KR101143982B1 - Complex oxide film and method of manufacturing the same - Google Patents

Abstract

The present invention is an oxide film formed on the surface of a metal base material by plasma electro-oxidation (PEO), the metal salt component which causes synthesis, precipitation, and hydrolysis reaction with the electrolyte solution in the electrolyte solution for forming the oxide film Is added, wherein the oxide film contains a metal compound produced by a synthesis reaction of a component of the metal base material, an electrolyte solution, and a metal salt component, and a method for producing the composite oxide film.

As a result, by adding a metal salt component that causes a synthesis reaction with the electrolyte solution to the electrolyte solution, the metal compound component produced by the synthesis reaction and the precipitation reaction is included in the oxide film, thereby realizing a complex oxide film having new components and functions added thereto. Due to the addition of the metal salt component, it is possible to improve the formation rate of the oxide film formed of PEO and at the same time easily form a desired thickness of the oxide film.

Plasma, Anodized, Synthetic, Precipitated

Description

Composite oxide film and its manufacturing method {COMPLEX OXIDE FILM AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to a composite oxide film formed by Plasma Electronic Oxidation (PEO) and a method for manufacturing the same. More specifically, the present invention relates to an electrolyte solution and a metal salt component that causes synthesis, hydrolysis, precipitation reaction, and the like. The present invention relates to a composite oxide film in which a new compound and a function are added by including a metal compound component added to a solution by a synthesis reaction, a precipitation reaction, and the like, and a method of manufacturing the same.

In general, when the metal surface is oxidized by plasma electrolytic oxidation (hereinafter referred to as 'PEO' or 'MAO'), the passivated metal and its components are oxidized to form an oxide layer or contained in an electrolyte solution for PEO. Some cations or anions react with the metal matrix and the resulting compound is coated.

In this case, an oxide component of the metal base material is mainly present on the surface, and there existed a phenomenon in which various properties such as surface hardness and abrasion resistance conform to physical properties of the metal base material oxide to some extent.

In order to overcome this problem, there have been attempts to obtain various properties of the oxide layer by adding various kinds of metal salts or anions, but it is impossible to obtain an oxide layer that significantly improves the properties of the metal base oxide, and various properties and functionalities are formed by PEO. There existed a surface which is hard to give to the oxide film layer to become.

In particular, in the case of titanium (Ti) alloy, which is most widely used as a dental implant material for hip materials or as a material for hip and knee joints, the surface is a bioinert material that does not react with the living body.

In other words, hard tissues related to bone should be attached to the surface of the alloy first to grow, but in reality, soft tissues attach and grow first to prevent contact with hard tissues such as bones. As it becomes difficult to fix bones, biocompatibility is reduced.

Therefore, it is known to coat hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ), which is a component such as bone of the human body, in the biomaterial.

Recently, many attempts have been made to coat the hydroxyapatite on titanium (Ti) alloys, which are biomaterials. In particular, thermal spraying, vacuum deposition, sol-gel, sputtering, and the like have been attempted.

However, the above-described attempts have reduced the interfacial bond strength due to the thermal mismatch caused by the difference in the thermal expansion coefficient of the titanium (Ti) alloy and the hydroxyapatite due to the difference in the coefficient of thermal expansion.

In addition, due to the difference in the bonding properties between the titanium (Ti) alloy having a metal bond and hydroxyapatite ceramics having an ionic covalent bond, the interface strength is weak, and thus it is not applicable as a dental restorative or a joint substitute.

In addition, the PEO method with high interfacial bonding strength between the titanium (Ti) alloy and the hydroxyapatite coating layer was also attempted. The surface coating layer is composed of titanium oxide (TiO 2), an oxide of titanium (Ti), which is a base metal, and has a higher biocompatibility than a metal component. Some improvements were made.

However, such an attempt is also difficult to expect bioactive (hydroxyapatite) such as hydroxyapatite, and due to process problems, the product introduction is part of the product but is not commercialized at present.

In addition, some researchers attempted to disperse the ceramic powder in the PEO electrolyte solution, and then allow the powder to adhere to the surface of the PEO oxide by electrophoresis, thereby increasing the growth rate of the oxide layer or imparting a specific function.

However, since the ceramic powder dispersed in the electrolyte is precipitated due to gravity, the method uses agitation or a method of preventing precipitation of the powder by ultrasonic shock.

