JP2005290484A - Fiber-reinforced platinum-matrix composite material, its manufacturing method, and fiber-reinforced type platinum product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remarkably improve the strength and toughness of a material composed mainly of platinum or a platinum alloy without worsening its characteristics, such as heat resistance, corrosion resistance and oxidation resistance. <P>SOLUTION: In the fiber-reinforced platinum-matrix composite material, fibers composed of a metallic compound are dispersed in a matrix composed of platinum or a platinum alloy. Further, it is preferable that an interfacial layer composed of platinum or a platinum alloy of prescribed composition is formed on the surface of the fibers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to platinum or a platinum alloy material, and more particularly to a fiber reinforced platinum composite material in which platinum or a platinum alloy is used as a matrix and fibers are dispersed and composited to increase strength. Furthermore, the present invention relates to a method for producing the material, as well as a crucible, a glass production tool, a device and other fiber-reinforced platinum products constructed using the material.

  Platinum is a high-melting-point material that has both excellent corrosion resistance and oxidation resistance, so products that are used at high temperatures and in an oxidizing (atmosphere) atmosphere, especially products such as crucibles, glass manufacturing equipment, and equipment. Is widely used.

  However, in recent years, there has been a demand for a glass production process temperature as high as about 1600 ° C. This temperature was 0.92 TM, which is the melting point of platinum, and the strength and life of platinum or platinum alloy parts were significantly impaired. Therefore, various methods have been taken to improve the strength of platinum at high temperatures. For example, a platinum alloy in which an element such as hafnium, yttrium, lanthanum, or gadolinium is added to platinum (see, for example, Patent Document 1), or fine zirconium oxide particles are dispersed in platinum (for example, a patent) Reference 2)), it is said that the strength at high temperature is improved.

  The oxide particle dispersion-strengthening material described in Patent Document 2 is an example in which oxide particles are distributed in the grains to suppress transition movement, and the oxide particles are dispersed at grain boundaries to suppress crystal grain slip. Increased high temperature strength. However, although a large amount of oxide particles are dispersed at the grain boundaries, slip is suppressed, but the oxide particles have low bonding strength with platinum or a platinum alloy. This may accelerate the destruction from the grain boundaries. This has been a problem in increasing the heat resistance by further increasing the amount of oxide particles dispersed.

JP-A-10-195561 JP-A-8-134511

  Predetermined elements and oxide particles are blended with platinum or platinum alloys as described above, and are used as platinum parts that require high-temperature strength. There was a need for longer life. The present invention has been made in view of such circumstances, and the object thereof is a material mainly composed of platinum or a platinum alloy without impairing characteristics such as heat resistance, corrosion resistance, and oxidation resistance. The object is to provide a material with dramatically improved strength and properties. Another object of the present invention is to provide a product that requires high mechanical properties, corrosion resistance, and oxidation resistance at high temperatures, in particular, a fiber-reinforced platinum product that is used at high temperatures, such as crucibles, glass manufacturing instruments and devices. Furthermore, it is providing the manufacturing method for manufacturing such a material with improved high temperature creep strength.

  The present inventors examined various strengthening methods in order to improve the strength at high temperature without impairing the properties of platinum in a material mainly composed of platinum or a platinum alloy. It has been found that good characteristics can be obtained by using a fiber reinforced platinum composite material in which fibers having high temperature strength are dispersed, and the present invention has been completed. That is, the fiber-reinforced platinum composite material according to the present invention is characterized in that fibers made of a metal compound are dispersed in a platinum or platinum alloy matrix.

  In the fiber reinforced platinum composite material according to the present invention, the platinum alloy is preferably a platinum-gold alloy or a platinum-rhodium alloy. Since these platinum alloys are excellent in corrosion resistance and oxidation resistance at high temperatures, they are suitable as matrix materials.

  In the fiber-reinforced platinum composite material according to the present invention, the metal compound is one of zirconium oxide, aluminum oxide, hafnium oxide, yttrium oxide-stabilized zirconium oxide, aluminum nitride, boron nitride, or two or more of these. A mixture is preferred. A metal oxide or metal nitride is preferable as the metal compound. The metal compound is particularly suitable as a dispersion fiber because it has heat resistance and high temperature strength.

  In the fiber reinforced platinum composite material according to the present invention, the case where the fiber made of the metal compound is a whisker of the metal compound is included. Good characteristics can be obtained by dispersing whiskers made of a metal compound as fibers made of a metal compound in a matrix of platinum or a platinum alloy. The strength of the fiber reinforced platinum composite material can be improved by using a whisker with few defects and high strength.

