WO2007145234A1

WO2007145234A1 - Reflector, method for manufacturing the reflector, and heater unit and furnace using the reflector

Info

Publication number: WO2007145234A1
Application number: PCT/JP2007/061868
Authority: WO
Inventors: Kenji Tanaka; Kimio Kitamura
Original assignee: Teitokusha Co., Ltd.
Priority date: 2006-06-13
Filing date: 2007-06-13
Publication date: 2007-12-21
Also published as: JP4681051B2; JPWO2007145234A1

Abstract

Provided is a reflector which can maintain reflection performance even in a high-temperature atmosphere, has excellent reflection wavelength characteristics and can be manufactured at a low cost. A method for manufacturing such reflector, and a heater unit and a furnace using such reflector are also provided. One side of a base material, such as steel material or ceramics, is coated with a noble metal layer through an intermediate layer. Heat rays are reflected by the noble metal layer. The one side of the base material faces a high temperature atmosphere, and an intermediate layer (3b) is composed of frit. The thickness of the intermediate layer (3b) can eliminate a difference between the thermal expansion of the noble metal layer (3c) and that of the base material (3a) in the high temperature atmosphere and maintain the noble metal layer (3c).

Description

Specification

REFLECTOR, MANUFACTURING METHOD THEREFOR, HEATER UNIT AND FURNACE USING THE SAME

[0001] The present invention provides a noble metal layer by coating on the negative side of a base material such as a steel material or ceramics through an intermediate layer, a reflector that reflects heat rays by the noble metal layer, a manufacturing method thereof, and the use thereof. Heater unit and furnace.

Background art

[0002] As the above-described reflector, for example, those described in the following Patent Documents 1 to 4 are known.

Patent Document 1: Japanese Patent Laid-Open No. 7-111183

Patent Document 2: JP-A-7-114973

Patent Document 3: JP 2001-201062

Patent Document 4: Japanese Patent Application Laid-Open No. 2004-211703

[0003] In Patent Documents 1 and 2, when gold is coated on the surface of stainless steel as a base material, Cr and Ni in the stainless steel diffuse into the gold and the reflection performance is impaired. An intermediate layer such as silicon oxide or aluminum oxide is provided, and a gold coating is provided thereon. However, in the techniques described in these, since the intermediate layer is formed by the same method as the noble metal layer, the cost is increased, and the strength and the heat resistant temperature are insufficient.

[0004] In Patent Document 3, heat resistance is ensured by surrounding a metal film layer with a quartz protective layer. However, since the heat rays are reflected through the protective layer made of quartz, there is an inconvenience that the reflected heat rays have a limited wavelength due to the wavelength absorption characteristic of the protective layer.

[0005] In Patent Document 4, although heat resistance is improved, there is a problem in that the cost increases due to the provision of a ceramic thin film layer and its mirror finish.

Disclosure of the invention

Problems to be solved by the invention

[0006] In view of the conventional situation that has been used, the present invention is capable of maintaining reflection performance even under a high-temperature atmosphere, having a good reflection wavelength characteristic, and a reflector that can be manufactured at low cost. It is an object of the present invention to provide a manufacturing method and a heater unit and a furnace using the same. Means for solving the problem

[0007] In order to achieve the above object, the reflector according to the present invention is characterized in that a noble metal layer is provided by coating on the negative side of a base material such as steel or ceramics through an intermediate layer, and heat rays are reflected by the noble metal layer. The one side faces a high temperature atmosphere, the intermediate layer is constituted by a frit, and the thickness of the intermediate layer absorbs a difference in thermal expansion between the noble metal layer and the base material in the high temperature atmosphere. In addition, the thickness is sufficient to maintain the noble metal layer.

[0008] It is desirable to apply a liquid frit after forming an oxide film on the one side by heat-treating the substrate.

[0009] The intermediate layer may be formed by applying a liquid frit to the substrate and then baking. In addition, the coating may be performed by at least one method selected from foil sticking, paste, resinate, plating, vapor deposition, sputtering, and ion plating power. The noble metal layer is preferably Pt, Au or Pd.

[0010] A feature of the heater unit using the reflector according to any one of the above is that it further includes a heating element that radiates heat rays to the reflector.

[0011] A feature of the furnace using the reflector according to any one of the above is that the reflector is used as a furnace wall, and heat rays of the heating element are reflected on the heated body by the noble metal layer of the reflector. Or heating by direct radiation.

