WO2022134154A1

WO2022134154A1 - Method and device for moving workpiece-type thermal electrochemical oxidation

Info

Publication number: WO2022134154A1
Application number: PCT/CN2020/140876
Authority: WO
Inventors: 李昊旻; 雷厉; 王连可; 高宇飞
Original assignee: 西比里电机技术苏州有限公司
Priority date: 2020-12-24
Filing date: 2020-12-29
Publication date: 2022-06-30
Also published as: CN112813477A

Abstract

An aspect of the present application provides a method for moving-workpiece type thermal electrochemical oxidation, comprising steps: S1, immersing a conductive metal having a valve metal outer surface in an electrolyte, two ends of the conductive metal being fixed by utilizing an unwinding apparatus and a winding apparatus; and S2, during thermal electrochemical oxidation, the conductive metal having a valve metal outer surface moves from an unwinding end towards a winding end, and in-situ growth of a thermal electrochemical oxidation ceramic layer occurs on a surface of the valve metal. Another aspect provides a device for moving workpiece-type thermal electrochemical oxidation, which comprises: a thermal electrochemical oxidation coating pool, an unwinding apparatus, and a winding apparatus, two ends of a conductive metal having a valve metal outer surface being fixed by utilizing the unwinding apparatus and the winding apparatus, the conductive metal being immersed in an electrolyte, and during thermal electrochemical oxidation, the conductive metal moves from an unwinding end towards a winding end, and in-situ growth of a thermal electrochemical oxidation ceramic layer occurs on a surface of the valve metal.

Description

A method and equipment for thermoelectrochemical oxidation of moving workpiece

technical field

The invention relates to the technical field of thermo-electrochemical oxidation, and in particular, the invention relates to a method and equipment for thermo-electrochemical oxidation of moving workpieces.

Background technique

Thermoelectrochemical oxidation is a new surface treatment technology that has developed rapidly at home and abroad in recent years. It is developed on the basis of anodic oxidation, and is also known as microplasma oxidation, plasma thermoelectrochemical oxidation, and plasma enhanced electrochemical oxidation. Surface ceramicization, etc. Thermo-electrochemical oxidation adopts a higher working voltage, and the working area of the voltage is introduced from the Faraday area of the ordinary anodizing method to the high-voltage discharge area, and the arc discharge is used to enhance and activate, so that the reaction that occurs on the anode is under a certain current density. , resulting in corona, glow, micro-arc discharge, and even spark spots on the surface of the workpiece, forming a dense ceramic film on the surface of the valve metal in situ, and then achieving the surface modification and strengthening of the workpiece. Valve metal has the function of electrolytic valve in metal-oxide-electrolyte system. Valve metal mainly includes six metals such as Al, Ti, Mg, Zr, Nb, Ta and their alloys, among which valve metal aluminum is the most widely used. The ceramic film and the substrate are metallurgically bonded, with good bonding strength, high hardness, good wear resistance, corrosion resistance, high voltage insulation and high temperature impact resistance, etc., which can improve the service life of the workpiece several times or even dozens of times. .

Thermoelectrochemical oxidation uses high voltage discharge, and a violent spark discharge reaction occurs on the surface of the workpiece. The spark discharge is too violent and difficult to control. The thermoelectrochemical oxidation process has an important impact on the effect and compactness of the ceramic film. How to control or how to slow down the violent spark discharge Sex is a worldwide problem.

In the prior art, in order to slow down the severity of the spark discharge, ultrasonic waves are added during the thermoelectrochemical oxidation process, which can promote the circulation of the electrolyte and reduce the resistance of the solution accordingly. On the other hand, the discharge breakdown in the later stage of the thermoelectrochemical oxidation is easier, and the spark discharge process of the thermoelectrochemical oxidation is overall slowed down violently, and the time is longer and more uniform. However, a big factor that hinders the promotion of thermoelectrochemical oxidation products in practice is the high production cost. The high cost comes from high voltage discharge on the one hand, and the cooling system on the other hand. If ultrasonic waves are used, the production cost will be further increased.

In view of this, the present invention provides a method and equipment for thermoelectrochemical oxidation of moving workpieces, which can slow down the severity of thermoelectrochemical oxidation, make thermoelectrochemical oxidation more uniform, and have low production cost.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and equipment for thermoelectrochemical oxidation of moving workpieces, which can reduce the severity of thermoelectrochemical oxidation, make thermoelectrochemical oxidation more uniform, and have low production cost.