  In the fiber-reinforced platinum composite material according to the present invention, the aspect ratio of the fiber is preferably 5 to 1000. Moreover, it is preferable that the wire diameter of the said fiber is 100 micrometers or less. Furthermore, the content of the fiber is preferably 0.1 to 50% by volume. Fibers can be dispersed under the above conditions to suppress crystal grain slip and improve high-temperature strength.

  In the fiber-reinforced platinum composite material according to the present invention, is an interface layer made of platinum formed on the surface of the fiber, or is an interface layer made of a platinum alloy having the same composition as the matrix formed on the surface of the fiber? Alternatively, the case where an interface layer made of a platinum alloy or a platinum group metal having a different composition from the matrix is formed on the surface of the fiber is included. By providing the interface layer, the adhesion between the fiber and the matrix can be improved, and the slip of crystal grains can be further suppressed.

  The fiber-reinforced platinum composite material according to the present invention is characterized in that it is formed and used for a crucible, a glass manufacturing instrument, a device, or all or a part of a product used at a high temperature. By using the fiber reinforced platinum composite material according to the present invention, the high-temperature creep strength is high and the service life is increased.

  The method for producing a fiber-reinforced platinum composite material according to the present invention is a method for producing a fiber-reinforced platinum composite material in which fibers made of a metal compound are dispersed in a matrix of platinum or a platinum alloy, A step of forming a coating layer made of platinum or a platinum alloy, and a powder and / or foil of platinum or a platinum alloy serving as the matrix by sintering around the fiber on which the coating layer is formed, and pressure sintering And performing the process. By providing the interface layer in advance before the sintering step, the adhesion between the fiber and the matrix can be enhanced without being influenced by the sintering conditions.

  According to the present invention, high temperature creep strength can be dramatically improved in a material mainly composed of platinum or a platinum alloy without impairing characteristics such as heat resistance, corrosion resistance, and oxidation resistance. This fiber reinforced platinum composite material is a product that requires high mechanical properties, corrosion resistance, and oxidation resistance at high temperatures, especially as crucibles, glass manufacturing equipment, equipment, and other fiber reinforced platinum products used at high temperatures. Is preferred. Moreover, according to the manufacturing method of this invention, the adhesiveness of a fiber and a matrix can be improved without being influenced by the sintering conditions of a fiber reinforced platinum composite material.

(Function)
The strengthening mechanism at a high temperature needs to suppress not only the dislocation movement suppressing effect but also the slip at the grain boundary, and the generation and growth of cavities in the material. As described in the background art, the conventional oxide particle dispersion reinforcing material has a large amount of oxide particles dispersed at the grain boundary, which prevents slipping, but the oxide particles have a bonding strength with platinum or a platinum alloy. Since it is low, the breakage from the grain boundary may be accelerated. On the other hand, in the fiber reinforced platinum composite material of the present invention, the metal compound fiber having a large aspect ratio is dispersed in the grains and / or the grain boundaries, and the slip of the crystal grains is stopped particularly in the form of a wedge. It has high temperature strength. Further, since the fibers can be distributed in a plurality of adjacent grains and / or across grain boundaries, it is easy to stop slip of crystal grains. Furthermore, it is effective that the specific surface area of the compound fiber is large in order to increase the bonding strength between the fiber made of the metal compound and platinum or the platinum alloy. When attention is paid to one dispersion, the specific surface area of the fiber dispersion is larger than that of the spherical dispersion if the dispersion has the same volume. Further, by providing a coating layer made of platinum or a platinum alloy in advance on the fiber surface, the matching of the interface between the fiber and the matrix is increased, and the bonding strength between the matrix and the fiber is increased.

  Hereinafter, although an embodiment and an example are shown and the present invention is explained in detail, the present invention is limited to these descriptions and is not interpreted.

  In the fiber-reinforced platinum composite material according to this embodiment, fibers made of a metal compound are dispersed in a matrix of platinum or a platinum alloy.

  The platinum alloy used as the matrix is preferably a solid solution alloy, and particularly preferably a platinum-gold alloy or a platinum-rhodium alloy. The metal compound as the fiber is preferably one of zirconium oxide, aluminum oxide, hafnium oxide, yttrium oxide-stable zirconium oxide, aluminum nitride, boron nitride, or a mixture of two or more of these. The stability of the fiber as a compound at high temperatures is also important, and the platinum alloy and the metal compound hardly react at high temperatures. A metal oxide fiber is particularly preferable as the fiber. Here, the fibers include whiskers and further single crystal whiskers. With such a combination, the high temperature creep strength can be drastically improved without impairing the high temperature corrosion resistance and oxidation resistance of platinum or a platinum alloy as a matrix. In consideration of use as a platinum material, metal carbide is not suitable as a fiber.

