Titanium base material containing corrosion-resistant coating and preparation method of titanium base material

Abstract

The invention provides a preparation method of a titanium base material containing a corrosion-resistant coating, which comprises the following steps: S01, pretreating the surface of the titanium base material to obtain a pretreated titanium base material; s02, surface oxidation is conducted on the pretreated titanium base material through high-temperature thermal shock, a titanium oxide base material is obtained, and a titanium oxide coating is formed on the surface of the titanium oxide base material; s03, the titanium oxide base material is reduced, and the titanium base material containing the corrosion-resistant coating is obtained; the corrosion-resistant coating is a TinO2n-1 coating, and n is at least one of 1, 2, 3, 4 or 5. The titanium substrate is subjected to oxidation and reduction treatment through high-temperature thermal shock, so that the TinO2n-1 coating with high conductivity, high corrosion resistance and oxidation resistance can be formed on the surface of the titanium substrate. The preparation method disclosed by the invention is short in time consumption, capable of preventing the substrate from being heated for a long time to generate mechanical stress, relatively low in preparation cost and capable of being applied on a large scale.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to a titanium substrate containing a corrosion-resistant coating and a preparation method thereof. Background Art

[0002] In fuel cells or electrolyzers, the polar plates are an indispensable and important component. The bipolar plates account for about 48% of the total cost. The materials have evolved from graphite to stainless steel and titanium. Although graphite has excellent electrical conductivity and corrosion resistance, its brittleness and complex channel processing limit its practical application. Stainless steel has the potential to replace graphite due to its excellent mechanical properties, ductility, and electrical and thermal conductivity. However, stainless steel has poor chemical stability and cannot be directly used in fuel cells or electrolyzers. It is necessary to introduce high corrosion resistance and conductive coatings (such as C, titanium nitride, Ti / TiN, Au / TiN, TiN / C and (Ti, Zr)N, etc.), and its poor bonding strength needs to be solved. Compared with stainless steel, Ti exhibits superior corrosion resistance, but in a highly oxidizing environment, semiconductor titanium dioxide is formed on the titanium surface with low electrical conductivity, which directly affects the power cost and thermal conductivity, significantly increases ohmic polarization under fuel cell conditions, and causes the operating voltage to increase significantly with the increase of current in electrolyzer applications.

[0003] In order to achieve a balance between corrosion resistance and electrical conductivity of titanium plates, the application of surface coating is a common method. At present, there have been reports on carbides, nitrides, oxides, precious metals and carbon-based coatings of metals. The biggest disadvantage of carbide, nitride and carbon-based coatings is poor adhesion to the substrate. Precious metal coatings have low practicality due to their high cost. Ti with high electrical conductivity, corrosion resistance and oxidation resistance n O 2n-1 Ti has great potential for protecting metal bipolar plates and has been shown to be effective in increasing surface electrical conductivity and improving corrosion resistance. n O 2n-1 Ti particles are used as raw materials and Ti is obtained by PVD methods such as magnetron sputtering and plasma spraying. n O 2n-1 The coating is expensive and not suitable for large-scale mass production, and the Ti n O 2n-1 The coating will have microscopic defects and be prone to local corrosion. A compact coating can be obtained by the CVD method, but the substrate needs to withstand high temperatures for a long time during the preparation process, which is prone to mechanical stress. The traditional heat treatment redox method is affected by many factors such as the titanium powder / titanium oxide ratio, temperature and time, and is prone to the formation of various sub-titanium oxide impurities, which is prone to local oxidation and reduces conductivity. At the same time, due to the long heat treatment time, the formed Ti n O 2n-1The grain size is several hundred nanometers and has twins. There are KirKendall voids inside the oxide layer and at the interface between the oxide and Ti metal due to the outward diffusion of elemental Ti. These defects reduce the durability of the plate. Summary of the invention

[0004] The embodiment of the present invention provides a titanium substrate with a corrosion-resistant coating and a preparation method thereof, aiming to solve the problem of Ti n O 2n-1 The coating produces large particles, many local defects, and large internal mechanical stress due to long-term heating.

