CN101051543A - Circular varistor with better soldering resistance and its producing method - Google Patents
Circular varistor with better soldering resistance and its producing method Download PDFInfo
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- CN101051543A CN101051543A CN 200610072620 CN200610072620A CN101051543A CN 101051543 A CN101051543 A CN 101051543A CN 200610072620 CN200610072620 CN 200610072620 CN 200610072620 A CN200610072620 A CN 200610072620A CN 101051543 A CN101051543 A CN 101051543A
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Abstract
Especially, the invention relates to loop type rheostat with enough soldering resistance in order to be accorded with requirement of soldering tin without lead. The method includes steps: first, preparing basal body of ceramics; next, carrying out heat treatment in multi section type for the basal body of ceramics to form ceramic body; afterward, forming multiple silver electrode on the ceramic body; then, plating a nickel coating on the silver electrode; finally, plating a tin coating on the nickel coating. The produced loop type rheostat includes a ceramic body, a layer of silver formed on ceramic body, a nickel coating on the silver electrode, and a tin coating on the nickel coating. Using the nickel coating, the invention raises soldering resistance of the loop type rheostat.
Description
Technical field
The invention relates to a kind of the have circular varistor and the manufacture method thereof of soldering resistance preferably, especially refer to a kind of for the Pb-free solder welding, and the soldering resistance with the higher welding temperature that can accord with Pb-free solder uses allowing electrode be unlikely to circular varistor and the manufacture method of being eaten up by scolding tin thereof.
Background technology
Circular varistor (Ring Varistor or Ring Variable Resistor) is that a kind of profile is ring-like resistor, its resistance value can change along with the difference of applied voltage, and this toroidal rheostat has a ceramic body and is located at least three segment electrodes on this ceramic body.
Circular varistor is mainly used in dc micro-motor (DC micro-motor) at present, and the electromagnetic interference (EMI) that is produced during in order to the inhibition motor operation is because electromagnetic radiation as waves is easy to exert an adverse impact for human body or electronic product.
Circular varistor divides according to employed ceramic material, can be divided into zinc oxide (ZnO) and strontium titanates (SrTiO
3) wait two big classes; Difference according to the outward appearance electrode material is divided, and then can be divided into silver electrode and copper electrode two classes.
And because circular varistor is directly to offer the client to use, therefore whether the welding characteristic of circular varistor is good, it is the requirement of client emphasis always, consider based on environmental protection, play countries in the world in 2006 and promptly begin to popularize in an all-round way Pb-free solder, and Pb-free solder when welding required temperature higher, use the circular varistor of silver electrode strontium titanates as material, electrode on it at all can't anti-this high temperature, therefore, " soldering resistance " of silver electrode strontium titanates circular varistor just becomes the big problem that those skilled in the art will overcome, solve.And traditionally, if will promote the soldering resistance of silver electrode strontium titanates circular varistor, nothing more than composition or the silver content of adjusting the elargol that uses, or with the thickness increase of silver electrode, be that these methods not only expend cost, and its effect is also rather limited.
This case inventor studies with great concentration at the disappearance of above-mentioned prior art, creates a kind of the present invention that can be improved really finally.
Summary of the invention
Main purpose of the present invention is to be to provide a kind of the have circular varistor and the manufacture method thereof of soldering resistance preferably; pass through nickel coating, tin coating and the innovation of being set up and special manufacture method; to produce circular varistor with enough soldering resistances; its nickel coating is in order to reach anti-weldering effect; its tin coating is then in order to reach oxidation resistant protection effect; use with the Pb-free solder that is suitable for having higher welding temperature, and meet the requirement of client and world's standard.
In order to reach aforesaid purpose, the invention provides a kind of circular varistor, it comprises:
One ceramic body;
One silver layer, it is formed on the described ceramic body;
One nickel coating, it is plated on the described silver layer; And
One tin coating, it is plated on the described nickel coating.
The present invention also provides a kind of manufacture method of circular varistor, and it may further comprise the steps:
Prepare a ceramic matrix;
Described ceramic matrix is carried out multisection type heat treatment, to form required ceramic body;
On described ceramic body, form a plurality of silver electrodes;
On these silver electrodes, electroplate a nickel coating respectively; And
On these nickel coatings, electroplate a tin coating respectively.
