A method for preparing an oxide composite insulating layer on a titanium alloy surface

Abstract

The application discloses a method for preparing an oxide composite insulating layer on a titanium alloy surface and relates to the technical field of insulating material preparation. The titanium alloy is subjected to high-temperature oxidation to obtain a porous titanium oxygen layer, then the porous titanium oxygen layer is subjected to ultrasonic-assisted sealing treatment by using an organic sealing agent, and after solidification, the oxide composite insulating layer is obtained on the titanium alloy surface. The oxide composite insulating layer prepared on the titanium alloy surface has good insulating capacity in a solution environment and is resistant to hydrochloric acid and nitric acid corrosion, and has good application on a gold plating and nickel plating hanger in the watch industry.

Description

Technical Field

[0001] This invention relates to the field of insulating material preparation technology, and in particular to a method for preparing an oxide composite insulating layer on the surface of a titanium alloy. Background Technology

[0002] Electroplating of gold and nickel has been widely used in high-end watchmaking and other industries, receiving high praise from users. Currently, most gold-plated and nickel-plated hangers on the market use TC4 titanium alloy hangers. Titanium alloy hangers typically require strong acid treatment with hydrochloric acid and nitric acid to remove impurities, making them prone to damage. Furthermore, titanium alloy hangers are conductive, causing a certain thickness of gold, nickel, and other precious metals to deposit on the non-working surfaces during electroplating, resulting in significant waste of the plating solution. Therefore, how to insulate the non-working surfaces of electroplated hangers has become a current challenge for the electroplating industry. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an oxide composite insulating layer on the surface of a titanium alloy, so as to solve the problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a method for preparing an oxide composite insulating layer on the surface of a titanium alloy, comprising the following steps:

[0006] (1) The degreased titanium alloy is oxidized at 750-900℃ for 5-10h, and then cooled to room temperature in the furnace to obtain a porous titanium oxide layer on the surface of the titanium alloy.

[0007] (2) Place the titanium alloy with a porous titanium oxide layer on the surface obtained in step (1) in an organic sealing agent solution, perform ultrasonic treatment, dry, and repeat the ultrasonic treatment process 5-10 times.

[0008] (3) The material treated in step (2) is cured at 120-500℃ for 1-5 hours to achieve the preparation of an oxide composite insulating layer on the surface of the titanium alloy.

[0009] The organic sealing agent solution is obtained by mixing an organic sealing agent and water at a volume ratio of 1:5 to 1:9. More preferably, it is mixed at a volume ratio of 1:9.

[0010] Furthermore, the organic sealing agent can be selected from commercially available silane or polyurethane sealing agents.

[0011] Further, step (1) involves oxidation at 700°C for 7 hours.

[0012] Furthermore, the power of the ultrasonic treatment in step (2) is 1 to 20 kW, and the time is 30 to 60 min; the number of ultrasonic treatments in step (2) is 8.

[0013] Further, step (3) involves curing at 150°C for 2 hours.

[0014] Furthermore, the thickness of the porous titanium oxide layer is 50-120 μm; the thickness of the organic sealing layer is 10-50 μm.

[0015] Both the porous titanium oxide layer and the organic sealing layer are insulating materials and resistant to strong acid corrosion. The key technical challenge lies in how to allow the organic sealing agent to penetrate into the porous structure. To address this issue, this invention employs a composite process of diluted sealing agent, ultrasonic assistance, and multiple sealing steps to achieve ideal sealing results.

[0016] The present invention also provides a titanium alloy with an oxide composite insulating layer on its surface, which is prepared by the above-described preparation method.

[0017] The present invention further provides the application of the titanium alloy with the oxide composite insulating layer on the surface as a watch hanger.

[0018] Currently, the impact of existing composite technologies combining thermal spraying, micro-arc oxidation, and sealing on the performance of titanium alloy hangers is unknown. Preliminary research in this invention revealed that the composite process of thermal spraying and sealing has high manufacturing costs, poor adhesion between the sprayed oxide layer and the substrate, and strong acid erosion of the interface during use, leading to coating peeling after eight electroplating cycles. Furthermore, the sprayed coating after sealing exhibits poor insulation; the composite process of micro-arc oxidation and sealing is unstable, resulting in uneven oxide layer thickness and poor insulation.

[0019] The present invention discloses the following technical effects:

[0020] This invention provides a method for preparing an oxide composite insulating layer on the surface of a titanium alloy, wherein the oxide composite insulating layer is composed of a subsurface porous titanium oxide layer and a surface organic sealing layer; the present invention involves high-temperature oxidation of the titanium alloy in an atmospheric environment to obtain a porous titanium oxide layer, followed by ultrasonic-assisted sealing of the porous structure using an organic sealing agent, and finally curing to obtain the oxide composite insulating layer.