[0005] To achieve the above object, on the one hand, an embodiment of the present invention provides a method for preparing a titanium substrate containing a corrosion-resistant coating, comprising the following steps:

[0006] S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate;

[0007] S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating is formed on the surface of the titanium oxide substrate;

[0008] S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; the corrosion-resistant coating is Ti n O 2n-1 Coating, n is at least one of 1, 2, 3, 4 or 5.

[0009] As a preferred embodiment, in step S01,

[0010] The pretreatment comprises the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it to obtain a pretreated titanium substrate.

[0011] Preferably, the annealing treatment is performed in an inert gas atmosphere or under vacuum conditions, the temperature of the annealing treatment is 873K to 1273K, and the time of the annealing treatment is ≤10min.

[0012] Preferably, the washing is performed by the following method: first washing with acid, and then washing with pure water and ethanol in sequence.

[0013] The acid is preferably at least one of hydrofluoric acid, nitric acid or sulfuric acid. Impurities on the surface of the titanium substrate can be removed by acid washing.

[0014] The cleaning time of the acid is ≤10min.

[0015] As a preferred embodiment, in step S02,

[0016] Preferably, the heating rate of the high temperature thermal shock is 10 3 K / s~10 5 K / s, the heating time is 15ms-800ms; the peak temperature of the high temperature thermal shock is 973K-1473K.

[0017] Preferably, the high temperature thermal shock is achieved by electric Joule heating (i.e. Joule thermal flash evaporation technology), microwave heating, thermal radiation heating, plasma heating or laser heating, preferably by Joule thermal flash evaporation technology.

[0018] Preferably, the high-temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 20ms to 800ms.

[0019] Preferably, the current of the power supply is 0A-20A, and the voltage of the power supply is 40V-80V.

[0020] Preferably, the thickness of the titanium oxide coating is 100 nm.

[0021] As a preferred embodiment, in step S03,

[0022] Preferably, the reduction is achieved by the following method: reducing the titanium oxide substrate by high-temperature thermal shock in an oxygen atmosphere; the peak temperature of the high-temperature thermal shock is 973K to 1473K; and the reduction time is 20ms to 800ms.

[0023] Preferably, the oxygen partial pressure of the oxygen atmosphere is 1.0*10 -4 atm~1.0*10 -10 atm.

[0024] Preferably, the high-temperature thermal shock comprises the following steps: connecting the titanium oxide substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 20ms to 800ms.

[0025] Preferably, the current of the power supply is 0A-20A, and the voltage of the power supply is 40V-80V.

[0026] Preferably, the reduction is achieved by the following method: heating the titanium oxide substrate to 773K-1273K by high temperature thermal shock in a hydrogen atmosphere.

[0027] Preferably, the high temperature thermal shock is achieved by electric Joule heating, microwave heating, thermal radiation heating, plasma heating or laser heating, preferably by electromagnetic laser radiation heating for 20ms to 800ms.

[0028] Preferably, the thickness of the corrosion-resistant coating is 30 nm to 70 nm.

[0029] On the other hand, an embodiment of the present invention further provides a titanium substrate containing a corrosion-resistant coating, and the titanium substrate containing the corrosion-resistant coating is prepared by the preparation method.

[0030] The present invention uses high temperature thermal shock to oxidize and reduce the titanium substrate, so that the surface of the titanium substrate can form a highly conductive, corrosion-resistant and oxidation-resistant Ti n O 2n-1 (n is at least one of 1, 2, 3, 4 or 5) coating. The present application can effectively reduce the heat treatment time by rapidly heating up, construct non-equilibrium high temperature conditions, realize the kinetic control process, shorten the diffusion time and diffusion distance of atoms, and thus limit the Ti n O 2n-1 The particle size increases and the thickness of the oxide layer is controlled, thereby reducing defects such as interface voids, improving the conductivity of the coating while ensuring high corrosion resistance of the coating, and effectively reducing the contact resistance of the coating.