Here, the method of stirring to prevent the precipitation of the powder is a known technique, and the method of introducing the sonication is disclosed in PCT WO 03/083181 A2.

However, the agitation or sonication method may not be a very efficient method because it acts as an obstacle to the normal electrophoresis of the ceramic powder.

The present invention has been made to solve the above problems, and an object of the present invention is to add a metal salt component that causes a synthesis reaction with an electrolyte solution to the electrolyte solution, the metal compound component produced by the synthesis reaction and precipitation reaction is an oxide film It is included in the present invention to provide a composite oxide film and a method of manufacturing the added new components and functions.

Still another object of the present invention is to provide a composite oxide film and a method of manufacturing the same that can easily form a desired oxide film thickness while improving the formation rate of the oxide film formed of PEO due to the addition of the metal salt component. There is.

The above object is an oxide film formed on the surface of a metal base material by plasma electrooxidation (PEO) according to the present invention, and the electrolyte solution for forming the oxide film is composed of an electrolyte solution, synthesis, precipitation, and water. A metal salt component that causes a decomposition reaction is added, and the oxide film may be achieved by a composite oxide film containing a metal compound produced by a synthesis reaction of a component of the metal base material, an electrolyte solution, and a metal salt component.

Here, the metal salt component is lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), potassium (K) , Ca (calcium), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) , Zinc (Zn), gallium (Ga), low maenyum (Ge), arsenic (As), selenium (Se), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), age Obium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), Tellurium (Te), Iodine (I), Cesium (Cs), Barium (Ba), Lanthanum (La), Cerium (Ce), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Terbium (Tb) ), Dysprosium (Dy), holmium (Ho), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os) , Metal salt of iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), lead (Pb), bismuth (Bi), thorium (Th), uranium (U) Or two It can be prepared by mixing the phases.

In addition, the composite oxide film may be formed at a voltage of 300 ~ 500 (V).

Here, the metal compound may be electrophoresed in the voltage range to form a composite layer on the oxide film.

In addition, the particle size of the metal compound may be provided to 10nm ~ 50㎛.

On the other hand, the metal base material may be provided with a metal alloy composed mainly of any one of aluminum (Al), magnesium (Mg), titanium (Ti), zirconium (Zr), zinc (Zn), niobium (Nb). .

In addition, a soluble calcium component or a phosphoric acid component may be added to the electrolyte solution to form an oxide film of the medical alloy.

On the other hand, the above object, according to the present invention, a method for producing an oxide film formed on the surface of a metal base material by plasma electro-oxidation (PEO: Plasma Electronic Oxidation), the electrolyte in the electrolyte solution for forming the oxide film Adding a metal salt component causing a synthesis reaction with the solution; Adjusting a hydrogen ion index (pH) of the electrolyte solution to which the metal salt component is added; Charging a metal base material to the electrolyte solution to perform a plasma electrolytic oxidation process; and in the adding of the metal salt component, synthesis, precipitation, and hydrolysis reaction of the metal base material, the electrolyte solution, and the metal salt component are performed. It can also be achieved by a method for producing a composite oxide film in which a metal compound is produced in the electrolyte solution.

Here, the metal salt component is lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), potassium (K) , Ca (calcium), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) , Zinc (Zn), gallium (Ga), low maenyum (Ge), arsenic (As), selenium (Se), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium ( Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), tellurium (Te), iodine (I), cesium (Cs), barium (Ba), lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), gadolinium (Gd), terbium (Tb), Dysprosium (Dy), holmium (Ho), ytterbium (Yb), ruthetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium Any one or two of metal salts of (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), lead (Pb), bismuth (Bi), thorium (Th), and uranium (U) this In may be provided with mixing.

In addition, performing the plasma electrolytic oxidation process may include applying a voltage of 300 to 500 (V) to the electrolyte solution loaded with the metal base material.

In addition, the performing of the plasma electrolytic oxidation process may include the step of forming a composite layer on the oxide film by the electrophoresis of the metal compound in the voltage range.

According to the present invention, by adding a metal salt component which causes a synthesis reaction with an electrolyte solution to the electrolyte solution, the metal compound component produced by the synthesis reaction and the precipitation reaction is included in the oxide film, thereby realizing a composite oxide film in which new components and functions are added. have.

In addition, due to the addition of the metal salt component, it is possible to improve the formation rate of the oxide film formed of PEO and at the same time easily form the desired thickness of the oxide film.

