阅读说明：本技术 一种稀土掺杂钴磷三元合金修饰纳米多孔铜的柔性无酶葡萄糖传感电极及其制备方法 (A kind of flexible enzyme-free glucose sensing electrode and preparation method thereof of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper ) 是由 奚亚男 胡淑锦 于 2019-08-19 设计创作，主要内容包括：本发明提供了一种稀土掺杂钴磷三元合金修饰纳米多孔铜的柔性无酶葡萄糖传感电极,在电极表面修饰Co-M-P/NPC复合结构,其中M可为无放射性稀土元素中的一种或空白,使其具有极高的电化学活性面积和较低的电荷转移电阻,通过多孔结构及活性物质大幅提升电极的电催化活性。本发明提供的Co-M-P/NPC复合电极具有较高的灵敏度,极低的检出限,较低的检出限以及良好的稳定性和抗干扰性能,在0.5～10.0mM的检出范围内其灵敏度为1920μA/mM·cm<Sup>2</Sup>,检出限为182nM,响应时间小于4s,可应用于人体血糖的实际检测。(The present invention provides a kind of flexible enzyme-free glucose sensing electrodes of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper, in electrode face finish Co-M-P/NPC composite construction, wherein M can be one of "dead" rare earth element or blank, high electrochemical surface area and lower charge transfer resistance are made it have, the electro catalytic activity of electrode is substantially improved by porous structure and active material.Co-M-P/NPC combination electrode sensitivity with higher provided by the invention, extremely low detection limit, lower detection limit and good stability and interference free performance, its sensitivity is 1920 μ A/mMcm in the inspection range of 0.5~10.0mM 2 , detect and be limited to 182nM, the response time is less than 4s, can be applied to the actually detected of blood sugar for human body.)

1. a kind of flexible enzyme-free glucose sensing electrode of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper, feature exist In the electrode is made of electrode basement, buffer layer, conversion zone；The electrode base materials are macromolecule flexible parent metal；It is described Electrode basement is equipped with the buffer layer, and the buffer-layer surface is equipped with the conversion zone；The buffer layer is layers of copper；It is described anti- Answering layer is Co-M-P/NPC composite construction；The electrode by three electrodes integrate it is coplanar form, wherein working electrode surface be rare earth The nano porous copper of cation doping phosphorus ternary alloy three-partalloy modification, is platinum to electrode surface, and reference electrode surface is silver-silver chloride；It is described Working electrode and the distance to electrode are 50~100 μm.

2. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 1 is without enzyme grape Sugared sensing electrode, which is characterized in that the M element in the Co-M-P/NPC composite construction can be in "dead" rare earth element One kind or blank.

3. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 1 is without enzyme grape Sugared sensing electrode, which is characterized in that the nano porous copper of the rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification has three-dimensional continuous more Pore structure, reaction bore dia are 100~200nm.

4. a kind of preparation side of the flexible enzyme-free glucose sensing electrode of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper Method, which comprises the following steps:

(1) standard integrate three electrodes to platinum plating on electrode；

(2) silver-silver chloride is modified on the reference electrode that standard integrates three electrodes；

(3) electric deposited copper floor on the working electrode that standard integrates three electrodes；

(4) in working electrode front deposited Au tin alloy, then metallic tin is removed, obtains the electrode of modification nano porous copper；

(5) in the ternary alloy three-partalloy chemical combination object or cobalt phosphorus compound of the rear-earth-doped cobalt phosphorus of working electrode front electro-deposition, Co-M- is obtained The flexible enzyme-free glucose sensing electrode of P/NPC modification.

5. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme grape The preparation method of sugared sensing electrode, it is characterised in that: in the step (1), platinum plating bath group becomes H₂PtCl₆1mM and KCl 0.1M。

6. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme grape The preparation method of sugared sensing electrode, it is characterised in that: in the step (2), plate the solution composition of silver-silver chloride are as follows: silver nitrate 40~45g/L, 200~240g/L of sodium thiosulfate, 40~45g/L of potassium metabisulfite, 20~30g/L of ammonium acetate, sulfo-amino 0.6~0.9g/L of urea；Electroplating temperature is 25 DEG C, current density 0.3A/dm², the time is 15~25min.

7. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme grape The preparation method of sugared sensing electrode, it is characterised in that: in the step (3), the composition of copper electroplating liquid are as follows: Cu₂P₂O₇·3H₂O 65g/L、K₄P₂O₇·3H₂O 380g/L、C₆H₅O₇(NH₄)₃ 23g/L、C₆H₈O₇0.5g/L；The temperature of electro-coppering is 35 DEG C, electricity Current density is 2.0A/dm², time 300s.

8. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme grape The preparation method of sugared sensing electrode, it is characterised in that: in the step (4), the composition of copper-tin alloy plating solution used in electro-deposition are as follows: Cu₂P₂O₇·3H₂18~20g/L of O, Sn₂P₂O₇15~16g/L, K₄P₂O₇·3H₂250~280g/L of O, K₂HPO₄·3H₂O 75 ~95g/L, H₃PO₄3.5~4.5g/L；Electrodeposition temperature is 20~28 DEG C, and current density is 0.8~1.2A/dm², the time is 900~1000s.

9. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme grape The preparation method of sugared sensing electrode, it is characterised in that: in the step (4), removal metallic tin be using chemical corrosion method, it is used Corrosive liquid is acid solution, and removing alloy temperature is 70 DEG C, time 900min.

10. a kind of flexibility of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper according to claim 4 is without enzyme Portugal The preparation method of grape sugar sensing electrode, it is characterised in that: in the step (5), electroplate liquid used in electro-deposition cobalt phosphorus compound Composition are as follows: CoSO₄·7H₂180~200g/L of O, H₃PO₃45~55g/L, H₃PO₄15~20g/L, 10~15g/L of rare-earth salts； Reaction temperature is 55 DEG C, time 70s, current density 10.0A/dm²。

Technical field

The invention belongs to glucose detection sensor fields, are related to a kind of flexible sensing electrode of no enzyme detection glucose Preparation method, especially application of the sensing electrode in glucose quickly detects.

Background technique

Glucose is recycled in the form of blood glucose in mankind's body, and blood sugar concentration appropriate helps to promote memory and cognition Performance, blood sugar concentration is too low, will lead to the symptoms such as hypoglycemia or insulin shock, and blood sugar concentration is excessively high, will lead to obesity Or diabetes.Diabetes are one of most common diseases in the whole world, and in recent decades, the disease incidence of diabetes constantly rises, by It is classified as one of four big non-communicable diseases.Diabetes are a kind of chronic diseases, can cause multiple complications such as hypopsia, kidney function Energy failure, retinopathy and apoplexy etc. detect with treatment by social extensive concern the effective of diabetes.Blood sugar concentration It is the sole criterion of current diagnosis diabetes, therefore, developing the glucose sensor with highly sensitive efficient stable is Very it is necessary to.

Glucose sensor on the market is mostly enzyme base glucose sensor at present, this is one kind supplemented by electrochemical oxidation The glucose sensor based on glucose oxidase helped has very high sensitivity and accuracy.But enzyme base glucose sensing The storage and operation requirement of device are very stringent, in addition, the unstability of enzyme causes sensor that cannot reuse, because finding one Kind is necessary without the electrode material of enzyme detection glucose.

Material used in traditional enzyme-free glucose sensor is mainly noble metal (Pt, Au, Pd etc.) or transition metal (Cu, Co, Ni etc.) and its oxide, however noble metal and its cost of alloy are excessively high, and the electric conductivity of most metals oxide It is poor, it is therefore necessary to develop a kind of glucose catalyticing oxidation material with high conductivity, high-performance and low cost.

In recent years, nano material and nanostructure are gradually widely used in no enzymology sensor field, possess Porous structure and higher specific surface area can provide more chemical reaction sites, so that the detection performance of electrode is promoted, and will be steady Fixed and cheap active material can further promote the catalytic of active material in conjunction with the electrically-conductive backing plate with nanostructure Can, greatly improve the sensitivity of electrode.