[0031] The titanium substrate containing the corrosion-resistant coating prepared by the method of the present application contains conductive particles Ti n O 2n-1 , Ti n O 2n-1 The small particles make the coating dense and uniform without obvious local defects. It can be used in fuel cells or electrolytic cell plates, and can solve the problem of decreased electrical conductivity and thermal conductivity during the application of titanium as a plate. The preparation method of the present application takes a short time, can avoid mechanical stress caused by long-term heating of the substrate, has a low preparation cost, and can be used on a large scale. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] Specifically, an embodiment of the present invention provides a method for preparing a titanium substrate containing a corrosion-resistant coating, comprising the following steps:

[0038] S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate;

[0039] S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating (Ti / TiO2) is formed on the surface of the titanium oxide substrate;

[0040] S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; the corrosion-resistant coating is Ti n O 2n-1 coating, n is at least one of 1, 2, 3, 4 or 5 (the value of n can be adjusted according to the strength of the oxidation conditions and the corresponding reduction conditions).

[0041] As a preferred embodiment, in step S01,

[0042] The pretreatment comprises the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it to obtain a pretreated titanium substrate.

[0043] Preferably, the annealing treatment is carried out in an inert gas atmosphere or under vacuum conditions, the annealing treatment temperature is 873K~1273K (depending on the actual needs, it can be 873K, or 950K, or 1073K, or 1273K, etc.), and the annealing treatment time is ≤10min (depending on the actual needs, it can be 3min, or 5min, or 8min, or 10min, etc.).

[0044] Preferably, the washing is performed by the following method: first washing with acid, and then washing with pure water and ethanol in sequence.

[0045] The acid is preferably at least one of hydrofluoric acid, nitric acid or sulfuric acid. Through acid washing, impurities on the surface of the titanium substrate can be removed, effectively ensuring the oxidation and reduction effects of the titanium substrate.

[0046] The acid cleaning time is ≤10 min (depending on the actual use requirements, it can be 3 min, 5 min, 8 min, 10 min, etc.).

[0047] As a preferred embodiment, in step S02,

[0048] Preferably, the heating rate of the high temperature thermal shock is 10 3 K / s~10 5 K / s (depending on the actual use needs, it can be 10 3 K / s, or 2*10 3 K / s, or 10 4 K / s, or 10 5 K / s, etc.), the heating time is 15ms~800ms (depending on the actual needs, it can be 15ms, or 60ms, or 300ms, or 800ms, etc.); the peak temperature of the high temperature thermal shock is 973K~1473K (depending on the actual needs, it can be 973K, or 1050K, or 1273K, or 1473K, etc.).

[0049] Preferably, the high temperature thermal shock is achieved by electric Joule heating (i.e. Joule thermal flash evaporation technology), microwave heating, thermal radiation heating, plasma heating or laser heating, preferably by Joule thermal flash evaporation technology.

[0050] Preferably, the high-temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, turning on the power supply for high-temperature thermal shock for 20ms to 800ms (depending on the actual needs, it can be 20ms, or 60ms, or 300ms, or 800ms, etc.).

[0051] Preferably, the current of the power supply is 0A-20A (depending on the actual use requirements, it can be 2A, or 5A, or 15A, or 20A, etc.), and the voltage of the power supply is 40V-80V (depending on the actual use requirements, it can be 40V, or 45V, or 65V, or 80V, etc.). In this way, the surface of the pretreated titanium substrate is oxidized by the Joule heat generated by the current, and a uniform titanium oxide coating is formed on the surface of the pretreated titanium substrate.

[0052] Preferably, the thickness of the titanium oxide coating is 100 nm.

