JP6558649B2 - Surface treatment method and surface treatment apparatus - Google Patents

Description

  The present invention relates to a surface treatment method and a surface treatment apparatus for performing a surface treatment on an object to be treated. More specifically, a surface treatment method and a surface treatment apparatus for forming an oxide film on a surface to be processed made of a valve metal such as aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. About. The valve metal is also called a valve metal or a valve metal.

  As shown in FIG. 7, a surface treatment method is known in which an oxide film is formed on the surface of a target object by performing an anodic oxidation process including a micro-arc oxidation process on a target object 111 having a small area. In FIG. 7, reference numeral 121 represents an electrolytic solution tank, and reference numeral 122 represents an electrolytic solution. When the object to be processed 111 has a small area, an oxide film may be formed by immersing the entire object to be processed 111 in the electrolytic solution 122. However, as the object to be processed 111 becomes a large area, in the method shown in FIG. 7, that is, in the anodic oxidation process including the micro arc oxidation process that requires high voltage and high current density, facilities such as a power source and a chiller are provided. Becomes large, and it becomes difficult to process a large-scale object to be processed.

  In order to solve this problem, an oxide film is formed on the entire surface of the target object by dividing the surface of the target object with a large area and performing anodization including micro-arc oxidation in several steps. The present inventor has previously proposed a surface treatment method (Patent Document 1). Here, the micro-arc oxidation treatment (anodic oxidation treatment with spark discharge) is a kind of anodizing treatment and means a surface treatment method capable of forming an excellent oxide film. However, the method disclosed in Patent Document 1 has a problem that work efficiency is poor because there is a step of pulling up the object to be processed from the electrolytic solution and removing the mask material.

  In order to solve the problem in the method of Patent Document 1, the present inventor has further proposed a method of performing surface treatment without using a mask (Patent Document 2). Thereby, the process of removing the mask material becomes unnecessary, and the work efficiency is improved. However, in the method disclosed in Patent Document 2, a striped pattern remains on the processing surface of the object to be processed, and an improvement in the appearance of the processing surface has been demanded.

In view of this, the present inventor has studied a method of performing micro-arc oxidation treatment on a workpiece of several m ² without dividing the surface of the workpiece having a large area. In the case of micro-arc oxidation treatment (anodic oxidation treatment with spark discharge), the treatment is performed at a higher current density and high voltage as compared with normal anodic oxidation treatment without spark discharge. For this reason, when an oxide film is formed on an object to be processed having a large processing area by micro arc oxidation treatment, a large-scale power supply facility, a large-scale electrolyte cooling mechanism, etc. are required, which is expensive in terms of facilities. There was a problem.

Japanese Patent No. 4836921 Japanese Patent No. 5770575

  The present invention has been made in view of the above circumstances, and even with a low-current power supply device and a simple electrolyte cooling mechanism, a large area is covered by anodic oxidation treatment including micro-arc oxidation treatment. It is an object to provide a surface treatment method and a surface treatment apparatus capable of intermittently forming an oxide film on a treatment body.

In order to solve the above problems, the present invention provides the following surface treatment method and surface treatment apparatus. That is,
The invention according to claim 1, to be processed surface of the object consisting of valve metal, sets a plurality of processing sections, including a micro-arc oxidation process by immersing each processing compartment Intermittent manner electrolyte A surface treatment method for performing an anodic oxidation treatment and forming an oxide film on the surface to be treated,
The anodic oxidation treatment comprises first M step consists of the object to be processed from a plurality of steps Before moving to each of the processing section having a depth direction of the width of the electrolyte,
The Mth step includes
Said only the first processing compartment is immersed in the electrolytic solution of the object to be processed, held to a low voltage V _M than the maximum voltage V _max of the anodic oxidation treatment, so as to have a predetermined current I _1, the Following the step of forming the desired oxide film in the first processing section,
The workpiece having been subjected to the immediately preceding step, was immersed in the electrolyte until processing compartment you adjacent to said processing compartment have been processed, the first and last in the previous step and the same voltage V _M Conditions for the processing compartment between repeats the steps of forming a desired oxide layer,
Until the end of the treatment compartment is immersed in the electrolyte, by performing the step of forming the desired oxide film on the end of the processing compartment with the same voltage V _M conditions the previous step, and held in the voltage V _M wherein it is as forming an oxide film over the entire surface to be treated
Further, the M-th step is a step that is repeatedly performed a plurality of times,
The first of the M step of performing a voltage of the anodic oxidation treatment at a voltage V _M, between a voltage of the anodic oxidation treatment to the end of the M step carried out at the maximum voltage V _max, the voltage of the anodic oxidation treatment the in Rukoto from the voltage V _M is stepwise increased until the maximum voltage V _max, to form the oxide film in which the total film thickness over the entire treated surface is made of a desired thickness,
It is characterized by that.