One aspect of the present application provides a method for moving workpiece thermoelectrochemical oxidation, comprising the steps of:

S1, the conductive metal whose outer surface is valve metal is immersed in the electrolyte, and the two ends of the conductive metal are fixed by an unwinding device and a winding device;

S2, during thermoelectrochemical oxidation, the conductive metal whose outer surface is valve metal moves from the unwinding end to the winding end, and a thermoelectrochemically oxidized ceramic layer is grown on the surface of the valve metal in situ.

In the method for thermoelectrochemical oxidation of moving workpieces of the present application, the conductive metal moves from the unwinding end to the winding end during the thermoelectrochemical oxidation, and only the unwinding device and the winding device are required to play the role of fixing and moving. In, the workpiece in the thermo-electrochemical oxidation process is all fixed, concretely, adopt the device to clamp the workpiece, immerse in the electrolyte to be fixed and carry out thermo-electrochemical oxidation, and then take out the workpiece after the thermo-electrochemical oxidation finishes, and the workpiece of the application ( The conductive metal whose outer surface is valve metal) is mobile during the thermoelectrochemical oxidation process, which is the first of its kind. On the one hand, the conductive metal moves during the thermoelectrochemical oxidation process, and the movement of the conductive metal drives the movement of the electrolyte around the conductive metal, which promotes the circulation of the electrolyte, and the bubbles in the electrolyte escape from the electrolyte more quickly, so that the resistance of the solution is obtained. Correspondingly reduces the intensity of thermo-electrochemical oxidation, which makes thermo-electrochemical oxidation more uniform, the ceramic layer has better compactness, better wear resistance and corrosion resistance; on the other hand, the mobile conductive metal has almost no cost, and its production cost much lower than the addition of ultrasound.

In some embodiments, a conductive metal whose outer surface is a valve metal is immersed horizontally in the electrolyte, the conductive metal comprising: one of aluminum, aluminum alloy, zirconium, zirconium alloy, copper, copper alloy, zinc, or zinc alloy, the valve The metal includes: one of Al, Ti, Mg, Zr, Nb, Ta, Al alloy, Ti alloy, Mg alloy, Zr alloy, Nb alloy, or Ta alloy, preferably, the valve metal is Al, Ti, Mg, One of Al alloy, Ti alloy, or Mg alloy.

Further, the conductive metal is composed of one or a plurality of conductive metals. When the conductive metal is composed of a plurality of conductive metals, the plurality of conductive metals are arranged in parallel or in a woven and entangled manner.

Further, the cross section of the conductive metal is a circle, an ellipse or a polygon.

In some embodiments, the conductive metal whose outer surface is valve metal is wound on the unwinding device, the unwinding device fixes the conductive metal before thermoelectrochemical oxidation, the unwinding device and the winding device can be rotated, and the unwinding device and the winding device can be controlled by controlling the unwinding device and the winding device. The rotation speed of the coil device controls the movement speed of the conductive metal.

Further, between the unwinding device and the thermo-electrochemical oxidation plating tank, or/and between the thermo-electrochemical oxidation plating tank and the winding device, a straightening device is also provided, and the straightening device can straighten the conductive device.

Further, during thermo-electrochemical oxidation, the conductive metal moves too slowly to achieve a more uniform effect of thermo-electrochemical oxidation, while the conductive metal moves too fast, the time for thermo-electrochemical oxidation is not enough, and the thickness of the ceramic film is reduced. Therefore, After a lot of experiments, during thermoelectrochemical oxidation, the moving speed of the conductive metal is set to: 0.1m/min-5m/min, preferably, the moving speed of the conductive metal is: 0.5m/min-2m/min.

In some embodiments, the power source for thermoelectrochemical oxidation is one of DC, single-phase pulse, AC, asymmetric AC, or bidirectional asymmetric pulse power source. Preferably, the power source adopts a bidirectional asymmetric pulse power source.