[0053] As a preferred embodiment, in step S03,

[0054] Preferably, the reduction is achieved by the following method: reducing the titanium oxide substrate by high-temperature thermal shock in an oxygen atmosphere; the peak temperature of the high-temperature thermal shock is 973K~1473K (depending on the needs of actual use, it can be 973K, or 1000K, or 1373K, or 1473K, etc.); the reduction time is 20ms~800ms (depending on the needs of actual use, it can be 20ms, or 60ms, or 300ms, or 800ms, etc.).

[0055] Preferably, the oxygen partial pressure of the oxygen atmosphere is 1.0*10 -4 atm~1.0*10 -10 atm.

[0056] Preferably, the high-temperature thermal shock comprises the following steps: connecting the titanium oxide substrate to a conductive copper sheet, turning on the power supply for high-temperature thermal shock for 20ms to 800ms (depending on the actual use needs, it can be 20ms, or 60ms, or 300ms, or 800ms, etc.).

[0057] Preferably, the current of the power supply is 0A-20A (depending on the actual use requirements, it can be 2A, or 5A, or 15A, or 20A, etc.), and the voltage of the power supply is 40V-80V (depending on the actual use requirements, it can be 40V, or 45V, or 65V, or 80V, etc.). In this way, the Joule heat generated by the current causes the titanium ions of the titanium oxide substrate to diffuse and react with oxygen at the interface of the substrate Ti / TiO2 film, shortening the diffusion time and diffusion distance of the atoms, thereby limiting the Ti n O 2n-1 The particle size grows, the thickness of the oxide layer is controlled, and Ti is formed. n O 2n-1 The coating (i.e., dense film) reduces defects such as interface voids. The thickness of TiO2, oxygen partial pressure, and thermal shock treatment time can be adjusted to n O 2n-1 The thickness of the coating.

[0058] Preferably, the reduction is achieved by the following method: in a hydrogen atmosphere, the titanium oxide substrate is heated to 773K-1273K by high temperature thermal shock (depending on the actual use requirements, it can be 773K, or 1000K, or 1173K, or 1273K, etc.).

[0059] Preferably, the high temperature thermal shock is achieved by electric Joule heating, microwave heating, thermal radiation heating, plasma heating or laser heating, preferably by electromagnetic laser radiation heating for 20ms to 800ms. In a hydrogen atmosphere, the titanium oxide substrate is heated by high temperature thermal shock so that the temperature of the local site of the titanium oxide substrate reaches 773K to 1273K, and the hydrogen reduces TiO2 to form Ti n O 2n-1 , forming a local TiO2 encapsulating Ti n O 2n-1 coating, which enhances the conductivity of the coating.

[0060] Preferably, the thickness of the corrosion-resistant coating is 30 nm to 70 nm.

[0061] Example 1

[0062] A method for preparing a titanium substrate containing a corrosion-resistant coating comprises the following steps:

[0063] S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate;

[0064] S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating is formed on the surface of the titanium oxide substrate;

[0065] S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; the corrosion-resistant coating is Ti n O 2n-1 coating.

[0066] In step S01,

[0067] The pretreatment comprises the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it (low temperature drying is sufficient, generally drying below 30° C.) to obtain a pretreated titanium substrate.

[0068] The annealing process is performed in an Ar gas atmosphere, the annealing temperature is 1073K, and the annealing time is 10s.

[0069] The washing is performed by the following method: firstly washing with acid, and then washing with pure water and ethanol in sequence.

[0070] The acid is 0.5wt% HF+2wt% HNO3. The cleaning time of the acid is 10 minutes.

[0071] In step S02,

[0072] The heating rate of the high temperature thermal shock is 10 4 K / s, the heating time is 400ms; the peak temperature of the high temperature thermal shock is 973K.

[0073] The high temperature thermal shock is achieved by Joule heat flash evaporation technology.

[0074] The high-temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 400ms.