Hereinafter, the configuration of the present invention will be described in detail.

Prior to this, terms used in the present specification and claims should not be construed in a dictionary meaning, and the inventors may properly define the concept of terms in order to explain their invention in the best way. It should be construed as meaning and concept consistent with the technical spirit of the present invention.

Therefore, the configuration described herein is only a preferred embodiment of the present invention, and does not represent all of the technical spirit of the present invention, there may be various equivalents and variations that can replace them at the time of the present application. Should be understood.

The composite oxide film according to the present invention is an oxide film formed on the surface of a metal base material by plasma electro-oxidation (PEO). The electrolyte solution for forming the oxide film includes an electrolyte solution, synthesis, precipitation, and water A metal salt component causing a decomposition reaction is added, and the oxide film may include a metal compound produced by a synthesis reaction of a component of the metal base material, an electrolyte solution, and a metal salt component.

Here, the plasma electrolytic oxidation method is a coating and surface treatment technique, also referred to as a micro arc oxidation technique or a plasma deoxidation technique, and forms an oxide film on a metal base material such as magnesium (Mg), aluminum (Al), titanium (Ti), or the like. This is how you do it.

In the plasma electrolytic oxidation method, a high voltage of several hundred volts is applied between a metal (anode) and a stainless electrode (cathode) charged in an alkaline electrolyte solution to form a plasma reaction on the surface of the metal base material to form an ultrahard oxide film.

In addition, the plasma electrolytic oxidation method can form an oxide film having a thickness and property that cannot be manufactured by conventional methods such as anodizing, electroplating or plasma spray coating, and using a weak alkali electrolyte solution. It is an environmentally friendly method.

Here, the metal base material may be provided with a metal alloy mainly composed of any one of aluminum (Al), magnesium (Mg), titanium (Ti), zirconium (Zr), zinc (Zn), niobium (Nb). .

Here, the electrolyte solution may be provided as an aqueous solution containing Na ₂ SiO ₃ , NaAl ₂ , NaF-Na ₂ CO ₃ , and the like at a concentration of 0.01-15% based on the mass of the solution, but is not limited thereto. The composite oxide film may be provided as an electrolyte solution to which various components are added for exhibiting a specific function.

In addition, the metal salt component added to the electrolyte solution is lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S) , Potassium (K), Ca (calcium), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni) , Copper (Cu), zinc (Zn), gallium (Ga), low maenyum (Ge), arsenic (As), selenium (Se), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr ), Niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony ( Sb), tellurium (Te), iodine (I), cesium (Cs), barium (Ba), lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), gadolinium (Gd), Terbium (Tb), dysprosium (Dy), holmium (Ho), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium Metal salts of (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), lead (Pb), bismuth (Bi), thorium (Th), uranium (U) medium It may be provided in any one or two or more mixtures.

That is, by adding various metal salt components to the electrolyte solution, the electrolyte solution and the metal salt components cause a synthetic reaction such as hydrolysis, oxidation, and at the same time, precipitation and coprecipitation (other substances or ions that have not yet reached solubility during precipitation) are precipitated together. Precipitation reactions such as

Therefore, in the electrolyte solution, a metal compound representing an oxide component generated by the synthesis reaction and a compound component generated by the precipitation reaction is present, and the oxide and compound particles generated by the reactions are browned in the electrolyte solution. There is no sedimentation due to motion.

Here, the Brown motion is a diffusion phenomenon that occurs because the microparticles that make up the object are in thermal equilibrium even when the object is not moving, so that the brown particles collide with other microparticles and perform translational motion.

That is, due to the Brownian movement, particles of the oxide and the compound may exist in a dispersed state in an electrolyte solution.

Here, the pH is adjusted so that the surface charge of the oxide and compound present in the electrolyte solution is negative (-), or a small amount of metal salt is added to adjust the surface of the desired oxide or compound to be negative charge.

Subsequently, when an oxide film is formed on the surface of the metal base material by applying a constant voltage in an electrolyte solution in which the oxide and the compound are present, the composite oxide film including the oxide and the compound components is implemented.

In more detail that the composite oxide film is formed, the composite oxide film may be formed at a voltage of 300 to 500 (V).

