Method for preparing zirconia ceramic layer on surface of titanium alloy in situ

Abstract

The invention provides a method for in-situ preparation of a zirconia ceramic layer on a titanium alloy surface, which is characterized by comprising the following steps: (1) surface pretreatment: grinding and polishing a titanium alloy sample, and then cleaning and drying; (2) zirconium ion implantation: metal zirconium is used as an ion implantation source, and ion implantation is carried out on the sample subjected to surface pretreatment under a vacuum condition; and (3) thermal oxidation is conducted, specifically, the sample subjected to zirconium ion implantation is placed in the oxygen atmosphere, heating and heat preservation are conducted, a zirconium oxide ceramic layer is formed, and the titanium alloy with the in-situ modified zirconium oxide ceramic layer is obtained after cleaning and drying. The method is not influenced by the size and shape of the titanium alloy part, the zirconium oxide ceramic layer formed on the surface of the titanium alloy in situ is compact, stable, free of an obvious interface and high in bonding strength, the surface hardness, the frictional wear performance and the corrosion resistance of a matrix are greatly improved, and the method is simple, high in efficiency and suitable for large-scale application and popularization.

Description

Technical Field

[0001] The invention relates to the technical field of surface modification engineering, in particular to a method for in-situ preparing a zirconium oxide ceramic layer on the surface of a titanium alloy. Background Art

[0002] Titanium alloys have been widely used in aerospace, marine equipment and other fields due to their low density, high specific strength and good corrosion resistance. However, titanium alloys have problems such as low hardness and poor wear resistance, which limit their performance in some applications. Therefore, surface strengthening treatment technology has emerged to improve the surface properties of titanium alloys and extend their service life.

[0003] Traditional titanium alloy surface strengthening treatment technologies mainly include shot peening, hard coating, laser cladding and other methods, but the above technologies have problems such as poor strengthening effect, poor coating adhesion, easy coating peeling, complex process, etc., which are not conducive to large-scale application and promotion.

[0004] For example, CN200410043763.0 discloses a method for preparing a zirconium oxide coating on the surface of a titanium alloy. The method can directly form oxide ceramics on the surface of a base metal by changing the composition of the electrolysis, so that the oxide has both the high performance of ceramics and the bonding force with the base, and can achieve the purpose of functionalization of structural materials. The microplasma oxidation used is a new technology for in-situ growth of oxide ceramics on the surface of valve metals. It can oxidize and sinter into oxide ceramics on the surface of the base metal by changing the composition of the electrolysis, controlling the temperature of the electrolyte, and adjusting the electrical parameters and reaction time to achieve the purpose of in-situ growth of zirconium oxide ceramics on the surface. The method is complex to implement, has many control variables, and the electrolyte has a local uneven composition. In addition, affected by the geometric shape of the sample, the resistance difference at each position of the sample is large, and the current and voltage fluctuate significantly, resulting in an uneven prepared zirconium oxide layer.

[0005] CN201420344222.0 discloses an implant provided with a nano-zirconia coating, which includes an implant body and a base, the body is conical and provided with threads, the base includes a gingival part, a shoulder and a base, and the surface of the gingival part and the shoulder is evenly provided with a nano-zirconia coating. Nano-zirconia granulated powder with a particle size of 70 to 110 nm is used as a raw material, the granulated powder is agglomerated into a spherical or elliptical spherical powder, and the nano-zirconia granulated powder is sprayed on the surface of the gingival part and the shoulder, and the nano-zirconia coating is evenly provided. This patent application adopts a surface plasma spraying method to prepare a nano-zirconia coating, and a large amount of powder is wasted during the spraying process, and the manufacturing cost is high. In addition, the zirconia coating prepared by the spraying process is thicker but less uniform. There is an obvious interface between the sprayed zirconia coating and the substrate, the bonding strength is poor, and the coating is easy to peel off.

