CN1310262C

CN1310262C - Methof for manufacturing foil of cathode of electrolytic capacitor

Info

Publication number: CN1310262C
Application number: CNB03139759XA
Authority: CN
Inventors: 罗向军
Original assignee: DONGYANG ACTINIC FOIL FORMING Co Ltd SHENZHEN
Current assignee: DONGYANG ACTINIC FOIL FORMING Co Ltd SHENZHEN
Priority date: 2003-07-08
Filing date: 2003-07-08
Publication date: 2007-04-11
Anticipated expiration: 2023-07-08
Also published as: CN1480966A

Abstract

The present invention discloses a manufacturing method for a negative electrode foil used for an electrolytic capacitor. The present invention is characterized in that a zinc-series phosphorized liquid is adopted as a treating liquid for pretreatment, the treating liquid is composed of a phosphoric acid solution with the concentration of 2 to 30% by weight, a zinc oxide solution with the concentration of 0.1 to 5 g/l and a hydrofluoric acid solution with the concentration of 0.005 to 0.5%, the treating temperature of the pretreating liquid is 20 to 90 DEG C, and treating time is 20 to 200 seconds. When oil for rolling, impurities and a natural oxide film on the surface of an aluminum foil are removed, a layer of phosphorized film which has the function of protection for the surface of the aluminum foil is formed on the surface of the aluminum foil by adopting the pretreatment technology of the present invention. In the following process of corrosion treatment, the corrosion of the impurity enriching area of the surface of the aluminium foil is repressed, the corrosion of the area with low impurity content is reinforced so that the corrosion state of the surface of the whole aluminum foil turns to be uniform, and corrosion area expanding efficiency is greatly improved. Under the condition of ensuring constant mechanical strength, the specific volume of the aluminum foil is effectively improved.

Description

The electrolytic capacitor negative electrode foil making method

Technical field

The present invention relates to a kind of electrolytic capacitor negative electrode foil making method, particularly a kind of electrolytic capacitor negative electrode foil making method that has adopted special pre-treating method.

Background technology

Anode foil in the electrolytic capacitor is that 20-60 μ m, purity are that aluminium foil more than 97% expands face through excessive erosion and makes with thickness normally.For improving the specific volume of aluminium foil, generally need before corrosion, aluminium foil to be carried out pre-treatment, promptly carry out various physical or chemical treatments, its objective is greasy dirt, impurity and the natural oxide film of removing aluminium foil surface, adjust aluminium foil institutional framework, improve its surface state, make the evenly activation of its surface, form equally distributed hole when being beneficial to corrode, improve the specific volume of aluminium foil, existing pre-treating method generally adopts the lower acid of concentration, alkali or metal cleaner as pretreatment liquid.

Because manufacturer is for reducing production costs, the light paper tinsel purity of used production anode foil lower (aluminium content 〉=97%), wherein contain a large amount of copper, iron, impurity such as silicon, these impurity are very inhomogeneous in the distribution of aluminium foil surface, so the corrosion back also is very uneven at the formed raceway groove of aluminium foil surface, and existing pre-treating method can't solve the distribution of aluminium foil surface, so prolongation along with etching time, be easy to generate small channel in the zone of impurity enriched and merge into big raceway groove, generation table and degrading, not only lose original static capacity, and greatly reduced mechanical strength.

Summary of the invention

The present invention provides a kind of static capacity and mechanical strength that can not only improve aluminium foil for overcoming the deficiencies in the prior art, and can reduce the electrolytic capacitor negative electrode foil making method of aluminium foil corrosion weightlessness.

The technical solution used in the present invention is: a kind of manufacture method of electrolytic capacitor anode foil, comprise pre-treatment, and the pretreatment liquid that its pre-treatment is adopted comprises phosphoric acid 2-30wt%, zinc oxide 0.1-5g/l and hydrofluoric acid 0.005-0.5wt%.The treatment temperature of this pretreatment liquid is 20-90 ℃, and the processing time of pretreatment liquid is 20-200 second.

The variation of zinc oxide concentration is little to aluminium foil specific volume influence in the pretreatment liquid, but zinc oxide concentration is during greater than 1g/l, and aluminium foil surface begins to occur the dust phenomenon, and along with the increase dust of addition increases, the oxidation zinc concentration is low excessively, is unfavorable for pre-treatment again, and zinc oxide concentration is advisable with 0.5-1g/l; The concentration of hydrofluoric acid is bigger to the raising influence of aluminium foil specific volume, but when its concentration was excessive, just not too obvious to the influence of specific volume, hydrofluoric acid concentration was advisable with 0.01-0.1%; The too high or too low raising that all is unfavorable for specific volume of phosphoric acid concentration, its concentration is advisable with 5-15%.

The temperature of pretreatment liquid and processing time can replenish mutually, the high more then required time of treatment fluid temperature is short more, processing time is subjected to the restriction of device structure bigger, usually the processing time is good with 20-40 second, and after temperature was greater than 60 ℃, the high more then treatment effect of temperature was poor more, and it is coarse that aluminium foil shows as phosphate coating, the dust phenomenon takes place easily, so treatment temperature is advisable with 45-55 ℃.