Further, the electrolyte during thermoelectrochemical oxidation adopts one of a silicate system, a borate system, or an aluminate system. Preferably, the electrolyte for thermoelectrochemical oxidation is a silicate system. The silicate system includes: potassium hydroxide, sodium silicate, and deionized water, the concentration range of potassium hydroxide is: 0.5g/L-10g/L, preferably, the concentration range of potassium hydroxide is: 3g/L -5g/L, the concentration range of sodium silicate is: 1g/L-30g/L, preferably, the concentration range of sodium silicate is: 5g/L-15g/L.

Further, during thermoelectrochemical oxidation, the temperature of the electrolyte is controlled at: 10°C-50°C, preferably, the temperature of the electrolyte is controlled at: 22°C-35°C, more preferably, the temperature of the electrolyte is controlled at: 29°C -31°C.

In some embodiments, the thickness of the ceramic layer is: 20-70 μm, and preferably, the thickness of the ceramic layer is: 25-65 μm.

Further, when the valve metal is aluminum, the main material of the ceramic layer is α-type and/or 'Y-type Al ₂ O ₃ .

Another aspect of the present application provides a device for thermoelectrochemical oxidation of a moving workpiece, comprising: a thermoelectrochemical oxidation plating bath, a rewinding device, and a rewinding device, and the two ends of the conductive metal whose outer surface is a valve metal are unwinding The device and the winding device are fixed, the conductive metal is immersed in the electrolyte, and during thermoelectrochemical oxidation, the conductive metal moves from the unwinding end to the winding end, and a thermoelectrochemically oxidized ceramic layer is grown on the surface of the valve metal in situ.

In some embodiments, the moving speed of the conductive metal during thermoelectrochemical oxidation is: 0.1m/min-5m/min, preferably, the moving speed of the conductive metal is: 0.5m/min-2m/min.

In some embodiments, between the unwinding device and the thermo-electrochemical oxidation plating bath, further includes: a straightening device and a tension measuring device, the straightening device straightens the conductive metal, and the tension measuring device tests the tension of the conductive metal to ensure that the conductive metal stretch is within a reasonable range.

Further, there are multiple positive guiding devices between the unwinding device and the thermo-electrochemical oxidation plating bath, some of which are close to the unwinding device, and some are close to the thermo-electrochemical oxidation plating bath.

Further, the guiding device is composed of multiple groups of vertically distributed disks and horizontally distributed disks. Half of the disks are located above the conductive metal and half are located below the conductive metal. The disks rotate passively to increase the frictional force. Straighten the conductive metal.

In some embodiments, between the thermo-electrochemical oxidation plating bath and the winding device, further includes: a straightening device, a linear speed measuring device, a tension testing device and a wire arranging device, the straightening device straightens the conductive metal, and the linear speed is measured. The device detects the moving speed of the conductive metal, the tension measuring device tests the tension of the conductive metal to ensure that the stretching of the conductive metal is within a reasonable range, and the wire arrangement makes the conductive metal after thermoelectrochemical oxidation evenly wound on the winding device .

Technical effect: The conductive metal produced by the method and equipment for thermoelectrochemical oxidation of moving workpieces of the present application, in the early stage of thermoelectrochemical oxidation, the appearance of discharge sparks is advanced, and in the later stage of thermoelectrochemical oxidation, due to the movement of conductive metal and The conductive metal is stretched, and there are more micro-arc discharge points, reducing the phenomenon that the discharge breakdown caused by the thickening of the ceramic film is more and more difficult.

Description of drawings

FIG. 1 is a schematic structural diagram of the apparatus for thermoelectrochemical oxidation of moving workpieces of the present invention.

Detailed ways

The following examples are described to assist the understanding of the present application, and the examples are not and should not be construed in any way to limit the scope of protection of the present application.

In the following description, those skilled in the art will recognize that, throughout this discussion, components may be described as separate functional units (which may include sub-units), but those skilled in the art will recognize that various components or Parts thereof may be divided into separate components, or may be integrated together (including within a single system or component).

Also, connections between components or systems within the drawings are not intended to be limited to direct connections. Rather, data between these components may be modified, reformatted, or otherwise changed by intervening components. Additionally, additional or fewer connections may be used. It should also be noted that the terms "coupled," "connected," or "input" "fixed" should be understood to include direct connection, indirect connection or fixation through one or more intermediaries.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that a component is required to be absolutely horizontal or overhang, but rather may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal than "vertical", it does not mean that the structure must be completely horizontal, but can be slightly inclined.