[0006] CN200710046705.7 discloses a pure monoclinic zirconium oxide coating that is stable at low temperatures, a preparation method and an application thereof. Commercially available monoclinic zirconium oxide powder is used as a raw material, and after pre-treatment and ball milling, the powder is spheroidized or directly prepared into a monoclinic low-temperature stable zirconium oxide coating by a plasma spraying process without spheroidization. The bonding strength of the said low-temperature stable zirconium oxide coating with the titanium alloy substrate is between 20 and 40 MPa, and the characteristic is that the surface of the zirconium oxide coating is dense and free of cracks. This patent application uses an atmospheric plasma spraying process to prepare a monoclinic zirconium oxide coating on a titanium alloy substrate, which also has the problems of a large amount of powder waste, a thick coating thickness but poor uniformity, etc.

[0007] In order to overcome the problems of poor strengthening effect, poor coating adhesion, easy peeling of the coating, etc., the present invention urgently needs to develop a new method for preparing the zirconia ceramic layer. Summary of the invention

[0008] In view of the shortcomings of the prior art, the object of the present invention is to provide a method for in-situ preparing a zirconium oxide ceramic layer on the surface of a titanium alloy.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for in-situ preparing a zirconium oxide ceramic layer on a titanium alloy surface, characterized in that the method comprises the following steps:

[0011] (1) Surface pretreatment: The titanium alloy sample was ground and polished, and then cleaned and dried;

[0012] (2) zirconium ion implantation: using metal zirconium as an ion implantation source, ion implantation is performed on the sample that has undergone surface pretreatment in step (1) under vacuum conditions;

[0013] (3) Thermal oxidation: placing the sample implanted with zirconium ions in step (2) in an oxygen atmosphere, heating and keeping the temperature low to form a zirconium oxide ceramic layer, and then washing and drying to obtain a titanium alloy with an in-situ modified zirconium oxide ceramic layer.

[0014] The ion implantation and thermal oxidation described in the present invention are two relatively independent and mature technologies, each with independent application fields. Ion implantation is suitable for improving the surface hardness, wear resistance, corrosion resistance, etc. of materials, especially in the fields of semiconductors, aerospace, etc. Thermal oxidation technology has long been used to generate a protective oxide layer on the metal surface to improve the high temperature resistance and corrosion resistance of the material.

[0015] However, ion implantation is usually performed at lower temperatures, while thermal oxidation requires higher temperatures. The difference in temperature control between the two also means that their combined application has not been widely explored in the past.

[0016] In addition, the oxide layer generated during the thermal oxidation process may affect the depth distribution of ion implantation. How to find a balance between the two and avoid negative effects is a key challenge in the combined application of ion implantation and thermal oxidation. The present invention combines the characteristics of ion implantation and thermal oxidation. First, a high-voltage electric field is used to accelerate the ionized Zr metal element to sufficient kinetic energy and inject it into a certain depth range on the surface of the titanium alloy substrate, changing the surface and subsurface composition of the titanium alloy and introducing zirconium elements; then, after high-temperature thermal oxidation treatment, the oxygen elements in the atmosphere undergo a process of contact collision, adsorption, decomposition, diffusion, maturation, and growth under high-temperature conditions, and a zirconium-based oxide ceramic layer is generated in situ on the surface of the substrate. There is an oxygen-rich diffusion layer between the ceramic layer and the substrate, and there is no risk of peeling.

[0017] In addition, the present invention selects Zr as the ion implantation source, which can form a ZrO2 ceramic layer on the surface of the material. If other ions such as nitrogen (N), carbon (C), boron (B), silicon (Si), etc. are selected, they may compete with oxygen to form other compounds (such as nitrides, carbides or borides) to prevent oxygen from diffusing into the titanium matrix. At the same time, the order of ion implantation and thermal oxidation technology cannot be reversed, otherwise the ZrO ceramic layer cannot be generated. The technology provided by the present invention enables ion implantation and thermal oxidation to cooperate with each other and act together on the surface of the titanium alloy, so that the product performance is comprehensively improved, which not only retains the excellent surface strengthening effect brought by ion implantation, but also uses thermal oxidation to generate a high temperature resistant and corrosion resistant zirconium oxide layer to form multiple protections.