The invention according to claim 2 is the invention according to claim 1, wherein the repetition of the Mth step is 2 or more.
It is characterized by that.
According to a third aspect of the invention, according to claim 1, the value of the predetermined current at the time of performing repeatedly as the first M Engineering is the same as the previous SL current I _1,
It is characterized by that.
Invention according to claim 4, in claim 1, wherein when immersing in the electrolyte a plurality of pre Kisho physical Ward image sequentially in the object to be processed is該被process to the depth direction of the electrolyte solution Controlling the position of the object to be treated relative to the liquid level of the electrolyte so that the body advances or stops;
It is characterized by that.
According to a fifth aspect of the present invention, in the fourth aspect, in order to control the position of the object to be processed with respect to the liquid surface of the electrolytic solution, a height position of the liquid surface of the electrolytic solution is fixed, and the electrolytic solution Adjusting the height position of the object to be processed with respect to the liquid level of
It is characterized by that.
In order to control the position of the object to be processed with respect to the liquid surface of the electrolytic solution, the height of the object to be processed is fixed, and the invention described in claim 6 fixes the height of the object to be processed. Adjusting the height of the electrolyte surface relative to the height position;
It is characterized by that.
The invention according to claim 7, following the first M steps before Symbol last in claim 1,
A step P for performing the anodic oxidation process by continuously or intermittently dropping the voltage to a voltage V _M− lower than the voltage VM _{M in} which the last Mth step has been performed;
A step Q of performing constant voltage processing with the voltage V _M− , in order;
It is characterized by that.

Invention of Claim 8 is a surface treatment apparatus which performs an anodic oxidation process by the surface treatment method of Claim 1, and forms an oxide film in the said to-be-processed object,
An anode means for forming the oxide film by the anodic oxidation processing on the target surface of the object to be processed,
An electrolytic bath containing the electrolytic solution and having an opening that allows the anode means to be immersed in the electrolytic solution;
Cathode means disposed opposite to the anode means in the electrolyte solution;
In a state in which the anode means and said cathode means is immersed in the electrolyte, the by generating a current I ₁ between the anode means and said cathode means, and power supply means for performing the anodic oxidation treatment,
Wherein in order is immersed in the electrolytic solution to a specific processing compartment of the processing compartment of the object to be processed, wherein moving the workpiece to a depth direction of the electrolyte, and, until the particular processing compartment wherein the moving means of the object to be processed having a function to quiesce the workpiece to the position immersed in the electrolyte,
Said moving means, said each time the first M step Ru Wataru the entire area of the object is completed, the from the electrolyte to a position where the whole is exposed to the workpiece, electrolytic solution該被processed Configured to move the anode means in the direction of lifting from
It is characterized by that.
Invention of Claim 9 is a surface treatment apparatus which performs an anodic oxidation process by the surface treatment method of Claim 1, and forms an oxide film in the said to-be-processed object,
An anode means for forming the oxide film by the anodic oxidation processing on the target surface of the object to be processed,
An electrolytic bath containing the electrolytic solution and having an opening that allows the anode means to be immersed in the electrolytic solution;
Cathode means disposed opposite to the anode means in the electrolyte solution;
In the state where the anode means and the cathode means are immersed in the electrolytic solution, a power supply means for generating an electric current between the anode means and the cathode means to perform the anodization treatment;
Wherein in order is immersed in the electrolytic solution to a specific processing compartment of the object to be processed, wherein the workpiece is moved in the depth direction of the electrolyte, and the predetermined current value I ₁ and the current handling comparing a value, wherein the moving means of the object to be processed having a function to quiesce the workpiece when it exceeds the predetermined current value I _1,
Said moving means, said each time the first M step Ru Wataru the entire area of the object is completed, the from the electrolyte to a position where the whole is exposed to the workpiece, electrolytic solution該被processed is configured to move said anode means in a direction to pull from, and, in the next M th step of the first M step is applied to the workpiece a voltage higher than the predetermined voltage as a predetermined voltage ,
It is characterized by that.

According to the surface treatment method according to the present invention, the treated surface of the object to be processed is, intermittent oxidation (maintained at a low voltage V _M than the maximum voltage V _max of the micro-arc oxidation process, a predetermined current I ₁ and under conditions that), so as to be covered by the oxide film, performing as a M Engineering described above (repetition of the M step is 2 or more). Further, said voltage V _M is increased in order in the direction of the highest voltage V _max is a predetermined numerical V M _{+ n,} by repeating the first M step, the oxidation final thickness consists of desired thickness Form a film. As a result, the present invention provides a power supply device with a small current density and a simple electrolytic solution cooling mechanism. This contributes to the provision of a surface treatment method capable of forming an oxide film.
Moreover, the treated surface of the object to be processed by the surface treatment method of the present invention, by holding to a low voltage V _M than the maximum voltage V _max during formation of the oxide film, and a predetermined current I _1, intermittently Even if the processing is performed, a colored pattern does not remain on the processing surface. For this reason, it becomes possible to obtain an oxide film excellent in the homogeneity of the appearance of the treated surface.
Incidentally, the surface treatment method of the present invention, the anodic oxidation treatment, the repetition of the M step is equal to or greater than 2, wherein the step that make up the first M step, the object to be processed continuously or intermittently the It can also be immersed in the electrolytic solution. At that time, the value of the predetermined current definitive to the first M step is the same value at a predetermined current I _1.