Patent CN106226382B discloses a kind of nano porous copper/Cu (OH)₂Nano-wire array sensor electrode material And preparation method thereof, main technical schemes are controllable growth Cu (OH) in nano porous copper film substrate₂Nano-wire array, Obtain the nanometer combined electrode material of similar " sandwich " structure, Cu (OH)₂It is distributed in nanometer to nano-wire array even compact In the substrate of Porous Cu, electro catalytic activity with higher, the linear response range for the enzyme-free glucose sensing electrode prepared For 0.2~9.0mM, sensitivity is 2090 μ A/mMcm², detect and be limited to 200nM, the response time is less than 1s.However this method It is excessively cumbersome, and preparation condition also there are certain requirements, it is unfavorable for reducing preparation cost.

In conclusion this field needs, a kind of preparation process is simple, reusable enzyme-free glucose quickly detects Sensing electrode simplifies detecting step to reduce preparation cost, so that glucose detection is more efficient, stablizes.

Summary of the invention

The object of the present invention is to provide a kind of flexibilities of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper without enzyme Portugal Grape sugar sensing electrode.

The electrode is made of electrode basement, buffer layer, conversion zone；Electrode base materials are macromolecule flexible parent metal；Electrode Substrate is equipped with buffer layer, and buffer-layer surface is equipped with conversion zone；Buffer layer is layers of copper；Conversion zone is Co-M-P/NPC composite junction Structure；Electrode by three electrodes integrate it is coplanar form, wherein working electrode surface be rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nanometer Porous Cu, is platinum to electrode surface, and reference electrode surface is silver-silver chloride；Working electrode and be 50~100 to the distance of electrode μm。

The electrode solve the problems, such as three-electrode system can not be applied to microsensor, and interdigital electrode obtained due to It working electrode and is closer between electrode, the concentration polarization in Electrochemical Test Procedure can be substantially eliminated.

Frame of the nano porous copper prepared by the present invention as support catalysis material, the nanoporous with high-specific surface area Copper skeleton and cobalt phosphorus active layer with high electrochemical activity can all be substantially improved the catalytic performance of combination electrode, and rare earth element With outstanding catalytic performance, by rear-earth-doped in cobalt phosphorus compound, modify on nano porous copper skeleton, it can be with maximum limit The catalytic performance of the promotion electrode of degree.

M element in electrode Co-M-P/NPC composite construction can be one of "dead" rare earth element or blank.

After rear-earth-doped three alloy cpd of cobalt phosphorus of nano porous copper surface electro-deposition, electrode surface conversion zone retains Three-dimensional continuous poriferous structure, surface have a large amount of slot gaps, and width range concentrates on 100~200nm, this structure can Increase electrode specific surface area, increases electrode active surface site, electrode catalyst performance is substantially improved.

Co-M-P/NPC combination electrode prepared by the present invention surface is that the nanometer of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification is more Hole steel structure has compound porous structure, frame of the nano porous copper as support catalysis material, receiving with high-specific surface area Rice Porous Cu skeleton, the cobalt phosphorus active layer with high electrochemical activity, the rare earth element with high catalytic activity all can be mentioned substantially The catalytic performance for rising combination electrode, can be used for the efficient detection of glucose sensing.

It is a further object of the present invention to provide a kind of flexible nothings of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper The preparation method of enzymatic glucose sensing electrode.

The flexible enzyme-free glucose of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper provided by the invention senses electricity The preparation method of pole, specifically includes the following steps:

(1) standard integrate three electrodes to platinum plating on electrode；

(2) silver-silver chloride is modified on the reference electrode that standard integrates three electrodes；

(3) electric deposited copper floor on the working electrode that standard integrates three electrodes；

(4) in working electrode front deposited Au tin alloy, then metallic tin is removed, obtains the electricity of modification nano porous copper Pole；

(5) it in the ternary alloy three-partalloy chemical combination object or cobalt phosphorus compound of the rear-earth-doped cobalt phosphorus of working electrode front electro-deposition, obtains The flexible enzyme-free glucose sensing electrode of Co-M-P/NPC modification.

Sensing electrode prepared by the present invention uses three-electrode system, therefore to electrode face finish platinum, in reference electrode Surface modification silver-silver chloride.