[0018] The method of the present invention is not affected by the size and shape of titanium alloy parts. The zirconium oxide ceramic layer formed in situ on the surface of the titanium alloy is dense and stable, has no obvious interface, and has high bonding strength, which greatly improves the surface hardness, friction and wear properties and corrosion resistance of the substrate. The method is simple and efficient and is suitable for large-scale promotion and application.

[0019] As a preferred technical solution of the present invention, after the grinding and polishing treatment in step (1), the surface roughness of the obtained titanium alloy sample is ≤0.5μm; for example, it can be 0.5μm, 0.4μm, 0.3μm, 0.2μm, 0.1μm, 0.09μm, 0.08μm, 0.07μm, 0.06μm, 0.05μm, 0.04μm, 0.03μm, 0.02μm or 0.01μm, etc.

[0020] In the present invention, the lower the roughness of the titanium alloy material, the more obvious the effect of ion implantation and oxidation process on the performance improvement of the titanium alloy substrate. Taking into account the polishing difficulty and polishing cost of the titanium alloy material, the present invention sets the lower limit of the roughness of the titanium alloy material used to 0.05 μm, so the surface roughness of the titanium alloy sample is preferably 0.5 μm-0.05 μm.

[0021] Preferably, the cleaning in step (1) is ultrasonic cleaning, and the ultrasonic cleaning is performed using any one of acetone, deionized water or anhydrous ethanol, or two or more of the reagents.

[0022] Preferably, the drying method in step (1) is air drying.

[0023] As a preferred technical solution of the present invention, the parameters of the zirconium ion implantation in step (2) are set as: suppression voltage 0.9-1.1 kV, suppression current 0.1-2 mA, extraction voltage 45-50 kV, extraction current ≤5 mA, workpiece target current ≤4 mA.

[0024] Among them, the suppression voltage is 0.9~1.1kV, for example, it can be 0.9kV, 0.95kV, 1kV, 1.05kV, 1.1kV, etc.; the suppression current is 0.1~2mA, for example, it can be 0.1mA, 0.2mA, 0.4mA, 0.5mA, 0.6mA, 0.8mA, 1mA, 1.2mA, 1.5mA, 1.6mA, 1.8mA, 2mA, etc.

[0025] The lead voltage is 45-50kV, for example, it can be 45kV, 45.5kV, 46kV, 46.5kV, 47kV, 47.5kV, 48kV, 48.5kV, 49kV, 49.5kV, 50kV, etc.; the lead current is ≤5mA, for example, it can be 5mA, 4mA, 3mA, 2mA, 1mA, etc.

[0026] The workpiece target current is ≤4mA, for example, it can be 4mA, 3mA, 2mA, 1mA, etc.

[0027] Preferably, the injection time of the zirconium ion implantation in step (2) is 30 to 180 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 70 min, 80 min, 90 min, 100 min, 120 min, 150 min or 180 min, etc., preferably 30 to 60 min.

[0028] As a preferred technical solution of the present invention, the vacuum degree of the vacuum condition in step (2) is 3.0×10 -3 ~6.0×10 -4 Pa, for example, can be 3.0×10 -3 Pa, 2.5×10 -3 Pa, 2×10 -3 Pa, 1×10 -3 Pa, 6.0×10 -4 Pa et al.

[0029] As a preferred technical solution of the present invention, during the ion injection process in step (2), the sample rotation speed is set to 5 to 10 r / min, for example, it can be 5 r / min, 6 r / min, 7 r / min, 8 r / min, 9 r / min, 10 r / min, etc.

[0030] Preferably, the sample and the ion injection tube form an angle of 75-90°, for example, 75°, 80°, 85° or 90°.