The surface treatment apparatus according to the present invention moves the object to be treated in the depth direction of the electrolytic solution in order to immerse the object to be treated up to a specific treatment section in the electrolytic solution. An object to be processed is provided with a function of stopping the object to be processed at a position where the section is immersed in the electrolytic solution. The moving means applies a predetermined voltage over the entire area of the object to be processed and exposes the entire area of the object to be processed from the electrolytic solution every time a series of anodic oxidation processes are completed. The anode means is moved to a position in a direction to pull up the object to be processed from the electrolytic solution. Thus, according to the present invention, since it is possible to retain the current at the anode oxidation process comprising micro-arc oxidation process in a predetermined current I ₁ or less, large-capacity power supply is not required. Furthermore, since the heat generation during the formation process of all oxide films can be actively reduced, the system for cooling the processing system can be made smaller than the conventional system.
Therefore, the present invention can form an oxide film intermittently on an object to be processed having a large area by micro arc oxidation treatment even with a power supply device with a small current density and a simple electrolyte cooling mechanism. Resulting in a surface treatment device capable of
In addition, since the surface treatment apparatus of the present invention includes the above-described anode means, an oxide film having a desired film thickness is formed on a large-area workpiece to automatically cover the workpiece. it can.

The block diagram which shows the surface treatment apparatus which concerns on this invention. The flowchart which shows the surface treatment method which concerns on this invention. Explanatory drawing which shows the surface treatment method which concerns on this invention. It is a graph which shows the relationship between voltage and electric current, and processing time, and is the voltage-current curve at the time of processing by the method of this invention. It is a graph which shows the relationship between voltage and electric current, and processing time, and is a voltage-current curve at the time of processing collectively. The batch treatment is a method in which the entire surface of the object to be treated (whole) is immersed in an electrolytic solution at the same time. The graph which shows the relationship between the position of to-be-processed object in the direction to immerse, and processing time. Explanatory drawing which shows the conventional surface treatment method.

  Hereinafter, the best mode of a surface treatment apparatus and a surface treatment method according to the present invention will be described with reference to the drawings. The present embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified.

FIG. 1 is a block diagram showing a surface treatment apparatus according to the present invention.
As shown in FIG. 1, the surface treatment apparatus of the present invention is a surface on which an object to be treated 11 made of aluminum or an aluminum alloy is immersed in an electrolytic solution 22 for anodic oxidation to form an oxide film on the object to be treated. It is a processing device.
In this surface treatment apparatus, the object 11 on which an oxide film is formed by anodic oxidation functions as an anodic means.

In this surface treatment apparatus, the electrolytic solution tank 21 that stores the electrolytic solution 22 has an opening that allows the anode means (the object 11 to be treated) to be immersed in the electrolytic solution.
In the electrolytic solution 22, the cathode means 17 is disposed at a position facing the anode means (the object to be processed 11) that is immersed.
The surface treatment apparatus of the present invention includes power supply means 30 for performing the anodic oxidation treatment. The power source means 30 generates a current between the anode means (object 11) and the cathode means 17 in a state where the anode means (object 11) and the cathode means 17 are immersed in the electrolytic solution 22. The anodizing treatment is performed.

  The surface treatment apparatus of the present invention includes a moving means (for example, an actuator) 40 for the object 11 to be processed. The moving means 40 holds the workpiece 11 via the first support part 41 and the second support part 42. The moving means 40 has a function of moving the object to be processed 11 in the depth direction (Z direction) of the electrolyte solution 22 in order to immerse the object to be processed 11 up to a specific processing section in the electrolyte solution 22. And a function of causing the object to be processed 11 to stand still at a position immersed in the electrolytic solution 22 up to a specific processing section.

  That is, the moving means 40 connects the first support part 41 that can be moved up and down, the other end of the first support part 41 and the upper end of the object to be processed 11, and hangs the object 11 to be processed. The 2nd support part 42 to keep is provided. As a result, the object 11 is subjected to a series of anodizing treatments by applying a predetermined voltage over the entire region (all areas in the direction (Z direction) in which the object 11 is immersed in the electrolytic solution 22). It can be performed. Further, each time the series of anodic oxidation processes is completed, the moving means 40 moves the object to be processed 11 from the electrolyte 22 to a position where the entire area of the object 11 is exposed from the electrolyte 22. The anode means (object 11) is configured to move.

