JP2000281470A - Ceramic surface modifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the chemical reaction rate of an etching solution selected for surface modification applied to ceramics and ceramic composite materials, realize stable etching and increase the amount of energy resources used. To provide a surface modifier for ceramics having a composition capable of suppressing cracking. SOLUTION: An etching comprising a solution containing an oxidizing agent selected according to the purpose of surface modification, a solution containing an oxidizing agent and an acid, a solution containing an oxidizing agent and an alkali, a solution containing an oxidizing agent, an acid and an alkali, and the like. Liquid and a solution of a chelating reagent,
By performing etching while capturing cations generated during etching in a solution with a chelating reagent, the efficiency of target surface modification is improved, and various controls of the modification are enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an etching solution for performing surface modification on various ceramics, and more particularly, to a method for applying a chelating reagent to an etching solution selected for a specific surface modification on required ceramics. The present invention relates to a ceramic surface modifier and a method for modifying the surface thereof, in which the content of a predetermined amount is improved to improve the efficiency of the intended surface modification and enable various control of the modification.

[0002]

2. Description of the Related Art Ceramics include so-called piezoelectric transducers.
PZT and composite PZT porcelain, ZnO-based porcelain (Li ・ Na) (Nb ・ Ta) O ₃
System porcelain, microwave dielectric porcelain, so-called electromagnetic transducer
(Mn ・ Ni) Zn ferrite etc. spinel porcelain, garnet type ferrite porcelain, oxide semiconductor porcelain mainly composed of ZrO ₂ etc.
A wide variety of materials are known, such as structural material porcelain supporting various elements and performing functions such as protection, porcelain for thermoelectric conversion, porcelain for fuel cell separators, and the like.

[0003] Not only the above-mentioned metal oxides, nitrides and carbides alone but also composite forms of these ceramics with glass and / or other metal materials and resin materials are known, and they have a very wide range of purposes and applications. It is used for

[0004] Various improvements have been made to such ceramics and ceramic composite materials in order to achieve the desired function or to improve the function. For example, regarding the input and output of electric signals to and from ceramics, it is an improvement in electrode attachment properties and an improvement in adhesion strength against external force and the like.

[0005] Further, regarding the input of radio waves or infrared rays,
It is a reduction in reflection loss, an increase in the exchange efficiency when it comes to the exchange of ions and electrons in the gas and electrolyte, and an improvement in the bond strength when it is involved in the composite construction of ceramics and ceramics or other materials. It is an increase in surface area when it comes to chemical reactions involving adsorption with chemical substances containing, and when it comes to contact sliding with other materials and components, such as improving the sliding characteristics,
There are as many improvements as there are intended uses and functions.

[0006] Various solutions have already been adopted for these purposes, but one of the common solutions among them is a method of surface modification of ceramics. There is a method called surface roughening focusing on the surface shape, for example, an etching technique for etching the surface of ceramics using a chemical.

[0007] When the surface is roughened by using this etching technique, an anchor effect is exerted on the electrode attachment to improve the adhesion strength of the electrode, and the reflection loss of the electromagnetic wave is irregular reflection and black. The absorption effect is improved by the effect of the embodiment, and the efficiency of charged particle exchange can be improved by increasing the specific surface area.

[0008] With respect to the fixing strength in a composite construction such as lamination, when a fixing agent such as glass, an adhesive or a brazing agent is used, an increase in the area of the fixing agent in contact with the material surface increases the strength. Alternatively, in the case of partial welding of one material without using a fixing agent, it is possible to improve the strength by increasing the area of the other material.

Further, as for the chemical reaction, the chemical reaction proceeds at the interface between the chemical substance and the ceramics, and therefore the degree of progress of the reaction is increased by increasing the surface area. (2) Sliding characteristics are improved by reducing the contact area between materials and ensuring sufficient gas flow paths.
It is possible to reduce frictional resistance.

[0010]

The above-mentioned etching technique involves selecting and containing various acids and / or various alkalis and / or various oxidizing agents, etc., depending on the target ceramic material and its purpose of modification. Etching solutions having various compositions are used.