[0031] As a preferred technical solution of the present invention, the oxygen atmosphere in step (3) is 20% to 30% oxygen partial pressure, for example, it can be 20%, 21%, 22%, 25%, 26%, 28% or 30%, preferably 20% oxygen partial pressure.

[0032] Preferably, the oxygen atmosphere in step (3) is: when the vacuum degree is ≤0.1 Pa, 20% oxygen partial pressure is introduced, and the pressure is 1 standard atmosphere.

[0033] As a preferred technical solution of the present invention, the heating rate of step (3) is 5-10°C / min, for example, it can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.

[0034] Preferably, the insulation temperature in step (3) is 500-600°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc., and the insulation time is 120-300min, for example, it can be 120min, 140min, 150min, 160min, 180min, 200min, 220min, 240min, 250min, 260min, 280min, 300min, etc.

[0035] As a preferred technical solution of the present invention, after the insulation in step (3) is completed, a gas washing operation is also included.

[0036] Preferably, the operation of the gas washing is as follows: after the heat preservation is completed, the gas is cooled to below 200° C., the vacuum degree is drawn to ≤0.1 Pa, and then air is introduced to atmospheric pressure.

[0037] As a preferred technical solution of the present invention, the cleaning in step (3) is ultrasonic cleaning, and the ultrasonic cleaning is performed using anhydrous ethanol.

[0038] Preferably, the drying in step (3) is wiping with a dust-free cloth or air drying.

[0039] As a preferred technical solution of the present invention, the method can be carried out by the following steps:

[0040] (1) Surface pretreatment

[0041] The titanium alloy samples were subjected to conventional grinding and polishing treatment, and there were no special size requirements for the samples;

[0042] After grinding with 200#, 500#, 1000#, and 2000# sandpaper, polishing was performed with a polishing disc and a polishing wheel, and Ra was controlled within the range of 0.5μm-0.05μm;

[0043] Then, the titanium alloy sample was immersed in acetone, deionized water and anhydrous ethanol for ultrasonic cleaning for 5 to 15 minutes, and the surface was air-dried.

[0044] (2) Surface zirconium ion implantation

[0045] Use a metal ion implanter to perform zirconium ion implantation, and select metal zirconium as the implantation cathode material; place the cleaned sample in the vacuum process chamber of the ion implanter, and rotate it on a turntable. The sample rotation speed is set to 5-10r / min, and the sample and the ion implantation tube form an angle of 75-90°;

[0046] Close the process chamber and evacuate the vacuum to 3.0×10 -3 ~6.0×10 -4Pa; the ion implantation parameters are set as suppression voltage 0.9-1.1 kV, suppression current 0.1-2 mA, extraction voltage 45-50 kV, extraction current ≤5 mA, workpiece target current ≤4 mA, and implantation time 30-60 min;

[0047] After the vacuum degree reaches the standard, ion implantation is carried out; after the implantation is completed, the temperature in the process chamber drops to room temperature, air is filled in, the sample is taken out, and the zirconium ion implantation is completed.

[0048] (3) Preparation of zirconia ceramic layer

[0049] The sample after zirconium element injection is implanted into a crucible, and the crucible containing the sample is placed in a vacuum tube heat treatment furnace chamber; after the vacuum degree in the furnace is evacuated to 0.1 Pa, an oxygen atmosphere with an oxygen partial pressure of 20% is introduced until the pressure reaches 1 standard atmosphere;

[0050] Set the heating parameters to a heating rate of 5-10°C / min, a holding temperature of 500-600°C, a holding time of 120-300min, and keep the furnace temperature constant during the holding time;

[0051] After the heat preservation is completed, the furnace is cooled to below 200°C, and a gas washing treatment is performed. After the vacuum degree in the furnace is evacuated to 0.1 Pa, air is introduced to atmospheric pressure, and the sample can be taken out, completing the thermal oxidation in-situ preparation of the zirconia ceramic layer;

[0052] After taking out the sample, it is ultrasonically cleaned in anhydrous ethanol for 5 to 10 minutes, and wiped with a dust-free cloth or air-dried to complete the sample preparation.