  The vertical movement of the moving means 40 is controlled from the information processing device 60 via the sequencer 50. The information processing device 60 controls information (voltage, current) applied from the power supply means 30 to the anode means (object 11) and the cathode means 17 through the communication line. Although FIG. 1 shows a configuration example in which the sequencer 50 and the information processing device 60 are divided and arranged, a control device that integrates them may be used (not shown). The control unit included in the control device preferably includes a comparison unit having a function of comparing the predetermined current value and the processing current value.

FIG. 2 is a flowchart showing the surface treatment method according to the present invention. FIG. 3 is an explanatory view showing a surface treatment method according to the present invention. In the explanation based on Figure 3 below, the anode oxidation treatment, the number of the steps is "3 or more", the first M Engineering as (repetition of the M step is 2 or more) constituting a second M A step (step), · · · the M N step (step) is described in detail for the case of immersing the said electrolytic solution to be processed to "intermittently".
In the surface treatment method according to the present invention, a plurality of treatment sections A, B, C,... N are set on the surface to be treated 11 of aluminum or an aluminum alloy [FIG. Anodizing treatment is performed by intermittently immersing in the electrolytic solution for each processing section, and an oxide film is formed on the surface to be processed. Here, “intermittent” means that the processing section A is first, then the processing section B, then the processing section C, and finally the processing section N (that is, the object 11 to be processed). The entire surface to be treated) is immersed in an electrolyte solution in order, and the anodic oxidation treatment is performed.
In FIG. 3A, x1 represents the width of the object 11 to be processed, x2 represents the height of the object 11 to be processed, and x3 represents the thickness of the object 11 to be processed.

The anodic oxidation treatment in the surface treatment method of the present invention comprises the Mth step (M is an integer of 2 or more) described later. That is,
Wherein the M (M is an integer of 2 or more) steps, the M A step described below (step), the M B step (step), the M C step (step), ... a M N step ( Step) .

The M A step (step) moves the workpiece 11 in the Z-direction distance Δa only. Thereby, only the 1st process division A among the to-be-processed bodies 11 is made into the state immersed in the electrolyte solution 22. As shown in FIG. While maintaining this immersed state, as held in the maximum voltage V _max low voltage V _M than the anodic oxidation process including micro-arc oxidation process, a predetermined current I _1, a first processing of the object 11 the section a to form the desired oxide film [Fig. 3 (b) → Fig. 3 (c): the M a step (step). In FIG. 3B and FIG. 3C, the symbol Δa is the width of the first processing section A in the Z direction. In FIG. 3C, reference numeral 15a1 denotes an oxide film formed in the first processing section A. Here, the predetermined current is one in which the operator inputs this current value. The surface treatment apparatus (FIG. 1) of the present invention also includes an input unit for a predetermined current value.

Then, the object to be processed 11 which has finished the first M A step (step) to move in the Z direction by a distance [Delta] b. Thereby, let the to-be-processed object 11 be the state immersed in the electrolyte solution 22 to the 2nd process area B adjacent to this 1st process area A with the 1st process area A. While maintaining this immersed state, the M A step (step) to form the desired oxide film on the second processing compartment B under the same conditions [Figure 3 (d): The M B step (step).
At that time, almost no oxide film is formed in the first processing section A. In FIG. 3D, the symbol Δb is the width of the second processing section B in the Z direction. In FIG. 3D, reference numeral 15b1 is an oxide film formed in the second processing section B.

Then, the object to be processed 11 which has finished the first M B step (step) to move in the Z-direction distance Δc only. Thereby, let the to-be-processed object 11 be the state immersed in the electrolyte solution 22 to the 3rd process area C adjacent to this 2nd process area B with the 1st process area A and the 2nd process area B. While maintaining this immersed state, the M A step (step) to form the desired oxide film on the third processing compartment C under the same conditions [Figure 3 (e): The M C step (step). At that time, almost no oxide film is formed in the first processing section A and the second processing section B. In FIG. 3E, the symbol Δc is the width of the third processing section C in the Z direction. In FIG. 3 (e), reference numeral 15 c 1 is an oxide film formed in the third processing section C.

Similarly, after the third processing section C, the workpiece 11 is moved by a predetermined distance in the Z direction, and is sequentially immersed in the electrolytic solution 22 to the adjacent processing sections. While maintaining this immersed state, to form the desired oxide film on the processing compartment adjacent under the same conditions and the M A step (step).
Thus, M B step (step), M C repeated step (step) with the same step (step) in this order, until the end of the processing compartment N of the object 11 (i.e., all of the of the object 11 The treated surface is immersed in the electrolytic solution 22. While maintaining this immersed state, the M A step (step) last processing compartment with the same conditions as (n-th processing compartment) N to form a desired oxide film [Fig. 3 (f): The M N step ( Step) ]. At that time, almost no oxide film is formed in the processing section immediately before the first processing section A to the last processing section N. Thereby, the state by which the oxide film was formed over the whole to-be-processed surface of the to-be-processed object 11 is obtained. In FIG. 3F, the symbol Δn is the width of the last processing section N in the Z direction. In FIG. 3E, reference numeral 15n1 denotes an oxide film formed in the last processing section N.

