JP2007112642A - Functionally gradient material, method for producing functionally gradient material and bulb - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an easily producible functionally gradient material for sealing in which the generation of cracks is suppressed by strengthening the coupling between layers. <P>SOLUTION: The functionally gradient material is provided with an insulating first functional material layer 1 essentially consisting of silicon oxide and a second functional material layer 2 composed of a mixture of silicon oxide and an electrically conductive substance, and having electric conductivity. In a state where the first and second functional material layers are mutually contacted, energizing pressurization is performed by a discharge plasma sintering process, thus the silicon oxide is melted and sintered, so as to couple the layers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a functionally gradient material, a method for producing the functionally gradient material, and a tube using the functionally gradient material as a sealing means.

  Conventionally, in a tube provided with an arc tube made of quartz glass such as a halogen bulb or a high-pressure discharge (HID) lamp, a foil sealing structure of an airtight container using a molybdenum foil is generally used. In recent years, there has been an increasing demand for high efficiency and miniaturization of these lamps. As a result, HID lamps are required to have further heat resistance, pressure resistance, and chemical resistance in the arc tube as the size and power density increase. On the other hand, in the halogen lamp, the temperature rise of the sealing portion becomes remarkable due to the high efficiency and miniaturization, and the lamp short life due to the oxidation of the Mo foil is a problem.

  However, for reasons such as the limit of the allowable current value in the sealed metal foil, attempts have been made to use functionally graded materials instead of the sealed metal foil.

  As countermeasures against such problems, the pressure resistance, heat resistance, and chemical resistance are improved by using a laser instead of a conventional burner at the time of sealing and precisely controlling the shape of the sealing portion. However, with the current sealing method using Mo foil as the sealing material, the sealing strength largely depends on the Mo material properties such as oxidation temperature and chemical resistance. With Mo foil sealing, the sealing strength and reliability It is not possible to expect a significant improvement.

  Further, a sealing material using a functionally graded material has been proposed to improve the reliability of the sealing portion (see, for example, Patent Document 1). However, since the conventional functional gradient material has a weak bond strength between the gradient material layers and has not been sufficiently reliable, such as cracking during use, there are almost no actual use examples.

Further, since the gradient material layer has a multilayer structure, the sealing portion tends to be large, and the manufacturing and the process are complicated and expensive.
JP 2000-260395 A

  The present invention solves the above-mentioned problems, is a functionally graded material that is highly reliable, small in size and easy to manufacture, a method for producing this functionally graded material, and a tube sealed using this functionally graded material The purpose is to provide.

  In order to solve the above problems, the functionally gradient material of the present invention is a mixture of an insulating first functional material layer mainly composed of silicon oxide, and a conductive material having a particle size of 15 μm or less. And a second functional material layer having electrical conductivity, and in a state where these first and second functional material layers are in contact with each other, by energizing and pressing by a discharge plasma sintering method, The silicon oxide is melted and sintered to bond the layers. There is no limitation on the particle size, and the particle size is in an appropriate range up to the submicron order particle size currently in practical use.

  In the functionally graded material of the present invention, the conductive substance in the second functional material is Mo or W, and the volume mixing ratio of the conductive substance to the silicon oxide is 15% or more. It is a feature.

  Furthermore, in the functionally gradient material of the present invention, at least one third functional material layer made of silicon oxide and a conductive substance is provided between the first functional material layer and the second functional material layer. The conductive material in the third functional material layer is made of Mo or W, and the volume mixing ratio of the conductive material to the silicon oxide of the conductive material is 15% or less. It is.

  Furthermore, the functionally graded material of the present invention is characterized by comprising a conductive electrode shaft that penetrates the first functional material layer and has one end inserted into the second functional material layer. Is.

  Furthermore, in the functionally graded material of the present invention, one end is inserted into the second functional material layer, and the other end is provided with a conductive feeding shaft led out from the second functional material layer. It is characterized by having.

  The tube of the present invention is characterized by using the functional gradient material as a sealing material.