[0012] On the other hand, in the method for manufacturing a reflector according to any one of the above features, a liquid frit is applied to the substrate, the intermediate layer is formed by baking, and the noble metal layer is further formed by coating. It is characterized by forming. In addition, any of the other reflector manufacturing methods described above is characterized in that a liquid frit is applied to the substrate, the foil is brought into close contact before the frit is dried, and then baked. .

The invention's effect

[0013] According to the characteristics of the reflector according to the present invention, the method for manufacturing the same, and the heater unit and furnace using the reflector, an inexpensive and easy-to-handle material called a frit is used, and the flexibility of the frit is used to make a precious metal. Absorbing the difference in thermal expansion between the layer and the substrate, a highly durable reflective surface that can maintain reflective performance even at high temperatures has been obtained. Also, since the noble metal layer is supported using the flexibility of the frit, it is not necessary to provide a protective layer on the surface of the noble metal layer. It has become possible to provide an efficient reflecting surface with high reflection performance.

[0014] Other objects, configurations, and effects of the present invention will be apparent from the following embodiments of the present invention.

Brief Description of Drawings

FIG. 1 is a schematic view of a furnace using a reflector.

FIG. 2 is a longitudinal sectional view of a reflector.

FIG. 3 is a schematic diagram of a furnace incorporating a heater unit using a reflector.

Explanation of symbols

[0016] 1: furnace, 2: furnace wall, 3: reflector, 4: electric heating element, 5: inner surface, 6: inside, 7: reflector, 8: heater unit, 100: heated object, RA: Direct heating wire, RB: Reflection heating wire

BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be described in more detail with reference to the accompanying drawings as appropriate.

As shown in FIG. 1, in the furnace 1 using the reflector 3, the inner surface 5 which is one side of the furnace wall 2 is a mirror surface, and the electric heating element 4 is located in the interior 6 thereof. Internal 6 has a high temperature atmosphere of 800 ° C or higher due to the heat generated by the electric heating element 4, and the heated body 100 is further heated by the direct heat rays RA from the heating element 4 and the heat rays RB reflected by the inner surface 5. . The reflector 3 according to the present invention is required to endure the high temperature atmosphere and maintain the mirror surface state of the inner surface 5.

As shown in FIG. 2, the reflector 3 is formed by forming an intermediate layer 3b by frit on a base material 3a and further forming a noble metal layer 3c. The substrate 3a is made of stainless steel, Fe—Cr—A1 alloy, heat resistant steel, ceramics or the like.

[0019] The intermediate layer 3b is a thin film formed by applying an aqueous solution of frit powder, drying, and melting at a baking temperature. For the frit composition, Na O— B O— SiO— Al O, etc. are used.

In addition, CaO, BaO, K 2 O, Li 2, PbO, etc. may be included. As a frit,

twenty two

Thermal expansion coefficient is ^{^{5 X 10- 6 ~15 X 10- 6}} , can be used for liquid catalyst at baking temperatures.

[0020] As the noble metal layer, Pt, Au, or Pd can be used. The coating of the noble metal layer is performed by at least one method selected from foil sticking, paste, resinate, plating, vapor deposition, sputtering and ion plating force. [0021] The frit of the intermediate layer is required to have a thickness that absorbs the difference in thermal expansion coefficient between the base material and the noble metal layer. If it is too thin, adhesion will be insufficient and the difference in thermal expansion cannot be absorbed, or if the base material is a steel material such as stainless steel or an alloy, the base material components such as Fe and Cr will diffuse into the noble metal layer 3c. As a result, it becomes dark and disturbs the reflection performance. On the other hand, if the thickness is too thick, the softness of the frit acts on the minus and the noble metal layer 3c flows or peels and cannot be supported.

[0022] According to the inventors' experiment, it is considered that the thickness of the intermediate layer 3b is 0.05 to 200 μm or less as a calculated value. This thickness can be obtained by calculation from, for example, the coating area, etc. when the liquid frit is about 8% solid content.

[0023] The thermal expansion coefficients of the base material, the intermediate layer, and the noble metal layer are as shown in Table 1 below.

[0024] [Table 1]

[0025] As the intermediate layer 3b, those having an intermediate thermal expansion coefficient between the base material and the noble metal layer capable of absorbing other thermal expansion differences can be used. In particular, it is desirable that the intermediate layer 3b be in a molten state at a particularly high temperature and can absorb the difference in thermal expansion coefficient, such as a frit. In addition, it is desirable that the base material and the noble metal layer have a close thermal expansion coefficient. For example, if an Au layer is provided for steel materials such as stainless steel and alloys, and a Pt layer is provided for ceramics, the burden on the intermediate layer is reduced.

