CN1382833A

CN1382833A - Electroplating method with rotating hanger

Info

Publication number: CN1382833A
Application number: CN 02113377
Authority: CN
Inventors: 余泽玲
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-17
Filing date: 2002-02-17
Publication date: 2002-12-04

Abstract

An electroplating method with rotating hanger suitable for single metal, alloy and nano composite layer features that it integrates the merits of hanging plating and barrel plating. Its advantages are high thickness uniformity no burr, pit and pinhole on the plated layer, and high productivity.

Description

A kind of electro-plating method of hanger rotation

The present invention be adopt the hanger rotation make workpiece in coating bath by the up time direction or inverse time direction do from top to bottom rotation, its direction that suspends of periodic variation, thus obtain the electro-plating method of desirable coating.

In common plating, generally be according to the different shapes of plating piece and to the requirement of coating, select rack plating method or barrel plating method for use.And these two kinds of methods exist relative merits in use range.Conventional rack plating is because anodic area size and put positional factor, divide for negative and positive two interpolar power lines and bring defective, when plating piece and anodic relative position than fixedly the time, its electric force lines distribution can not change, and causes the coating became uneven.The solid impurity that exists occasionally in the plating bath can make coating produce burr particularly on the horizontal plane of plating piece when serious, coating produces pit when slight.The hydrogen of separating out when the horizontal surface area below the plating piece is big easily is trapped in its surface and forms pin hole.Particularly in nano compound electroplating, obtain certain content and the composite deposite of the differential that is evenly distributed, except the metal oxide that uses nano-scale and with it mutually the Recipe, the important condition of another one is the behavior of reasonably stirring.The normal at present alr mode that adopts has: pneumatic blending formula, mechanical agitation type, swing, the plating piece plane rotary type of negative electrode, and ultrasonic wave or Electromagnetically vibrating, circulating continuously or the like.Yet all these alr modes only play suspending and disperse micro mist and carry the effect of these micro mists to the negative electrode surface, when making micro mist that negative electrode absorption take place on negative electrode with metal ion generation codeposition formation composite deposite.This is the co-electrodeposition method that generally adopts in the present composite plating.Because micro mist is subjected to influence of gravity, both just under the ideal stirring state, can preferentially be deposited in equally on the horizontal plane of plating piece and makes its powder content be higher than the vertical surface of plating piece.Thereby in the composite plating of the co-electrodeposition method that only adopt to stir produces, micro mist exists macroscopic view inhomogeneous on distributing, thereby influences the function of composite deposite.

The electro-plating method that the purpose of this invention is to provide a kind of hanger rotation makes conventional rack plating also have the advantage of barrel plating.Be used for the plating of various single-layer metal coating and various alloy layer and nano-composite plate.Improve sedimentation velocity, eliminate burr pit, the pin hole of coating, guarantee that the coating thickness is even.Particularly guarantee the content and the uniform distribution of micro mist in the nano-composite plate.

The object of the present invention is achieved like this: rotary rack is that the mobile jib upper end is used for and extremely excellent location for hook, on mobile jib, be provided with drive unit, mobile jib combines with the workpiece frame and can make it by rotating mechanism to rotate, the workpiece frame is used for hanging workpiece, the permanent joint of peace one conductor wire and power supply is done sliding contact and is given workpiece with conduction of current on the workpiece edge, and hanger is pressed up time direction or the rotation from top to bottom of counter-clockwise direction do in coating bath.

In the plating of various elemental metals, alloyed metal and nanometer composite layer, along with the rotational workpieces of the hanger also direction and of suspending of conversion self periodically in the locus of coating bath, form a kind of motion that rotation and revolution are arranged simultaneously, improve electric force lines distribution with this, thereby reach the uniform purpose of coating thickness.Also play a part stirred solution in the time of the hanger rotation, thereby reduced the concentration polarization of cathode surface, current density allows to strengthen and the sedimentation velocity of raising coating.When there is granule foreign in plating bath, this particle only is deposited in the long slightly time on the horizontal plane of workpiece and forms burr, since workpiece suspend direction ceaselessly conversion the chance of particles settling on a certain position reduced, avoided the formation of burr, pit.In nano compound electroplating because of the workpiece conversion direction that suspends periodically, make the workpiece most surfaces all have the equal time to be the horizontal plane position, evenly be subjected to the sedimentation codeposition of micro mist and metal ion, the also collaborative simultaneously codeposition of having strengthened by the negative electrode absorption generation of micro mist, solved that micro mist deposits the very few contradiction that loses function on burr that the deposition of micro mist on the plating piece horizontal plane too much produces, coarse and the vertical surface, guaranteed to have in the composite deposite powder content and the uniform distribution of q.s.

The present invention has following advantage:

(1) adopts electro-plating method of the present invention, make rack plating combine the advantage of barrel plating, improve the deficiency that exists in the rack plating method commonly used in the past, can increase work efficiency, eliminate coating burr, pit, pin hole.Particularly in nano compound electroplating, avoided becoming in a long time the part of horizontal plane position, all there is the micro mist of same amount at the burr that causes because of too much micro mist deposition and coarse and each position of assurance work.

(2) rotary rack is made simply, and this electro-plating method is implemented only need use rotary rack instead and just can easily.Be suitable for all platings.

Embodiments of the invention are as follows:

(1) nickel plating technology: prescription and technological specification: 50-60 ℃ of current density 4-6A/dm of single nickel salt 250-300g/L nickelous chloride 35-50g/L boric acid 40-50g/L asccharin 0.6-1g/L butynediol 0.3-0.5g/L sodium lauryl sulphate 0.05-0.1g/L PH3.8-4.2 temperature ²Hanger speed of rotation 5-10 circle/min

The result: nickel layer is light entirely

(2) nano compound electroplating technology: prescription and technological specification, single nickel salt 250-300g/L nickelous chloride 35-50g/L boric acid 40-50g/L asccharin 0.6-1g/L butynediol 0.3-0.5g/L polyoxyethylene glycol or dodecane trimethyl ammonium chloride 0.1-0.5g/L

Micro mist: aluminium sesquioxide silicon-dioxide PTFE diamond (selecting wherein a kind of footpath grain for use) 40-50 ℃ of current density 4-8A/dm of 10-100g/L PH3.5-4.0 temperature at 10-200nm ²Mechanical stirring or pneumatic blending hanger speed of rotation 2-4 circle/min

The result: coating contains micro mist amount 5-15% sedimentation velocity 0.8-1.0um/min and adopts double-deck nickel/micro mist composite deposite combination, single stage method is without mechanical polishing, coating is light entirely, and coating total thickness 16-19um reached 9 grades in 24 hours through chromium plating 0.25um CACC test.

Claims

1. the electro-plating method of hanger rotation is characterized in that: hanger in coating bath by the up time direction or inverse time direction do from top to bottom rotation.

2. the electro-plating method of hanger rotation according to claim 1 is characterized in that: be used for the plating of various elemental metals, alloyed metal and nanometer composite layer.