In step (1) of the present invention, the preferred neutral soluble salt of the supporting electrolyte of plating solution can increase the ionic conductance of plating solution Rate.Platinum plating bath group becomes H₂PtCl₆1mM and KCl 0.1M.

In step (2) of the present invention, the solution composition of silver-silver chloride is plated are as follows: 40~45g/L of silver nitrate, sodium thiosulfate 200 ~240g/L, 40~45g/L of potassium metabisulfite, 20~30g/L of ammonium acetate, 0.6~0.9g/L of thiosemicarbazide；Electroplating temperature is 25 DEG C, current density 0.3A/dm², the time is 15~25min.

Sensing electrode prepared by the present invention has multi-layer metal structure, in electrode basement electroplating surface layers of copper as buffering Layer, can effectively promote the binding force of electro-deposition copper and tin and substrate, improve the stability of electrode.

In step (3) of the present invention, the composition of copper electroplating liquid are as follows: Cu₂P₂O₇·3H₂O 65g/L、K₄P₂O₇·3H₂O 380g/ L、C₆H₅O₇(NH₄)₃ 23g/L、C₆H₈O₇0.5g/L；The temperature of electro-coppering is 35 DEG C, current density 2.0A/dm², the time is 300s。

Because of the process characteristic that the electro-deposition of Cu-Sn has speed fast, at low cost, the present invention selects copper-tin alloy as system The presoma of standby nano porous copper.

The nano porous copper of suitable performance in order to obtain needs to carry out a large amount of experiment screening to the electroplate liquid of electro-deposition, The concentration of main salt, the process conditions of electro-deposition and complexing agent, additive can influence the property of copper and tin coating in plating solution.If plating The ratio of stannous pyrophosphate is too low in liquid, then is difficult to form the continuous porous pattern with higher porosity, if its ratio mistake Height, the group branch for forming porous framework is difficult to support three-dimensional porous structure because content is too low, so as to cause material binding force It is too poor.

In step (4) of the present invention, the composition of copper-tin alloy plating solution used in electro-deposition are as follows: Cu₂P₂O₇·3H₂18~20g/ of O L、Sn₂P₂O₇15~16g/L, K₄P₂O₇·3H₂250~280g/L of O, K₂HPO₄·3H₂75~95g/L of O, H₃PO₄3.5~ 4.5g/L；Preferably, Cu₂P₂O₇·3H₂O 19g/L、Sn₂P₂O₇ 15.6g/L、K₄P₂O₇·3H₂O 280g/L、K₂HPO₄·3H₂O 80g/L、H₃PO₄ 3.95g/L。

When acid copper tin alloy, the too high or too low copper and tin coating surface that will lead to of current density is coarse and uneven, Current density reduction causes Theil indices to decline, and causes the hole of Porous Cu small and lacks, current density is excessively high, leads to Theil indices It improves, causes dissolution component excessive, maintain rock-steady structure after being unfavorable for alloy.

In step (4) of the present invention, electrodeposition temperature is 20~28 DEG C, preferably 25 DEG C；Current density is 0.8~1.2A/ dm², preferably 1.0A/dm²；Time is 9001000s；Preferably 900s.

When copper-tin alloy removes alloy, the present invention uses acid reagent, although also can achieve removal tin using alkaline reagent Purpose, such as use the mixed solution of alkali and hydrogen peroxide, but Cu can be generated in solution simultaneously²⁺, so that hydrogen peroxide decomposes rapidly, make At the uncontrollable of rate of dissolution, while the oxygen for decomposing generation can damage the fine porous structure of generation, so that Decorative layer short texture, and be easy to remove with basal layer.

In step (4) of the present invention, removal metallic tin is using chemical corrosion method, and corrosive liquid used is acid solution, goes alloy temperature Degree is 70 DEG C, time 900min.

By being amorphous in the cobalt phosphorus of the rear-earth-doped cobalt phosphorus ternary alloy three-partalloy chemical combination object of nano porous copper surface electro-deposition, preparation The cobalt phosphorus compound of state can be evenly distributed on porous copper substrate surfaces, and can the intact porous pattern for keeping substrate.