  The fiber aspect ratio is preferably 5 to 1000. When the aspect ratio is less than 5, the fiber-reinforced properties are weakened. On the other hand, if the aspect ratio exceeds 1000, the fiber length becomes too long, and the strength as a composite material also decreases. Moreover, it is preferable that the wire diameter of a fiber is 100 micrometers or less. When the wire diameter exceeds 100 μm, the generation of a separation layer between the matrix and the fibers becomes remarkable. Therefore, the bonding strength between the matrix and the fibers cannot be ensured, and the strength of the fiber reinforced platinum composite material also decreases. Further, the fiber content is preferably 0.1 to 50% by volume. When the fiber content is less than 0.1% by volume, the effect of fiber reinforcement is small. On the other hand, if the fiber content exceeds 50%, the characteristics of the material due to the matrix of platinum or platinum alloy are lowered, and the strength is lowered.

  For the purpose of densely bonding the fiber and the matrix, an interfacial layer made of platinum is formed on the surface of the fiber, or an interfacial layer made of a platinum alloy having the same composition as the matrix is formed on the surface of the fiber, or It is preferable that an interface layer made of a platinum alloy or a platinum group metal having a different composition from the matrix is formed on the surface of the fiber. When the fiber and the matrix are combined, the fiber and the fiber may be sintered in contact. In such a case, since there is no bonding strength between the fibers, the strength of the fiber-reinforced platinum composite material is significantly reduced. It is preferable to prevent the fibers from coming into contact with each other, and it is preferable from the viewpoint of securing strength that the interface layer is formed on the surface of the fiber, preferably the entire surface, with the platinum, platinum alloy or platinum group metal. Platinum group metals include rhodium, iridium, ruthenium, and rhenium. Furthermore, in order to alleviate the difference in physical properties due to the difference in composition between the fiber and the matrix, the interface layer is preferably formed from a platinum alloy containing at least one element contained in the fiber or matrix.

  The fiber-reinforced platinum composite material according to the present embodiment dramatically improves the high-temperature creep strength with the fibers without impairing properties such as corrosion resistance and oxidation resistance. Its applications include products that require high mechanical properties, corrosion resistance, and oxidation resistance at high temperatures, especially crucibles, glass manufacturing equipment, equipment, and other materials used to form fiber-reinforced platinum products used at high temperatures. is there.

  Next, an example is shown about the manufacturing method of the fiber reinforced platinum composite material which concerns on this embodiment. First, fibers made of a metal compound such as alumina having the above aspect ratio and wire diameter are prepared. The fibers may first be formed into a fiber structure and then combined. The ceramic fiber can be produced by an ejection method, a spray method, or the like. Alternatively, the polymer precursor may be formed into fibers and then thermally decomposed. Further, the ceramic whisker can be manufactured using a PVD method, a CVD method, or the like.

  Here, by forming a coating layer made of platinum, a platinum alloy, or a platinum group metal on the surface of the fiber, preferably the entire surface, contact between the fiber and the fiber is prevented, wettability with the matrix is increased, and sintering is performed. It is preferable to provide for preventing the promotion of sex. The coating layer is preferably formed by the PVD method in order to increase the adhesion strength between the coating layer (coating layer) and the compound fiber.

  Examples of the PVD method include vacuum deposition methods such as resistance heating deposition or electron beam heating deposition, various sputtering methods such as DC sputtering, high frequency sputtering, magnetron sputtering, ECR sputtering, or ion beam sputtering, high frequency ion plating, activated vapor deposition, or There are various ion plating methods such as arc ion plating, molecular beam epitaxy method, laser ablation method, ionized cluster beam evaporation method, and ion beam evaporation method.

  In the PVD method, it is basically possible to easily form a coating layer of any material with poor workability and is inexpensive. It is also possible to easily coat a metal material having a composition that cannot be obtained by the melting method. The optimum film thickness of the interface layer varies depending on conditions such as pressure during pressure sintering, sintering temperature, and fiber content, but is, for example, 0.05 to 1 μm.