By the circular varistor that method for making of the present invention is finished, have preferable soldering resistance, and this soldering resistance can accord with the requirement that Pb-free solder has higher welding temperature.
Description of drawings
Fig. 1 is the calcspar () of circular varistor manufacture method of the present invention.
Fig. 2 is the calcspar (two) of circular varistor manufacture method of the present invention.
Fig. 3 is the schematic diagram of circular varistor of the present invention.
Fig. 4 is the profile of circular varistor of the present invention.
The figure number explanation:
1... circular varistor
11... ceramic body 12... silver layer
13... nickel coating 14... tin coating
Embodiment
See also Fig. 1～shown in Figure 4, the invention provides a kind of the have circular varistor and the manufacture method thereof of soldering resistance preferably, meet Pb-free solder required higher welding temperature when the welding in order to promote ring-like rheostatic soldering resistance, to use.
As shown in Figure 1, the manufacture method of this circular varistor comprises: the powdered formula (S101) of preparing ceramic body earlier; Again this powdered formula is mixed into slurry (S103); Then then this slurry is given drying (S105); After drying, calcined (S107) then again; Pass through ground and mixed (S109) and mist projection granulating and dry-pressing formed (S111) after the calcining again and form ceramic matrix; (S113a～S113c) is to form required ceramic body to carry out the syllogic heat treatment of atmosphere sintering, reduction and oxidation etc. more then; And then this ceramic body is carried out electrode make to form a plurality of silver electrodes (S115), the making of its electrode is that the silver slurry is printed out required silver electrode in the screen painting mode on ceramic body, uses the circular varistor that forms before electroplating; Then carry out electrode plating step (S117) at last.
As shown in Figure 2, aforesaid electrode plating step (S117) comprising: the surperficial resistance that changes the preceding circular varistor of this plating earlier, or on ceramic body, evenly attach resinae clad material (S201), use when avoiding these silver electrodes in electroplate liquid, to electroplate and can produce the plating diffusion effect; To accompany the plating thing to be mixed in the electroplate liquid (S203) again; Then then power in the silver electrode of this circular varistor and plate out a nickel coating (S205), cleaned again to reach anti-weldering effect by this electroplate liquid; Then then on the nickel coating of this circular varistor re-plating go out a tin coating (S207) to reach oxidation resistant protection effect, cleaned again; Pass through drying steps (S209) again; Then will accompany the plating thing to be disperseed (S211) at last.According to the manufacture method that has comprised above-mentioned steps, can produce the circular varistor of the embodiment of the invention really with preferable soldering resistance.
Plating diffusion effect is wherein avoided step (S201).Because the employed ceramic body of the embodiment of the invention belongs to " semiconductive ceramic ", therefore, if when parameter taking place in electroplating process controlling improper situation, will be very easily in all can be coated with metal (plating diffusion effect) together with ceramic body.And by the surperficial resistance of the change of this step, or evenly attach the resinae clad material, can avoid electroplating the generation of diffusion effect.
Plating thing step (S203) is accompanied in mixing wherein.Uses by collocation institute and to accompany the different of the size of plating thing (plating pearl) and weight, just can control the current density of electroplating bath content, that is: during current density big (it is little that electric current is big, voltage is high, plating pearl size reaches plating pearl weight greatly), its rate of deposition is very fast, but the stress of electrodeposited coating can be bigger; Otherwise during current density less (electric current is little, voltage is low, plating pearl size is little and plating pearl weight big), the stress of its electrodeposited coating is less, but electroplating time can prolong.In other words, current density is related to the length and the thickness of plating layer of electroplating time, and the current density control when therefore electroplating is the important key of electroplating success or failure, and can allows current density be controlled in the suitable scope by this step.
The preferably, the nickel liquid in the above-mentioned electroplate liquid, it is at employed nickelous sulfate and the nickel sulfamic acid of mainly comprising of industrial quarters, and the former advantage is inexpensive, and shortcoming is that the stress that nickel coating produces is bigger; The latter's characteristic is then just opposite with the former, and its shortcoming is the price height, and advantage is that the stress that nickel coating produced is less.Therefore, this embodiment of the invention is to use the latter.