In step (5) of the present invention, the composition of electroplate liquid used in electro-deposition cobalt phosphorus compound are as follows: Co5O₄·7H₂O 180~ 200g/L、H₃PO₃45~55g/L, H₃PO₄15~20g/L, 10~15g/L of rare-earth salts；Reaction temperature is 55 DEG C, and the time is 70s, current density 10.0A/dm²。

Wherein rare-earth salts selects soluble rare-earth salt compound.

It is a further object of the present invention to provide a kind of flexible nothings of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper The application method of enzymatic glucose sensing electrode.

The present invention by high performance nano-porous materials in conjunction with interdigital electrode, by the interdigitated electrode structure of small spacing, Ohmmic drop is reduced, concentration polarization is slowed down, enhances signal-to-noise ratio, greatly improves the performance of enzyme-free glucose sensing electrode.

Nanoporous decorative layer prepared by the present invention is answering for the cobalt phosphorus particle modification nano porous copper of rare earth doped element Structure is closed, the nano porous copper with high-specific surface area and high porosity, the cobalt phosphorus activity with high electrochemical activity are combined Layer and the rare earth element with high catalytic activity, greatly improve electrode catalyst performance, and the catalysis suitable for glucose senses.

In alkaline solution, Co-M-P/NPC combination electrode mainly passes through CoOOH/ to the electrochemical oxidation of glucose CoO₂(catalytic active substance) mutually converts realization, and the generation of catalytic active substance and consumption (Co^δ+It is arrived again to CoOOH CoO₂Process and its inverse process) belong to will definitely back reaction process, the oxidation of glucose that surface occurs belongs to adsorption Control process.

Mechanism of the Co-M-P/NPC combination electrode to the electrochemical oxidation of glucose are as follows:

2CoO₂+C₆H₁₂O₆→2CoOOH+C₆H₁₀O₆

0 < δ < 3, n=3- δ in the above reaction equation.

The present invention in electrode face finish Co-M-P/NPC composite construction, because of it with high electrochemical surface area and Lower charge transfer resistance, it is known that porous structure and active material can effectively promote electro catalytic activity.

Co-M-P/NPC combination electrode sensitivity with higher provided by the invention, extremely low detection limit, lower inspection Rising limit and good stability and interference free performance, its sensitivity is 1920 μ A/ in the inspection range of 0.5~10.0mM mM·cm², detect and be limited to 182nM, the response time is less than 4s.

The beneficial effects of the present invention are:

(1) energy-efficient technique: in electrode face finish Co-M-P/NPC composite construction, high electrochemistry is made it have Active area and lower charge transfer resistance, the electro catalytic activity of electrode is substantially improved by porous structure and active material, Provide a kind of energy-efficient, simple process and the high method for preparing composite electrode of adjustability.

(2) three electrode coplanar structures: the copolymerization of three electrodes is integrated in same electrode plane, and constant distance, passes through fork Refer to the design of electrode structure, effectively reduces the spacing between electrode, reduce solution itself ohmmic drop, slow down concentration polarization, favorably In the conduction of electronics, the sensitivity of electrode is enhanced；Using flexible parent metal, it can bend repeatedly and not cause rupture of line, and can It is bonded human skin.

(3) without enzyme stable detection: modifying working electrode using Co-M-P/NPC, combine with high-specific surface area and high hole The nano porous copper of gap rate, the cobalt phosphorus active layer with high electrochemical activity and the rare earth element with high catalytic performance, substantially Electrode catalyst performance is improved, the catalysis suitable for glucose senses.

Detailed description of the invention

Invention is described further using attached drawing, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention, For those of ordinary skill in the art, without creative efforts, it can also be obtained according to the following drawings Its attached drawing.

