CN103938192A - Chemical deposition preparation method of piezoelectric composite metal electrode - Google Patents

Abstract

The invention relates to a method for preparing piezoelectric composite metal electrode chemical deposition. The chemical deposition preparation method is especially aimed at the composite material where PZT ceramics and polymers coexist, and is carried out in the following preparation sequence: piezoelectric composite material→cleaning→oil removal→hydrophilic→one-step roughening→reduction→two-step roughening→colloid Palladium activation → degelling → electroless plating → passivation. The metal plating layer chemically deposited on the surface of the piezoelectric composite material has a bright surface and fine crystals, can evenly cover the surfaces of ceramics and polymers, and has good bonding force with ceramics and polymers. The medium and low temperature process used can ensure that the piezoelectric composite metal electrode has no deformation and no material detachment. The invention does not need expensive equipment, has low cost and is suitable for large-scale production.

Description

A method for preparing piezoelectric composite metal electrodes by chemical deposition

technical field

The invention relates to a method for preparing piezoelectric composite material metal electrodes by chemical deposition, and belongs to the field of research and development of composite material electrodes.

Background technique

Lead zirconate titanate (PZT) ceramic/polymer composite has the characteristics of high piezoelectric coefficient, low density, low acoustic impedance and good mechanical quality. As a transducer element, it is used in underwater acoustic transducers, biomedical imaging, ultrasonic It has always dominated the field of engineering. In piezoelectric composite transducers, electrodes have a great influence on the performance and service life of components. Therefore, developing a preparation method to obtain a metal electrode with good bonding force and uniform distribution on the composite material has become the key to the good performance of the transducing component.

At present, magnetron sputtering film deposition technology is generally used in the preparation of piezoelectric composite electrodes. Document 1 ^[1] discloses a method for preparing composite electrodes by magnetron sputtering, but this technology has the following disadvantages: (1) High requirements on equipment and site; (2) The utilization rate and production efficiency of electrode raw materials are low ; (3) The combination of the obtained electrode and the piezoelectric composite material is poor.

The traditional wet chemical deposition technology can obtain a well-bonded and uniform coating on parts with complex shapes. At the same time, the method is simple in process and low in cost. The composite contains both lead zirconate titanate (PZT) ceramics and organic polymers. For polymer materials, conventional wet chemical deposition technology is used, and the pretreatment process requires a roughening treatment at 60-75°C for several to tens of minutes. After the polymer material is coarsened, the piezoelectric composite material is prone to deformation, and the PZT ceramics and polymer in the composite material are separated. The invention patent ^[2] with the publication number of 102337526 discloses a preparation method of a piezoelectric composite nickel electrode. , activation and chemical deposition of nickel film treatment to obtain nickel electrodes of piezoelectric composite materials. However, inorganic acids can only roughen PZT ceramics, but cannot effectively roughen polymer materials. Therefore, by roughening the piezoelectric composite material by this method, the chemically deposited nickel film can obtain a good bonding force with the PZT ceramic, but cannot obtain a good bonding force with the polymer material.

1. Yuanyuan Wan, Li Li, Likun Wang, Lei Qin, Bing Wei. Preparation of Type 1-3 Piezoelectric Composite Electrodes[J]. Functional Materials, 2007, 38(02), 738-740.

2. Cheng Xin, Zhang Ying, Huang Shifeng, Sun Min, Zhou Meijuan, Hao Chao. A preparation method of piezoelectric composite nickel electrode [P].CN102337526.

Contents of the invention

The purpose of the present invention is to avoid the deficiencies in the background technology, and to invent a method for preparing a piezoelectric composite metal electrode by chemical deposition.

The technical scheme adopted by the present invention to solve the technical problem is: a method for preparing a piezoelectric composite metal electrode by chemical deposition, which is carried out in the following preparation order:

Piezoelectric composite material→cleaning→oil removal→hydrophilic→one-step roughening→reduction→two-step roughening→colloidal palladium activation→degelling→electroless plating→passivation. Between each step of the preparation sequence, wash with tap water and deionized water successively.

The specific steps are:

1. Cleaning: Clean the piezoelectric composite material with tap water and deionized water successively. The purpose of cleaning is to clean the pollutants attached to the surface of the composite material.

