CN1089312A - A kind of electrode that is used for electrophoretic deposition - Google Patents

Abstract

Be used for carrying out a kind of electrode of electrophoretic deposition, comprise the cylindrical tube or the real core right cylinder of conduction, it is characterized in that only its exterior side surfaces applies with insulation compound, just except the one or more annular region of coated object on the electrical conductor surface.

Description

A kind of electrode that is used for electrophoretic deposition

The present invention relates to be used for carrying out on the electrical conductor surface a kind of electrode of electrophoretic deposition.

Known metal object (or being electrical conductor at least) go up the electrophoretic deposition plastics for example varnish be on the position of an electrode by above-mentioned object being placed on direct supply, another electrode is connected with another line end of the direct supply of suitable shape, and above-mentioned electrode is placed in the electrophoresis bath.

Problem to be solved is the settling that obtains thin layer, and general thickness is 2-20 μ m, and settling should be even as much as possible on coated body surface.

Have turning axle at object, drum for example is with an end and require under the surface applies within it the situation, by prior art, the electrode of one conduction is arranged on the turning axle of above-mentioned object, preferably adopts the conduction cast of real core cylinder type or ring section, and coaxial with above-mentioned object.But fringing effect produced near the edge in the hole of object institute's deposition greater than surperficial rest part a kind of like this result of sedimentary amount.

The applicant has been found that, in order to obtain the more settling of uniform thickness,, and be to crack in a place or the place more than the place of the annular section of e at width with the electrode coated fully outer surface of an insulation layer, reach several mm and width e is extensible, so that expose the surface of electrical conductor.The seams this or these incisions of configuration are facing to wanting coated object.

The width of every seam is preferably between the 0.5-3mm, particularly about 1mm.

Find that after test the equipotential line of electric field that puts on coated surface is approaching more evenly, the thickness of coating is just even more so.

Term evenly is and the equidistant basically meaning of axle that the axle that promptly arrives coated surface is the distance of 7%-90% near being interpreted as.

The result can accurately be done by the method for calculation of determining equipotential line by the accurate mensuration of the position in the definite slit of experience to make, for example to the method for finished part, be the most approaching place (initial surface of coated metal object is to be represented by an equipotential plane of " construction ") on coated surface, this surface is that the bus of the object of Any shape rotates formed surface around one.The equipotential line of various measurements determination makes determines that optimum shape becomes possibility.

Therefore, corresponding device thereof is to be made of a conductive electrode real core or the tubular cylinder bodily form, and the exterior side surfaces of this electrode applies with the insulating coating, just except one or several annular region of the minimum width relevant with coated object.The width of each annular region is preferably between the 0.5-3mm less than several mm, usually near 1mm.Their number is less than or equal to 3 usually.

Though the electrode of the present invention that is directed to substantially of description here and example uses at axial location, but, outer position at the exterior coating of object also can use electrode of the present invention, and the object (for example container of square or square-section) of any symmetry rotation particularly needn't be arranged.

The present invention will more clearly be understood by go through the following embodiment that describes in Fig. 1-3.

Fig. 1 is the semisectional view of device, and the resin electrophoresis is deposited on the internal surface of an employed container body in the example 1; Size is represented with mm.

Fig. 2 represents the part of a finished container body (B) of the geometrical shape of example 1 and electric configuration, the equi-potential curve of the semisectional view of measuring with computer software, and this container body is that ideal is cylindric, has one flat, as shown in the figure.The equidistant of equipotential line is 20V.

Fig. 3 is the equi-potential curve of the semisectional view of the geometry of example 1 and electricity condition, and electrode has two slits that 1mm is wide, and container body B is that ideal is cylindric, and have one flat, as shown in FIG..

Example 1

Diameter is that 65mm applies with high container (1) for aluminium 3004 alloys of 125mm (using the trade mark of aluminium association regulation), use the hollow edged electrode (2) that does not have coating on the one hand, external diameter 1.4 * the internal diameter 10 of electrode * high 100mm, use identical electrode on the other hand, outside at electrode applies with the thick polymer insulation coating (3) of 3mm, the 40mm place, bottom of distance electrode is provided with the wide slit of 1mm.

Mode of deposition is as follows:

Container (1) is connected with the anode (+) of the direct supply of 200V, and electrode (2) links to each other with the other end of power supply.Insert bathe based on the anaphoresis varnish of epoxy in (the flow rate 10g/L in the water, PH are 7.7, electric conductivity 1.76ms/m and maintain 30 ℃), feed pulsed current: 50ms has electric current, and+20ms does not have electric current, continues to handle for 7 seconds.

The gained test-results is as follows:

Mean thickness: 4 μ m

Fluctuation relatively: 8%

" fluctuation relatively " meaning of term thickness is:

(100 * (maximum ga(u)ge-minimum thickness))/(mean thickness)

And mean thickness is:

(maximum ga(u)ge-minimum thickness)/2

Or

Or

H(x wherein) or hn be local thickness (local thickness).

Kind electrode has all found application under all electrophoretic coating situations, and the relative fluctuation of thickness remains on＜and 10%.

Claims (9)

1, is used for a kind of electrode that electrophoretic deposition is carried out on the electrical conductor surface, the cylindrical tube or the real core right cylinder that comprise conduction, it is characterized in that only its exterior side surfaces applies with insulation compound, just except the one or more annular region of coated object.

2, by the electrode of claim 1, it is characterized in that the number of annular region is less than or equal to 3.

3, by the electrode of claim 1 or 2, the width that it is characterized in that one or several annular zone is between 0.5-3mm.

4, by the electrode of claim 3, it is characterized in that the width of one or several annular zone is about 1mm.

5, by the electrode of claim 1-4, it is characterized in that the position of one or several annular zone is determined by means of the equipotential line trace.

6, by the electrode of claim 5, it is characterized in that at least one equipotential line is positioned at apart from axle a distance, this distance for want coated object surfaces spool apart between the 70%-90%.

7, the method that is used for the electrophoretic deposition electrode by a kind of acquisition of one of claim 1-6 is characterized in that the exterior side surfaces of solid cylinder or pipe is covered with insulation compound; One or more annular regions are cut off this coating; Remove the ring or a plurality of ring that slice off.

8, by the method for claim 7, the width (e) that it is characterized in that one or more annular zonees is between the 0.5-3mm.

9, by the method for claim 1, it is characterized in that the width of one or more annular zonees is about 1mm.

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