Fig. 1 is electron microscope of the Co-M-P/NPC combination electrode prepared by the present invention under (A) low range and (B) high magnification；

Fig. 2 is that Co-M-P/NPC combination electrode and Co-P electrode prepared by the present invention, NPC electrode and blank electrode are containing With the cyclic voltammetry figure in the 0.1M KOH buffer without glucose, scanning speed 50mV/s；

Fig. 3 is that glucose is added dropwise to continuous in 0.1M KOH buffer in Co-M-P/NPC combination electrode prepared by the present invention The test chart when ampere meter of the response of solution, test potential 0.60V, glucose concentration range are 0.5 μM~5.0mM；

Fig. 4 is that the Portugal 0.5mM is continuously added dropwise in 0.1M KOH buffer in Co-M-P/NPC combination electrode prepared by the present invention The test chart when ampere meter of the response of grape sugar juice, test potential 0.60V, it is 20 times that number, which is added dropwise,；

Fig. 5 is the anti-interference test chart of Co-M-P/NPC combination electrode prepared by the present invention.

Specific embodiment

For a better understanding of the present invention, below with reference to the embodiment content that the present invention is furture elucidated, but it is of the invention Content is not limited solely to the following examples.

A kind of preparation of the flexible enzyme-free glucose sensing electrode of rear-earth-doped cobalt phosphorus ternary alloy three-partalloy modification nano porous copper Method, specifically includes the following steps:

(1) standard integrate three electrodes to platinum plating on electrode；

(2) silver-silver chloride is modified on the reference electrode that standard integrates three electrodes；

(3) electric deposited copper floor on the working electrode that standard integrates three electrodes；

(4) in working electrode front deposited Au tin alloy, then metallic tin is removed, obtains the electricity of modification nano porous copper Pole；

(5) it by the ternary alloy three-partalloy chemical combination object or cobalt phosphorus compound of the rear-earth-doped cobalt phosphorus of working electrode front electro-deposition, obtains The flexible enzyme-free glucose sensing electrode of Co-M-P/NPC modification.

Further, in step (1), platinum plating bath group becomes H₂PtCl₆1mM and KCl 0.1M.

Further, in step (2), the solution composition of silver-silver chloride is plated are as follows: 40~45g/L of silver nitrate, sodium thiosulfate 200~240g/L, 40~45g/L of potassium metabisulfite, 20~30g/L of ammonium acetate, 0.6~0.9g/L of thiosemicarbazide；Plating temperature Degree is 25 DEG C, current density 0.3A/dm², the time is 15~25min.

Further, in step (3), the composition of copper electroplating liquid are as follows: Cu₂P₂O₇·3H₂O 65g/L、K₄P₂O₇·3H₂O 380g/ L、C₆H₅O₇(NH₄)₃ 23g/L、C₆H₈O₇0.5g/L；The temperature of electro-coppering is 35 DEG C, current density 2.0A/dm², the time is 300s。

Further, in step (4), the composition of copper-tin alloy plating solution used in electro-deposition are as follows: Cu₂P₂O₇·3H₂18~20g/ of O L、Sn₂P₂O₇15~16g/L, K₄P₂O₇·3H₂250~280g/L of O, K₂HPO₄·3H₂75~95g/L of O, H₃PO₄3.5~ 4.5g/L；Preferably, Cu₂P₂O₇·3H₂O 19g/L、Sn₂P₂O₇ 15.6g/L、K₄P₂O₇·3H₂O 280g/L、K₂HPO₄·3H₂O 85g/L、H₃PO₄ 3.95g/L。

Further, in step (4), electrodeposition temperature is 20~28 DEG C, preferably 25 DEG C；Current density is 0.8~1.2A/ dm², preferably 1.0A/dm²；Time is 900~1000s；Preferably 900s.

Further, in step (4), removal metallic tin is using chemical corrosion method, and corrosive liquid used is acid solution, goes alloy temperature Degree is 70 DEG C, time 900min.

Further, in step (5), the composition of electroplate liquid used in electro-deposition cobalt phosphorus compound are as follows: Co5O₄·7H₂O 180~ 200g/L、H₃PO₃45~55g/L, H₃PO₄15~20g/L；Preferably, CoSO₄·7H₂O 180g/L、H₃PO₃ 50g/L、 H₃PO₄15g/L, 10~15g/L of rare-earth salts；Reaction temperature is 55 DEG C, time 70s, current density 10.0A/dm²。

The contents of the present invention are described in further detail below by way of specific embodiment.