[0075] The current of the power supply is 20A, and the voltage of the power supply is 60V.

[0076] The thickness of the titanium oxide coating is 100 nm.

[0077] In step S03,

[0078] The reduction is achieved by the following method: reducing the titanium oxide substrate by high-temperature thermal shock in an oxygen atmosphere; the peak temperature of the high-temperature thermal shock is 1173K; and the reduction time is 400ms.

[0079] The oxygen partial pressure of the oxygen atmosphere is 1.0*10 -5 atm.

[0080] The high-temperature thermal shock comprises the following steps: connecting the titanium oxide substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 400ms.

[0081] The current of the power supply is 20A, and the voltage of the power supply is 60V.

[0082] SEM test shows that the surface of the titanium substrate with corrosion-resistant coating is smooth, dense and uniform. XRD and XPS test shows that the surface of the titanium substrate with corrosion-resistant coating has formed Ti n O 2n-1 Coating. TEM test results show that the thickness of the corrosion-resistant coating is about 60nm. n O 2n-1 The particles are about 15nm. Electrochemical tests have shown that the corrosion potential of the titanium substrate with corrosion-resistant coating is 0.607V (vs. RHE) and the corrosion current density is 0.063uA / cm 2 (Test conditions: 0.5M / L sulfuric acid + 2ppm hydrofluoric acid electrolyte, test temperature 70°C), contact resistance 5mΩcm 2 (Pressure condition 140N).

[0083] Example 2

[0084] A method for preparing a titanium substrate containing a corrosion-resistant coating comprises the following steps:

[0085] S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate;

[0086] S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating is formed on the surface of the titanium oxide substrate;

[0087] S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; the corrosion-resistant coating is Ti n O 2n-1 coating.

[0088] In step S01,

[0089] The pretreatment comprises the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it (low temperature drying) to obtain a pretreated titanium substrate.

[0090] The annealing process is performed in an Ar gas atmosphere, the annealing temperature is 1073K, and the annealing time is 10s.

[0091] The washing is performed by the following method: firstly washing with acid, and then washing with pure water and ethanol in sequence.

[0092] The acid is 0.5wt% HF+2wt% HNO3. The cleaning time of the acid is 10 minutes.

[0093] In step S02,

[0094] The heating rate of the high temperature thermal shock is 10 5 K / s, the heating time is 400ms; the peak temperature of the high temperature thermal shock is 1073K.

[0095] The high temperature thermal shock is achieved by Joule heat flash evaporation technology.

[0096] The high-temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 400ms.

[0097] The current of the power supply is 20A, and the voltage of the power supply is 80V.

[0098] The thickness of the titanium oxide coating is 100 nm.

[0099] In step S03,

[0100] The reduction is achieved by the following method: reducing the titanium oxide substrate by high-temperature thermal shock in an oxygen atmosphere; the peak temperature of the high-temperature thermal shock is 1173K; and the reduction time is 400ms.

[0101] The oxygen partial pressure of the oxygen atmosphere is 1.0*10 -5 atm.

[0102] The high-temperature thermal shock comprises the following steps: connecting the titanium oxide substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 400ms.

[0103] The current of the power supply is 20A, and the voltage of the power supply is 60V.

[0104] SEM test shows that the surface of the titanium substrate with corrosion-resistant coating is smooth, dense and uniform. XRD and XPS test shows that the surface of the titanium substrate with corrosion-resistant coating has formed Ti n O 2n-1 Coating. TEM test results show that the thickness of the corrosion-resistant coating is about 70nm. n O 2n-1 The particles are about 15nm. Electrochemical tests have shown that the corrosion potential of the titanium substrate with corrosion-resistant coating is 0.686V (vs. RHE) and the corrosion current density is 0.057uA / cm 2(Test conditions: 0.5M / L sulfuric acid + 2ppm hydrofluoric acid electrolyte, test temperature 70°C), contact resistance 4.6mΩcm 2 (Pressure condition 140N).