  The method for producing a functionally gradient material according to the present invention comprises a step of forming an insulating first functional material layer mainly composed of silicon oxide, and a mixture comprising silicon oxide and a conductive substance. A step of forming a second functional material layer, and a step of energizing and pressing the first functional material layer and the second functional material layer in contact with each other by a discharge plasma sintering method. The silicon oxide is melted and sintered to bond the layers.

  In addition, the method for producing a functionally gradient material includes a step of forming an insulating first functional material layer mainly composed of silicon oxide, and a second conductive material comprising a mixture of silicon oxide and a conductive substance. Forming the functional material layer, and a conductive axis penetrating the first functional material layer and inserted into the second functional material layer, or the conductive axis and the second functional material layer. A step of providing a conductive axis inserted into the second functional material layer and led out to the outside from the second functional material layer; and a state in which the first and second functional material layers are in contact with each other, and discharge plasma sintering And a step of energizing and pressurizing by the method, and melting and sintering the silicon oxide, thereby bonding the layers.

  According to the present invention, these functions can be achieved by applying and pressurizing and firing the first and second functionally gradient material layers in contact with each other using the spark plasma sintering method (SPS). It is possible to melt and sinter silicon oxide that is commonly contained in the material gradient material layer, and to increase the bond strength between the layers. As a result, it is possible to obtain a functionally graded material that is highly reliable, small in size, easy to manufacture, and can be sufficiently put to practical use as a sealing material for a tube.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment in which the functionally gradient material of the present invention (hereinafter referred to as FGM) is applied to a sealing portion of a discharge lamp. In the present embodiment, the FGM is composed of an insulating first functional material layer 1 mainly composed of silicon oxide (hereinafter referred to as SiO ₂ ) and a mixture of SiO ₂ and a conductive substance and having conductivity. 2 functional material layers 2 and a third functional material layer 3 interposed between the first functional material layer 1 and the second functional material layer 3. The third functional material layer 3 is also composed of SiO ₂ and a conductive material, but the amount of the conductive material is smaller than that of the second functional material layer 2 and is non-conductive as a whole. The conductive substance contained in the second functional material layer 2 and the third functional material layer 3 is molybdenum (hereinafter referred to as Mo) or tungsten (hereinafter referred to as W), and has a predetermined content with respect to SiO ₂ . By mixing at a mixing ratio, conductivity is imparted to the functional material layer 2 and not imparted to the functional material layer 3. For example, the predetermined mixing ratio is desirably 20% or more in the capacity ratio in the second functional material layer 2, and is desirably 15% or less in the capacity ratio in the third functional material layer 3. Further, in each of the functional material layers 1 to 3, the particle diameter of SiO ₂ is desirably 20 μm or less, and the particle diameter of Mo or W is desirably 15 μm or less.

The third functional material layer 3 interposed between the first functional material layer 1 and the second functional material layer 2 is a buffer layer that absorbs the difference in thermal expansion coefficient between the layers 1 and 2 on both sides. Works. Adjustment of the coefficient of thermal expansion can be done by adjusting the mixing ratio of Taishirube conductive material SiO _2. The buffer layer can be not only one layer but also a plurality of layers. In this case, the thermal expansion coefficient is arranged so as to decrease sequentially from the first functional material layer 1 that is an insulating layer toward the second functional material layer 2 that is a conductive layer.

  Each of these functional material layers 1 to 3 is formed in a substantially cylindrical shape, and a conductive electrode shaft 4 and a conductive power supply shaft 5 are inserted along their central axes. The electrode shaft 4 and the feed shaft 5 are made of Mo or W. One end 4a of the electrode shaft 4 is inserted into the second functional material layer 2, penetrates through the first functional material layer 1 and the third functional material layer 3, and the other end is described later. The discharge electrode is connected to a discharge electrode provided in an airtight container of the discharge lamp. One end 5 a of the power supply shaft 5 is inserted into the second functional material layer 2, and the other end is led out of the second functional material layer 2. The electrode shaft 4 and the end portions 4a and 5a of the power feeding shaft 5 inserted into the second functional material layer 2 are spaced apart from each other.