Example 1:

A method for moving workpiece thermoelectrochemical oxidation, comprising the steps of:

The conductive metal whose outer surface is valve metal is immersed in the electrolyte horizontally. The conductive metal whose outer surface is valve metal is wound on the unwinding device. The unwinding device fixes the conductive metal before thermoelectrochemical oxidation. The unwinding device and the winding device can rotate. By controlling the rotation speed of the unwinding device and the winding device, Controls the speed at which the conductive metal moves. Between the unwinding device and the thermo-electrochemical oxidation plating tank, and between the thermo-electrochemical oxidation plating tank and the rewinding device, a straightening device is also arranged, and the straightening device can straighten the conductive device.

During thermoelectrochemical oxidation, the power source adopts a two-way asymmetric pulse power supply, and the current density is 5A/mm ² . The silicate system is: 10% Na ₂ AlO ₂ , 15% NaClO ₃ , 6% kOH solution , the temperature is 22 ℃. Under other conditions being the same, the moving speed of the conductive metal of sample 1 is 1.0 m/min, and the conductive metal of sample 2 is fixed.

Then, the flat aluminum wires pass through the plating bath and enter the oven. The oven temperature is set at 150°C, and the flat aluminum wire passes through the oven for 30 to 45 seconds to evaporate the residual moisture. Tested: the thickness of the ceramic layer of the mobile thermo-electrochemical oxidation: 5 ~ 300μm, the surface roughness of the ceramic layer: 0.272 ± 0.018 (Ra), in terms of wear resistance and corrosion resistance, the hardness of the mobile ceramic layer is: 2000 ~ 3000HV, Corrosion resistance of ceramic layer: C5H.

In this embodiment, a control group is also designed, and the workpiece of the control group is fixed, which is fixed during thermoelectrochemical oxidation, and other steps and conditions are the same as the above. After testing, the data of the control group were obtained as follows: the thickness of the fixed thermoelectrochemical oxidation ceramic layer: 5-60 μm, and the surface roughness of the ceramic layer: 0.375±0.022 (Ra). In terms of wear resistance and corrosion resistance, the fixed thermoelectrochemical oxidation ceramics Layer hardness: 1500 ~ 2000HV, ceramic layer corrosion resistance: C5L.

It can be seen that, compared with the traditional fixed thermoelectrochemical oxidation method of the present invention, the method of the present invention has a thicker ceramic layer, a more uniform and smooth surface of the ceramic layer, and has better wear resistance and corrosion resistance. better.

Example 2:

A moving workpiece type thermo-electrochemical oxidation equipment, as shown in Figure 1, includes: a thermo-electrochemical oxidation plating tank, an unwinding device, and a rewinding device, and the two ends of the conductive metal whose outer surface is valve metal adopts the unwinding device and The rewinding device is fixed, the conductive metal is immersed in the electrolyte, and during thermoelectrochemical oxidation, the conductive metal moves from the unwinding end to the rewinding end, and a thermoelectrochemically oxidized ceramic layer is grown on the surface of the valve metal in situ.

The conductive metal whose outer surface is valve metal is immersed in the electrolyte horizontally.

Between the unwinding device and the thermo-electrochemical oxidation plating bath, it also includes: a straightening device and a tension measuring device. The straightening device straightens the conductive metal, and the tension measuring device tests the tension of the conductive metal to ensure that the stretching of the conductive metal is reasonable. within the range. There are multiple positive guiding devices between the unwinding device and the thermo-electrochemical oxidation plating bath, some of which are close to the unwinding device, and some are close to the thermo-electrochemical oxidation plating bath. The guiding device is composed of multiple groups of vertically distributed disks and horizontally distributed disks. Half of the disks are located above the conductive metal, and half are located below the conductive metal. The disks rotate passively to increase friction, so that the conductive metal Straighten.

Between the thermo-electrochemical oxidation plating tank and the winding device, it also includes: a guiding device, a linear speed measuring device, a tension testing device and a wire arranging device. The guiding device straightens the conductive metal, and the linear speed measuring device detects the movement of the conductive metal. The speed and tension measuring device tests the tension of the conductive metal to ensure that the stretching of the conductive metal is within a reasonable range, and the wire arrangement makes the conductive metal after thermoelectrochemical oxidation evenly wound on the winding device.

