Background technology:
Since maxwell sets up electromagnetic theory, hertz finds electromagnetic wave for over 100 years more than a hundred years, electromagnetic energy is fully utilized.Especially in today of science prosperity, electromagnetic energy has obtained development rapidly in fields such as broadcasting, TV, communication, navigation, radar, remote measuring and controlling and computers, create huge material wealth to the mankind, the particularly explosivity of information, network technology development, the dialogue distance and the time in the world are shortened suddenly, the world assumes an entirely new aspect, and the dream of global village will become a reality.Yet, follow the utilization of electromagnetic energy, also brought the generation of electromagnetic interference.Useless electromagnetic field can be by the approach of radiation and conduction, and with the form of field and electric current (voltage), the sensitive electronic devices that intrusion work makes it can't operate as normal.And, as ecological environmental pollution, along with science and technology development.The pollution of electromagnetic environment is also more and more serious.It not only produces harm to the safety and the reliability of electronic product, also can be to human and ecological generation harmful effect.Each industrially developed country of the world more and more payes attention to this problem, particularly since nineteen seventies, has carried out a large amount of theoretical researches and experimental work.And then proposed how to make electronic equipment or system in its residing electromagnetic environment, can move normally, and the new problem that the miscellaneous equipment of working in this environment or system are not introduced the electromagnetic interference that can not bear yet, promptly so-called " electromagnetic shielding ".
Electromagnetic shielding is exactly to stop electromagnetic wave in spatial transmission or a kind of measure of stoping electromagnetic wave to enter institute's guard space with shield, and shield has played the effect on barrier layer, weighs with the screening effectiveness index usually.Electromagnetic shielding is to suppress to disturb, and strengthens the reliability of equipment and the effective means of improving the quality of products.Reasonably use electromagnetic shielding, can suppress the interference of external frequency electromagnetic waves, also can avoid removing to influence other equipment as interference source.As in broadcast receiver, cover on the coil outside with the hollow aluminum hull, thereby make it not be subjected to the interference of extraneous time-varying field to avoid noise.The audio frequency feeder line also is this reason with shielding conductor.Oscilloscope tube is wrapping with iron sheet, also is in order to make the stray EM field not influence the scanning of electron ray.The frequency electromagnetic waves that element or equipment produced in metal shielding inside does not go out metal-back and the unlikely external equipment that influences thoroughly yet.Electromagnetic interference is divided into two big class, i.e. conducted interference and radiated interference usually.Filtering, shielding and ground connection are to suppress electromagnetic interference three big technology, and the former two all needs the soft magnetic material of excellent performance.Filtering mainly is used to suppress conducted interference; And shield technology adopts high conductivity material (as copper and aluminium) shielding High-frequency Interference usually, adopts high permeability materials (as permalloy, ferrocobalt, iron cobalt nickel alloy etc.) shielding low-frequency disturbance.The material that is suitable as most at present the shielding High-frequency Interference is copper or aluminium, and the material that is suitable as the shielding low-frequency disturbance is permalloy, nanocrystalline or non-crystaline amorphous metal.But the existing ubiquitous problem of electromagnetic shielding material is that kind is single, and the shielding frequency range is narrow, can not shield the wide band interference needs from the low frequency to the high frequency simultaneously.
Summary of the invention
The purpose of this invention is to provide a kind of high magnetic permeability and high conductivity performance of having concurrently, and can shield composite electromagnetic shield materials and manufacture method thereof that the broadband from the low frequency to the high frequency is disturbed simultaneously.
The present invention is in order to remedy the electromagnetic shielding material heaviness, and the operation construction is inconvenient, the narrow and a kind of novel composite electromagnetic shield materials of special exploitation of shield ranges.Described composite electromagnetic shield materials is at nanocrystalline or amorphous soft-magnetic alloy strip surface electrodeposit metals copper, makes it to have the characteristic of high permeability and high conductivity, thereby has the screening effectiveness of wideband section.This composite shielding material is made up of nanocrystalline metal or non-crystaline amorphous metal base band and copper electroplating layer, has good chemical bond combination between two-layer.