Through the above first M step (a M A step (step) to the M N step (step)), a series of steps of forming an oxide film and held to a predetermined voltage V _M is completed. Thereafter, the object 11 on which the oxide film is formed is pulled up (moved in the −Z direction) from the state where it is immersed in the electrolyte 22, and the object 11 is exposed from the electrolyte 22.

Then, it is maintained at a voltage V _{M + 1} (V _M <V _{M + 1} <V _max ) that is higher than the previously set predetermined voltage V _{M and} lower than the maximum voltage V _max of the micro arc oxidation treatment, and a predetermined current while managing so that I _1, to form the desired oxide film on the first processing compartment a of the object to be processed 11. Hereinafter, as in the case of the voltage VM as described above, a series of steps (the M A step (step) to the M N step (step)). Thus, over the entire surface to be processed of the workpiece 11, obtained on the oxide film formed at a predetermined voltage V _M, the state in which the oxide film formed at a predetermined voltage V _{M + 1} is formed It is done.

Said voltage _{V M} is increased in order in the direction of the highest voltage _{V max} is a predetermined numerical _{(V M <V M + 1} <V M + 2 <V M + 3 <·· <V M + n <V max), wherein the M step (a By repeating the M A process (step) to the MN process (step) ), the oxide film having a desired total thickness is formed over the entire surface to be processed of the object 11 to be processed. can do.

That is, the surface treatment method according to the present invention, the treated surface of the object to be processed is intermittent oxidation (maintained at a low voltage V _M than the maximum voltage V _max of the micro-arc oxidation process, a predetermined current I ₁ The above-described Mth step is performed so as to be covered with the oxide film. Further, said voltage V _M is increased in order in the direction of the highest voltage V _max is a predetermined number, by repeating the first M step to form the oxide film total thickness is composed of desired thickness .

Above with reference to FIG. 3, in the anodic oxidation treatment, the number of the steps is "3 or more", constituting the first M step, the first M A step (step), the first M B step (step), ... Although the description has been given of the case where the MN process (step) immerses the object to be processed “intermittently” in the electrolytic solution, the present invention is not limited thereto.
The number of steps may be “1 or 2”. Further, the M-th A process (step) , the M-th B process (step) ,... The M- N process (step) constituting the M-th process “intermittently” the object to be processed. Instead of immersing in the electrolytic solution, a method of immersing the object to be processed in the electrolytic solution “continuously” may be adopted.
That is, in the anodic oxidation treatment, the number of the steps is "1", constituting the first M step, the first M A step (step), the first M B step (step), ... the first M N process (step) can also immerse the said to-be-processed object in the said electrolyte solution "continuously" or "intermittently". At that time, the first M B step (step), the value of the predetermined current in ... the first M N step (step) is, the first M A step numerically equal to a predetermined current _{I 1} in (step) It is preferable that

In the following, the case of adopting a control unit which integrates the control device comprises the first M A step of the M step (M is an integer of 2 or more) (step), the first M B step (step), ... the Typical of “target value, current value, operation amount, movement amount” used to control “intermittently” when the object to be processed is immersed in the electrolytic solution in the MN process (step) I will describe the correspondence.
The target value is a predetermined current value input by the operator.
The current value is the processing current (current during anodic oxidation).
The operation amount is the speed at which the workpiece is immersed. This immersion speed is typically a fixed speed input by the operator, but may be a speed obtained by multiplying the difference between the target value and the current value by a proportional constant. In the latter case, the surface treatment can be performed in a shorter time.

The movement amount is the movement distance of the workpiece in the Z direction. The movement amount is taken into the control unit by a sensor or the like (not shown). At this time, the immersion to a certain processing section is synonymous with moving in the Z direction from the initial position until the movement amount corresponding to the next processing section is reached.
Alternatively, a value obtained by integrating the operation amount over time may be used as the movement amount, and the sensor may not be necessary, and the movement amount may be moved in the Z direction until it matches the movement amount corresponding to the next processing section. Here, the definition of the movement amount corresponding to the processing section is an arbitrary value input by the operator, but it is desirable to set a value corresponding to the control cycle time of the control unit. This is because the minimum processing section can be realized by performing this setting.

The control unit detects that the immersion to a certain processing section is completed by comparing the “movement amount” with the “movement amount corresponding to the processing section”, and then “target value” and “current value”. Make a comparison. As a result of this comparison, if it is equal to or less than a predetermined current value, it is not necessary to stop, so movement corresponding to the next processing section is permitted.
In addition, when exceeding a predetermined electric current value, the process which stops immersion, ie, an operation amount, is made into zero. However, a slight movement of the workpiece in the reverse direction is acceptable within the adjustment range of the actual machine.
As described above, in the present invention, the control unit by repeatedly executing a plurality of times the series of processes, the first M A step (step), the first M B step (step), ... the first M The process of N process (step) is performed. In other words, depending on the result of comparing the target value with the current value, it may be “intermittent processing”, “partly continuous processing”, or “all continuous processing”. is there.

