CN104233296A - Method for silvering aluminum and aluminum alloy - Google Patents

Method for silvering aluminum and aluminum alloy Download PDF

Info

Publication number
CN104233296A
CN104233296A CN201310246601.6A CN201310246601A CN104233296A CN 104233296 A CN104233296 A CN 104233296A CN 201310246601 A CN201310246601 A CN 201310246601A CN 104233296 A CN104233296 A CN 104233296A
Authority
CN
China
Prior art keywords
aluminum
zinc
current
plating
silvering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201310246601.6A
Other languages
Chinese (zh)
Inventor
戴颖锋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZHENJIANG JIANGCHENG METAL PRODUCTS Co Ltd
Original Assignee
ZHENJIANG JIANGCHENG METAL PRODUCTS Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ZHENJIANG JIANGCHENG METAL PRODUCTS Co Ltd filed Critical ZHENJIANG JIANGCHENG METAL PRODUCTS Co Ltd
Priority to CN201310246601.6A priority Critical patent/CN104233296A/en
Publication of CN104233296A publication Critical patent/CN104233296A/en
Pending legal-status Critical Current

Links

Abstract

The invention provides a method for silvering aluminum and aluminum alloy, and belongs to the technical field of metal plating. The method for silvering aluminum and aluminum alloy is achieved by the following technical scheme: (1) carrying out chemical zinc immersion on an aluminum part in a zinc dipping solution, removing surface oxides of the aluminum part, and simultaneously replacing a layer of thin and dense zinc coating; (2) timely transferring the aluminum part after zinc immersion into a cyanide copper plating process, wherein the cuprous cyanide in a cyanide plating solution is high in content, and a work-piece is connected with a cathode of a power supply, carrying out flash plating for 1-2 minutes by using current which is 3-5 times greater than normal current, and then plating for 40-60 minutes at normal current; and (3) silvering after copper plating, electrifying and putting in a slot, impacting for 1-2 minutes by using current of 0.6-1.0A/dm<2>, and reducing the current to 0.3-0.4A/dm<2>. The coating obtained by the method disclosed by the invention is bright and silver in surface, and has fine crystal and uniform appearance.