Wherein nanocrystalline or amorphous soft magnet matrix band designs in order to shield the low frequency low-intensity magnetic field, and conductivity good metal copper layer designs in order to shield high frequency magnetic field.
The thickness of composite electromagnetic shield materials is 21~90 μ m, and wherein nanocrystalline or amorphous soft magnet metallic matrix thickness of strip is 20~40 μ m, and the two-sided thickness of copper electroplating layer is 1~50 μ m.
The composition of matrix soft magnetic material is by Fe, Co, and Ni, Cu, Nb, Zr, Hf, Si, B, metal among the P and nonmetalloid are formed, and this soft magnetic material adopts single roller or the preparation of two roller quick-quenching method, and the material of conductive metal layer is the metal copper layer of electro-deposition method preparation.
The method that the present invention prepares composite electromagnetic shield materials is to adopt two-sided electrodeposit metals copper layer on the soft magnetic metal base band.Promptly this composite electromagnetic shield materials is in the nanocrystalline or amorphous soft magnet strip surface of utilizing the quick-quenching method preparation, through the strict pretreatment procedure two-sided copper plate that forms of copper-plating technique in two steps then, nanocrystalline or the amorphous soft magnet band of negative electrode at first passes through the alkaline copper plating layer through after the pre-treatment, is referred to as pre-copper plate; Carry out acid copper-plating rapidly after cleaning then, this step copper facing is formal copper facing.Copper plate is to deposit to form in the acidity or the alkaline electrolysis aqueous solution, and copper layer thickness decision sedimentation time as required carries out electro-deposition under the technology electro-deposition current density of the best.
The step that the present invention prepares composite electromagnetic shield materials is as follows:
1. clean through electrolytic degreasing, heat alkali liquid cleaning, pickling, cold water and hot water injection, activation and cold water and hot water before the soft magnetic materials matrix plated metal copper layer;
2. according to the soft magnetic materials matrix of required deposition, prepare the electrolytic aqueous solution of the copper metal of desired concn, the concrete component of electrolytic aqueous solution is two kinds, a kind of is alkali plating solution: basic copper carbonate 40~100g/L, citric acid 150~300g/L, sodium carbonate 8~20g/L, excess water;
Another kind is an acidic bath: copper sulphate 160~240 grams per liters, sulfuric acid 40~90 grams per liters, chloride ion 60~190mg/L (can add hydrochloric acid or sodium chloride solution), brightener 5~20ml/L, leveling agent 0.2~1.2ml/L, excess water;
Brightener is 2-mercaptobenzimidazole (M) and ethylene thiourea (N), sodium polydithio-dipropyl sulfonate (SP), polyethylene glycol, ethylene thiourea, two sulphur benzimidazoles, the tetrahydro-thiazoles thioketones, in the dodecyl sodium sulfate any one or more.
Leveling agent is aliphatic amine polyoxyethylene ether (AEO), polymine, 210 acidic copper plating additives any one or more.
3. prepare negative electrode soft magnetism band, the negative electrode band is fixed as requested, anode copper ball is put into double anode titanium basket, and is fixed on corresponding position; The electro-deposition form that this method is used is to adopt vertical electro-deposition mode, adopts the two-sided electro-deposition of double anode simultaneously.Ratio of cathodic to anodic area 1 in the electrodeposition process: (2~10); Plating bath is used yarn core and pp material filter element filtering respectively;
4. circulating pump is opened, behind the plating bath stable circulation, is connected DC power supply, pass to required electro-deposition electric current, electroplate according to following technological parameter:
(1) in the alkaline copper plating solution during pre-copper plate:
40~60 ℃ of plating temperatures
Current density 0.5~3.5A/dm2
PH value scope 8-10
Ratio of cathodic to anodic area 1: 5~1: 10
Cathode and anode spacing 10~30mm
Alr mode air stirring or negative electrode move, flow circuit stirs
Phosphorous 0.04~0.06% phosphorus copper plate of anode material or copper ball
Electrodeposition time is 1~10min;
(2) in the acid copper plating solution during formal copper layer:
20~30 ℃ of electrodeposition temperatures
Bath pH value 1.0~2.0
Cathode-current density 0.5~10A/dm
2
Ratio of cathodic to anodic area 1: 5~1: 10
Cathode and anode spacing 10~30mm
Alr mode air stirring or negative electrode move, flow circuit stirs
Phosphorous 0.04~0.06% phosphorus copper plate of anode material or copper ball
Electrodeposition time 5~50min.