[0053] In a second aspect, a titanium alloy with an in-situ modified zirconia ceramic layer prepared by the method described in the first aspect.

[0054] A third aspect is the use of the method described in the first aspect or the titanium alloy described in the second aspect in the preparation of aerospace equipment, marine equipment or medical materials.

[0055] The application of titanium alloys in high-end manufacturing fields such as aerospace, automobiles, and marine engineering is increasing, and these fields have put forward higher requirements on the surface properties of materials, especially in terms of corrosion resistance, wear resistance, high temperature resistance, etc. Therefore, the preparation method and the prepared titanium alloy material provided by the present invention can provide better solutions for these fields.

[0056] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) The present invention combines the characteristics of ion implantation and thermal oxidation to generate a zirconium-based oxide ceramic layer in situ on the surface of a titanium alloy substrate, and an oxygen-rich diffusion layer exists between the ceramic layer and the substrate; the ceramic layer is dense and stable, has no obvious interface, has high bonding strength, and greatly improves the surface hardness, friction and wear performance, and corrosion resistance of the substrate; the method is simple and efficient, and is suitable for large-scale promotion and application;

[0059] (2) Compared with the titanium alloy substrate, the surface microhardness of the zirconium oxide ceramic layer sample prepared by the present invention is increased by 22-34%, the nanoindentation hardness is increased by 120-160%, the wear rate is increased by 14-33%, and the corrosion resistance is improved by 79-81%. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Schematic diagram of the structure of a titanium alloy sample with an in-situ prepared zirconium oxide ceramic layer on the surface, wherein 1 is the zirconium oxide ceramic layer, 2 is the oxygen-rich diffusion layer, 3 is the zirconium element injection layer, and 4 is the titanium alloy substrate.

[0061] Figure 2 Surface photographs of samples of Examples 1 to 3 and a TC4 titanium alloy substrate (Comparative Example 1); Figure I is Comparative Example 1, Figure II is Example 1, Figure III is Example 2, and Figure IV is Example 3. DETAILED DESCRIPTION

[0062] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0063] In the following examples, unless otherwise specified, all reagents and consumables used were purchased from conventional reagent manufacturers in the field; unless otherwise specified, all experimental methods and technical means used were conventional methods and means in the field.

[0064] The structure of the titanium alloy sample obtained according to the preparation method of the present invention is as follows: Figure 1 As shown, from the surface to the inside, there are zirconia ceramic layer 1, oxygen-rich diffusion layer 2, zirconium element injection layer 3 and titanium alloy substrate 4. It is obvious from the structure diagram that the zirconium element injection depth is greater than the thickness of the zirconia ceramic layer.

[0065] Example 1

[0066] This embodiment provides a method for in-situ preparing a zirconium oxide ceramic layer on a titanium alloy surface, the steps are as follows:

[0067] (1) Surface pretreatment

[0068] The titanium alloy sample uses Ti-6Al-4V (grade TC4) as the matrix, and there is no special size requirement for the sample.

[0069] The sample surface was ground and polished using 200#, 500#, 1000#, and 2000# sandpaper, and then polished using a polishing disc and a polishing wheel, with Ra controlled below 0.5μm. The titanium alloy sample was then immersed in acetone, deionized water, and anhydrous ethanol for ultrasonic cleaning for 5 minutes, and the surface was air-dried.

[0070] (2) Surface zirconium ion implantation

[0071] Using a metal ion implanter to perform zirconium ion implantation, metal zirconium is selected as the implantation cathode material;

[0072] Place the cleaned sample in the vacuum process chamber of the ion implanter and rotate it on the turntable. The sample rotation speed is set to 5r / min, and the sample and the ion implantation tube form an angle of 75°.