Description

The method that Al and Alalloy is silver-plated
Technical field
The invention belongs to metal plating technique field, particularly relate to a kind of method that Al and Alalloy is silver-plated.
Background technology
Al and Alalloy is silver-plated, and its degree of difficulty is more silver-plated than copper piece much bigger, and its reason is:
(1) Al and Alalloy has very strong affinity to oxygen, and oxide on surface, once removing, can generate new uneven oxide compound rapidly, affect coating and matrix metal bonding force.
(2) standard potential of aluminium relatively more negative (-1.67V).When alumiaum article immerses containing other metal ion electrolytic solution, can replacement(metathesis)reaction be there is, be loosened, coarse coating.Have a strong impact on coating and matrix metal bonding strength.
(3) aluminium is amphoteric metal, and easy and soda acid reacts, and makes component corrosion, makes plating be difficult to carry out.
Therefore, must take to electroplate different treatment processs from routine, the good coating of bonding force could be obtained on aluminum products.
Summary of the invention
The invention provides a kind of method that Al and Alalloy is silver-plated, adopt the Deposit appearance that the inventive method obtains: surface-brightening silvery white, has careful crystallization and homogeneous outward appearance.
The method that Al and Alalloy of the present invention is silver-plated, is realized by following technical proposals:
(1) alumiaum article carries out chemical zincation in zincate solution, while removing alumiaum article oxide on surface, and the zinc layers that displacement one deck is thin and fine and closely woven;
(2) alumiaum article after soaking zinc should proceed to cyanide electroplating operation in time, and in cyaniding plating solution, cuprous cyanide content is higher, negative electrode of being connected with the mains by workpiece, with 3-5 times flash 1-2min larger than normal current, then under normal current, plates 40-60min;
(3) silver-plated after copper facing, charged lower groove, and with 0.6 ~ 1.0A/dm2, rush of current 1 ~ 2min, then be down to 0.3 ~ 0.4A/dm2.
Embodiment
Below by specific embodiment, the present invention is further illustrated.
1 electroless plated zinc and pre-treatment thereof:
The master operation of chemical zincation has:
Deoil conventional gasoline or clean containing the weak lye of tensio-active agent.
Remove except descaling and remain in piece surface dirt and oxide film, comprise caustic dip and bright dipping
Caustic dip specification
NaOH 50 ~100g/L
Temperature 60 ~ 80 C
Time 0.5 ~ 10.min
Low for surfaceness, the aluminum component that precision is high, should not remove oxide film containing in NaOH weak lye.Work
Specification is:
Na2CO3 20 ~30g/L
Na3PO4 50 ~70g/L
Temperature 70 ~ 80 C
Time 1 ~ 2min
The piece surface of removing oxide film has grey residue, should bright dipping in following solutions:
HNO4 500ml/L
HF 100ml/L
Temperature room temperature
Time 3 ~ 10s
(3) soaking zinc chemical leaching zinc process is in zincate solution, replaces the thin and fine and closely woven zinc layers of one deck, thus prevent oxide film again to generate while removing oxide on surface.Its mechanism is when the aluminum hardware processed is immersed in alkaline zincate, oxide film dissolves, and during AL3O3+2NaOH=2NaAlO2-H2O exposed out purified aluminum surface is heavy by octylate, zinc swaps out, and zinc and aluminium current potential are relatively, it is relatively slower that replacement(metathesis)reaction is carried out, so coating is dense.
Add iron trichloride in zincate solution, make in zinc layers by aluminium displace a small amount of iron, form zinc-iron alloy, its oxidation potential is smaller, is conducive to improving displacement layer and metal level bonding force, and erosion resistance is improved.
First be that Al2O3 dissolves just generation zinc precipitation during first time leaching zinc, therefore zinc-impregnating layer compares rough porous.Its first zinc-impregnating layer need be taken off in 1:1HNO3 and remove.Carry out second time and soak zinc, second time zinc-impregnating layer is even, fine and closely woven, good with basal body binding force, is suitable for aluminum and its alloy treatment before plating.
Chemical zincation liquid technological specification:
Caustic soda 500g/L
Zinc oxide 100g/L
Seignette salt 10g/L
Iron trichloride 1 ~ 2g/L
Temperature 15 ~ 27 C
Time 0.5 ~ 1.0min
Precaution:
Pharmaceutical chemicals used is chemical pure, and technical grade affects qualification rate.
Normal zinc immersion plating layer is Steel Gray or Dark grey, and uniform color is consistent, when occurring piebald, zinc film should be exited in 1:1HNO3 and again processing when color and luster is uneven.
Zinc immersion should use aluminium hanger, because different metal material potential difference is different, has impact to aluminium current potential, causes leaching zinc difficulty, makes contact point out coating decortication.
Note swinging part during leaching zinc, prevent part impact wreckage zinc layers.
2 Al and Alalloy copper facing
2.1 cyanide electroplating
Alumiaum article after leaching zinc should proceed to cyanide electroplating operation in time, for the copper-plated cyaniding plating solution of aluminum component, not containing NaOH and also cuprous cyanide content higher, immersing plating solution for preventing part in an instant causes zinc film to dissolve and copper contact precipitation, workpiece should to be connected with the mains negative electrode, with 3-5 times flash 1-2min larger than normal current, then under normal current, plate 40-60min.
Technological specification is as follows:
Copper hydroxide 60 ~ 70g/L
Sodium cyanide 20 ~ 25g/L
Sodium carbonate 30 ~ 50g/L
Seignette salt 60g/L
Sodium Thiocyanate 99 3 ~ 8g/L
Dk 0.4 ~0.6A/dm
t 40~55
3 Al and Alalloy are silver-plated
Silver-plated after copper facing, silver-colored current potential comparatively copper just, should prevent replacement(metathesis)reaction, notes charged lower groove, and with 0.6 ~ 1.0A/dm2, rush of current 1 ~ 2min, then be down to 0.3 ~ 0.4A/dm2
Technological specification
Silver chloride 25 ~ 35g/L
Potassium cyanide (dissociating) 35 ~ 45g/L
Salt of wormwood 30 ~ 80g/L
Dh 0.3~0.4A/dm2
T room temperature
Sedimentation speed 10 ~ 12.

Claims (1)

1. the method that Al and Alalloy is silver-plated, is characterized in that comprising the following steps:
(1) alumiaum article carries out chemical zincation in zincate solution, while removing alumiaum article oxide on surface, and the zinc layers that displacement one deck is thin and fine and closely woven;
(2) alumiaum article after soaking zinc should proceed to cyanide electroplating operation in time, and in cyaniding plating solution, cuprous cyanide content is higher, negative electrode of being connected with the mains by workpiece, with 3-5 times flash 1-2min larger than normal current, then under normal current, plates 40-60min;
(3) silver-plated after copper facing, charged lower groove, and with 0.6 ~ 1.0A/dm2, rush of current 1 ~ 2min, then be down to 0.3 ~ 0.4A/dm2.
CN201310246601.6A 2013-06-21 2013-06-21 Method for silvering aluminum and aluminum alloy Pending CN104233296A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201310246601.6A CN104233296A (en) 2013-06-21 2013-06-21 Method for silvering aluminum and aluminum alloy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201310246601.6A CN104233296A (en) 2013-06-21 2013-06-21 Method for silvering aluminum and aluminum alloy

Publications (1)

Publication Number Publication Date
CN104233296A true CN104233296A (en) 2014-12-24

Family

ID=52222169

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201310246601.6A Pending CN104233296A (en) 2013-06-21 2013-06-21 Method for silvering aluminum and aluminum alloy