2. Degreasing: Degreasing in the degreasing liquid at 30-40°C for 5-10 minutes. The oil removal solution is prepared according to the following formula ratio: anhydrous sodium carbonate (Na ₂ CO ₃ ) 40-60g/L, sodium phosphate (Na ₃ PO ₄ 12H ₂ O) 40-60g/L, sodium hydroxide (NaOH) 10 ~50g/L, sodium silicate (Na ₂ SiO ₃ ·9H ₂ O) 5~20g/L, OP-10 emulsifier 1~3ml/L. The purpose of degreasing is to remove saponified oil and mineral oil from the composite surface.

3. Hydrophilic: Stir and soak in the hydrophilic liquid at 30-40°C for 3-5 minutes. The hydrophilic liquid is prepared according to the following formula in volume ratio: acetonitrile (C ₂ H ₃ N) 10-20%, dichloromethane (CH ₂ Cl ₂ ) 5-10%, N,N-dimethylformamide (C ₃ H ₇ NO) 70-85%. The purpose of hydrophilicity is to improve the hydrophilicity of the composite surface.

4. One-step roughening: soak in one-step roughening solution at 40-50°C for 2-3 minutes. The one-step roughening solution is prepared according to the following formula ratio: chromic anhydride (CrO ₃ ) 350-400g/L, sulfuric acid (H ₂ SO ₄ ) 250-300ml/L, hydrofluoric acid (HF40%) 4-10ml/L. The purpose of one-step roughening is mainly to etch and micro-roughen the organic polymer, and to improve the hydrophilicity of the organic polymer surface.

5. Reduction: In the reduction solution, soak at room temperature for 0.5-1.5 minutes. The reducing solution is prepared according to the following formula ratio: sodium metabisulfite (Na ₂ S ₂ O ₆ ) 5-20g/L. The purpose of the reduction is to reduce the hexavalent chromium attached to the surface of the composite material to trivalent chromium.

6. Two-step roughening: Soak in the second-step roughening solution for 3 to 5 minutes at room temperature. The two-step roughening solution is prepared according to the following formula ratio: hydrofluoric acid (HF40%) 100-250ml/L, ammonium bifluoride (NH ₄ ·HF ₂ ) 10-20g/L. The purpose of the second-step roughening is to mainly etch and micro-roughen the PZT ceramics, and to improve the hydrophilicity of the ceramic surface.

7. Colloidal palladium activation: soak in colloidal palladium solution for 3-5 minutes at 30-35°C. The colloidal palladium activation solution is prepared according to the following formula ratio: dichlorodiammine palladium (Pd(NH ₃ ) ₂ Cl ₂ ) 0.05～1.0g/L, stannous chloride (SnCl ₂ 2H ₂ O) 8～16g/L, Hydrochloric acid 10-60ml/L, sodium stannate (Na ₂ SnO ₃ ·3H ₂ O) 0.4-0.8g/L, sodium chloride (NaCl) 100-150g/L. The purpose of the colloidal palladium activation is to make the palladium colloid adhere to the surface of the composite material.

8. Degumming: Soak in the degumming solution for 2 to 3 minutes at 45-55°C. The degumming solution is prepared according to the following formula ratio: sulfuric acid (H ₂ SO ₄ ) 150~250ml/L. The purpose of degumming is to expose the nano palladium particles with catalytic activity on the surface of the composite material.

9. Electroless plating: Electroless plating at 30-40°C for 10-60 minutes in the electroless copper solution. The chemical deposition solution is prepared according to the following formula ratio: copper sulfate (CuSO ₄ 5H ₂ O) 10-15g/L, disodium ethylenediaminetetraacetic acid (EDTA 2Na) 29-44g/L, glyoxylic acid (C ₂ H ₂ O ₃ ) 7~12g/L, potassium ferrocyanide 10~20mg/L, a,a'-bipyridine 10~30mg/L, pH13-14. The purpose of electroless plating is to deposit copper plating on the surface of composite materials. The surface of the copper coating is bright and crystallized finely, can evenly cover the surface of ceramics and polymers, and has good bonding force with both ceramics and polymers.

10. Passivation: in passivation solution, passivation at room temperature for 1 to 5 minutes. The passivation solution is prepared according to the following formula ratio: sodium molybdate (Na ₂ MoO ₄ 2H ₂ O) 1~5g/L, cerium nitrate (Ce(NO ₃ ) ₃ 6H ₂ O) 0.5~2g/L, benzo Triazole (BTA) 0.2-3g/L. The purpose of passivation is to improve the corrosion resistance and discoloration resistance of the electroless copper plating layer.

In each of the above steps, deionized water was used to prepare the solution.