In the etching of ceramics, unlike the metal, the etching efficiency, in other words, the chemical reaction rate between the ceramic material and the etching solution is low,
The reaction may be unstable due to other factors and the control may become unstable.To solve these problems, raise the processing temperature of the solution, increase the solution concentration, or strictly control the solution composition. Many measures have been taken, such as devising, or devising stirring and rocking.

[0012] However, these countermeasures complicate the etching apparatus, complicate the management of operations and processes, and further increase the use of chemicals and energy resources, causing problems for various environments. I have.

An object of the present invention is to improve the surface modification method applied to the ceramics and the ceramic composite material described above, and to make the chemical reaction rate of the etching solution selected for the desired surface modification appropriate and stable. It is an object of the present invention to provide a ceramic surface modifier having a composition capable of realizing etching and suppressing an increase in the amount of energy resources used.

[0014]

The inventor of the present invention has noticed that etching is not a simple reaction between ceramics and each chemical solution, but rather consists of several parallel reactions. We believe that it is indispensable to minimize the reaction that causes a disturbing effect or to disturb the system as much as possible in order to increase the speed of the chemical reaction called etching, reduce the variation in the reaction, and stabilize it. As a result of various studies, a predetermined amount of a chelating reagent is contained in an etching solution selected for specific surface modification of required ceramics, and cations generated during etching are captured in the solution by the chelating reagent to perform etching. Thereby, it was found that the efficiency of the intended surface modification was improved, and that various modifications of the modification were possible, and the present invention was completed.

That is, the present invention provides a solution containing an oxidizing agent selected according to the purpose of surface modification, a solution containing an oxidizing agent and an acid, a solution containing an oxidizing agent and an alkali, and a solution containing an oxidizing agent, an acid and an alkali. The present invention proposes a ceramic surface modifier comprising a solution of an etchant such as a solution and a chelating reagent.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Ceramics are constituent elements.
Oxides or nitrides or carbides of metals
Composites, assuming that they are soluble in water,
Is a cation (M ^{n +}Oxygen, nitrogen, and carbon are
Each may be used alone or in combination to form an anion.

When a ceramic reacts with an acid as a general etching, the base of the acid and the cation of the ceramic become a counter ion and disperse and dissolve to the solubility limit. On the other hand, the counter ion reacts to form a salt, and at this time, the reverse reaction in which the salt is decomposed into the original ion always proceeds in parallel (hereinafter, referred to as a salt).
This is called (1) forward / reverse parallel reaction).

When the amount of the salt produced exceeds the solubility,
Precipitation occurs (hereinafter, this is referred to as (2) precipitation). Further, the surface to be provided to the reaction is disturbed (hereinafter, this is referred to as (3) surface roughness). Oxygen, nitrogen and carbon of ceramics react with H ⁺ of acid to form soluble matter. Such etching is a reaction which does not require the above-mentioned (1) forward / reverse parallel reaction, (2) precipitation, and (3) surface roughness, has an adverse effect, or disturbs the reaction system.

When an alkali is reacted with a ceramic, the reaction does not proceed as much as an acid because the alkali is also a cation in the solution, and the reaction rate is low (hereinafter, this is referred to as (4) low reaction rate). . However, ceramics cations and alkali hydroxide ion OH ^- in some cases react to produce M (OH) _n becomes amphoteric compounds. In this case, the solubility is often small and precipitates (hereinafter, this is referred to as (5) precipitate),
It will also disturb the surface to be donated to the reaction
(Hereinafter, this is referred to as (6) surface roughness). In this case, the reaction is originally (4) low in reaction rate, (5) precipitation, and (6) no need for surface roughness, an adverse effect, or a reaction that disturbs the reaction system.

When an oxide is used in combination with the acid and / or alkali acting on the ceramic, the oxidizing agent promotes the cationization of metal atoms in the ceramic. The reaction between the ceramic and the acid and / or the alkali promoted by the cationization of the metal atom is the same as in the case where no oxidizing agent is used, (1) to
The reaction of (6) occurs.