  FIG. 2 is a schematic configuration diagram showing an example of a discharge plasma sintering (SPS) apparatus for manufacturing the FGM. A graphite sintered die 22 made of graphite is disposed in the water-cooled vacuum chamber 21, and the inside thereof is filled with the FGM shown in FIG. An upper punch 23 and a lower punch 24 are provided on the upper and lower sides of the sintering die 22 to pressurize the FGM, which is a workpiece filled inside, from above and below. The upper punch electrode 25 and the lower punch electrode 26 are disposed in contact with the upper punch 23 and the lower punch 24, respectively. Upper and lower ends of the upper punch electrode 25 and the lower punch electrode 26 are led out of the water-cooled vacuum chamber 21. A large pulse current is supplied between the upper punch electrode 25 and the lower punch electrode 26 from a pulse power supply 27 for sintering. This pulse current is supplied to the FGM through the upper punch 23 and the lower punch 24 and energized. Further, a downward and upward pressure P is applied to the upper punch electrode 25 and the lower punch electrode 26 by a pressurizing mechanism 28 for sintering. The upper punch electrode 25 and the lower punch electrode 26 are provided so as to be movable in the vertical direction, and move downward and upward by the pressure P, respectively. The cylinder portions of the upper punch 23 and the lower punch 24 are inserted from the upper end and the lower end of the hollow portion of the sintering die 22, respectively, and the pressure P is transmitted by the upper punch electrode 25 and the lower punch electrode 26 to fill the inside of the sintering die 22. Compress the FGM from above and below. The control device 29 controls the pulse power source 27 for sintering and the pressurizing mechanism 28 for sintering, and controls the pulse current and pressurizing pressure supplied to the FGM.

  FIG. 3 is an enlarged cross-sectional view showing a main part of the manufacturing apparatus of the shaft-integrated FGM in which the electrode shaft 4 and the power feeding shaft 5 are integrally sintered. Since the configuration of this apparatus is the same as that of the apparatus of FIG. 2 as a whole, the same reference numerals are given to the same components as those of FIG. An upper punch 23 and a lower punch 24 are inserted above and below the hollow portion of the sintering die 22. The upper punch 23 moves in the vertical direction in the hollow portion of the sintering die 22, while the lower punch 24 is fixed in the vertical direction in the hollow portion. The upper punch 23 is formed with a pore 23-1 that opens at the lower end thereof, and an end 4b of the electrode shaft 4 inserted into the FGM is inserted therein. In the pore 23-1, when the FPS SPS sintering is started, a space in which the end 4b can move upward is formed in the upper part. The lower punch 24 has a fine hole 24-1 that opens at the upper end, and an end 5b of the power feeding shaft 5 inserted into the FGM is inserted therein. The end 5 b of the power feeding shaft 5 is inserted so as to abut on the bottom of the pore 24-1 of the lower punch 24.

In the hollow portion of the sintering die 22, the functional material layers 1 to 3 described above are filled in a powder state before the start of SPS sintering. That is, first, the upper punch 23 is removed, the feeding shaft 5 is introduced into the hollow portion of the sintering die 22 from above, the end portion thereof is inserted into the pore 24-1, and the substantially central axis in the hollow portion. Stand up along. Next, a powder in which SiO ₂ and Mo constituting the functional material layer 2 are mixed at a volume ratio of 75% to 25% is filled. Next, powder in which SiO ₂ and Mo constituting the functional material layer 3 are mixed at a volume ratio of 90% to 10% is filled in the hollow portion of the sintering die 22 and laminated on the functional material layer 2. In this case, the functional material layer 2 is stacked and filled with such a thickness that the upper end 5 a of the power supply shaft 5 stops in the functional material layer 2. Further, the SiO ₂ 100% powder constituting the functional material layer 1 is filled in the hollow portion of the sintering die 22 and laminated on the functional material layer 3. Thereafter, the electrode material 4 is inserted so that the functional material layers 1 and 3 pass through the powder of the functional material layer 1 that has been stacked and filled, and the end portion 4 a reaches the functional material layer 1. Thereafter, the upper end of the hollow portion of the sintered die 22 is closed by the upper punch 23. At this time, the upper punch 23 closes the upper end of the hollow portion so that the end portion 4a of the electrode shaft 4 is inserted into the pore 23-1.

