample, and a heating furnace for heating the sample, wherein the sample stage and the sample tube are each provided with engaging parts that engage with each other to position the sample stage.

[0009] This thermomechanical analyzer allows the sample stage to be positioned in a predetermined location on the sample tube by the engaging mechanism, and the sample stage can be securely locked to the sample tube. This suppresses movement of the sample stage during measurement and improves measurement accuracy when using a sample stage.

[0010] In the thermomechanical analyzer of the present invention, a slit for engaging a chuck for tensile measurement is formed on the bottom surface of the sample tube, and the slit becomes one of the engaging parts. The sample stage is placed on the bottom surface of the sample tube, and a projection that fits into the slit may be formed on the bottom surface of the sample stage as the other of the engaging parts. This thermomechanical analyzer allows for the effective application of the present invention to sample tubes that can also be used for tensile measurements. [Effects of the Invention]

[0011] According to the present invention, a thermomechanical analyzer with improved measurement accuracy when using a sample stage can be obtained. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the configuration of a thermomechanical analyzer according to an embodiment of the present invention. [Figure 2] This is a perspective view showing the sample tube. [Figure 3] This is a perspective view showing an example of using a sample tube for tensile testing. [Figure 4] This is a perspective view showing the sample stage. [Figure 5] This is a perspective view showing a modified sample stage. [Figure 6] It is a top view showing a mode in which the sample stage of FIG. 5 is placed on a sample tube. [Figure 7] It is a perspective view showing yet another modification of the thermomechanical analyzer and the sample stage.

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a thermomechanical analyzer 1 according to an embodiment of the present invention. The thermomechanical analyzer 1 includes a sample stage 15 on which a sample S is placed, a sample tube 11 on which the sample stage 15 is placed and fixed to a measurement system (frame 14), a rod-shaped probe 10 extending in the axial direction L (the vertical direction in FIG. 1), a load generator 5 that generates a load in the axial direction L of the probe 10, a load transmission shaft 17 that connects between the load generator 5 and the probe 10, displacement detectors 6a to 6b that detect displacement in the axial direction L of the probe 10, and heating furnaces 12a and 12b for heating the sample S.

[0014] Each member of the thermomechanical analyzer 1 is supported by the frame 14. Further, a bottomed cylindrical sample tube (also referred to as a reference tube and a sample holding member) 11 extends downward (toward the sample S) from the frame 14, and a cylindrical sample stage 15 is placed on the bottom surface 11b of the sample tube 11. And in this example, one end side (lower end) of the probe 10 directly contacts the upper end of the sample S placed on the sample stage 15 so as to apply a load to the sample S. Furthermore, a thermocouple 22 for temperature measurement is arranged near the sample S.

[0015] The load transmission shaft 17 is rod-shaped and extends in the axial direction L. The upper end (one end) is fixed (connected) to the load generator 5, and a connection joint 17c is provided at the lower end (the other end). Although not shown, the load generator 5 includes a coil and a magnetic circuit composed of a permanent magnet surrounding the coil. When an electric current flows through the coil, it is displaced in the axial direction L to generate a load.

[0016] On one side, a probe joint 10c is connected to the other end (upper end) of the probe 10. By connecting the connection joint 17c to the probe joint 10c, the load of the load generator 5 is transmitted to the probe 10. The probe 10 and the load transmission shaft 17 are coaxially connected.

[0017] Also, along the axial direction L, a core (magnetic material) 6b made of a conductor is fixed to the outer periphery of the portion of the load transmission shaft 17 between the connection joint 17c and the load generator 5, and a differential transformer (primary coil and secondary coil) 6a is arranged around the core 6b. Further, a detector 6c detects the voltage of the differential transformer 6a. When the temperature is changed and the length of the sample S changes due to thermal expansion, if the position of the core 6b (and thus the probe 10) changes with respect to the differential transformer 6a, a voltage is generated in the differential transformer 6a according to the displacement. Therefore, the displacement of the core 6b (and thus the probe 10) in the axial direction L can be detected. These differential transformer 6a and core 6b constitute a "displacement detector".