[0073] Close the process chamber and evacuate the vacuum to 3.0×10 -3 Pa;

[0074] The ion implantation parameters were set as follows: suppression voltage 0.9 kV, suppression current 0.1 mA, extraction voltage 45 kV, extraction current 5 mA, workpiece target current 4 mA, and implantation time 30 min;

[0075] After the vacuum degree reaches the standard, ion implantation is carried out; after the implantation is completed, the temperature in the process chamber drops to room temperature, air is filled in, the sample is taken out, and the zirconium ion implantation is completed.

[0076] (3) Preparation of zirconia ceramic layer

[0077] The sample after zirconium element injection is implanted into a crucible, and the crucible containing the sample is placed in a vacuum tube heat treatment furnace chamber;

[0078] After the vacuum degree in the furnace is evacuated to 0.1 Pa, an oxygen atmosphere with an oxygen partial pressure of 20% is introduced to reach a pressure of 1 standard atmosphere;

[0079] Set the heating parameters to a heating rate of 5°C / min, a holding temperature of 50°C, and a holding time of 120min, and keep the furnace temperature constant during the holding time;

[0080] After the heat preservation is completed, the furnace is cooled to below 200°C, and a gas washing treatment is carried out. After the vacuum degree in the furnace is evacuated to 0.1 Pa, air is introduced to atmospheric pressure, and the sample can be taken out, completing the thermal oxidation in-situ preparation of the zirconia ceramic layer.

[0081] (4) Preparation of zirconium oxide layer is completed

[0082] After taking out the sample, it was ultrasonically cleaned in anhydrous ethanol for 5 minutes, and wiped with a dust-free cloth or air-dried to complete the sample preparation.

[0083] Example 2

[0084] This embodiment provides a method for in-situ preparing a zirconium oxide ceramic layer on a titanium alloy surface. The operation steps are consistent with those in Example 1, and the parameters of each step are shown in Table 1.

[0085] Example 3

[0086] This embodiment provides a method for in-situ preparing a zirconium oxide ceramic layer on a titanium alloy surface. The operation steps are consistent with those in Example 1, and the parameters of each step are shown in Table 1.

[0087] Table 1

[0088]

[0089]

[0090] Comparative Example 1

[0091] An unprocessed titanium alloy sample Ti-6Al-4V (grade TC4) is used as comparative example 1.

[0092] Surface photos of samples of Examples 1 to 3 and TC4 titanium alloy substrate (Comparative Example 1) are shown in Figure 2 As shown, Figure I corresponds to the sample of Example 1, Figure II corresponds to Example 1, Figure III corresponds to Example 2, and Figure IV corresponds to Example 1.

[0093] Comparative Example 2

[0094] The surface roughness was adjusted to 0.6 μm, and the remaining steps were consistent with Example 1.

[0095] Comparative Example 3

[0096] The surface roughness was adjusted to 0.01 μm, and the remaining steps were consistent with Example 1.

[0097] Comparative Example 4

[0098] The ion implantation process is performed separately, and the remaining steps are consistent with those in Example 1.

[0099] Comparative Example 5

[0100] The thermal oxidation process is performed alone, and the remaining steps are consistent with those in Example 1.

[0101] Comparative Example 6

[0102] During the surface zirconium ion implantation process, the extraction voltage was set to 30 kV; the remaining steps were consistent with Example 1.

[0103] Comparative Example 7

[0104] During the surface zirconium ion implantation process, the extraction voltage was set to 60 kV; the remaining steps were consistent with Example 1.

[0105] Comparative Example 8

[0106] During the thermal oxidation process, the insulation temperature rises to 620° C.; the remaining steps are consistent with Example 1.

[0107] Performance Testing

[0108] 1. Microhardness

[0109] According to GB / T 4340.1-2009 "Metallic Materials Vickers Hardness Test Part 1: Test Method", at the 100gf force position, the loading and holding time is set to 10s, and 5 points are measured for each sample. Compared with the titanium alloy substrate, the surface microhardness of the prepared zirconia ceramic layer sample is increased by 22-34%, and the microhardness is significantly improved. The surface microhardness performance test results are shown in Table 2.