FIG. 2A is a flowchart showing the above-described surface treatment method according to the present invention, and shows that the Mth process (the Mth MA process (step) to the MNth process (step) ) is repeated. . FIG. 2B is a diagram schematically showing the positional relationship between the object to be processed 11 and the electrolytic solution 22 corresponding to FIGS. 3B and 3F.
That is, FIG. 2 (a), the relationship between the current value I and the predetermined current I ₁ during anodic oxidation treatment, if they meet the 'I ₁ ≧ I "represents that the process proceeds in the direction of YES.
Even when “I ₁ ≧ I” is satisfied, the actuator position may be Z ₁ <Z. When this condition is satisfied, the “Mth A process (step) to the MN process (step) ” constituting the Mth process are regarded as one continuous process without being divided. Here, Z ₁ represents the position (height) of the rear side surface of the substrate when the front side surface of the substrate is in contact with the liquid surface, and Z represents the position (height) of the rear side surface of the substrate during the anodic oxidation treatment. [FIG. 2 (b)].

  Therefore, the present invention can form an oxide film intermittently on an object to be processed having a large area by micro arc oxidation treatment even with a power supply device with a small current density and a simple electrolyte cooling mechanism. Resulting in a surface treatment method.

In addition, the surface to be processed of the object to be processed by the surface treatment method of the present invention is covered with a multilayer structure of oxide films formed by intermittent oxidation treatment. Maintained at a low voltage V _M than the maximum voltage V _max during formation of the oxide film, by which a predetermined current I _1, even if the intermittent processing, it is never remain chromatic patterns on treated surface . For this reason, this invention contributes to provision of the oxide film excellent in the homogeneity of the external appearance of the processing surface.

FIG. 4 is a graph showing the relationship between the voltage and current applied during the formation of the oxide film and the treatment time, and is a voltage-current curve when the treatment is performed by the method of the present invention. In FIG. 4, the solid line represents the voltage, and the dotted line represents the current.
From FIG. 4, in the surface treatment method of the present invention, when held at a low voltage V _M than the maximum voltage V _max during formation of the oxide film, it can be seen that are controlled so as to maintain a predetermined current I ₁ . In the present invention also as shown in FIG. 4, said voltage _{V M} is increased in order in the direction of the highest voltage _{V max} predetermined value _{(V M <V M + 1} <V M + 2 <V M + 3 <·· <V M + n <V _max ), and even when the Mth process (the Mth MA process (step) to the MNth process (step) ) is performed, the current I ₁ is controlled to be maintained.

Furthermore, as shown in FIG. 4, following the end of the M step (a M A step (step) to the M N step (step)), the last of the voltage V _M to the M step is performed A process P for performing the anodizing process by continuously or intermittently dropping the voltage to a lower voltage V _M− at a predetermined time and a process Q for performing a constant voltage process at the voltage V _M−. You may provide further in order.
Thus, without the latter voltage (V _M-) In breakdown, as higher the former voltage (V _M) in breakdown than the latter voltage (V _M-), fully repair the weak It becomes possible to obtain an oxide film having higher withstand voltage and corrosion resistance.
It is preferable to repair the film more reliably by repeating such a voltage change between the former voltage (V _M ) and the latter voltage (V _M− ) a plurality of times.

FIG. 5 is a graph showing the relationship between the voltage and current applied during the formation of the oxide film and the treatment time, and is a voltage-current curve when the treatment is performed in a lump. In FIG. 5, the solid line represents the voltage, and the dotted line represents the current.
By comparing FIG. 4 and FIG. 5, when batch processing is performed, the processing time is 1/3 of the case of processing by the method of the present invention, but the processing current is three times that of processing by the method of the present invention. I understand that it is necessary. From this, it has been clarified that the continuous processing according to the present invention can suppress a processing current and can process a large-sized object to be processed with a small facility.

FIG. 6 is a graph showing the relationship between the position of the object to be treated and the treatment time in the immersion direction.
FIG. 6 shows that when the processing voltage is low, the entire sample is immersed and the time until the processing at that voltage is completed is short. On the other hand, when the treatment voltage is high, it can be seen that the entire sample is immersed and the time until the treatment at that voltage is completed is long.

In the surface treatment method of the present invention, when the first treatment section, the second treatment section, and the n-th section in the object to be treated are immersed in the electrolyte solution in order, the depth of the electrolyte solution It is preferable to control the position of the object to be processed with respect to the liquid surface of the electrolytic solution so that the object to be processed advances or stops in the direction.
Thereby, the operation | movement where the area | region in which the film | membrane is not yet formed among the to-be-processed surfaces of the to-be-processed object 11 comes in and out with respect to the liquid level of the electrolyte solution 22 can be prevented. Therefore, it is possible to stably form the oxide film in a state where the phenomenon of dielectric breakdown is unlikely to occur.