[0105] Example 3

[0106] A method for preparing a titanium substrate containing a corrosion-resistant coating comprises the following steps:

[0107] S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate;

[0108] S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating is formed on the surface of the titanium oxide substrate;

[0109] S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; the corrosion-resistant coating is Ti n O 2n-1 coating.

[0110] In step S01,

[0111] The pretreatment comprises the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it (low temperature drying) to obtain a pretreated titanium substrate.

[0112] The annealing process is performed in an Ar gas atmosphere, the annealing temperature is 1073K, and the annealing time is 10s.

[0113] The washing is performed by the following method: firstly washing with acid, and then washing with pure water and ethanol in sequence.

[0114] The acid is 0.5wt% HF+2wt% HNO3. The cleaning time of the acid is 10 minutes.

[0115] In step S02,

[0116] The heating rate of the high temperature thermal shock is 10 4 K / s, the heating time is 400ms; the peak temperature of the high temperature thermal shock is 973K.

[0117] The high temperature thermal shock is achieved by Joule heat flash evaporation technology.

[0118] The high-temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, and connecting a power source to perform a high-temperature thermal shock for 400ms.

[0119] The current of the power supply is 20A, and the voltage of the power supply is 60V.

[0120] The thickness of the titanium oxide coating is 100 nm.

[0121] In step S03,

[0122] The reduction is achieved by the following method: heating the titanium oxide substrate to 1173K by high temperature thermal shock in a hydrogen atmosphere.

[0123] SEM test shows that the surface of the titanium substrate with corrosion-resistant coating is smooth, dense and uniform. XRD and XPS test shows that the surface of the titanium substrate with corrosion-resistant coating has formed Ti n O 2n-1 Coating. TEM test results show that the thickness of the corrosion-resistant coating is about 30nm. n O 2n-1 The particles are about 15nm. Electrochemical tests have shown that the corrosion potential of the titanium substrate with corrosion-resistant coating is 0.59V (vs. RHE) and the corrosion current density is 0.064uA / cm 2 (Test conditions: 0.5M / L sulfuric acid + 2ppm hydrofluoric acid electrolyte, test temperature 70°C), contact resistance 2.8mΩcm 2 (Pressure condition 140N).

[0124] Comparative Example 1

[0125] A method for preparing a titanium oxide coating substrate by high-temperature stepwise oxidation, using a tubular furnace to gradually oxidize and reduce a Ti substrate to prepare a titanium oxide coating substrate, comprising the following steps:

[0126] S01: Ti substrate surface cleaning.

[0127] S02: oxidizing the surface of the Ti substrate by slowly heating and keeping the temperature, forming a titanium oxide coating (Ti / TiO2) on the surface of the Ti substrate, and obtaining a titanium oxide coating substrate;

[0128] S03: In a low-pressure oxygen atmosphere, a titanium substrate is used to reduce a titanium oxide coating (Ti / TiO2) substrate to obtain a Ti n O 2n-1 Coating substrate.

[0129] In step S01, the titanium substrate is polished with sandpaper and then annealed at an annealing temperature of 1073K for 10 seconds in an Ar atmosphere. The surface impurities are then removed by pickling, wherein the acid is preferably 0.5wt% HF+2wt% HNO3 for 10 minutes. The titanium substrate is then ultrasonically washed with pure water and ethanol and dried at low temperature for later use.

[0130] Furthermore, in the oxidation reaction in step S02, the heating rate is 5K / s, the heating time is 70min, the peak temperature is 973K, and the insulation time is 3h.

[0131] Furthermore, the reduction reaction in step S03 is carried out by the following scheme to prepare Ti n O 2n-1 Coating substrate. In oxygen atmosphere, oxygen partial pressure is 1.0*10 -5 Atm, the temperature was raised to 1173 K at 5 K / S and then cooled in the furnace.