[0021] The oxide composite insulating layer prepared on the surface of titanium alloy by this invention has good insulation ability in solution environment and is resistant to hydrochloric acid and nitric acid corrosion, and has good application in gold-plated and nickel-plated hangers in the watch industry. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a test diagram of the bonding force of the oxide composite insulating layer in Embodiment 1 of the present invention;

[0024] Figure 2 This is a surface SEM image of the oxide composite insulating layer in Embodiment 1 of the present invention;

[0025] Figure 3 This is a cross-sectional SEM image of the oxide composite insulating layer in Embodiment 4 of the present invention;

[0026] Figure 4 This is a test diagram of the bonding strength of the oxide composite insulating layer in Embodiment 4 of the present invention;

[0027] Figure 5 The image shows the SEM morphology of the oxide layer surface in Comparative Example 1.

[0028] Figure 6 This is a test diagram of the bonding strength of the oxide layer in Comparative Example 6. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] In the following embodiments and comparative examples of the present invention, the ratio of organic sealing agent to water is a volume ratio.

[0035] Example 1

[0036] Method for preparing oxide composite insulating layers on titanium alloy surfaces:

[0037] S1: The titanium alloy is subjected to ultrasonic degreasing and degreasing treatment, and then dried;

[0038] S2: The dried titanium alloy was placed in the furnace and oxidized in an atmospheric environment. The oxidation process parameters were: oxidation temperature 750℃, holding time 7h; the sample was cooled to room temperature with the furnace to obtain a titanium alloy sample with a porous titanium oxide layer on the surface; the thickness of the porous titanium oxide layer was 104.3μm.

[0039] S3: Mix polyurethane sealing agent and water in a ratio of 1:9 (also known as diluent), then place the mixture into an ultrasonic device. Place the titanium alloy sample with a porous titanium oxide layer on the surface into the diluent and perform ultrasonic permeation treatment at 20kW for 30 minutes. Then remove and air dry. Repeat the above operation 8 times.

[0040] S4: The titanium alloy sample with a porous titanium oxide layer on the surface that has undergone the above sealing treatment is placed in a furnace for curing treatment. The drying temperature is 150℃ and the drying time is 2h to obtain a sealing layer with a thickness of 28μm. Finally, a titanium alloy with an oxide composite insulating layer on the surface is obtained.

[0041] The adhesion strength of porous titanium oxide layers was tested using the Rockwell indentation method under a load of 60 kg. The adhesion strength testing standards referenced international standards ISO 26443:2008 and GB / T 1.1-2009. Coating adhesion strength was defined as HF1 to HF6, with lower grades indicating higher adhesion strength. Coatings with HF and HF2 adhesion strengths are suitable for industrial applications.

[0042] Insulation performance test: A 15*15*5 test piece was used as the cathode for electroplating and then immersed in a nickel plating solution for 1 hour. Afterward, it was removed, and the proportion of the nickel plating layer to the surface area of ​​the coating was observed to determine the insulation performance of the oxide insulating layer. If the test piece was completely covered with nickel, it indicated poor insulation; if the test piece had no nickel plating layer, it indicated good insulation. According to industrial application requirements, only insulating oxide composite layers can meet industrial needs.

[0043] HCl corrosion resistance: The corrosion potential of the test piece in a 10 vol.% solution was tested using an electrochemical workstation. The lower the corrosion potential value, the worse the corrosion resistance.

[0044] Examples 2-6

[0045] Examples 2-6 provide porous titanium oxide layers and organic sealing layers of different thicknesses.

[0046] The specific parameters for each step in Examples 2-6 are shown in Tables 1-4:

[0047] S1. Same as Example 1;

[0048] S2. Adjusting the oxidation process parameters to prepare oxide layers of different thicknesses, as shown in Table 1:

[0049] Table 1

[0050]

[0051] S3. Adjust process parameters such as the ratio of sealing agent to water and the number of sealing cycles, as shown in Table 2:

[0052] Table 2

[0053]

[0054] S4. The titanium alloy sample with a porous titanium oxide layer on the surface after sealing is cured to obtain a composite insulating layer. The parameters are adjusted, including curing temperature and holding time, as shown in Table 3.

[0055] Table 3

[0056]

[0057]

[0058] Comparative Example 1

[0059] The only difference from Example 1 is that steps S3 and S4 are not performed.

[0060] Comparative Example 2

[0061] The only difference from Example 1 is that the temperature in step S2 is adjusted to 710°C and the time is adjusted to 11 hours.