In addition, because the size of product (circular varistor) is big more, its surface area is also big more, and under identical plating condition, the product that size is big more, because itself and the contact probability of plating between the pearl increase, therefore the thickness of coating that is obtained under identical electroplating time can increase; Otherwise, the product that size is more little, its thickness of coating can be thinner, and the outside dimension of this embodiment of the invention circular varistor comprises 3.0mm～16.5mm.Product at different size, if voltage, electric current when electroplating, accompany plating thing size and weight ... etc. the condition homogeneous phase simultaneously, in principle, the electroplating time that product size is little need increase, for example, the product of 3.0mm is under identical plating condition, its electroplating time is compared with the product of 8.0mm, and the time that need increase by 1 times could obtain identical electrodeposited coating thickness.
In addition, thickness of plating layer (being the gross thickness that nickel coating adds tin coating), best thickness less than original silver electrode on the product.If blocked up, then when carrying out 350～380 ℃ of weld jobs, very easily because the thermal coefficient of expansion difference between two-layer, and produce stress between two-layer and silver electrode is burst apart, and cause tin sweat(ing) splash phenomenon.And preferable nickel layer thickness is between 1～2.5um, preferable tin coating thickness so can obtain good soldering resistance about about 3～6um, when welding with 380 ℃ of flatiron temperatures, can also continue for 10 seconds, its silver electrode (containing coating) can not eaten up by scolding tin yet.
See also Fig. 3, shown in Figure 4, comprise a ceramic body 11, a silver layer 12, a nickel coating 13 and a tin coating 14 by the made circular varistor 1 of above-mentioned method for making.Wherein, this silver layer 12 is to be printed on the ceramic body 11 in the screen painting mode, uses at least three silver electrode portions of formation; On this silver layer 12, electroplate out a nickel coating 13 with plating mode again, make respectively and form a nickel plating portion respectively in this silver electrode portion; And on this nickel coating 13, electroplate out a tin coating 14 with plating mode again, make respectively and form a zinc-plated portion respectively again in this nickel plating portion.Nickel coating 13 is in order to reaching anti-weldering effect, and tin coating 14 is then in order to reach oxidation resistant protection effect.So make the circular varistor 1 of this embodiment of the invention have the anti-weldering requirement that accords with Pb-free solder.
The circular varistor of finishing by method for making of the present invention, has preferable soldering resistance, and this soldering resistance can accord with the requirement that Pb-free solder has higher welding temperature, for example, even weld for 380 ℃ with flatiron temperature, the circular varistor of this embodiment of the invention still can continue to weld for 10 seconds, and its silver electrode (containing coating) can not eaten up by scolding tin yet, and really tool is better than the advantage of known circular varistor.
In sum, a kind of the have circular varistor and the manufacture method thereof of soldering resistance preferably provided by the present invention, really can solve the described defective of prior art, and can reach described lifting soldering resistance effect, and has the progressive of promoting on industry applications, novelty and the effect, really met the patent of invention important document, special according to Patent Law proposition application for a patent for invention.
The above; only be a preferable feasible embodiment of the present invention; be not so just limited the scope of the present invention, the equivalence that every utilization specification of the present invention and graphic content are done changes, and all is contained in the scope of the present invention.
Claims (14)
1, a kind of circular varistor is characterized in that comprising:
One ceramic body;
One silver layer, it is formed on the described ceramic body;
One nickel coating, it is plated on the described silver layer; And
One tin coating, it is plated on the described nickel coating.
2, circular varistor as claimed in claim 1 is characterized in that, described silver layer is that elargol is printed on the described ceramic body in the screen painting mode, and this ceramic body is a semiconductive ceramic.
3, circular varistor as claimed in claim 1, it is characterized in that, described silver layer is to form at least three silver electrode portions on described ceramic body, and described nickel coating is plated on respectively respectively in this silver electrode portion and forms at least three nickel plating portions, and this tin coating then is plated on respectively in this nickel plating portion.
4, a kind of method for making of circular varistor is characterized in that may further comprise the steps:
Prepare a ceramic matrix;
Described ceramic matrix is carried out multisection type heat treatment, to form required ceramic body;
On described ceramic body, form a plurality of silver electrodes;
On described silver electrode, electroplate a nickel coating respectively; And
On described nickel coating, electroplate a tin coating respectively.
5, the method for making of circular varistor as claimed in claim 4 is characterized in that, described preparation ceramic matrix step comprises:
Prepare the powdered formula of ceramic body;
Described powdered formula is mixed into slurry;
Described slurry is given drying;
After drying, give calcining again;
After calcining, pass through ground and mixed again; And
After ground and mixed, then give mist projection granulating and dry-pressing formed and form ceramic matrix.