[0110] Table 2 Test standards and Vickers hardness test results of Examples 1, 2, and 3 of the present invention

[0111]

[0112]

[0113] 2. Nanoindentation hardness

[0114] According to the technical specification of JB / T 12721-2016 "In-situ Nanoindentation Scratch Tester for Solid Materials", the indenter used is the commonly used Berkovich diamond tip. Each sample is tested at 10 points, and the results are averaged. The maximum loading load is 5000μN, the loading rate is 500-1000μN / s, and the holding time is 2s. Compared with the titanium alloy substrate, the nanoindentation hardness of the prepared zirconia ceramic layer sample is increased by 120-160%, and the surface nanoindentation hardness is significantly enhanced. The nanoindentation hardness performance test results are shown in Table 3.

[0115] Table 3 Test standards and nanoindentation test results of Examples 1, 2, and 3 of the present invention

[0116]

[0117]

[0118] 3. Friction and wear performance

[0119] The friction and wear test parameters are set as load 2N; friction pair is Si3N4 ball; friction radius 7mm; speed is 200r / min; time is 30min. Compared with the titanium alloy substrate, the wear rate of the prepared zirconia ceramic layer sample is increased by 14-33%, and the friction and wear performance is significantly improved. The friction and wear performance test results are shown in Table 4.

[0120] Table 4 Test standards and friction and wear test results of Examples 1, 2, and 3 of the present invention

[0121]

[0122]

[0123] 4. Corrosion resistance

[0124] According to GB / T 10125-2012 "Artificial atmosphere corrosion test salt spray test", a neutral salt spray test was carried out in a 5% sodium chloride solution environment. The samples were cleaned, weighed, placed, observed, and the salt spray test machine was maintained and adjusted in accordance with the standard. The test cycle was 720 hours (1 month). Compared with the titanium alloy substrate, the corrosion resistance of the prepared zirconia ceramic layer sample was improved by 79-81%, and the corrosion resistance was significantly improved. The corrosion resistance test results are shown in Table 5.

[0125] Table 5 Test standards and salt spray test results of Examples 1, 2, and 3 of the present invention

[0126]

[0127]

[0128] In summary, compared with Comparative Example 1, the surface microhardness of Examples 1 to 3 is increased by 22 to 34%, the nanoindentation hardness is increased by 120 to 160%, the wear rate is increased by 14 to 33%, and the corrosion resistance is improved by 79 to 81%.

[0129] Compared with Comparative Examples 2 to 3, in Example 1, the roughness > 0.5 μm leads to a decrease in the microhardness of the material, a decrease in the surface nanoindentation hardness, an increase in the wear rate, and a decrease in the corrosion resistance; and when the roughness is < 0.05 μm, although the microhardness and nanoindentation hardness will be further increased, the increased roughness makes polishing more difficult and more expensive; considering the performance and preparation difficulty, the present invention limits the roughness to 0.5 μm-0.05 μm.

[0130] Compared with Comparative Examples 4 to 5, when the ion implantation process and the thermal oxidation process are performed separately, the material performance improvement of Example 1 is not obvious;

[0131] Compared with Comparative Examples 6 to 7, in the ion implantation process, each parameter must be guaranteed to be within the parameter range. Taking the extraction voltage as an example, if the extraction voltage is low, the injection energy is low and the effect is insufficient, resulting in insufficient Zr injection; if the extraction voltage is high, the injection energy is high, resulting in a sputtering effect, causing Zr sputtering, resulting in excessive Zr injection;

[0132] Compared with Comparative Example 8, in Example 1, if the holding temperature exceeds 600°C during the thermal oxidation process, the strengthening effect of the implanted area will be reduced, and the oxide layer will be prone to cracking after the thickness increases, and the wear resistance will decrease;

