thermocouple

Abstract

To provide a thermocouple capable of conducting a high-temperature measurement at lower cost.SOLUTION: The thermocouple has a metal conductor made of a Ru alloy containing Ru (ruthenium) in a concentration of at least 50 at%. The Ru alloy has a solid-phase line temperature of at least 1700°C. The other metal or alloy of the thermocouple has a metal point temperature or a solid-phase line temperature of at least 1700°C. The thermocouple, which includes the Ru alloy and one of the metal and the alloy, has a thermoelectric power of at least 0.1μV / K in a certain temperature region.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermocouple.

Background Art

[0002] In the manufacture of semiconductor devices using nitride semiconductors, temperature control is performed in a high-temperature range of 2000°C, and highly accurate temperature measurement in such a high-temperature region is required. As a thermocouple capable of measuring such high temperatures, for example, an iridium-iridium rhodium thermocouple is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-mentioned thermocouple generally uses expensive metal materials. For example, the prices of Ir and Rh are about 8 to about 30 times that of Ru, and there is a problem of high cost.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a thermocouple capable of measuring high temperatures at a lower cost.

Means for Solving the Problems

[0006] One of the thermocouples according to the present invention is composed of a Ru alloy in which the ratio of Ru is 50 at% or more.

[0007] In one configuration example of the thermocouple, the Ru alloy has a solidus temperature of 1700°C or higher.

[0008] In one configuration example of the thermocouple, the other metal or alloy has a melting point or solidus temperature of 1700°C or higher.

[0009] In one configuration example of the thermocouple, the Ru alloy is Ru 1-x M x (0 < x ≤ 0.5, M is at least one or more elements in the group of A, B, C, D), A is a platinum group element group including Rh, Pd, Re, Ir, Pt, B is a refractory metal element group including Nb, Mo, Hf, Ta, W, C is a transition metal group, and D is a typical element and rare earth element group.

Advantages of the Invention

[0010] As described above, according to the present invention, since one is composed of a Ru alloy in which the ratio of Ru is 50 at% or more, a thermocouple capable of performing high-temperature measurement at a lower cost can be provided.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is a characteristic diagram showing the thermoelectromotive force characteristics of the thermocouples of Examples 1, 2, and 3.

Modes for Carrying Out the Invention

[0012] Hereinafter, the thermocouple according to an embodiment of the present invention will be described. This thermocouple is composed of a Ru alloy in which the composition ratio of Ru (ruthenium) on one side is 50 at% or more. The Ru alloy has a solidus temperature of 1700°C or higher. Also, the other metal or alloy constituting the thermocouple has a melting point or solidus temperature of 1700°C or higher. Further, the thermocouple composed of a combination of one Ru alloy and the other metal or alloy has a thermoelectric power of 0.1 μV / K or more in a certain temperature range.

[0013] The Ru alloy is Ru 1-x M x(0 < x ≤ 0.5, where M is at least one element from the group of A, B, C, and D). Here, A can be a group of platinum group elements including Rh, Pd, Re, Ir, Pt; B can be a group of refractory metal elements including Nb, Mo, Hf, Ta, W; C can be a group of transition metals; and D can be a group of typical elements and rare earth elements. The group of transition metal elements can be, for example, V, Cr, Mn, Fe, Ni, Cu, Ag, Au, Sc, Ti, Zr. The group of typical elements and rare earth elements can be, for example, Li, B, C, Na, Mg, Ca, Al, Si, P, S, Sn, Pb, Y, La, Ce, Gd, Tb, Dy, Yb, Lu.

[0014] Also, the other metal can be, for example, Pt. Also, the other metal can be, for example, Ir. Also, the other metal can be, for example, Ru. Also, the other alloy can be Pt·Rh.

[0015] For example, a thermocouple can be constituted by the wire of the Ru alloy described above and the wire of a metal or alloy having a melting point or solidus temperature of 1700 °C or higher and a thermoelectric power of 1 μV / K or higher. Each wire can be produced, for example, by the micro-pulling method (see Patent Document 2).

[0016] Hereinafter, it will be described in detail using examples. Thermocouples were fabricated using the wire of pair 1 and the wire of pair 2 with the compositions of Examples 1 to 10 shown in Tables 1, 2, and 3 below. Also, for comparison purposes, a thermocouple of Comparative Example 1 was also fabricated.

[0017]

Table 1

[0018]

Table 2

[0019]

Table 3

[0020] The characteristics of the thermocouples shown in the comparative examples and examples are shown in Table 4.

[0021] [Table 4]

[0022] As an example, Figure 1 shows the thermoelectric power (EMF) characteristics of the thermocouples in Examples 1, 2, and 3. The thermocouples in Examples 1, 2, and 3 were compared with calibrated Class 1 R thermocouples using a tubular furnace and ice water reference junction. In this comparison, the thermoelectric power characteristics of the thermocouples composed of pairs 1 and 2 in Examples 1, 2, and 3 were measured using a nanovoltmeter, and the thermoelectric power characteristics of Examples 1, 2, and 3 were determined as the relative characteristics of pair 1 to pair 2. For the analysis, measurement points with a temperature change rate of less than 0.05 K / s were used.

[0023] As explained above, according to the present invention, since one of the components is made from a Ru alloy with a Ru content of 50 at% or more, the thermocouple can be constructed from a Ru-based alloy that is more readily available at a lower cost, thus providing a thermocouple capable of high-temperature measurement at a lower cost. Ru has the advantage of having a high melting point (2334°C) and being chemically stable. Furthermore, Ru is much cheaper than Ir or Rh, costing only a fraction to a tens of times less. Thus, by using ruthenium, a thermocouple can be provided at a lower cost.

[0024] It should be noted that the present invention is not limited to the embodiments described above, and it is clear that many modifications and combinations can be implemented within the technical concept of the present invention by those with ordinary skill in the art.

Claims

1. A thermocouple in which one end is composed of a Ru alloy with a Ru ratio of 50 at% or more, and the other end is composed of an alloy with a Pt ratio of 78 at% and a Rh ratio of 22 at%.

2. In the thermocouple according to claim 1, The Ru alloy is characterized by having a solidus temperature of 1700°C or higher.

3. In the thermocouple according to claim 1 or 2, The thermocouple is characterized in that the other metal or alloy has a melting point or solidus temperature of 1700°C or higher.

4. In the thermocouple according to any one of claims 1 to 3, The Ru alloy is Ru 1-x M x A thermocouple characterized by (0 < x ≤ 0.5, M is at least one element from groups A, B, C, and D), where A is the platinum group elements including Rh, Pd, Re, Ir, and Pt; B is the refractory metal elements including Nb, Mo, Hf, Ta, and W; C is the transition metals; and D is the main group elements and rare earth elements.

Images