5. the soft magnetism band has deposited and has used behind the copper layer cold water and hot water injection clean respectively, through oven dry, promptly obtains composite electromagnetic shield materials of the present invention then.
The composite electromagnetic shield materials of the present invention's preparation, soft magnetic material wherein is to use the nanocrystalline or amorphous band of quick-quenching method preparation, does not only reduce increasing substantially on the contrary.Adopt the random orientation anisotropic model of Alben this to be made satisfied explanation, think that magnetic permeability is inversely proportional to six powers of crystallite dimension and coercive force is proportional to six powers of crystallite dimension.Before Nano soft magnetic material was found, generally the alloy representative nanocrystalline or amorphous soft magnetic material of Shi Yonging was Finemet, and it is equaled at first to succeed in developing in 1988 by FDAC metal company Ji Zeke benevolence, and the typical composition of Finemet is Fe
73.5Cu
1Nb
3Si
13.5B
9, have excellent soft magnet performance, high saturation magnetization, high initial permeability, low-coercivity and low-loss.Its magnetic permeability is up to 10
5, saturation induction density is 1.30T.
When the present invention prepares composite electromagnetic shield materials, in the water-soluble plating bath of cupric electrolysis the method that adopts two step electro-deposition.The pre-copper plate of alkali plating solution is in order to obtain the slow and good pre-copper plate of leveling property of compact crystallization, deposition velocity, is that the acid copper-plating of back is made a transition zone, has good bonding force to guarantee copper coating and nanocrystalline or amorphous soft magnet sheet metal strip.The advantage of alkaline copper plating makes the copper coating densification exactly, and defective is few, and coating is tight with combining of lower floor, has eliminated the defective of the spongy foam copper coating of flash plate copper, makes the conductivity of coating and increase substantially with the adhesion of substrate.
The present invention utilizes with low cost, the advantage conveniently of aqueous solution electrodeposition, the method of employing deposited copper coating on nanocrystalline or amorphous soft magnet band, technological parameter by the control electro-deposition, prepare flexible, with low cost and have the composition metal electromagnetic shielding material of wideband section electromagnet shield effect, in order to satisfy the demand that guarantees various electronic equipment operate as normal in the electromagnetic environment that day by day worsens.
Prepare with other shielding material and different to be, the electromagnetic shielding material among the present invention is by the method preparation of electro-deposition, and combines with the good nanocrystalline or amorphous band of soft magnet performance, reaches good effectiveness.
The present invention is surperficial at the good nanocrystalline or amorphous alloy strips of soft magnet performance, utilize twice plated metal copper layer in the electrolytic aqueous solution, thereby obtain to have good capability of electromagnetic shielding, the frequency range of its shielding is at 50Hz~20MHz, and screening effectiveness reaches more than the 80dB.
Compare with existing shielding material, the present invention has following advantage:
(1) material with the different process preparation combines, and realizes higher using value;
(2) thickness nanocrystalline or amorphous soft magnetic material layer and electric deposited copper floor can be controlled by regulating technological parameter;
(3) composite electromagnetic shield materials be thickness at 21~90 microns, light and flexible is operated easy for installation;
(4) Zhi Bei composite electromagnetic shield materials is flexible material;
(5) described composite electromagnetic screen film material can reach the effect of wideband section shielding;
(6) described composite electromagnetic screen film material range of application is not subjected to the restriction of sole mass, shielding shape;