In such a state, under the control of the control device 29 of the SPS apparatus, the sintering pulse power supply 27 and the sintering pressure mechanism 28 start to operate, and the SPS sintering of the FGM is started. That is, a large pulse current is supplied from the sintering pulse power supply 27 to the hollow portion FGM of the sintering die 22 via the upper punch electrode 25 and the lower punch electrode 26. This pulse current is supplied to the powdered FGM filled and laminated in the hollow portion of the sintering die 22 through the upper punch 23 and the lower punch 24, and energized. Further, a downward pressure P is applied to the upper punch electrode 25 by the pressurizing mechanism 28 for sintering. The upper punch electrode 25 is provided so as to be movable in the vertical direction. The upper punch electrode 25 is moved downward by the pressure P and pushes down the FGM through the upper punch 23. Since the lower punch 24 and the lower punch electrode 26 are fixed in the vertical direction, the FGM is compressed by the pressure P from above. By flowing a large current pulse current through the FGM, SiO ₂ contained in each layer of the FGM is uniformly heated, melted and sintered by spark discharge and Joule heat generated in the green compact particle gap. As a result, it is possible to firmly bond the functional material layers 1 to 3 constituting the FGM.

The SPS method does not heat from the outside like the conventional atmospheric pressure sintering method and the HIP method, and the sample temperature is raised by energizing the sample to perform firing. Therefore, when SiO ₂ particles are used as an insulator, The temperature of the _two particles can be raised above the melting temperature. Thus, a first functional material layer of insulating made of SiO _2, the junction of the first non-conductive consisting of a mixture of SiO ₂ and Mo or W 3 of the functional material layer, or the third At the joint between the functional material layer and the second functional material layer 2, SiO ₂ is melted and bonded to each other, making it possible to strongly bond the two layers. A strong functionally graded material can be obtained.

  Furthermore, according to the method of manufacturing the functionally gradient material of the present invention, since the functionally gradient material can be sintered even when the electrode shaft 4 or the power feeding shaft 5 is inserted in the axial direction of the FGM, This makes it very easy to produce functionally graded materials. In the conventional atmospheric pressure sintering method or the HIP method, if the functional gradient material is sintered with the electrode shaft 4 or the feeding shaft 5 inserted, a part of the functional gradient material is cracked or cracked. A complicated manufacturing process, such as forming a through hole in a part of the functionally gradient material after firing and inserting the electrode shaft 4 or the power supply shaft 5 into the through hole, is required.

  In producing the functional gradient material described above, various experiments were conducted in order to find optimum production conditions for the composition, average particle diameter, firing temperature, and the like of each layer. The experimental results will be described below. In these experiments, an FGM of only a plurality of functionally graded material layers was sintered without inserting the electrode shaft 4 or the feeding shaft 5. In this case, it is not necessary to use the upper punch 23 or the lower punch 24 having the pores 23-1 or 24-1 as shown in FIG. Further, an upward pressure P may be simultaneously applied to the lower punch 24 by the pressurizing mechanism 28 for sintering.

(Experimental example 1)
Mixed Mo of mean grain size 3μm in average particle size 5MyumSiO _2, firing the FGM of two-layer structure in which the volume ratio of Mo with respect to SiO ₂ was varied between 5-30% in the discharge plasma sintering method (SPS method) Six samples were prepared. The firing temperature (surface temperature) of the sample is 1000 ° C. The firing temperature is measured with an infrared thermometer. Table 1 shows the results of confirming the conductivity of each fired material. From the table, conduction was obtained when the Mo volume mixing ratio was 20% or more. For this reason, it turned out that a conductive layer needs to contain 15% or more of electrically conductive materials. Further, when this capacity ratio of 15% is converted into a weight ratio, the weight of Mo with respect to SiO ₂ is about 0.67 times, and in the case of W, it is about 1.28 times or more.