[0133] In addition, the present invention also attempts to perform the thermal oxidation step in an air atmosphere. However, after the Zr element is injected into the surface of the TC4 titanium alloy, a zirconium oxide ceramic layer is generated through high-temperature oxidation. The Ti in the TC4 alloy itself is easy to generate TiO2. If the oxygen concentration is insufficient, it may cause the mixing of TiO2 and ZrO2 at the interface, thereby affecting the purity and performance of the oxide layer. In a high-purity oxygen atmosphere, the oxidation process is faster and more uniform, which is conducive to the complete oxidation of the Zr element to generate a high-quality ZrO2 ceramic layer.

[0134] In summary, the present invention combines ion implantation with thermal oxidation process, finds a balance between the two processes, overcomes negative effects including uneven distribution of ion implantation depth, and comprehensively improves product performance.

[0135] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for in-situ preparation of a zirconium oxide ceramic layer on a titanium alloy surface, characterized in that: The method comprises the following steps: (1) Surface pretreatment: The titanium alloy sample was ground and polished, and then cleaned and dried; (2) zirconium ion implantation: using metal zirconium as an ion implantation source, ion implantation is performed on the sample that has undergone surface pretreatment in step (1) under vacuum conditions; (3) Thermal oxidation: placing the sample implanted with zirconium ions in step (2) in an oxygen atmosphere, heating and keeping the temperature low to form a zirconium oxide ceramic layer, and then washing and drying to obtain a titanium alloy with an in-situ modified zirconium oxide ceramic layer.

2. The method according to claim 1, characterized in that After the grinding and polishing treatment in step (1), the surface roughness of the titanium alloy sample obtained is ≤0.5 μm; The cleaning in step (1) is ultrasonic cleaning, and the ultrasonic cleaning is performed using any one of acetone, deionized water or anhydrous ethanol, or two or more reagents; The drying method in step (1) is air drying.

3. The method according to claim 1, characterized in that The parameters of the zirconium ion implantation in step (2) are set as follows: suppression voltage 0.9-1.1 kV, suppression current 0.1-2 mA, extraction voltage 45-50 kV, extraction current ≤5 mA, workpiece target current ≤4 mA; The zirconium ion implantation time in step (2) is 30 to 60 minutes.

4. The method according to claim 1, characterized in that: The vacuum degree of the vacuum condition in step (2) is 3.0×10 -3 ~6.0×10 -4 Pa; During the ion injection process of step (2), the rotation speed of the sample is 5 to 10 r / min, and the sample and the ion injection tube form an angle of 75 to 90 degrees.

5. The method according to claim 1, characterized in that The oxygen atmosphere in step (3) is 20% oxygen partial pressure; The oxygen atmosphere in step (3) is: when the vacuum degree is ≤0.1Pa, 20% oxygen partial pressure is introduced, and the pressure is 1 standard atmosphere.

6. The method according to claim 1, characterized in that The heating rate of step (3) is 5 to 10°C / min; The insulation temperature in step (3) is 500-600° C., and the insulation time is 120-300 min.

7. The method according to claim 1, characterized in that After the heat preservation in step (3) is completed, a gas washing operation is also included; The operation of the gas washing is as follows: after the heat preservation is completed, the gas is cooled to below 200° C., the vacuum degree is drawn to ≤0.1 Pa, and then air is introduced to the atmospheric pressure.

8. The method according to claim 1, characterized in that The cleaning in step (3) is ultrasonic cleaning, and the ultrasonic cleaning is performed using anhydrous ethanol; The drying in step (3) is performed by wiping with a dust-free wipe or air drying.

9. A titanium alloy with an in-situ modified zirconium oxide ceramic layer prepared by the method according to any one of claims 1 to 8.

10. Use of the method according to any one of claims 1 to 8 or the titanium alloy according to claim 9 in the preparation of aerospace equipment, marine equipment or medical materials.

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