[0132] The SEM results show that the surface of the sample is rough, and the XRD and XPS results show that Ti is formed on the titanium surface. n O 2n-1 Coating, TEM results show that the oxide coating thickness is about 3um, Ti n O 2n-1 The particle size is about 150nm. The electrochemical test results show that the corrosion potential is 0.2V (vs. RHE) and the corrosion current density is 0.094uA / cm 2 (Test conditions: 0.5M / L sulfuric acid + 2ppm hydrofluoric acid electrolyte, test temperature 70°C), contact resistance 3mΩcm 2 (Pressure condition 140N).

[0133] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0134] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a titanium substrate containing a corrosion-resistant coating, characterized in that: The steps include: S01, pretreating the surface of the titanium substrate to obtain a pretreated titanium substrate; S02, oxidizing the surface of the pretreated titanium substrate by high-temperature thermal shock to obtain a titanium oxide substrate, wherein a titanium oxide coating is formed on the surface of the titanium oxide substrate; S03, reducing the titanium oxide substrate to obtain a titanium substrate containing a corrosion-resistant coating; The corrosion-resistant coating is Ti n O 2n-1 Coating, n is at least one of 1, 2, 3, 4 or 5.

2. The method for preparing a titanium substrate containing a corrosion-resistant coating according to claim 1, characterized in that: In step S01, the pretreatment includes the following steps: polishing the titanium substrate with sandpaper to obtain a polished titanium substrate; annealing the polished titanium substrate, washing it, and drying it to obtain a pretreated titanium substrate.

3. The method for preparing a titanium substrate containing a corrosion-resistant coating according to claim 2, characterized in that: The annealing treatment is carried out in an inert gas atmosphere or under vacuum conditions, the annealing treatment temperature is 873K to 1273K, and the annealing treatment time is ≤10min; The washing is performed by the following method: firstly washing with acid, and then washing with pure water and ethanol in sequence.

4. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 1, characterized in that: In step S02, the heating rate of the high temperature thermal shock is 10 3 K / s~10 5 K / s, the heating time is 15ms-800ms; the peak temperature of the high temperature thermal shock is 973K-1473K.

5. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 1, characterized in that: In step S02, the high temperature thermal shock is achieved by electric Joule heating, microwave heating, thermal radiation heating, plasma heating or laser heating.

6. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 1, characterized in that: In step S02, the high temperature thermal shock comprises the following steps: connecting the pretreated titanium substrate to a conductive copper sheet, connecting a power source to perform a high temperature thermal shock for 20ms to 800ms; The current of the power supply is 0A to 20A, and the voltage of the power supply is 40V to 80V; The thickness of the titanium oxide coating is 100 nm.

7. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 1, characterized in that: In step S03, the reduction is achieved by the following method: reducing the titanium oxide substrate by high-temperature thermal shock in an oxygen atmosphere; the peak temperature of the high-temperature thermal shock is 973K to 1473K; the reduction time is 20ms to 800ms; The oxygen partial pressure of the oxygen atmosphere is 1.0*10 -4 atm~1.0*10 -10 atm.

8. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 7, characterized in that: In step S03, the high temperature thermal shock comprises the following steps: connecting the titanium oxide substrate to a conductive copper sheet, connecting a power source to perform a high temperature thermal shock for 20ms to 800ms; The current of the power supply is 0A-20A, and the voltage of the power supply is 40V-80V.

9. The method for preparing a titanium substrate with a corrosion-resistant coating according to claim 1, characterized in that: In step S03, the reduction is achieved by: heating the titanium oxide substrate to 773K-1273K by high temperature thermal shock in a hydrogen atmosphere; The high temperature thermal shock is achieved by electric Joule heating, microwave heating, thermal radiation heating, plasma heating or laser heating.

10. A titanium substrate with a corrosion-resistant coating, characterized in that: The titanium substrate containing the corrosion-resistant coating is prepared by the preparation method according to any one of claims 1 to 9.