Compared with prior art, the present invention adopts Zinc phosphating solution as pretreatment liquid, when removing aluminium foil surface ROLLING OIL, impurity and natural oxide film, has generated one deck phosphating coat at aluminium foil surface, and this layer phosphating coat has the certain protection effect to aluminium foil surface.In corrosion treatment process subsequently, the zonal corrosion of aluminium foil surface impurity enriched has been subjected to inhibition, the zonal corrosion that impurity content is low has obtained reinforcement, the etch state of whole like this aluminium foil surface becomes more even, corrosion expansion face efficient has obtained bigger raising, guaranteeing not only improved the specific volume of aluminium foil, and the surface dust of aluminium foil to have lacked also much under the constant situation of mechanical strength.

Description of drawings

Fig. 1 is the curve chart of making according to embodiment in the embodiment and specific volume that Comparative Examples is surveyed and remaining weight numerical value.

Embodiment

The invention will be further described below in conjunction with embodiment, in the manufacturing of this electrolytic capacitor anode foil, and the light paper tinsel of using homemade 50 μ m negative pole light paper tinsels in being, purity 〉=97%.The production technology of anode foil is: put paper tinsel → pre-treatment → corrosion → cleaning → middle processing → cleaning → reprocessing → drying → receipts paper tinsel.The pre-treatment temperature is 50 ℃, and the time is 30 seconds, and used pretreatment liquid is 2% sodium hydroxide solution; Corrosive liquid consists of: free acid 1.5 ± 0.5N, and total acid 5.5 ± 0.5N, aluminium ion 4.2 ± 0.7N, chloride ion 5.5 ± 0.5N, corrosion temperature are 98 ± 3 ℃, the time is 15-30 second; Middle treatment fluid is 0.9N ± 0.1 nitric acid, and middle treatment temperature is 40 ± 5 ℃, and the time is 60 seconds; Aftertreatment fluid is 0.5% ammonium dihydrogen phosphate, and post-processing temperature is 70 ± 5 ℃, and the time is 60 seconds; Bake out temperature is 325 ± 25 ℃, 30 seconds time.

Comparative Examples adopts existing pre-treating technology, and used pretreatment liquid is 2% sodium hydroxide solution, when temperature is 50 ℃, the light paper tinsel is handled 30 seconds, is carrying out subsequent treatment; Embodiment adopts pre-treating method of the present invention, and used pretreatment liquid is a Zinc phosphating solution, comprises 10% phosphoric acid, 0.5g/l zinc oxide and 0.05% hydrofluoric acid, when temperature is 50 ℃, the light paper tinsel is handled 30 seconds, carries out the subsequent treatment with Comparative Examples the same terms again.Table 1 is that the detailed numerical value of Comparative Examples and specific volume that embodiment surveys and remaining weight compares.Data declaration adopts pre-treating method of the present invention can improve specific volume 10-20% under the identical situation of weightlessness in the table 1, and Fig. 1 has reflected this point more intuitively.

Table 1

Comparative Examples	Pretreatment liquid is 2% NaOH, 50 ℃ of pre-treatment temperature, 30 seconds processing times
Comparative Examples							Etching time (S)	10	12	14	16	18	20
Remaining weight (g)	0.0675	0.0647	0.0574	0.0519	0.0476	0.0404	Etching time (S)	10	12	14	16	18	20
Remaining weight (g)	0.0675	0.0647	0.0574	0.0519	0.0476	0.0404	0V specific volume (μ F/cm ²)	280	316	449	552	598	731
Embodiment	Pretreatment liquid is that 10% phosphoric acid+0.5g/l zinc oxide+0.05% hydrofluoric acid pre-treatment temperature is 50 ℃, 30 seconds processing times						0V specific volume (μ F/cm ²)	280	316	449	552	598	731
Embodiment							Etching time (S)	12	14	16	18	20	22
Remaining weight (g)	0.0743	0.0707	0.0644	0.0611	0.0580	0.0518	Etching time (S)	12	14	16	18	20	22
Remaining weight (g)	0.0743	0.0707	0.0644	0.0611	0.0580	0.0518	0V specific volume (μ F/cm ²)	222	343	525	614	706	805

Claims

1. an electrolytic capacitor is with the manufacture method of anode foil, comprise pre-treatment, it is characterized in that the pretreatment liquid of described pre-treatment comprises that concentration is that the phosphoric acid solution of 5-15wt%, burnett's solution and the concentration that concentration is 0.5-1g/L are the hydrofluoric acid solution of 0.01-0.1wt%.

2. the electrolytic capacitor according to claim 1 manufacture method of anode foil, the treatment temperature that it is characterized in that described pretreatment liquid is 20-90 ℃, the processing time is 20-200 second.

3. the electrolytic capacitor according to claim 2 manufacture method of anode foil, the treatment temperature that it is characterized in that described pretreatment liquid is 45-55 ℃, the processing time is 20-40 second.

According to any described electrolytic capacitor among the claim 1-3 with the manufacture method of anode foil, it is characterized in that described anode foil is an aluminium content more than or equal to 97% aluminium foil.