[0018] Around the sample S, a heating furnace composed of a furnace body 12a and a heater 12b arranged around the furnace body 12a is provided, and the temperature of the heating furnace is controlled by a predetermined control unit.

[0019] The load signal generator 20 generates a load signal for operating the load generator 5. The load signal generator 20 is, for example, an electronic circuit in which various electronic components and chips are mounted on a circuit board. An analog signal is output from the load signal generator 20 to the load generator 5, and a predetermined load is generated.

[0020] The load generated by the load generator 5 is applied to the sample S via the load transmission shaft 17 and the probe 10. On the other hand, the displacement and the like generated in the sample S due to this load are transmitted to the core 6b through the probe 10 and the load transmission shaft 17, and are detected as the displacement of the position of the core 6b with respect to the differential transformer 6a.

[0021] The displacement detection signals from the differential transformer 6a and core 6b are sent to the detector 6c and converted into a displacement signal. The displacement signal, which is the output of the detector 6c, is sent to the arithmetic unit 9, and together with the load signal previously input to the load signal generator 20, the physical quantities (mechanical properties) of the sample S are calculated.

[0022] Specifically, in this example, a load is applied to the sample S using probe 10 as part of thermomechanical analysis (TMA), and the resulting change in the shape of the sample S (such as a change in length) is determined as a physical quantity. Furthermore, this invention applies to various measurements in expansion / compression and penetration measurement modes (e.g., linear thermal expansion coefficient, glass transition temperature, etc.), but does not apply to tensile measurements.

[0023] Here, as shown in Figure 2, the sample tube 11 is substantially cylindrical in shape and extends in the axial direction L, has an opening 11k at the front of the side surface of the sample tube 11, and a rectangular slit 11s is provided at the bottom surface 11b of the sample tube 11. Furthermore, the side surface 11w of the sample tube 11, excluding the opening 11k, surrounds the bottom surface 11b in an arc shape. A notch, the slit 11s, is opened on the side of the bottom surface 11b facing the opening 11k.

[0024] Furthermore, the sample stage 15 is placed on the bottom surface 11b so as to cover the slit 11s. The sample S is then installed or replaced by opening the heating furnace, lowering the sample tube 11, and inserting or removing the sample S through the opening 11k. After that, the sample tube 11 is moved to an appropriate position to match the axial length L of the sample S, the heating furnace is closed, and the measurement is performed. As shown in Figure 3, the sample tube 11 can be used for tensile measurement in this embodiment. However, as previously stated, tensile measurement is not the target of this embodiment.

[0025] Next, the distinctive features of the present invention will be described. As shown in Figures 2 and 4, in the thermomechanical analyzer 1 of the present invention, a projection 15E is provided on the lower surface of the sample stage 15 opposite to the upper surface 15a of the sample stage 15, projecting downward in a rectangular shape. The outer shape of this projection 15E is slightly smaller than the size of the slit 11s in the bottom surface 11b of the sample tube 11.

[0026] Therefore, as shown in Figure 2, when the sample stage 15 is placed over the bottom surface 11b of the sample tube 11 and the projection 15E of the sample stage 15 is inserted through the notch of the slit 11s, the projection 15E fits into the slit 11s and engages with each other. This allows the sample stage 15 to be positioned in a predetermined location on the sample tube 11 and securely locked to the sample tube 11, thereby improving the measurement accuracy when using the sample stage 15. Furthermore, the projection 15E and the slit 11s correspond to the "engaging portion" in the claims, respectively.

[0027] Furthermore, it is preferable to use the same material for the sample stage 15, sample tube 11, and probe 10, as this minimizes measurement errors. Examples of materials for the sample stage 15, sample tube 11, and probe 10 include quartz glass and alumina. In the above embodiment, the projection 15E and the slit 11s were described as examples of the "engaging portion," but the slit 11s may also have a concave shape that engages with the projection 15E.