(Experimental example 2)
A first functional material layer of an insulating layer made of SiO ₂ having an average particle diameter of 5 μm, and a conductive second functional material layer in which 25 vol% of SiO ₂ having an average particle diameter of 5 μm and Mo having an average particle diameter of 3 μm are mixed. Was formed by a third functional material layer in which Mo ₂ having an average particle diameter of 3 μm was mixed with SiO ₂ having an average particle diameter of 5 μm. The volume ratio of Mo in the third functional material layer as the intermediate layer was changed between 1-25%, and four materials (No.1-No.4) having the same volume ratio were prepared and fired. It was investigated whether or not the material was cracked. The results are shown in Table 2. The firing temperature (surface temperature) of the sample is 1000 ° C. The firing temperature is measured with an infrared thermometer. As shown in the firing conditions of the samples in Table 2, when the Mo volume mixture ratio was 15% or less, the sample was good without cracking, but when it was 17% or more, the first functional material layer which was an insulating layer And a third functional material layer, which is an intermediate layer, has cracked. Thus, it can be seen that the mixing ratio of the conductive substance Mo in the intermediate layer that can be combined with the first functional material layer as the insulating layer is 15% or less. Further, when the capacity ratio of 15% of Mo to SiO ₂ is converted to a weight ratio, it is about 0.67 times. The weight ratio in the case of W is about 1.28 times.

(Experimental example 3)
A first functional material layer that is an insulating layer made of SiO _{2 having an} average particle diameter of 5 μm, and a _second functional material in which 10 vol% of Mo having an average particle diameter of 3 μm and 90 vol% of SiO ₂ having an average particle diameter of 5 μm are mixed. The FGM sample having a two-layer structure in which the layers were combined was fired while changing the firing temperature (surface temperature) from 700 ° C. to 1300 ° C. Four (No.1-No.4) FGM samples were fired for each temperature. The firing temperature is measured with an infrared thermometer. Table 3 shows the results of the firing conditions. When the firing temperature was 700 ° C. and 800 ° C., the sample was cracked, and when the inner cross section at this time was observed, SiO ₂ was not melted and remained as particles. When the firing temperature was 900 ° C. or higher, SiO ₂ was completely melted in the sample cross section, and Mo was uniformly present in the amorphous SiO ₂ .

(Experimental example 4)
Six types of one-layer FGM samples in which 25 vol% of Mo having an average particle diameter of 25, 20, 15, 10, 5, and 1 μm and 75 vol% of SiO ₂ having an average particle diameter of 5 μm were mixed were fired and prepared. In the firing, the firing temperature (surface temperature) is fixed at 1000 ° C. Table 4 shows the resistance value indicating the conduction state of the prepared FGM sample or the presence or absence of conduction. The conduction was observed when the Mo particle size was 10 μm or less, but there was no conduction when the particle size was 15 μm or more. This is considered that when the Mo particle size is increased, the mutual contact of Mo present in SiO ₂ is lost, and thus conduction cannot be obtained. There is no limit on the lower limit value, and the smaller the particle size, the easier the conduction. It can be used with submicron conductive materials that are currently in practical use.

  FIG. 4 is a view showing an embodiment of the tube of the present invention, and is a cross-sectional view of a main part of a tube-type halogen bulb using the functionally gradient material for sealing. In the figure, a tubular halogen light bulb BP includes an airtight container 11, a tube actuating member 12 (filament), and a functional gradient material for sealing FGM.

  The hermetic container 11 includes an opening 11a to be sealed. And the opening 11a is sealed with the functional gradient material FGM for sealing. Since the airtight container 11 of this embodiment is a case of an illumination tube, it is made of a translucent and refractory material such as quartz glass or translucent alumina ceramics, but is made of quartz glass and is straight. It has a cylindrical shape, and both ends thereof form a pair of openings 11a.

  The tube operating member 12 is housed in the airtight container 11 in an airtight manner and performs a required operation as the tube BP, and is allowed to have various configurations. That is, the bulb BP is a member that is supplied with power from the outside and performs a desired electrical operation in the hermetic container 1. For example, in the case of a halogen bulb, an incandescent filament and an accompanying member. In the case of a high-pressure discharge lamp, it is a discharge electrode and an accompanying member.