When the voltage for forming the composite oxide film is 250V or more, most surface contaminants are removed in the electrolyte solution, but the formation of the composite oxide film is delayed or hardly oxidized at portions where there is a variation in the composition of the alloy system. Since a phenomenon occurs and surface roughness cannot be adjusted, the case of 300V or more is preferable.

In addition, when a voltage exceeding 500V is applied, it is difficult to control the process such as the composite oxide layer is peeled off or the composite oxide layer is formed at a high speed to increase the surface roughness.

Therefore, it is preferable to form a composite oxide film by applying an appropriate voltage in consideration of the compositional component ratio of each alloy system, etc. between 300 to 500 (V) voltage.

Here, the metal compound (oxide and compound) may be electrophoresed in the voltage range to form a composite layer on the oxide film, the particle size of the metal compound should be provided in 10nm ~ 50㎛. do.

Here, the electrophoresis is a phenomenon in which the particles present in the solution move toward one of the electrodes when the electrode is placed in a solution and a DC voltage is applied, and the moving speed of the particles varies depending on the concentration and type of the electrolyte solution and the size of the particles. get affected.

That is, the particle size of the oxide and the compound should be formed in the range of 10nm ~ 50㎛.

Here, when the size of the particles is formed less than 10nm, the surface area is small, the presence of the particles is unstable, when the size of the particles are formed exceeding 50㎛ the sedimentation of the particles in the electrolyte solution is made smooth electrophoresis I do not lose.

That is, the composite oxide film according to the present invention forms an electrolyte solution in which an oxide and a compound are present in a dispersed state, loads a metal base material, and then performs an PEO process to form an oxide film on the surface of the metal base material.

At the same time, the voltage applied by the PEO process electrophores the oxide and compound particles formed by the synthesis, precipitation, hydrolysis, etc., whereby the oxide and compound particles are deposited on the surface of the oxide film to form a composite layer. .

Therefore, the composite layer is formed on the oxide film by the electrophoresis, and the oxide and the compound particles are deposited on the oxide film, thereby providing a separate atomic component and various functionalities that cannot be exhibited in the general oxide film.

In addition, through the above configuration, the oxide and the compound can be maintained in the dispersed state in the electrolyte solution without physical stirring and sonication according to the prior art.

As described above, the composite oxide film according to the present invention can not only provide various functionalities compared to the existing oxide film, but also the oxide film formation rate formed of PEO is higher than the film formation rate obtained by simple oxidation. There is an advantage that the formation rate and the thickness of the coating layer can also be obtained.

For example, during the oxidation treatment of an aluminum base alloy with PEO, a Ti precursor for forming a submicron-sized TiO ₂ photocatalyst in an electrolyte solution is added to the electrolyte solution, followed by pH adjustment, and then a PEO process. Let's do it.

That is, the composite oxide film in which the TiO ₂ photocatalyst is present on the surface oxide film may be formed by electrophoresis simultaneously with the synthesis and precipitation reactions in the electrolyte solution.

In this case, when the composite oxide film is irradiated with light, it may cause a photocatalytic effect such as organic matter decomposition, odor removal, and sterilization.

In this case, the photocatalyst is fixed to a polymer in most cases. When the photocatalyst is irradiated with light, the polymer required for the immobilization is also decomposed to destroy the immobilization.

However, if the TiO ₂ photocatalyst, such as alumina, is fixed to the aluminum surface by the PEO process by synthesis, precipitation reaction, and electrophoresis as described above, such immobilization destruction does not occur and can be used permanently.

In another example, a composite oxide film may be formed on a medical Ti alloy to obtain hydroxyapatite, which is a component such as human bone.

Here, after adding an appropriate amount of H ₃ PO ₄ containing a soluble Ca component and phosphoric acid component to the electrolyte solution for the PEO process, and proceeds with the PEO process in the oxide film formed on the surface of the Ti alloy by electrophoresis simultaneously with the precipitation reaction Precursors of hydroxyapatite are present.

The surface of the Ti alloy thus made can significantly shorten the surgical period by significantly improving biocompatibility, and can also extend the service life of dental restorations and dental implants.

Another example is to oxidize the aluminum surface with PEO to increase the surface hardness and wear resistance.

Here, when aluminum alcohol (Al (RO) ₃ ) or aluminum hydroxide having a pH adjusted is dispersed in the electrolyte solution, and the PEO process is performed, the precipitated material dispersed in the electrolyte solution adheres to the oxide film by electrophoresis and is complex. An oxide film is formed.

The composite oxide film has crystallinity and higher hardness than the oxide film formed by a general PEO process.

In addition, the oxide film formation rate is significantly faster, and thicker oxide films can be formed in a shorter time.

As described above, in the composite oxide film according to the present invention, a metal compound component produced by the synthesis reaction and the precipitation reaction by adding a metal salt component that causes a synthesis reaction with the electrolyte solution to the electrolyte solution is included in the oxide film, thereby providing new components and functions. Can be added.

In addition, due to the addition of the metal salt component, it is possible to improve the formation rate of the oxide film formed of PEO and at the same time easily form the desired thickness of the oxide film.

As mentioned above, although the present invention has been described with respect to the above-described limited content, the technical idea of the present invention is not limited to the above, and by those skilled in the art to which the present invention pertains, Various modifications and variations may be made without departing from the scope of the appended claims.

Claims (11)

An oxide film formed on the surface of a metal base material by plasma electro-oxidation (PEO), To the electrolyte solution for forming the oxide film is added a metal salt component causing synthesis, precipitation, hydrolysis reaction with the electrolyte solution, In the oxide film, It includes a metal compound produced by the synthesis reaction of the components of the metal base material, the electrolyte solution and the metal salt component, The composite oxide film is formed at a voltage of 300 ~ 500 (V), The metal compound is electrophoresized in the voltage range to form a composite layer on the oxide film. Particle size of the metal compound is a composite oxide film, characterized in that provided in 10nm ~ 50㎛. The method of claim 1, The metal salt component is lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), potassium (K), Ca (Calcium), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), low maenyum (Ge), arsenic (As), selenium (Se), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb) , Molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), tellurium (Te) ), Iodine (I), Cesium (Cs), Barium (Ba), Lanthanum (La), Cerium (Ce), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Terbium (Tb), Dispro Calcium (Dy), Holmium (Ho), Ytterbium (Yb), Ruthetium (Lu), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir ), Or a mixture of two or more metal salts of platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), lead (Pb), bismuth (Bi), thorium (Th), and uranium (U) Composite oxide film to that provided by the feature. delete delete delete The method of claim 1, The metal base material is provided with a metal alloy containing any one or more of aluminum (Al), magnesium (Mg), titanium (Ti), zirconium (Zr), zinc (Zn), niobium (Nb). Composite oxide film. The method of claim 1, A composite oxide film, characterized in that a soluble calcium component or a phosphoric acid component is added to the electrolyte solution to form an oxide film of the medical alloy. As a method of manufacturing an oxide film formed on the surface of a metal base material by plasma electro-oxidation (PEO), Adding a metal salt component which causes a synthesis reaction with the electrolyte solution to an electrolyte solution for forming the oxide film; Adjusting a hydrogen ion index (pH) of the electrolyte solution to which the metal salt component is added; Charging a metal base material to the electrolyte solution to perform a plasma electrolytic oxidation process; In the step of adding the metal salt component, Synthesis, precipitation, and hydrolysis of the components of the metal base material, the electrolyte solution, and the metal salt component produce a metal compound having a particle size of 10 nm to 50 μm in the electrolyte solution. The performing of the plasma electrolytic oxidation process includes applying a voltage of 300 to 500 (V) to the electrolyte solution loaded with the metal base material. The performing of the plasma electrolytic oxidation process includes the step of forming the composite layer on the oxide film by electrophoretic the metal compound in the voltage range. The method of claim 8, The metal salt component is lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), potassium (K), Ca (calcium), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), Zinc (Zn), Gallium (Ga), Low Maenium (Ge), Arsenic (As), Selenium (Se), Rubidium (Rb), Strontium (Sr), Yttrium (Y), Zirconium (Zr), Niobium (Nb) ), Molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), tellurium ( Te, Iodine (I), Cesium (Cs), Barium (Ba), Lanthanum (La), Cerium (Ce), Neodymium (Nd), Samarium (Sm), Gadolinium (Gd), Terbium (Tb), Dies Prosium (Dy), holmium (Ho), ytterbium (Yb), ruthetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium ( Any one or more of metal salts of Ir, platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), lead (Pb), bismuth (Bi), thorium (Th), and uranium (U) spirit The method of producing a composite oxide film, characterized in that is provided with. delete delete