[0062] Comparative Example 3

[0063] The only difference from Example 1 is that the temperature in step S2 is adjusted to 910°C and the time is adjusted to 4 hours.

[0064] Comparative Example 4

[0065] The only difference from Example 1 is that the ratio of organic sealing agent to water in step S3 is adjusted to 1:4, and the number of sealing cycles is adjusted to 4.

[0066] Comparative Example 5

[0067] The only difference from Example 1 is that the ratio of organic sealing agent to water in step S3 is adjusted to 1:11, and the number of sealing cycles is adjusted to 11.

[0068] Comparative Example 6

[0069] The only difference from Example 1 is that the furnace cooling in step S2 is changed to air cooling.

[0070] Comparative Example 7

[0071] The only difference from Example 1 is that the ultrasonic permeation treatment in step S3 is not performed.

[0072] Comparative Example 8

[0073] The only difference from Example 1 is that step S4 is not performed.

[0074] Comparative Example 9

[0075] The only difference from Example 1 is that the temperature in step S4 is adjusted to 110°C and the time is adjusted to 5 hours.

[0076] Comparative Example 10

[0077] The only difference from Example 1 is that the temperature in step S4 is adjusted to 210°C.

[0078] Comparative Example 11

[0079] The only difference from Example 1 is that the porous titanium oxide layer in step S2 is replaced with ZrO2 of the same thickness applied by plasma spraying.

[0080] Comparative Example 12

[0081] The only difference from Example 1 is that the porous titanium oxide layer in step S2 is replaced with an oxide layer of the same thickness prepared by the micro-arc oxidation process.

[0082] The test results of the oxide composite insulation layer on the surface of the titanium alloy samples in Examples 1-6 are shown in Table 4:

[0083] Table 4

[0084]

[0085] The test results of the insulation layer performance of the titanium alloy samples in Example 1 and Comparative Examples 1-12 are shown in Table 5:

[0086] Table 5

[0087]

[0088] The testing method for the bonding strength of oxide composite insulation layers is the same as that for porous titanium oxide layers.

[0089] As can be seen from Tables 4 and 5, the oxide composite insulating layers prepared in Examples 1-6 of the present invention have high bonding strength, corrosion resistance and insulation performance, which can meet the needs of industrial production.

[0090] In comparison, the porous titanium oxide layer without sealing treatment (Comparative Example 1) has poor insulation and corrosion resistance, which cannot meet production requirements; the coating with air cooling (Comparative Example 6) or no ultrasonic assistance (Comparative Example 7) in step S2 has poor corrosion resistance and insulation; the process parameters in S2, S3 and S4 are not within the requirements of this invention, and it is difficult to obtain the requirements of insulation, corrosion resistance and high adhesion; the coating using plasma spraying or micro-arc oxidation + sealing composite technology has poor protective effect.

[0091] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing an oxide composite insulating layer on the surface of a titanium alloy, characterized in that, Includes the following steps: (1) The degreased titanium alloy is oxidized at 750-900℃ for 5-10h, and then cooled to room temperature in the furnace to obtain a porous titanium oxide layer on the surface of the titanium alloy. (2) Place the titanium alloy with a porous titanium oxide layer on the surface obtained in step (1) in an organic sealing agent solution, perform ultrasonic treatment, dry, and repeat the ultrasonic treatment process 5-10 times. (3) The material treated in step (2) is cured at 120-200℃ for 1-5 hours to obtain an organic sealing layer on the surface of the porous titanium oxide layer, thereby realizing the preparation of an oxide composite insulating layer on the surface of the titanium alloy. The organic sealing agent solution is obtained by mixing organic sealing agent and water in a volume ratio of 1:5 to 1:9; The organic sealing agent includes silane sealing agents or polyurethane sealing agents; The thickness of the porous titanium oxide layer is 50-120 μm; the thickness of the organic sealing layer is 10-50 μm.

2. The method according to claim 1, characterized in that, Step (1) Oxidize at 750℃ for 7h.

3. The method according to claim 1, characterized in that, Step (2) The power of ultrasonic treatment is 1 to 20 kW and the time is 30 to 60 min.

4. The method according to claim 1, characterized in that, The number of ultrasonic treatments in step (2) is 8.

5. The method according to claim 1, characterized in that, Step (3) is cured at 150°C for 2 hours.

6. A titanium alloy with an oxide composite insulating layer on its surface, characterized in that, It is prepared by the method described in any one of claims 1-5.

7. The application of the titanium alloy with an oxide composite insulating layer on its surface as described in claim 6 as a watch hanger.

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