  The illustrated tube operating member 12 is mainly composed of an incandescent filament, and a filament leg portion 12a (only one end is shown) extends from both ends thereof, and the filament leg portion 12a is disposed at both ends of the airtight container 11. The electrode shaft 4 (only one is shown) is connected to the inside of the airtight container 11 by welding or the like. The filament is composed of a double coil filament, and a plurality of ring anchors 12b are attached to prevent drooping during lighting.

As shown in FIG. 1, the sealing FGM includes a first functional gradient material layer 1, a second functional gradient material layer 2, and a third functional gradient material layer 3, and is an insulating layer. The functional gradient material layer 1 is welded to the inner wall of the airtight container 11. Since the first functional gradient material layer 1 is composed of 100% SiO ₂ , it has the same thermal expansion coefficient as the hermetic container 11 and may cause cracks due to the difference in thermal expansion coefficient during use of the halogen bulb. Absent.

  Since the tube BP shown in FIG. 4 is a halogen bulb, an organic halide such as iodine or bromine and argon (Ar) and the like are enclosed in the airtight container 11 as an appropriate amount of halogen at an appropriate pressure. Yes. Further, an infrared light reflection / visible light transmission type dichroic reflection film can be formed on the outer surface of the airtight container 11 as desired.

  FIG. 5 is a cross-sectional view of an FGM showing another embodiment of the present invention. In this embodiment, the feed shaft 5 made of Mo or W has a shaft diameter (a) other than the other portion (b) in the non-conductive first and third functional gradient material layers 1 and 3. It is formed larger. In the portion where the shaft diameter of the power feeding shaft 5 is enlarged, the resistance to the current flowing therethrough is reduced, so that heat generation is also reduced. As a result, heat generated in the vicinity of the joint axis between the conductive first functional gradient material layer 1 and the non-conductive third functional gradient material layer 3 during the lighting of the tube is reduced, and the thermal shock is reduced. Can prevent internal cracks. This was confirmed experimentally. Note that the shaft diameter of the coupling portion between the first functional gradient material layer 1 and the third functional gradient material layer 3 of the power feeding shaft 5 and the shaft diameter near the take-out portion of the second functional gradient material layer 2 are as follows. They are formed in substantially the same (b). That is, the portion in which the shaft diameter is expanded to (a) with respect to the axial length (A) of the first functional gradient material layer 1 and the third functional gradient material layer 3 which are non-conductive layers The length (B) in the axial direction is formed short.

  FIG. 6 is a cross-sectional view of an FGM showing still another embodiment of the present invention. In this embodiment, the ends of the electrode shaft 4 and the feeding shaft 5 made of Mo or W are formed in a special shape. For example, as shown in FIG. 7C, the end 5a of the electrode shaft 4 in the second functional gradient material layer 2 has a tapered diameter (b) and a tip having a smaller diameter. It is flat in (c). With such a shape, the thermal shock is alleviated by gradual change in the amount of heat generation in the axial direction in the second functional gradient material layer 2, and the distortion in the second functional gradient material layer 2 and this Generation of cracks based on the above can be prevented.

  Moreover, as shown in FIG. 8C, the end 4a of the power supply shaft 5 in the second functionally graded material layer 2 has a shaft diameter (b) that expands stepwise (d) and a tip. The taper decreases toward the portion, and the tip is flat. With such a shape, the feeding shaft 5 moves from the second functional gradient material layer 2 due to vibration or the like during compression sintering during use of the FGM or when a tube mounted as a windshield member is used. Alternatively, it can be prevented from falling out of the FGM.