The above-mentioned phenomena of (1) forward-reverse parallel reaction, (2) precipitation, (4) low reaction rate, and (5) precipitation are all related to the generation of cations from ceramics. That is, cations are generated and increased, which is unnecessary, has an adverse effect, or causes a reaction that disturbs the reaction system. In addition, since the above (3) (6) surface roughness is caused by an increase in the precipitation phenomenon (2) (5), respectively (2) (5)
The solution is to solve the phenomenon of precipitation.

The inventor considered how the increasing number of cations could be reduced or could have the same effect as the reduced cations. It has been found that it is essential to ionize the metal element, generate cations, form cations into complex ions at the same time as stabilizing the solution, and always provide the surface of the ceramic to the reaction.

However, a so-called complexing agent for forming complex ions forms a complex not only with metal ions in the solution but also with metal atoms on the ceramic surface, and conversely, the surface to be provided to the reaction from the ceramic surface. As a result.

The inventors of the present invention have made various studies on the formation of a complex ion that is stable only in a solution. As a result, it is indispensable to chelate and stabilize ionized metal atoms on the surface of ceramics. It has been found that when an etchant and a chelating reagent are allowed to act on ceramics at the same time, metal atoms ionized on the surface of the ceramics are trapped in molecules of the chelating reagent and stabilized, forming a kind of complex ion.

[0025] In the surface modifier according to the present invention, the chelating reagent always stabilizes the cations generated from the ceramic surface in the solution, so that the ceramic surface is always affected by the etchant and etched. become. That is, only the effective reaction of the etching proceeds, and the speed of the chemical reaction is kept high.

It is assumed that the etching reaction proceeds until the etching solution acting on the ceramic surface is consumed, or until the cation generated from the ceramic surface and the base in the etching solution are stoichiometrically equimolar. For example, the chelating reagent constantly captures cations during the progress of this reaction and stabilizes the cations in the solution, thereby suppressing variations in the chemical reaction and stabilizing the control of surface modification.

Therefore, the amount Q _{1 of the} chelating reagent is the same as the amount Q _{2 of the} cation generated from the ceramic surface stoichiometrically equimolar to the base in the etching solution, and Q ₁ / Q ₂ = 1 is appropriate.

[0028] However, even in Q ₁ / Q _{2 <1,} be only the action of the above is reduced, without changes to the above effect is exhibited than in the case of Q ₁ = 0, whereas Q ₁ In the case of / Q ₂ > 1, the speed of the chemical reaction is further increased, and any case is suitable for the surface modification method of the present invention.

According to experiments by the inventors, the ratio of an etching solution to a chemical such as an oxidizing agent, an acid, or an alkali in the etching solution is such that the chemical amount / etching solution = 1 × 10 ⁻² to 1 (weight) ratio), the ratio of the chelating agent and the etching solution, a chelating agent weight / etchant = 1 × 10 ^- it was confirmed that it is preferable to select a range of ^{5 ~1} × 10 ^-1 (molar M) .

[0030] The surface modifier comprising an etching solution and a chelating reagent according to the present invention can be used to raise the processing temperature more than necessary,
It is not necessary to increase the concentration, it is only necessary to appropriately control the chemical composition, and the swinging and stirring may be performed by appropriate operations.

The chemicals used in the etching solution according to the present invention include, for example, hydrogen peroxide (H ₂ O ₂ ) as an oxidizing agent, acetic acid (CH ₃ COOH), formic acid (HCOOH), and sulfuric acid (H ₂ SO ₂ ) as acids. Ammonia (NH ₃ ), sodium carbonate (Na ₂ CO ₃ ), potassium carbonate (K ₂ CO ₃ ), etc. can be adopted as the alkali such as ₄ ), and other known etching acids and alkali liquids can be used in appropriate combination. can do.