  When it is set as the said film thickness, you may divide into several times by adjusting sputtering conditions. You may heat-process for every film-forming. For example, the annealing treatment or the diffusion treatment may be performed by heating at 400 to 1200 ° C. for 10 to 120 minutes in vacuum or in an inert gas. After sintering the fiber reinforced platinum composite material, at least one element contained in the fiber diffuses toward the coating layer that becomes the interface layer by heat treatment, and the difference in physical properties due to the difference in composition with the fiber is alleviated. . When the heat treatment conditions are a low temperature of 400 ° C. or lower and a short time of less than 10 minutes, the effect of the heat treatment is small. On the other hand, in the case of a long time of 120 minutes or more at a high temperature of 1200 ° C. or higher, diffusion is excessive and the composition of each coating layer changes, which is undesirable.

  In addition, when forming a coating layer on the whole surface of a fiber, it forms into a film, making a fiber float in airflow during film formation, and rotating. Alternatively, the film formation position is changed, and film formation is performed a plurality of times until a coating layer is formed on the entire outer surface of the fiber.

  In addition, an intermediate layer made of platinum or a platinum alloy having a composition different from that of the coating layer may be provided between the fiber and the coating layer to prevent peeling of the coating layer.

  Next, platinum or platinum alloy powder and / or foil, which becomes a matrix by sintering, is placed around the fiber and subjected to pressure sintering. At this time, the volume ratio of the fiber to the matrix is preferably the above-described ratio, that is, the fiber content is 0.1 to 50% by volume. The pressure and sintering temperature during pressure sintering depend on the fiber content, but the pressure is, for example, 50 to 200 MPa. The sintering temperature is, for example, 1000 to 1500 ° C. The atmosphere in the pressure sintering is, for example, in a vacuum or in an inert gas. By pressure sintering, at least one element contained in the fiber or matrix diffuses toward the interface layer, and the difference in physical properties due to the difference in composition from the fiber or matrix is alleviated.

  In the above process, the process of forming a coating layer serving as an interface layer on the surface of the fiber by the PVD method has been shown. The coating layer may be formed by a growth method) or a thermal spraying method. In the above process, the fiber and the matrix are combined by heating and sintering, but the matrix is formed on the fiber by a thermal spraying method, a CVD method, a CVI method (chemical vapor infiltration method), a coprecipitation method, or a combination of these methods. The fiber and the matrix may be combined from the forming step.

  Furthermore, the fiber-reinforced platinum composite material may be manufactured by a vacuum melting method by reducing the specific gravity difference between the fiber and the matrix.

(Example 1)
The surface of 5 g (1.8 vol%) of zirconia fibers having a diameter of φ (diameter) of 5 μm and L (length) of 200 μm was uniformly coated with a thickness of 100 mm by the PVD method. This formed a platinum coating layer on the fiber. The aspect ratio is 40. This fiber was mixed with 1000 g of platinum powder having a particle size of 200 μm or less, which is a raw material of the matrix, in a ball mill. The yield was 85%. This was sintered with HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. Next, the sintered body was rolled to produce a 2 mm plate sample.

(Example 2)
The surface of 5 g (1.8 vol%) of zirconia fibers having a diameter of φ (diameter) of 5 μm and L (length) of 200 μm was uniformly coated with a thickness of 50 mm by the PVD method. This formed a platinum coating layer on the fiber. The aspect ratio is 40. This fiber, 2270 g of ammonium chloroplatinate crystals, and 50 g of ethyl alcohol were added and mixed with a three roll. This was placed in an electric furnace at 400 ° C. for 1 hour and fired and decomposed to obtain a mixture of platinum and zirconia fibers. This was pulverized and sintered with HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. Next, the sintered body was rolled to produce a 2 mm plate sample.

(Example 3)
A zirconia fiber 5 g (1.8 vol%) (aspect ratio 40) having a diameter of 5 μm and L 200 μm was mixed with a 1000 g platinum powder having a particle size of 200 μm or less by a ball mill without coating. The yield was 85%. This was sintered with HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. The next sintered body was rolled to produce a 2 mm plate sample.

Example 4
Aluminum nitride seeds were placed on the film formation stage and grown using a CVD method to produce 5 g (1.8 vol%) whiskers having a diameter of about 10 nm × 100 nm. The aspect ratio is 10. The whisker and the matrix raw material, 1000 g of platinum powder having a particle size of 200 μm or less, were mixed with a ball mill. The yield was 85%. This was sintered with HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. Next, the sintered body was rolled to produce a 2 mm plate sample.