[0026] During production, the surface of the substrate 3a is brushed with a frit aqueous solution and dried. Thereafter, the frit is baked and melted to form the intermediate layer 3b, and a noble metal film is formed thereon by the method such as the above-mentioned method. In addition, it is desirable to heat-treat the base material 3a to form an oxide film on the surface of the base material 3a, and then brush the surface with the aqueous frit solution. This is because the adhesion between the base material and the frit can be improved by forming the oxide film. In the case of foil sticking, the foil may be brought into close contact before the frit is dried and then baked. [0027] The liquid frit may be applied by spraying or dipping in addition to brushing. In addition to water, various organic solvents can be used as the frit solvent. However, in the case of foil sticking, it is necessary to use water as a solvent because the foil needs to be in close contact before the frit dries. Therefore, in the case of foil sticking, an organic solvent may be used as long as it has a drying rate comparable to that of water.

Next, a heater unit using a reflector will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the member similar to said embodiment. Here, the heater unit 8 comprises an electric heating element 4 and a reflector 7 and is incorporated in the furnace 1. In the reflector 7, the inner surface 5 on the side of the electric heating element 4 is a mirror surface, and as in the above embodiment, the heated object 100 is heated directly from the heating element 4 RA and reflected from the inner surface 5. Further heat with RB.

Example

[0029] As Example 1, a 100 mm square stainless steel base material 3a was prepared, baked at 900 ° C to form a frit layer 3b, a Pt thin film 3c was formed by vapor deposition, and heat resistant at 850 ° C for 500 hours. A test was conducted. Also, as Examples 2 and 3, a 100 mm square stainless steel base 3a was prepared, and after applying a frit aqueous solution, Pt foil was pasted and dried, and baked at 900 ° C, and at 850 ° C. A 500 hrs heat resistance test was conducted. The results are shown in Table 2 below.

[0030] [Table 2]

On the other hand, the first comparative example is the same as the first example except that the same material as that of the first example is formed to a thickness shown in Table 3. The second and third comparative examples are the same as the second and third examples except that the same material as that of the second and third examples is formed to the thickness shown in Table 3. It is. The results are shown in Table 3.

[0032] [Table 3]

[0033] As shown in Tables 2 and 3, in each of the above examples, Pt as the noble metal layer was formed in a good state, and sufficient reflection performance was confirmed. However, in the first and third comparative examples, since the frit layer was too thin, Pt which is the noble metal layer was blackened. In the second comparative example, since the frit layer was too thick, Pt which is the noble metal layer was cut off, and even in the comparative example of V and deviation, sufficient reflection performance could not be obtained. .

[0034] From the above, it has been clarified that a reflective surface having excellent heat resistance can be obtained by using an intermediate layer having an appropriate thickness by frit.

Industrial applicability

The present invention can be used as a highly durable reflector capable of reflecting heat rays in a high-temperature atmosphere, in addition to furnace wall materials.

Claims

The scope of the claims

[1] A reflector in which a noble metal layer is provided by coating on the negative side of a base material such as steel or ceramics, and the heat ray is reflected by the noble metal layer, the one side facing a high temperature atmosphere The intermediate layer is made of frit, and the thickness of the intermediate layer is a thickness capable of absorbing the difference in thermal expansion between the noble metal layer and the base material and maintaining the noble metal layer in the high temperature atmosphere. A reflector characterized by that.

[2] The reflector according to [1], wherein a liquid frit is applied after an oxide film is formed on the one side by heat-treating the base material.

[3] The reflector according to claim 1, wherein the intermediate layer is formed by applying a liquid frit to the base material and then baking.

[4] The reflector according to claim 1, wherein the coating is performed by at least one method selected from foil sticking, paste, resinate, plating, vapor deposition, sputtering, and ion plating.

5. The reflector according to claim 1, wherein the noble metal layer is Pt, Au, or Pd.

6. A heater unit using the reflector according to any one of claims 1 to 5, further comprising a heating element that radiates heat rays to the reflector.

[7] A furnace using the reflector according to any one of claims 1 to 5, wherein the reflector is used as a furnace wall, and a heat ray of a heating element is applied to a heated body as a noble metal of the reflector. Furnace characterized in that heating is carried out by reflecting off the layer or by direct radiation.

[8] The method for producing a reflector according to any one of claims 1 to 5, wherein a liquid frit is applied to the base material, the intermediate layer is formed by baking, and further the noble metal is formed by the coating. A method for producing a reflector, comprising forming a layer.

[9] The method for producing a reflector according to any one of claims 1 to 5, wherein a liquid frit is applied to the base material, the foil is brought into close contact before the frit is dried, and then baking is performed. A method for producing a reflector, characterized in that: