46 results about "Cobalt compounds" patented technology

The invention belongs to the technical field of chemical catalysis, and particularly relates to a preparation method of an alkali metal cation modified cobalt-nitrogen-carbon monatomic catalyst and application of the catalyst in electrosynthesis of hydrogen peroxide. The Co-N-C / X catalyst is obtained by taking a cobalt-containing compound as a metal source, mixing the metal source with a nitrogen-containing organic matter and a carbon material, performing rotary evaporation, grinding and high-temperature pyrolysis in an inert atmosphere, performing acid washing with strong acid to construct surface defects, and finally performing stirring adsorption with an alkali metal salt solution, suction filtration and drying. Alkali metal cations are physically adsorbed and anchored on the surface and interface of the Co-N-C catalyst instead of being dissolved in a solution, so that the electronic structure of Co active sites and the adsorption energy of the * OOH intermediate are optimized, and the problem of separation of alkali metal and a product is solved. When the catalyst is used for electro-catalytic oxygen reduction reaction, the H2O2 selectivity reaches up to 98%, the preparation process is simple, the cost is low, large-scale production can be realized, and the problems that the traditional method is high in energy consumption and large in pollution and the existing catalyst is insufficient in selectivity are solved.

A positive electrode active material having both higher capacity and safety is provided. Provided is a method for manufacturing a positive electrode active material, including forming a mixed solution containing a cobalt compound and a nickel compound dissolved; making the mixed solution react with an alkaline aqueous solution to obtain a suspension in which a cobalt nickel hydroxide is precipitated; performing first suction filtration of the suspension with use of water; and after the first suction filtration, performing second suction filtration with use of an organic solvent. In the cobalt nickel hydroxide, an atomic ratio of nickel in the sum of an atomic ratio of cobalt and the atomic ratio of nickel is greater than 0 and less than or equal to 0.01.

The application relates to the technical field of lithium ion batteries, in particular to a coated ternary positive electrode material and a preparation method and application thereof. The coated ternary positive electrode material comprises a ternary positive electrode material and a coating layer on the surface of the ternary positive electrode material, and the coating layer comprises an aluminum oxide chemically modified cobalt compound layer; in the coating layer, the molar ratio of aluminum oxide and the cobalt compound is (0.001-2):100. The provided coated ternary positive electrode material can improve the specific capacity and cycle performance of a battery.

This invention discloses a method for synthesizing acetate-promoted amidine cobalt complexes. Specifically, when an N,N'-dialkyl-substituted amidine alkali metal salt reacts with a cobalt precursor, acetate is added as a promoter. The chelating effect of acetate regulates the reaction activity and selectivity, enabling the efficient preparation of amidine cobalt compounds. The reaction yield can reach up to 95%, with a product purity >98%. This invention features readily available raw materials, simple operation, mild reaction conditions, good selectivity for the target product, high synthesis efficiency, and convenient post-processing, making it promising for industrial applications.

A particulate cathode active material comprising (A) a base material according to the general formula Li1 + xTM1-xO2, where TM is a combination of Ni with at least one of Mn, Co and Al, and optionally at least another metal selected from the group consisting of Mg, Ti, Zr, Nb, Ta and W, and x is in the range of 0 to 0.2, and (B) crystallites of one or more cobalt compounds, where at least some of the cobalt is in the oxidation state of + III, where the base material (A) is a polycrystalline material, where x is greater than 0 and less than 1. The secondary particles of which consist of primary particles, and crystallites (B) of a cobalt compound are coated on the outer surfaces of these secondary particles, and one or more cobalt compounds are enriched at the surfaces of the primary particles in the voids between adjacent primary particles, and wherein 90% to 99.5% of the secondary particles exhibit such cobalt compound enrichment, all the detection results are determined through EDX and SEM / TEM imaging.

The present application relates to the technical fields of catalyst design and ammonia synthesis, and discloses a preparation method of a pyrazole trinuclear cobalt-based catalyst, which comprises the following steps: step 1, dissolving a metal cobalt compound in water to obtain a first mixed solution, dissolving a pyridine molecule in a mixed organic solution to obtain a second mixed solution, mixing and stirring the first mixed solution and the second mixed solution, and then transferring the mixture to a high-vacuum reaction tube, and then placing the high-vacuum reaction tube in an oil bath to perform a solvothermal reaction; step 2, after the solvothermal reaction is completed, washing, centrifuging and drying the obtained substance to obtain a trinuclear cobalt-based compound powder. The present application uses nitrate as a nitrogen source, a pyrazole cobalt-based compound as a catalyst, and a mixture of potassium sulfate and potassium nitrate as an electrolyte, and effectively synthesizes ammonia through electrochemical reduction. The catalyst exhibits high Faraday efficiency and high yield under high-concentration nitrate conditions.

The invention relates to application of a cobalt compound, a solar cell, slurry of the solar cell and a photovoltaic solder strip. In the application of the cobalt compound in preparation of the photovoltaic module, the cobalt compound comprises anhydrous cobalt chloride and thiocyanide. The cobalt compound is applied to the photovoltaic module, and when water vapor intrudes into the photovoltaic module, anhydrous cobalt chloride in the cobalt compound becomes red when encountering water, so that the area, provided with the cobalt compound, in the photovoltaic module presents conspicuous red which is used as a visual warning signal; maintenance personnel can quickly find and process potential problems of the photovoltaic module; and when the temperature of the photovoltaic module is too high, the anhydrous cobalt chloride reacts with the thiocyanide to present black, so that maintenance personnel can be warned of possible problems of the photovoltaic module in time.

This application relates to a modified high-nickel ternary cathode material, its preparation method, and its applications. The modified high-nickel ternary cathode material includes a substrate and first, second, and third coating layers sequentially coated on the substrate; the substrate includes Li. 1.1‑a M a (Ni b Co c Mn d ) 1‑ e A e O2E f 0.01≤a≤0.2, 0.8≤b≤1, 0.01≤c≤0.2, 0.01≤d≤0.2, 0<e≤0.05, 0≤f≤0.1; M is selected from Na, K, Rb, Cs; A is selected from Al, Mg, Zr, Ti, W, Y, B, Co, Nb, Mo, Sb, Sr; E is selected from F, Cl, Br, and I; the first, second, and third coating layers respectively include Li2SO4, a cobalt-containing compound, and a compound containing M1. This invention can simultaneously improve the battery's capacity, cycle performance, structural stability, and safety, without introducing toxic or harmful products.

The invention provides a method for enhancing firmness of a coating of a tail gas pollutant treatment catalyst. The method comprises the following steps: S1, drying the tail gas pollutant treatment catalyst of which the coating falls off, and carrying out air pressure purging; s2, nano aluminum oxide is added into deionized water to be dispersed, and nano aluminum sol is obtained; s3, adding the nano aluminum sol into the cerium-containing oxide and dispersing, then adding an organic cobalt compound and dispersing, adding a pH regulator to regulate the pH of the mixed solution to 2-3, and dispersing to obtain composite nano sol; and S4, soaking the tail gas pollutant treatment catalyst into the composite nano sol, fixing one end of the catalyst by using an air seal, and carrying out negative pressure suction, drying and roasting. According to the invention, a layer of porous bonding active film is coated outside the catalyst coating, so that the catalyst coating does not fall off, and the performance is not negatively influenced, thereby avoiding the situations of catalyst scrapping and concession acceptance by customers, reducing the production cost and improving the product percent of pass.

(A) General formula Li 1+x TM 1-x a core material based on O2, wherein TM is a combination of Ni and at least two of Mn, Co and Al, and optionally at least one further metal selected from Mg, Ti, Zr, Nb, Ta and W, where x is in the range of -0.05 to +0.05, and the nickel content is in the range of 80 to 99 mol% of TM; (B) particles of cobalt compound(s) in which at least some of the cobalt is in the +III oxidation state; (C) a shell containing at least one oxide of B or W 1. A cathode active material comprising: The core material (A) is a polycrystalline material in which secondary particles are composed of primary particles, and particles (B) of a cobalt compound are concentrated on the surfaces of the secondary particles.

The invention provides basic cobalt carbonate with high carbonate content and a preparation method thereof, and belongs to the technical field of cobalt compound preparation. The basic cobalt carbonate can be used as a cobalt source or a cobalt compound precursor for a positive electrode material. The method comprises the following steps: introducing carbon dioxide into a sodium carbonate solution in advance to obtain a pre-carbonized sodium carbonate solution; synchronously dropwise adding the pre-carbonized sodium carbonate solution and the cobaltous sulfate solution for reaction under the condition of partial pressure of carbon dioxide, and controlling the pH value of the reaction solution to obtain reaction slurry; aging the reaction slurry under a carbon dioxide pressurization condition, regulating the pH value, and filtering to obtain a wet filter cake; the wet filter cake is sequentially subjected to sodium bicarbonate solution replacement washing and carbon dioxide saturated deionized water washing, then dried, smashed and screened, and a product is obtained; the method disclosed by the invention is beneficial to improving the carbonate introduction degree of basic cobalt carbonate and reducing soluble salt entrainment, and few insoluble residues are generated in acid medium dissolution evaluation.

The invention relates to a method for producing a Fischer-Tropsch synthesis catalyst. The present invention relates to a method for conveniently preparing a supported cobalt-containing Fischer-Tropsch synthesis catalyst having improved activity and selectivity for C5 + hydrocarbons. In one aspect, the present invention provides a process for preparing a supported cobalt-containing Fischer-Tropsch synthesis catalyst, the process comprising the steps of: (a) impregnating a support material with i) a cobalt-containing compound and ii) acetic acid or a manganese salt of acetic acid in a single impregnation step to form an impregnated support material; and (b) drying and calcining the impregnated support material; wherein the support material impregnated in step (a) is not previously modified with a metal source other than cobalt; and wherein when the cobalt-containing compound is cobalt hydroxide, a manganese salt of acetic acid is not used in step (a) of the process.

The invention discloses a Co9S8 / MoS2 / CNTs ternary composite catalyst and a preparation method and application method thereof, and relates to the technical field of catalysts.The preparation method comprises the following steps that S100, a precursor solution is prepared, specifically, a nitrogen-containing sulfur source compound, a transition metal cobalt compound and a transition metal molybdenum compound are jointly dissolved or dispersed in a first solvent, and a precursor solution is prepared; a uniform metal-sulfur coordination precursor solution is formed; s200, precursor curing: performing cryogenic freezing on the metal-sulfur coordination precursor solution, and then performing freeze drying to obtain a loose solid precursor; and S300, in-situ synthesis and compounding: carrying out one-step high-temperature heat treatment on the solid precursor in a protective gas atmosphere, and then cooling to room temperature to obtain the Co9S8 / MoS2 / CNTs ternary composite catalyst. The catalyst prepared by the preparation method is high in stability, good in catalytic performance, wide in pH application range and capable of being magnetically separated and recycled, and the efficiency of activating peroxymonosulfate to decompose organic pollutants is high.

The invention relates to a high-dispersity medium-high-nickel single-crystal ternary positive electrode material, a preparation method thereof and a lithium ion battery. The medium-high-nickel single-crystal ternary positive electrode material comprises single-crystal matrix particles, a symbiotic structure middle layer enriched on the interface of the single-crystal matrix particles, and a lithium-fluorine-cobalt compound coating layer coating the surface of the symbiotic structure middle layer. The preparation method comprises the following steps: mixing, sintering, cooling, crushing and sieving a nickel-cobalt-manganese hydroxide precursor, a lithium source and a high-valence dopant to obtain a high-dispersion primary sintering material; and mixing the obtained primary sintered material with a coating agent, sintering, crushing and sieving to obtain the high-dispersity medium-high nickel single crystal ternary positive electrode material. According to the method, excessive fusion of a single crystal matrix particle interface can be prevented, the primary sintering material is easy to crush and dissociate, the influence on subsequent coating treatment is avoided, and meanwhile, the problem of wastewater caused by water washing by a molten salt method and the problems of short cycle life and low capacity at high voltage and high temperature caused by degradation of the particle interface are avoided.

The invention provides a method for preparing methyl propionate in one step by taking ethylene, carbon monoxide and methanol as raw materials. According to the method, cobalt salt or a cobalt compound and a pyridyl-containing organic compound form a catalytic system, and ethylene can be effectively catalyzed to be converted into methyl propionate at the temperature of 80-180 DEG C and the pressure of 0.5-8 Mpa. The mechanism for realizing the method is that divalent cobalt is promoted to be converted into key active species Co2 (CO) 8 and HCo (CO) 4 by utilizing the alkalinity and coordination capability of a pyridyl organic matter in a CO atmosphere with enough pressure, and a characteristic peak of a key intermediate HCo (CO) 4 is captured through electrospray ionization mass spectrometry (figure 4). Compared with the prior art, the methyl propionate synthesis method has the advantages that carbonyl esterification of ethylene can be realized under relatively mild conditions without using noble metals and acidic auxiliaries, unreacted gas can be recycled, the catalyst can be recycled through rectification, and the methyl propionate synthesis method is green and economical.

A cathode active material comprising (A) a core material according to the general formula Li1 + xTM1-xO2, where TM is a combination of Ni with at least two of Mn, Co and Al, and optionally at least one plurality of metals selected from the group consisting of Mg, Ti, Zr, Nb, Ta and W, and x is in the range of-0.05 to + 0.05, and where the nickel content is in the range of 80 to 99 mol-% of TM, and (B) particles of one or more cobalt compounds, wherein at least some of the cobalt is in the oxidation state of + III, (C) a shell comprising an oxide of at least one of B or W, and wherein the core material (A) is a polycrystalline material, the secondary particles of which consist of primary particles, and the particles (B) of the cobalt compound are enriched at the surface of said secondary particles.

This invention discloses a chiral oxazoline-pyridine-imine cobalt compound, its synthesis method, and its applications. The synthesis method involves the condensation reaction of 2-cyano-6-acetylpyridine and an aniline derivative with p-toluenesulfonic acid to generate a pyridine-imine compound. This compound is then cyclized with different chiral amino alcohols in the presence of zinc trifluoromethanesulfonate to generate chiral oxazoline-pyridine-imine ligands. The reaction of these ligands with anhydrous cobalt chloride successfully prepared four chiral oxazoline-pyridine-imine cobalt compounds. The cobalt catalyst synthesized in this invention possesses different chiral groups, electronic effects, and steric hindrance, and can catalyze the polymerization of isoprene.

The application belongs to the field of olefin polymerization, and particularly relates to a cobalt-based catalyst and a preparation method of polybutadiene composite rich in 1,2-structure. The cobalt-based catalyst contains components A, B, C and D which are independently stored, the component A is a cobalt compound, the component B is an organic aluminum compound, the component C is carbon disulfide, and the component D is a silicon-containing compound. In the cobalt-based catalyst, the catalyst activity, the 1,2-addition directional selectivity and the 1,2-structure content in polybutadiene can be greatly improved by introducing the compound containing silicon-oxygen bond and the synergistic effect of the above components, the crystallization performance is improved to realize in-situ synthesis of polybutadiene composite material rich in 1,2-structure and silicon dioxide, and the production efficiency and product performance are improved.

The application belongs to the technical field of chemical catalysis, and particularly relates to a preparation method of an alkali metal cation modified cobalt-nitrogen-carbon single-atom catalyst and an application of the catalyst in electro-synthesizing hydrogen peroxide. A cobalt-containing compound is used as a metal source, mixed with a nitrogen-containing organic matter and carbon material, and then subjected to rotary evaporation, grinding, inert atmosphere high-temperature pyrolysis, and finally, surface defect construction through strong acid pickling. Finally, the Co-N-C / X catalyst is obtained through stirring adsorption of an alkali metal salt solution, suction filtration and drying. In the application, the alkali metal cation is physically adsorbed and anchored on the surface interface of the Co-N-C catalyst, rather than being dissolved in the solution, which not only optimizes the electronic structure of the Co active site and the adsorption energy of the OOH intermediate, but also avoids the difficulty in separating the alkali metal from the product. When the catalyst is used in the electro-catalytic oxygen reduction reaction, the selectivity of H2O2 is as high as 98%, and the preparation process is simple, low in cost and scalable, thereby solving the problems of high energy consumption, serious pollution and insufficient selectivity of existing catalysts in the traditional method.

The invention provides a method for recovering cobalt from co-precipitation waste liquid of aluminum-doped cobalt carbonate. The method comprises the following steps: providing co-precipitation waste liquid of aluminum-doped cobalt carbonate, wherein the co-precipitation waste liquid contains complex cobalt and free cobalt; mixing the coprecipitation waste liquid with a composite precipitator, carrying out cobalt precipitation treatment, and carrying out solid-liquid separation to obtain an enriched cobalt compound and a treatment liquid with the cobalt content reaching the standard; the composite precipitant comprises a complex cobalt precipitant and a free cobalt precipitant. According to the method, the cobalt precipitation process of synergistic precipitation of the complexing cobalt precipitant and the free cobalt precipitant is adopted, efficient and synergistic recovery of the free cobalt and the complexing cobalt in the waste liquid can be achieved, the technological process is simple, operation is convenient, cost is low, complex breaking in advance is not needed, extra energy consumption is effectively avoided, and the method is suitable for industrial production. And the problem of ammonia gas pollution possibly generated in the complex breaking process is also prevented. According to the process, resources are recycled thoroughly, the enrichment degree and purity of cobalt compounds are high, and the treatment liquid meets the environment-friendly discharge standard.

The invention relates to doped cobaltosic oxide and a preparation method and application thereof.The preparation method comprises the following steps that 1, a cobalt-aluminum mixed salt solution and a precipitant solution flow into a base solution in a parallel mode, a co-precipitation reaction is conducted, and an aluminum-doped cobalt compound is obtained; the coprecipitation reaction comprises a first reaction stage, a second reaction stage and a third reaction stage which are sequentially carried out; a first complexing agent and a second complexing agent are respectively added in the second reaction stage and the third reaction stage in a parallel flow manner, and the types of the first complexing agent and the second complexing agent are different; and (2) calcining the aluminum-doped cobalt compound in an oxygen-containing atmosphere to obtain the doped cobaltosic oxide, and the doped type cobaltosic oxide comprises aluminum doped cobaltosic oxide. By regulating and controlling the complexing agent in different stages of the coprecipitation reaction, the aluminum segregation phenomenon and the nuclear explosion and cracking phenomena of the material are avoided while the uniform distribution of the aluminum element in the obtained material is improved.

The present invention relates to a method for producing alcohol from synthesis gas, wherein alcohol selectivity is improved and alcohol can be obtained more selectively. Said method for producing alcohol includes steps 1 and 2 below. Step 1: a catalyst production step for, in a non-aqueous solvent, causing a cobalt-containing compound (a) and a lanthanoid element-containing compound (b), which are soluble in the non-aqueous solvent, to react with a divalent or higher carboxylic acid compound (c), and obtaining a catalyst from the reaction product. Step 2: An alcohol production step for obtaining alcohol by reacting synthesis gas in the presence of the catalyst obtained in step 1.

The invention discloses a catalyst component for olefin polymerization as well as a preparation method and application thereof, and relates to the technical field of olefin polymerization. The catalyst component for olefin polymerization comprises the following components or a reaction product of the following components: (1) a magnesium compound, (2) an organic phosphorus compound, (3) an organic epoxy compound, (4) an organic alcohol compound, (5) a titanium compound and (6) a cobalt compound, a catalyst prepared from the catalyst component for olefin polymerization is normal in activity, and an obtained polymer is high in molecular weight and obviously narrow in particle size distribution.

This invention discloses an in-situ surface-coated LiF-coated water-resistant 4.7V lithium cobalt oxide cathode material, its preparation method, and its applications. The chemical formula of the cathode material of this invention is Li. 1‑2x‑2y Co 1‑ z Mg x Ni y Al z O2@LiF, where 0≤x≤0.05, 0≤y≤0.05, 0≤z≤0.05, and x, y, and z cannot all be 0; LiF is Li 1‑2x‑2y Co 1‑z Mg x Ni y Al z O2 material coating layer. This invention mixes lithium metal salts, cobalt compounds, and an F-containing dopant to obtain a mixture; the mixture is sintered once at a high temperature, then cooled and ground uniformly, followed by a second sintering and cooling to obtain the in-situ surface-coated water-resistant 4.7V lithium cobalt oxide material. This invention constructs a complete, continuous, and uniformly distributed hydrophobic protective layer on the surface of lithium cobalt oxide particles through in-situ coating technology, effectively blocking the corrosion of the material by electrolyte and moisture; the simultaneously formed elemental doping enhances the metal-oxygen bond binding energy, synergistically improving the bulk structural stability and jointly ensuring the long cycle life of the electrode material.