As described above, as a method for controlling the position of the workpiece 11 with respect to the liquid surface of the electrolytic solution 22, there are two methods described below.
The first method is a method of fixing the height position of the liquid surface of the electrolytic solution and adjusting the height position of the object to be processed with respect to the liquid surface of the electrolytic solution.
The second method is a method of fixing the height position of the object to be processed and adjusting the height of the electrolytic solution with respect to the height position of the object to be processed.
In any method, the position of the workpiece 11 with respect to the liquid surface of the electrolytic solution 22 can be controlled. When the object 11 is small (the processing area is small), any method may be selected. However, when the object 11 is large (the processing area is wide), the electrolytic cell 21 for storing the electrolytic solution 22 also has a large capacity, and therefore the first method is suitable.

An example of the surface treatment apparatus of the present invention is a surface treatment apparatus as shown in FIG. That is,
The surface treatment apparatus according to the present invention moves the object to be treated in the depth direction of the electrolytic solution in order to immerse the object to be treated up to a specific treatment section in the electrolytic solution. An object to be processed is provided with a function of stopping the object to be processed at a position where the section is immersed in the electrolytic solution. The moving means applies a predetermined voltage over the entire area of the object to be processed and exposes the entire area of the object to be processed from the electrolytic solution every time a series of anodic oxidation processes are completed. The anode means is moved to a position in a direction to pull up the object to be processed from the electrolytic solution.

Thus, according to the present invention, since it is possible to retain the current at the anode oxidation process comprising micro-arc oxidation process in a predetermined current I ₁ or less, large-capacity power supply is not required. Furthermore, since the heat generation during the formation process of all oxide films can be actively reduced, the system for cooling the processing system can be made smaller than the conventional system.
Therefore, the present invention provides an oxide film that is intermittently applied to an object to be processed on a large area by an anodic oxidation treatment including a micro arc oxidation treatment, even with a small current power supply device and a simple electrolyte cooling mechanism. A surface treatment apparatus capable of forming the surface.
In addition, since the surface treatment apparatus of the present invention includes the above-described anode means, an oxide film having a desired film thickness is formed on a large-area workpiece to automatically cover the workpiece. it can.

The “current density” focused on in the present invention is the length around the surface of the target object specified by the liquid level of the electrolytic solution in a state where up to a specific processing section of the target object is immersed in the electrolytic solution. It is a numerical value obtained by dividing the current value by (circumference length), which is a so-called “linear current density”.
In FIG. 3A, when the size of the object to be processed is x1 = 2500 mm, x2 = 3000 mm, and x3 = 50 mm, the length (periphery) around the surface of the object to be processed is “2500 × 2 + 50 × 2”. " When the (maximum) voltage applied from the (DC) power supply device is 50 V and the (maximum) current is 50 A, the “linear current density” is calculated as 0.0098 A / mm (≈50 / 5100). That is, a very weak current only acts on the periphery (circumferential portion) of the surface of the workpiece to be in contact with the liquid surface of the electrolytic solution. Therefore, according to the present invention, it is possible to stably form the oxide film in a state where the dielectric breakdown phenomenon is unlikely to occur except in the growth region of the oxide film.

In the present invention, an oxide film can be formed only by the action of such a very weak current. Therefore, according to the present invention, there is no need for a power supply device that supplies a large current, and it is possible to sufficiently form an oxide film even with a power supply device with a low current density. Therefore, the present invention provides a surface capable of intermittently forming an oxide film on a workpiece having a large area by an anodic oxidation treatment including a micro-arc oxidation treatment even with a simple electrolyte cooling mechanism. Provide a processing device.
In addition, since the surface treatment apparatus of the present invention includes the above-described anode means, it is possible to stabilize an oxide film having a desired film thickness so as to automatically cover the workpiece with respect to the workpiece having a large area. To achieve the formation.

  The present invention can be widely applied to a surface treatment method of an object to be processed made of a valve metal. The present invention is suitably used as a surface treatment method for articles used in the internal space of a vacuum apparatus, such as a heater panel, a shower plate, and an inner wall material of a chamber.

  DESCRIPTION OF SYMBOLS 11 To-be-processed object, 21 Electrolyte tank, 22 Electrolyte, 22a Liquid surface, 15a1, 15b1, 15c1, ... 15n1 (15) Oxide film, A, B, C, ... N Processing division.