[0028] Figures 5 and 6 show modified versions of the sample stage 150. As shown in Figures 5 and 6, the sample stage 150 integrally comprises a disc-shaped base portion 150m having a contact surface (upper surface) 150a with respect to the sample S, and a side wall portion 150w that slopes downward from a part of the outer edge of the base portion 150m (in Figure 5, the approximately semicircular portion on the near side of the paper). Then, by placing the sample stage 150 over the bottom surface 11b of the sample tube 11 and inserting the sample stage 150 through the opening 11k of the sample tube 11, the semi-circular side wall portion 150w comes into contact with the semi-circular front wall portion 11f of the bottom surface 11b of the sample tube 11 from the outside.

[0029] This allows the sample stage 150 to be positioned in a predetermined location on the sample tube 11 and securely locked to the sample tube 11, thereby improving the measurement accuracy when using the sample stage 150. Furthermore, the side wall portion 150w and the front wall portion 11f correspond to the "engaging portion" in the claims, respectively.

[0030] Figure 7 shows yet another modified example of the thermomechanical analyzer and sample stage 250. Here, the thermomechanical analyzer in Figure 7 is identical to the thermomechanical analyzer 1 in Figure 1, except for the configuration of the sample tube 110 and the probe 100, so the explanation of the other components will be omitted.

[0031] As shown in Figure 7, the sample tube 110 is cylindrical, and the sample S is placed on its upper end surface (upward surface) 110a via the sample stage 250. On the other hand, the probe 100 is a rod-shaped device that extends in the axial direction L (up and down direction in Figure 1), with one end (upper end) bent downwards in a U-shape. The load generator is installed below the probe 100, and when the load generator pushes the probe 100 downwards, the upper end 100s of the U-shaped probe 100 applies a downward load to the sample S.

[0032] Here, the upward surface (the surface in contact with the sample) 110a of the sample tube 110 is provided with a cylindrical protrusion 110p. On the other hand, the sample stage 250 is disc-shaped, and a circular recess 250r is formed on its lower surface (the surface facing the upward surface 110a). This recess 250r is slightly larger in diameter than the protrusion 110p.

[0033] Then, by placing the sample stage 250 over the upward surface 110a of the sample tube 110, the recessed portion 250r engages with the convex portion 110p. This allows the sample stage 250 to be positioned in a predetermined location on the sample tube 110 and securely locked to the sample tube 110, thereby improving the measurement accuracy when using the sample stage 250. Furthermore, the recessed portion 250r and the protruding portion 110p correspond to the "engaging portion" in the claims, respectively.

[0034] The present invention is not limited to the embodiments described above. For example, the shape of the sample stage or sample tube is not limited. Furthermore, the number and shape of the engaging parts are not limited. [Explanation of Symbols]

[0035] 1 Thermomechanical analyzer 10, 100 probes 11, 110 sample tubes 11b Bottom surface of the sample tube 11s, 15E, 11f, 150w, 110p, 250r engaging part 11s Engagement part (slit) 15E Engagement part (protrusion) 12a, 12b Furnace S sample L axis direction

Claims

1. A sample stand on which the sample is placed, The sample tube is placed on the aforementioned sample stage and fixed to the measurement system, A probe that extends in the axial direction, with one end of itself in direct or indirect contact with the sample, and applies a load to the sample, A heating furnace for heating the aforementioned sample, In a thermomechanical analyzer equipped with, A thermomechanical analyzer characterized in that the sample stage and the sample tube are each provided with engaging parts that engage with each other to position the sample stage.

2. A slit is formed in the bottom surface of the sample tube for engaging a chuck for tensile measurement. The slit becomes one of the engagement portions, The thermomechanical analyzer according to claim 1, characterized in that the sample stage is placed on the bottom surface of the sample tube, and a projection that fits into the slit is formed on the bottom surface of the sample stage as the other of the engaging portion.

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