In the present invention, various chelating reagents can be used in consideration of various factors such as the composition of the target ceramic, the required purpose of surface modification, the situation and degree of surface modification, the etching solution and conditions to be used, and the like. It is appropriately selected from substances. As an example, chemicals that chelate metal atoms include:

Acetylacetone, ethylenediaminetetraacetic acid (E
DTA) and alkali metal salts, 2,2 ', 2 "-terpyridine, neotrin, nitrosophenylhydroxylamine NH ₄ salt
(Cuperone), diethyldithiocarbamic acid and alkali metal salts, trin (also called thoron), 4,7-diphenyl-
1,10-phenanthroline (vasophenanthroline), bismuthiol (2) (but Roman numerals), 1,10-phenanthroline, berylon (2) (but Roman numerals), oxine, nitrilotriacetic acid (NTA) and alkali metal salts, 1 , 2-Diaminocyclohexanetetraacetic acid (CyDTA) and alkali metal salts, N-
Oxyethylethylenediaminetriacetic acid (HEDTA) and alkali metal salts, ethylene glycol bis (β-aminoethylether) tetraacetic acid (GEDTA) and alkali metal salts, ethylenediaminetetrapropionic acid (EDTP) and alkali metal salts

[0034]

Example 1 Example 1 was applied to ceramics which had been subjected to mirror finish polishing as shown in Table 1.
Surface modification was performed at a temperature of 50 ° C. for 3 minutes using a surface modifying agent composed of an etching solution shown in Table 2 and a chelating reagent shown in Table 2. In order to evaluate the degree of surface modification, the center line average roughness Ra (nm) before and after the surface modification treatment was measured, and
Shown in 1.

The center line average roughness Ra (nm) indicates the state of the sliding surface.
Using an AFM (Atomic Force Microscope, Nano Scope 3 Digital Instruments Co., Ltd.), examine and use the resulting roughness curve to extract a portion of the measurement length L in the direction of the center line, and then extract the center line Is the X axis, the direction of the vertical magnification is the Y axis, and the roughness curve is represented by the following function of y = f (x).

[0036]

(Equation 1)

Comparative Example 1 For comparison, Ra (nm) was measured in the same manner as in Example 1 except that no chelating reagent was contained, and the results are shown in Table 1.

[0038] However, in Table 1, a circle indicates a surface before the surface modification treatment, and a circle indicates a comparative example. The etching solution is an aqueous solution containing various chemicals.
It was adjusted with a composition ratio of 100% conversion. For the chelating reagent, the composition ratio based on the chemical used and the etching solution is also shown in parentheses.

The abbreviations of the chelating reagents shown in Table 2 are as follows. NTA (Nitrilotriacetic acid), Bismuthiol (2) (however, Roman numeral) (C ₈ H ₅ KN ₂ S ₃ ), Cupron (Nitrosophenylhydroxylamine NH ₄ salt, EDTP
(Na salt of ethylenediaminetetrapropionate), EDTA (Na salt of ethylenediaminetetraacetic acid)

[0040]

【table 1】

[0041]

[Table 2]

[0042]

As can be seen from Tables 1 and 2, the present invention shows that the degree of surface modification using only the etching solution,
In contrast to Ra, it is clear that Ra is greatly improved in the case of the surface modifier according to the present invention containing a chelating reagent.

That is, according to the present invention, a predetermined amount of a chelating reagent is contained in an etching solution selected for surface modification, and cations generated at the time of etching are captured in the solution by the chelating reagent to perform etching. It improves the efficiency of the target surface modification and enables various controls of the modification. It is effective for all ceramics other than the ceramics shown in the examples, and is selected according to the purpose of the surface modification. A chelating reagent can be appropriately selected for any etching liquid.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takehiko 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Inside the Yamazaki Works, Sumitomo Special Metals Co., Ltd. (72) Inventor Shin Yokouchi 2 Egawa, Shimamoto-cho, Mishima-gun, Osaka Chome 15-17 Sumitomo Special Metals Co., Ltd., Yamazaki Works

Claims (5)

[Claims] 1. A ceramic surface modifier comprising a solution of an etching solution and a chelating reagent. 2. The ceramic surface modifier according to claim 1, wherein the etchant is a solution containing an oxidizing agent. 3. The ceramic surface modifier according to claim 1, wherein the etchant comprises a solution containing an oxidizing agent and an acid. 4. The ceramic surface modifier according to claim 1, wherein the etchant comprises a solution containing an oxidizing agent and an alkali. 5. The ceramic surface modifier according to claim 1, wherein the etching solution is a solution containing an oxidizing agent, an acid, and an alkali.