After the piezoelectric composite material undergoes one-step roughening and two-step roughening, it is necessary to control the uniform occurrence of pits with a diameter less than 200nm on the surface of the organic polymer material, so that the chemical deposition layer and the composite material have an "anchor" effect, ensuring that the obtained metal The bonding force between the electrode and the composite material is good. The more preferable range of pits is 60-150nm.

The preparation method of the invention is especially aimed at the piezoelectric composite material in which PZT ceramics and epoxy resin polymers coexist, and can uniformly roughen both the polymer and the PZT ceramics in the composite material. Through chemical deposition, the metal coating deposited on the surface of the piezoelectric composite material has a bright surface and fine crystallization, can evenly cover the surface of ceramics and polymers, and has good bonding force with both ceramics and polymers. The medium and low temperature process used can ensure that the piezoelectric composite metal electrode has no deformation and no material detachment. The metal electrode of the piezoelectric composite material prepared by the chemical deposition of the invention has low cost, does not need expensive equipment, and can realize large-scale production.

The copper electrode coating of the piezoelectric composite material obtained by the above method has a bright and fine crystal surface, can evenly cover the surface of ceramics and polymers, has good anti-corrosion and anti-discoloration capabilities, and has a good combination with both ceramics and polymers. force.

In the piezoelectric composite material of the present invention, the polymer is preferably epoxy resin; the ceramic is preferably lead zirconate titanate (PZT) ceramics.

The invention can prepare metal electrodes on the surface of the piezoelectric composite material. The technology used in the invention adopts medium and low temperature technology, which can ensure that the piezoelectric composite material is not deformed and the polymer and ceramics are not separated from each other during the preparation process of the metal electrode. The obtained electrode coating is bright and uniform, and has good bonding force with PZT ceramic and polymer material substrates. In addition, the present invention does not need expensive equipment, has low cost, and is suitable for large-scale production.

Description of drawings

Fig. 1 is the metallographic diagram of the piezoelectric composite material;

Fig. 2 is the metallographic diagram of the copper electrode of piezoelectric composite material chemical deposition;

Detailed ways

Below, the present invention is further elaborated by implementing examples. It should be understood that the following examples are only brief descriptions of the present invention, rather than limitations of the present invention. within the scope of protection of the invention.

Piezoelectric composite material (Figure 1) The metal electrode is a disc made of lead zirconate titanate ceramics and epoxy resin polymer, and the diameter of the disc is about 5cm.

The preparation sequence is as follows: clean the piezoelectric composite material, put it in a degreasing solution at 35°C, and remove oil for 10 minutes; in a hydrophilic solution at 35°C, treat it for 5 minutes; Soak for 2 minutes; in the reducing solution, soak for 1 minute at room temperature; in the two-step roughening solution, soak for 3 minutes at room temperature; in the colloidal palladium solution at 35°C, soak for 3 minutes; In the chemical deposition copper solution, the electroless plating is 30 minutes; in the passivation solution, the passivation is at room temperature for 5 minutes.

The solution formula used in the above-mentioned operation is as follows:

1. The degreasing liquid is prepared according to the following formula ratio:

2. The hydrophilic liquid is prepared according to the following formula ratio:

Acetonitrile (C ₂ H ₃ N) 15%,

Dichloromethane (CH ₂ Cl ₂ ) 10%,

N,N-Dimethylformamide (C ₃ H ₇ NO) 75%.

3. The coarsening solution is prepared according to the following formula ratio:

Chromic anhydride (CrO ₃ ) 350g/L,

Sulfuric acid (H ₂ SO ₄ ) 250ml/L,

Hydrofluoric acid (HF40%) 5ml/L.

4. The reducing solution is prepared according to the following formula ratio:

Sodium metabisulfite (Na ₂ S ₂ O ₆ ) 5g/L.

5. The two-step coarsening solution is prepared according to the following formula ratio:

Hydrofluoric acid (HF40%) 200ml/L,

Ammonium bifluoride (NH ₄ ·HF ₂ ) 20g/L.

6. The colloidal palladium solution is prepared according to the following formula ratio:

7. Degumming

Sulfuric acid (H ₂ SO ₄ ) 250ml/L.

8. The chemical deposition solution is prepared according to the following formula ratio:

9. The passivation solution is prepared according to the following formula ratio:

Sodium molybdate (Na ₂ MoO ₄ 2H ₂ O) 2g/L,

Cerium nitrate (Ce(NO ₃ ) ₃ 6H ₂ O) 1g/L,

Benzotriazole (BTA) 2g/L.