Claims (9)

Surface to be processed of the object consisting of valve metal, sets a plurality of processing sections performs anodized containing micro-arc oxidation process by immersing each processing compartment Intermittent to electrolyte, the treated A surface treatment method for forming an oxide film on a surface,
The anodic oxidation treatment comprises first M step consists of the object to be processed from a plurality of steps Before moving to each of the processing section having a depth direction of the width of the electrolyte,
The Mth step includes
Said only the first processing compartment is immersed in the electrolytic solution of the object to be processed, held to a low voltage V _M than the maximum voltage V _max of the anodic oxidation treatment, so as to have a predetermined current I _1, the Following the step of forming the desired oxide film in the first processing section,
The workpiece having been subjected to the immediately preceding step, was immersed in the electrolyte until processing compartment you adjacent to said processing compartment have been processed, the first and last in the previous step and the same voltage V _M Conditions for the processing compartment between repeats the steps of forming a desired oxide layer,
Until the end of the treatment compartment is immersed in the electrolyte, by performing the step of forming the desired oxide film on the end of the processing compartment with the same voltage V _M conditions the previous step, and held in the voltage V _M wherein it is as forming an oxide film over the entire surface to be treated
Further, the M-th step is a step that is repeatedly performed a plurality of times,
The first of the M step of performing a voltage of the anodic oxidation treatment at a voltage V _M, between a voltage of the anodic oxidation treatment to the end of the M step carried out at the maximum voltage V _max, the voltage of the anodic oxidation treatment the in Rukoto from the voltage V _M is stepwise increased until the maximum voltage V _max, to form the oxide film in which the total film thickness over the entire treated surface is made of a desired thickness,
A surface treatment method characterized by the above. The anodic oxidation treatment, Ru der repeatedly two or more of the first M step,
The surface treatment method according to claim 1. The value of the predetermined current at the time of performing repeatedly as the first M Engineering is the same as the previous SL current I _1,
The surface treatment method according to claim 1 . Wherein as the time of immersion in the electrolyte a plurality of pre Kisho physical Ward image sequentially in the object to be processed is該被treating body or progression, or stopped in the depth direction of the electrolyte solution, the electrolyte Controlling the position of the object to be processed relative to the liquid surface;
The surface treatment method according to claim 1. In order to control the position of the object to be processed with respect to the liquid surface of the electrolytic solution, the height position of the liquid surface of the electrolytic solution is fixed, and the height position of the object to be processed with respect to the liquid surface of the electrolytic solution Adjust the
The surface treatment method according to claim 4. In order to control the position of the object to be processed with respect to the liquid level of the electrolytic solution, the height position of the object to be processed is fixed, and the height of the liquid surface of the electrolytic solution with respect to the height position of the object to be processed is fixed. Adjust the height,
The surface treatment method according to claim 4. Before Symbol continued in the M step after the top,
A step P for performing the anodic oxidation process by continuously or intermittently dropping the voltage to a voltage V _M− lower than the voltage VM _{M in} which the last Mth step has been performed;
A step Q of performing constant voltage processing with the voltage V _M− , in order;
The surface treatment method according to claim 1. A surface treatment apparatus for performing an anodic oxidation treatment by the surface treatment method according to claim 1 to form an oxide film on the object to be treated,
An anode means for forming the oxide film by the anodic oxidation processing on the target surface of the object to be processed,
An electrolytic bath containing the electrolytic solution and having an opening that allows the anode means to be immersed in the electrolytic solution;
Cathode means disposed opposite to the anode means in the electrolyte solution;
In a state in which the anode means and said cathode means is immersed in the electrolyte, the by generating a current I ₁ between the anode means and said cathode means, and power supply means for performing the anodic oxidation treatment,
Wherein in order is immersed in the electrolytic solution to a specific processing compartment of the processing compartment of the object to be processed, wherein moving the workpiece to a depth direction of the electrolyte, and, until the particular processing compartment wherein the moving means of the object to be processed having a function to quiesce the workpiece to the position immersed in the electrolyte,
Said moving means, said each time the first M step Ru Wataru the entire area of the object is completed, the from the electrolyte to a position where the whole is exposed to the workpiece, electrolytic solution該被processed Configured to move the anode means in the direction of lifting from
The surface treatment apparatus characterized by the above-mentioned. A surface treatment apparatus for performing an anodic oxidation treatment by the surface treatment method according to claim 1 to form an oxide film on the object to be treated,
An anode means for forming the oxide film by the anodic oxidation processing on the target surface of the object to be processed,
An electrolytic bath containing the electrolytic solution and having an opening that allows the anode means to be immersed in the electrolytic solution;
Cathode means disposed opposite to the anode means in the electrolyte solution;
In the state where the anode means and the cathode means are immersed in the electrolytic solution, a power supply means for generating an electric current between the anode means and the cathode means to perform the anodization treatment;
Wherein in order is immersed in the electrolytic solution to a specific processing compartment of the object to be processed, wherein the workpiece is moved in the depth direction of the electrolyte, and the predetermined current value I ₁ and the current handling comparing a value, wherein the moving means of the object to be processed having a function to quiesce the workpiece when it exceeds the predetermined current value I _1,
Said moving means, said each time the first M step Ru Wataru the entire area of the object is completed, the from the electrolyte to a position where the whole is exposed to the workpiece, electrolytic solution該被processed is configured to move said anode means in a direction to pull from, and, in the next M th step of the first M step is applied to the workpiece a voltage higher than the predetermined voltage as a predetermined voltage ,
The surface treatment apparatus characterized by the above-mentioned.

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