6, the method for making of circular varistor as claimed in claim 4 is characterized in that, described multisection type heat treatment step comprises the syllogic heat treatment of atmosphere sintering, reduction and oxidation.
7, the method for making of circular varistor as claimed in claim 4 is characterized in that, described electrode making step is that silver is starched in the screen painting mode, print out required silver electrode on described ceramic body, and this ceramic body belongs to semiconductive ceramic.
8, the method for making of circular varistor as claimed in claim 4 is characterized in that, comprises also that between electrode making step and nickel plating step one electroplates diffusion effect and avoids step, uses and avoids described silver electrode can produce the plating diffusion effect when electroplating.
9, the method for making of circular varistor as claimed in claim 8 is characterized in that, described plating diffusion effect is avoided step, is the surperficial resistance of electroplating preceding circular varistor by changing, to avoid electroplating the generation of diffusion effect; Or by on ceramic body, evenly attaching the resinae clad material, to avoid electroplating the generation of diffusion effect.
10, the method for making of circular varistor as claimed in claim 4, it is characterized in that, comprise also that between electrode making step and nickel plating step one mixes and accompanies plating thing step, use the current density of control one electroplating bath content, and then correspondingly control the size of the speed and the electrodeposited coating stress of rate of deposition.
11, the method for making of circular varistor as claimed in claim 10, it is characterized in that, the current density control in the plating thing step is accompanied in described mixing, be big in Control current, voltage is high, accompany plating thing size big and accompany plating thing weight little, use and correspondingly control out rate of deposition and bigger electrodeposited coating stress faster.
12, the method for making of circular varistor as claimed in claim 4, it is characterized in that, employed nickel liquid is to use nickel sulfamic acid in the described nickel plating step, and in nickel plating step or zinc-plated step, larger-size plated body, its electroplating time must reduce, and the less plated body of size, its electroplating time must increase, and uses to obtain identical electrodeposited coating thickness.
13, the method for making of circular varistor as claimed in claim 4, it is characterized in that the thickness sum total of described nickel coating and tin coating must be less than the thickness of silver electrode, and the thickness of described nickel coating is between 1～2.5um, and the thickness of described tin coating is then between 3～6um.
14, the method for making of circular varistor as claimed in claim 4 is characterized in that, also comprises accompanying plating thing dispersion steps after zinc-plated step.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610072620 CN101051543A (en) | 2006-04-05 | 2006-04-05 | Circular varistor with better soldering resistance and its producing method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610072620 CN101051543A (en) | 2006-04-05 | 2006-04-05 | Circular varistor with better soldering resistance and its producing method |
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| Publication Number | Publication Date |
|---|---|
| CN101051543A true CN101051543A (en) | 2007-10-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200610072620 Pending CN101051543A (en) | 2006-04-05 | 2006-04-05 | Circular varistor with better soldering resistance and its producing method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102855959A (en) * | 2012-09-13 | 2013-01-02 | 上海交通大学 | Surface-layer silver paste for SrTiO3 piezoresistor and preparation method of surface-layer silver paste |
| CN110247527A (en) * | 2019-06-12 | 2019-09-17 | 东莞市宝润智能装备有限公司 | A kind of motor commutator and rheostat high frequency soldering all-in-one machine |
-
2006
- 2006-04-05 CN CN 200610072620 patent/CN101051543A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102855959A (en) * | 2012-09-13 | 2013-01-02 | 上海交通大学 | Surface-layer silver paste for SrTiO3 piezoresistor and preparation method of surface-layer silver paste |
| CN102855959B (en) * | 2012-09-13 | 2015-07-08 | 上海交通大学 | Surface-layer silver paste for SrTiO3 piezoresistor and preparation method of surface-layer silver paste |
| CN110247527A (en) * | 2019-06-12 | 2019-09-17 | 东莞市宝润智能装备有限公司 | A kind of motor commutator and rheostat high frequency soldering all-in-one machine |
| CN110247527B (en) * | 2019-06-12 | 2024-03-15 | 东莞市宝润智能装备有限公司 | Motor commutator and rheostat high-frequency soldering integrated machine |
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Open date: 20071010 |