The copper electrode coating of the piezoelectric composite material obtained by the above method has a bright surface and fine crystallization, and can evenly cover the surface of ceramics and polymers (Figure 2); the metal electrode of the piezoelectric composite material has no deformation, and the gap between ceramics and polymers No detachment from each other; the bonding force test shows that the coating has no peeling phenomenon, and the bonding force is good.

Bonding force test method: Adhere a fiber adhesive tape (adhesion strength value of the adhesive tape is about 8N per 25mm width) on the coating, and roll it on it with a rubber roller to remove air bubbles. After an interval of 10s, use a pulling force perpendicular to the coating to peel off the tape. If the coating does not peel off, it means that the bonding force is good. The metal electrode coating of the piezoelectric composite material obtained in the present invention passes through the above test method, and the coating has no peeling phenomenon, and the coating has good bonding force.

Claims (3)

1. A method for preparing a piezoelectric composite metal electrode by chemical deposition, comprising the following steps: piezoelectric composite material → cleaning → degreasing → hydrophilic → one-step coarsening → reduction → two-step coarsening → colloidal palladium activation → degelling →Electroless Plating→Passivation, where: (1) Composition and conditions of degreasing liquid: anhydrous sodium carbonate (Na ₂ CO ₃ ) 40-60g/L, sodium phosphate (Na ₃ PO ₄ ·12H ₂ O) 40-60g/L, sodium hydroxide (NaOH) 10～50g/L, sodium silicate (Na ₂ SiO ₃ 9H ₂ O) 5～20g/L, OP-10 emulsifier 1～3ml/L, 30～40℃, 5～10 minutes; (2) Composition and conditions of hydrophilic liquid: acetonitrile (C ₂ H ₃ N) 10-20%, dichloromethane (CH ₂ Cl ₂ ) 5-10%, N,N-dimethylformamide (C ₃ H ₇ NO) 70～85%, 30～40℃, 3～5 minutes; (3) Composition and conditions of one-step roughening solution: chromic anhydride (CrO ₃ ) 350-400g/L, sulfuric acid (H ₂ SO ₄ ) 250-300ml/L, hydrofluoric acid (HF40%) 4-10ml/L, 40 ～50℃, 2～3 minutes; (4) Composition and conditions of reducing solution: sodium metabisulfite (Na ₂ S ₂ O ₆ ) 5-20g/L, room temperature, 0.5-1.5 minutes; (5) The composition and conditions of the second-step roughening solution: hydrofluoric acid (HF40%) 100-250ml/L, ammonium bifluoride (NH ₄ HF ₂ ) 10-20g/L, room temperature, 3-5 minutes; (6) Composition and conditions of colloidal palladium solution: palladium dichloride (Pd(NH ₃ ) ₂ Cl ₂ ) 0.05～1.0g/L, stannous chloride (SnCl ₂ 2H ₂ O) 8～16g/L, Hydrochloric acid 10-60ml/L, sodium stannate (Na ₂ SnO ₃ 3H ₂ O) 0.4-0.8g/L, sodium chloride (NaCl) 100-150g/L, 30-35°C, 3-5 minutes; (7) Composition and conditions of degumming solution: sulfuric acid (H ₂ SO ₄ ) 150-250ml/L, 45-55°C, 2-3 minutes; (8) Composition and conditions of chemical deposition copper solution: copper sulfate (CuSO ₄ ·5H ₂ O) 10-15g/L, disodium ethylenediaminetetraacetic acid (EDTA·2Na) 29-44g/L, glyoxylic acid (C ₂ H ₂ O ₃ ) 7~12g/L, potassium ferrocyanide 10~20mg/L, a,a'-bipyridine 10~30mg/L, pH13-14, 30~40℃, 10~60 minutes; (9) Composition and conditions of passivation solution: sodium molybdate (Na ₂ MoO ₄ 2H ₂ O) 1~5g/L, cerium nitrate (Ce(NO ₃ ) ₃ 6H ₂ O) 0.5~2g/L, benzene Triazole (BTA) 0.2-3g/L, room temperature, 1-5 minutes. 2. the chemical deposition preparation method of a kind of piezoelectric composite material metal electrode as claimed in claim 1, is characterized in that: after piezoelectric composite material is through one-step coarsening and two-step coarsening, control organic polymer material surface to appear evenly Pit with diameter less than 200nm. 3. the chemical deposition preparation method of a kind of piezoelectric composite metal electrode as claimed in claim 1, is characterized in that: described electroless copper plating surface is bright, can be covered in pottery and polymer surface evenly, and pottery and pottery All polymers have good binding force.