(Example 5)
Aluminum nitride seeds were placed on the film formation stage and grown using a CVD method to produce 5 g (1.8 vol%) whiskers having a diameter of about 10 nm × 100 nm. The aspect ratio is 10. Next, platinum was uniformly coated on the surface of the whisker with a thickness of 100 mm by the PVD method. Next, the coated whisker and 1000 g of platinum powder having a particle size of 200 μm or less, which is a raw material of the matrix, were mixed in a ball mill. The yield was 85%. This was sintered with HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. Next, the sintered body was rolled to produce a 2 mm plate sample.

(Comparative Example 1)
A platinum ingot was prepared by vacuum melting. The ingot was rolled to produce a 2 mm plate sample.

(Comparative Example 2)
An ingot of a platinum rhodium alloy (platinum 90 wt% -rhodium 10 wt%) was prepared by vacuum melting. The ingot was rolled to produce a 2 mm plate sample.

(Comparative Example 3)
To 1000 g of platinum powder having a particle size of 200 μm or less, 2 g (0.73 vol%) of zirconia powder having a particle size of 1 μm or less was added, mixed by a ball mill, and sintered by HIP. The sintering temperature was 1400 ° C. and the pressure was 180 MPa. This sintered body was rolled to prepare a 2 mm plate-like sample.

  About each Example and each comparative example, the test piece (plate shape) for a high temperature creep test was cut out from the plate-shaped sample, and the creep strength was measured at 1500 degreeC in air | atmosphere. The test results are shown in FIG.

  Compared with Comparative Examples 1 and 2 which do not contain a dispersion, Comparative Example 3 which is oxide dispersion strengthened platinum has a very high strength. However, in Example 3 in which the fibers were dispersed, a creep strength 1.9 times that of Comparative Example 3 was confirmed. Further, Examples 1 and 2 in which a coating layer was provided on the fiber and the fiber was dispersed were confirmed to have a creep strength 2.2 times that of Comparative Example 3. In addition, Example 4 in which whiskers are dispersed has a creep strength 1.2 times that of Comparative Example 3, and Example 5 in which coated whiskers are dispersed has a creep strength 1.5 times that of Comparative Example 3. It was. In Examples 1 and 2, the high-temperature creep strength is further increased as compared with Example 3, but the bonding strength between the metal oxide fiber and the matrix is increased due to the presence of the coating layer, and thus the high-temperature exposure for a long time. This is considered to be because the peeling was further suppressed and the slipping of the crystal grains was further suppressed even if it was removed.

It is a graph which shows the creep rupture strength in 1500 degreeC and an atmospheric condition about Examples 1-5 and Comparative Examples 1-3.

Claims (10)

  A fiber-reinforced platinum composite material, wherein fibers made of a metal compound are dispersed in a platinum or platinum alloy matrix.   The fiber-reinforced platinum composite material according to claim 1, wherein the platinum alloy is a platinum-gold alloy or a platinum-rhodium alloy.   The metal compound is any one of zirconium oxide, aluminum oxide, hafnium oxide, yttrium oxide stable zirconium oxide, aluminum nitride, boron nitride, or a mixture of two or more thereof. Or the fiber reinforced platinum composite material of 2.   The fiber reinforced platinum composite material according to claim 1, 2 or 3, wherein the fiber made of the metal compound is a whisker of a metal compound.   The fiber-reinforced platinum composite material according to claim 1, 2, 3, or 4, wherein the fiber has an aspect ratio of 5 to 1000.   6. The fiber-reinforced platinum composite material according to claim 1, wherein the fiber has a wire diameter of 100 μm or less.   The fiber-reinforced platinum composite material according to claim 1, 2, 3, 4, 5 or 6, wherein the fiber content is 0.1 to 50% by volume.   An interface layer made of platinum is formed on the surface of the fiber, an interface layer made of a platinum alloy having the same composition as the matrix is formed on the surface of the fiber, or a surface different from the matrix on the surface of the fiber. 8. The fiber-reinforced platinum composite material according to claim 1, wherein an interface layer made of a platinum alloy or a platinum group metal having a composition is formed.   A crucible or glass manufacturing instrument, wherein the fiber-reinforced platinum composite material according to claim 1, 2, 3, 4, 5, 6, 7, or 8 is used as a whole or a part thereof. , Equipment and other fiber reinforced platinum products. A method for producing a fiber-reinforced platinum composite material in which fibers made of a metal compound are dispersed in a matrix of platinum or a platinum alloy, the step of forming a coating layer made of platinum or a platinum alloy on the surface of the fibers; A step of pressure sintering by placing platinum or a platinum alloy powder and / or foil serving as the matrix by sintering around the fiber on which the coating layer is formed. Material manufacturing method.

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