  FIG. 7 is a view showing various shapes of the electrode shaft end portion, and FIG. 8 is a view showing various shapes of the feed shaft end portion. In the end portion of the electrode shaft in FIG. 7A, the shaft diameter decreases in a tapered shape toward the end portion, and the tip is not flat but sharp. The end of the electrode shaft in FIG. 7B is formed in a spherical shape. 8A, the shaft diameter (b) increases stepwise (d) and decreases in a tapered shape toward the tip, as in FIG. 8C described above. The tip is not flat but pointed. Similarly, the end of the feeding shaft in FIG. 8B has a diameter (b) that expands stepwise (d) and decreases in a tapered shape toward the end, but the tip is formed in a spherical shape. Yes.

  Although the present invention has been described with reference to various embodiments, the present invention is not limited to these embodiments, and can be applied to various modifications within the scope of the claims. is there. For example, the number of layers of the FGM of the present invention includes at least a first functional gradient material layer and a second functional gradient material layer, and a third functional gradient material layer interposed between these layers as needed is You may provide not only one layer but two or more layers.

It is sectional drawing which shows embodiment at the time of applying the functional gradient material (henceforth FGM) of this invention to the sealing part of a discharge lamp. It is a schematic block diagram which shows an example of the discharge plasma sintering (SPS) apparatus for manufacturing FGM shown in FIG. It is sectional drawing which expands and shows the principal part of the manufacturing apparatus of the shaft integrated type FGM which integrally sinter-creates the electrode shaft 4 and the electric power feeding shaft 5. FIG. It is a figure which shows one Embodiment of the tube of this invention, Comprising: It is principal part sectional drawing of the tube-type halogen bulb which used said functional gradient material for sealing. It is sectional drawing of FGM which shows other embodiment of this invention. It is sectional drawing of FGM which shows other embodiment of this invention. FIG. 7 is a diagram showing various shapes of the end portion of the electrode shaft. FIG. 8 is a diagram showing various shapes of the feeding shaft end.

Explanation of symbols

1 ... 1st functional gradient material layer,
2 ... 2nd functional gradient material layer,
3 ... 3rd functional gradient material layer,
4 ... Electrode shaft 5 ... Feeding shaft,
FGM ... Functionally graded material

Claims (8)

  An insulating first functional material layer mainly composed of silicon oxide; and a second functional material layer made of a mixture of silicon oxide and a conductive substance having a particle size of 15 μm or less and having conductivity, In a state where these first and second functional material layers are in contact with each other, the silicon oxide is melted and sintered by applying pressure by a discharge plasma sintering method to bond the layers. A functionally graded material characterized by that.   2. The functionally gradient material according to claim 1, wherein the conductive material in the second functional material is Mo or W, and a capacity mixing ratio of the conductive material to the silicon oxide is 15% or more. .   At least one or more third functional material layers made of silicon oxide and a conductive substance are provided between the first functional material layer and the second functional material layer, and in the third functional material layer, The functionally gradient material according to claim 2, wherein the conductive material is made of Mo or W, and a capacitance mixing ratio of the conductive material to the silicon oxide of the conductive material is set to 15% or less. 4. The conductive electrode shaft according to claim 1, further comprising a conductive electrode shaft penetrating through the first functional material layer and having one end inserted into the second functional material layer. 5. Functional gradient material.   5. The functionally graded material according to claim 4, further comprising a conductive feeding shaft that is inserted into the second functional material layer at one end and is led out from the second functional material layer.   A tube using the functionally graded material according to claim 1 as a sealing material.   Forming an insulating first functional material layer mainly composed of silicon oxide, forming a conductive second functional material layer made of a mixture of silicon oxide and a conductive substance, The first functional material layer and the second functional material layer in contact with each other, and a step of applying current and pressure by a discharge plasma sintering method, and melting and sintering the silicon oxide, thereby The manufacturing method of the functional gradient material characterized by combining.   Forming an insulating first functional material layer mainly composed of silicon oxide, forming a conductive second functional material layer made of a mixture of silicon oxide and a conductive substance, A step of providing a conductive shaft penetrating one of these first and second functional material layers and having one end inserted into the functional material layer; and the first and second functional material layers And a step of energizing and pressurizing by a discharge plasma sintering method in a state where they are in contact with each other, and melting and sintering the silicon oxide, thereby bonding the layers, Production method.

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