The invention provides a high-nickel low-cobalt positive electrode material and a preparation method thereof, and the preparation method comprises the following steps: mixing NixMn1-x (OH) 2 and a lithium-containing compound to form a first mixture; performing first heat treatment on the first mixture in an oxygen-containing atmosphere to form a precursor containing lithium, nickel and manganese; the precursor containing lithium, nickel and manganese is placed in an oxygen atmosphere for second heat treatment, and LiNi < x > Mn < 1-x > O < 2 > is formed; mixing a cobalt-containing compound with LiNi < x > Mn < 1-x > O < 2 > to form a second mixture; performing third heat treatment on the second mixture, and grinding to form the high-nickel low-cobalt positive electrode material LiNi < x > Co < y > Mn < 1-x-y > O < 2 >, wherein x is more than or equal to 0.8 and less than 1, and y is more than or equal to 0 and less than 0.02, so that the specific capacity and the cycle performance of the positive electrode material are improved while the cobalt content is reduced.

This invention belongs to the field of olefin polymerization and relates to a conjugated diene coordination polymerization system and its application. It includes a cobalt compound (A), an organoaluminum compound (B), a silicon-containing compound (C), a conjugated diene monomer (D), and a solvent (E). In this cobalt-based catalytic conjugated diene polymerization system, the silicon-containing compound acts as both a catalyst component and participates in the polymerization reaction, effectively improving the catalytic activity of the polymerization reaction and allowing for adjustment of the microstructure content within a certain range.

This invention relates to a highly dispersed medium-high nickel single-crystal ternary cathode material, its preparation method, and a lithium-ion battery. The medium-high nickel single-crystal ternary cathode material comprises single-crystal matrix particles, a symbiotic intermediate layer enriched at the interface of the single-crystal matrix particles, and a lithium fluorine-cobalt compound coating layer covering the surface of the symbiotic intermediate layer. The preparation method includes: mixing a nickel-cobalt-manganese hydroxide precursor, a lithium source, and a high-valence dopant, sintering, cooling, crushing, and sieving to obtain a highly dispersed primary sintered material; then mixing the obtained primary sintered material with a coating agent, sintering, crushing, and sieving to obtain the highly dispersed medium-high nickel single-crystal ternary cathode material. This invention can prevent excessive fusion at the interface of the single-crystal matrix particles, ensure that the primary sintered material is easily crushed and dissociated, avoid affecting subsequent coating processes, and avoid the wastewater problems caused by molten salt washing and the problems of short cycle life and low capacity under high voltage and high temperature due to particle interface degradation.

A method of producing a positive electrode for a non-aqueous electrolyte secondary battery, includes: providing a lithium transition metal composite oxide having a layered structure, having a ratio D50 / DSEM of 1 or more and 4 or less, and having a certain content of nickel and a certain content of cobalt; bringing the lithium transition metal composite oxide into contact with a cobalt compound to obtain an adhered material; heat-treating the adhered material at a temperature higher than 700° C. and lower than 1100° C. to obtain a heat-treated product; obtaining a positive electrode composition containing the heat-treated product, a conductive auxiliary agent, and a binder; and applying and pressurizing the positive electrode composition onto a collector to form an active material layer having a density of 2.7 g / cm3 or more and 3.9 g / cm3 or less on the collector.

The present invention relates to a positive electrode material comprising a core material and a coating layer coated on the surface of the core material, the core material comprises nickel hydroxide, and the coating layer comprises a tetravalent cobalt compound; and based on the weight of the coating layer, the content of the tetravalent cobalt compound is no less than 45 wt %. The present invention also relates to a preparation method for the positive electrode material. The present invention further relates to an alkaline secondary battery containing the positive electrode material.

A non-aqueous electrolyte secondary battery capable of constructing a non-aqueous electrolyte secondary battery with excellent output characteristics. This invention provides a method for producing a positive electrode active material. [Solution] Average particle size D based on electron microscope observation SEM 50% particle size D of the cumulative particle size distribution based on volume 50 Ratio D 50 / D SEM The method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery comprises: preparing a lithium transition metal composite oxide having a layered structure, a ratio of the number of moles of nickel to the total number of moles of metals other than lithium of 0.3 or more and less than 1, and a ratio of the number of moles of cobalt to the total number of moles of metals other than lithium of 0 or more and less than 0.5; contacting the lithium transition metal composite oxide with a cobalt compound in a liquid medium to obtain a deposit with the cobalt compound attached; and heat-treating the deposit at a temperature of 800°C or more and 1000°C or less to obtain a heat-treated product.