Country Status (1)

Country Link
CN (1) CN104233296A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105463525A (en) * 2016-01-14 2016-04-06 深圳市瑞世兴科技有限公司 Aluminum-alloy silver plating method
CN108048883A (en) * 2017-12-04 2018-05-18 泰州康乾机械制造有限公司 Cast aluminium conductor silver-plated pre-treatment alkaline zinc-electroplating plating solution and its application method
CN108611668A (en) * 2016-12-12 2018-10-02 中国航空工业标准件制造有限责任公司 A method of improving cyanideless electro-plating zinc product presentation quality

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6257762B1 (en) * 1999-02-19 2001-07-10 General Electric Company Lead surface coating for an x-ray tube casing
CN102732922A (en) * 2012-06-13 2012-10-17 广州鸿葳科技股份有限公司 Cyanide-free zinc dipping solution and cyanide-free electroplating method of filter aluminium alloy by using the same
CN102943291A (en) * 2012-10-18 2013-02-27 中国电子科技集团公司第十研究所 Surface treatment method for weldability and protectivity of aluminium alloy tube shell

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6257762B1 (en) * 1999-02-19 2001-07-10 General Electric Company Lead surface coating for an x-ray tube casing
CN102732922A (en) * 2012-06-13 2012-10-17 广州鸿葳科技股份有限公司 Cyanide-free zinc dipping solution and cyanide-free electroplating method of filter aluminium alloy by using the same
CN102943291A (en) * 2012-10-18 2013-02-27 中国电子科技集团公司第十研究所 Surface treatment method for weldability and protectivity of aluminium alloy tube shell

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
王文忠: "铝及铝合金镀银", 《材料保护》, vol. 28, no. 5, 31 May 1995 (1995-05-31), pages 30 - 31 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105463525A (en) * 2016-01-14 2016-04-06 深圳市瑞世兴科技有限公司 Aluminum-alloy silver plating method
CN108611668A (en) * 2016-12-12 2018-10-02 中国航空工业标准件制造有限责任公司 A method of improving cyanideless electro-plating zinc product presentation quality
CN108611668B (en) * 2016-12-12 2020-05-05 中国航空工业标准件制造有限责任公司 Method for improving appearance quality of cyanide-free electrogalvanizing product
CN108048883A (en) * 2017-12-04 2018-05-18 泰州康乾机械制造有限公司 Cast aluminium conductor silver-plated pre-treatment alkaline zinc-electroplating plating solution and its application method

Similar Documents

Publication Publication Date Title
CN101525711B (en) Magnesium alloy with zinc and nickel compound plating layers and preparation method thereof
CN101643926B (en) Non-cyanide pre-plating copper plating solution
CN101638790A (en) Plating method of magnesium and magnesium alloy
CN1796609A (en) Technique for plating alnico in copper plate type of crystallizer of conticaster
CN102492968A (en) Copper plating method on brass base material
CN100999819A (en) Process of zine pressure casting non cyanogen alkaline immersion plating copper
CN103484909A (en) Pretreatment method for iron-based hardware electroplating
CN101922031B (en) Double-plating steel belt and plating process
CN105420770A (en) Color-change-preventing cyanide-free silver plating electroplating liquid and electroplating method thereof
CN105177650A (en) Nickel plating method of steel belts for steel battery shells
CN109957822A (en) Copper alloy electroplating technology
CN104233296A (en) Method for silvering aluminum and aluminum alloy
CN101781785A (en) Method for plating high corrosion resistant aluminum-manganese alloy on surface of magnesium alloy
CN107236977A (en) A kind of electroplating pretreatment process optimization method
CN1477237A (en) Brass-plating process in alkaline solution and its electroplating solution formula
CN104233416A (en) Method for electroplating zinc-nickel coating on magnesium alloy electroplate surface
CN1641075B (en) Magnesium and Mg alloy surface activating method and surface plating method
CN107245736A (en) A kind of auto parts and components electroplating technology
CN1058053A (en) The method of electroplating bright nickel on Nd-Fe-B alloy
CN103806033A (en) Method of electroplating metal layer on surface of zinc pressure casting
CN101857965A (en) Method for depositing zinc and zinc-nickel alloy on surface of magnesium alloy without cyanogen or fluorine
CN101634041B (en) Method and solution for electrogalvanizing surface of zinc alloy workpiece comprising blind hole
EP0030305B1 (en) Chemical pretreatment for method for the electrolytical metal coating of magnesium articles
CN105525319A (en) Method for treatment in electroplating process
KR20110125929A (en) Metal surface treatment method

Legal Events

Date Code Title Description
PB01 Publication
C06 Publication
SE01 Entry into force of request for substantive examination
C10 Entry into substantive examination
WD01 Invention patent application deemed withdrawn after publication

Application publication date: 20141224

C02 Deemed withdrawal of patent application after publication (patent law 2001)