Although the present application has disclosed various aspects and embodiments, other aspects and embodiments will be apparent to those skilled in the art, and several modifications and improvements can be made without departing from the concept of the present application. All belong to the protection scope of this application. The various aspects and embodiments disclosed in the present application are only used for illustration, and are not intended to limit the present application, and the actual protection scope of the present application is subject to the claims.

Claims

A method for moving workpiece type thermoelectrochemical oxidation, characterized in that, comprising the steps of:

S1, the conductive metal whose outer surface is valve metal is immersed in the electrolyte, and the two ends of the conductive metal are fixed by an unwinding device and a winding device;

S2, during thermoelectrochemical oxidation, the conductive metal whose outer surface is valve metal moves from the unwinding end to the winding end, and a thermoelectrochemically oxidized ceramic layer is grown on the surface of the valve metal in situ.
The method for thermoelectrochemical oxidation of a moving workpiece according to claim 1, wherein the conductive metal whose outer surface is valve metal is immersed in the electrolyte horizontally, and the conductive metal comprises: aluminum, aluminum alloy, zirconium, zirconium alloy, copper, One of copper alloy, zinc, or zinc alloy, valve metal includes: one of Al, Ti, Mg, Zr, Nb, Ta, Al alloy, Ti alloy, Mg alloy, Zr alloy, Nb alloy, or Ta alloy kind.
The method for thermoelectrochemical oxidation of moving workpieces according to claim 1, wherein the conductive metal whose outer surface is valve metal is wound on the unwinding device, the unwinding device fixes the conductive metal before the thermoelectrochemical oxidation, and the unwinding device fixes the conductive metal before the thermoelectrochemical oxidation. And the winding device can be rotated, and the moving speed of the conductive metal can be controlled by controlling the rotation speed of the unwinding device and the winding device.
The method for thermo-electrochemical oxidation of moving workpieces according to claim 3, characterized in that, between the unwinding device and the thermo-electrochemical oxidation plating tank, or/and between the thermo-electrochemical oxidation plating tank and the rewinding device, a conductor is also provided. Positive device, the guiding device can straighten the conductive device.
The method for thermoelectrochemical oxidation of moving workpieces according to claim 3, characterized in that, during thermoelectrochemical oxidation, the moving speed of the conductive metal is 0.1m/min-5m/min.
The method for thermoelectrochemical oxidation of moving workpieces according to claim 5, characterized in that, during thermoelectrochemical oxidation, the moving speed of the conductive metal is: 0.5m/min-2m/min.
The method for moving workpiece type thermoelectrochemical oxidation according to claim 1, wherein the power source during thermoelectrochemical oxidation adopts: one of direct current, single-phase pulse, alternating current, asymmetric alternating current, or two-way asymmetric pulse power source ; The electrolyte during thermoelectrochemical oxidation adopts one of silicate system, borate system, or aluminate system; during thermoelectrochemical oxidation, the temperature of the electrolyte is controlled at: 10°C-50°C.
A moving workpiece type thermo-electrochemical oxidation equipment is characterized in that, it comprises: a thermo-electrochemical oxidation plating tank, an unwinding device, and a winding device, and the two ends of the conductive metal whose outer surface is valve metal adopts the unwinding device and the winding device. The device is fixed, the conductive metal is immersed in the electrolyte, and during thermoelectrochemical oxidation, the conductive metal moves from the unwinding end to the winding end, and a thermoelectrochemically oxidized ceramic layer is grown on the surface of the valve metal in situ.
The equipment for thermoelectrochemical oxidation of moving workpieces according to claim 8, wherein the moving speed of the conductive metal during thermoelectrochemical oxidation is 0.1m/min-5m/min.
The equipment for thermo-electrochemical oxidation of moving workpieces as claimed in claim 8, characterized in that, between the unwinding device and the thermo-electrochemical oxidation plating tank, further comprising: a guiding device, a tension measuring device, a thermo-electrochemical oxidation plating tank and a rewinding device Between the devices, it also includes: a straightening device, a linear speed measuring device, a tension testing device and a wire arranging device, the straightening device straightens the conductive metal, the linear speed measuring device detects the moving speed of the conductive metal, and the tension measuring device tests the conductive metal. The tension ensures that the stretching of the conductive metal is within a reasonable range, and the wire arrangement makes the conductive metal after thermoelectrochemical oxidation evenly wound on the winding device.