JPH05339782A - Partial plating method for planar body and mask jig therefor - Google Patents

Abstract

PURPOSE:To provide a partial plating method for a planer body by which the smooth and sure partial plating is available and the damage of non-plated parts is prevented without using a mask agent and a mask jig therefor. CONSTITUTION:A non-plated part 4 inside the mask jig 10 is protected and not plated and the damage of the non-plated part 4 due to external force is prevented, as well by surrounding the non-plated part 4 of a strap 1 in the non-contact state by the mask jig 10, fitting the strap 1 to the mask jig 10 and partially plating the strap 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of partially plating a plate-like body such as a strap which constitutes a support grid of a fuel assembly and a mask jig used therefor.

[0002]

2. Description of the Related Art Generally, a support grid of a fuel assembly is formed by crossing a plurality of thin strip straps, and the crossing portions are joined by brazing. Then, in order to braze the intersection of the straps well, it is desirable to perform Ni plating by electroplating. On the other hand, if Ni adheres to the contact portion (spring, dimple portion) of the strap with the fuel rod, it causes embrittlement due to local hydrogenation of the fuel cladding tube.
The attachment of i must be suppressed as much as possible. Therefore, when Ni plating is applied to the strap, it is necessary to perform partial plating in which only the brazed portion is plated.

[0003]

By the way, conventionally, when partial plating is performed by electroplating, it is generally performed in a state where the non-plated portion is covered with a masking agent applied or pasted on the non-plated portion. Is. However, in this case, when the mask agent is removed after the plating process, it is necessary to confirm that Si, B, etc. contained in the mask agent are completely removed. In addition, the spring part of the strap is easily deformed, and it is undeniable that excessive force may be applied during the application, application, or removal of the mask agent, resulting in deformation. There is a problem that has to be. Therefore, the present inventors
As a result of diligent studies, in electroplating, in general, flat surfaces and convex portions have a high current density and are easily plated.
Focusing on the fact that the recesses and the inner surface of the tube have a low current density and are difficult to be plated, it was confirmed that the inner surface of the tube is hardly plated except for the inlet.

The present invention has been made on the basis of the above-mentioned findings. The object of the present invention is to enable partial plating to be carried out smoothly and reliably without using a masking agent, and the non-plated part can be plated. It is an object of the present invention to provide a method for partially plating a plate-like body that can prevent damage and a mask jig used for the method.

[0005]

In order to achieve the above object, the first aspect of the present invention relates to a mask jig which surrounds a non-plated portion of a plate-shaped body in a non-contact state so that the plate-shaped body is detached. The plate is freely attached, the plate is plated, and then the plate is removed from the mask jig. According to a second aspect of the present invention, there is provided a mask jig which surrounds a non-plated portion of a plate-shaped body in a non-contact state, wherein a slit having the plate-shaped body sandwiched therein is formed in a tubular body. Further, according to a third aspect of the present invention, the cylindrical body has a two-layer structure, and the outer layer portion thereof is formed of an insulating material and the inner layer portion thereof is formed of a conductive material.

[0006]

In the method of partially plating the plate-shaped body of the present invention,
The non-plated portion of the plate-shaped body is surrounded by the mask jig in a non-contact state, and the plate-shaped body is attached to the mask jig for partial plating, so that the non-plated portion in the mask jig is protected and plated. Also, the non-plated portion is prevented from being damaged by an external force. Further, in the mask jig of the present invention, by sandwiching the plate-shaped body in the slit formed in the cylindrical body, the non-plated portion of the plate-shaped body is completely housed and protected in the cylindrical body, The plate-like body is easily engaged with and disengaged from the tubular body before and after the plating process. Further, according to claim 3 of the present invention, the outer surface of the tubular body is not plated by the insulating material forming the outer layer portion of the tubular body, and the current density between the tubular bodies is increased. As a result, the plating portion requiring plating is intensively plated, which contributes to increase the plating thickness.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 and 2 show an example of a mask jig of the present invention to which the strap shown in FIG. 3 is attached. In these drawings, the strap 1 in the shape of a thin plate is formed on both sides in the lateral direction thereof. Dimples 2 arranged in rows are formed on both sides (upper and lower ends in FIG. 3) so as to project in one direction,
A spring 3 is formed between these row-shaped dimples 2 so as to protrude to the other side. A slit 5 is formed between the non-plated portion 4 composed of the pair of dimples 2 and the spring 3, and the slits 5 of the straps 1 orthogonal to each other are fitted to each other to form an intersecting portion (plated portion). ) 6 is configured.

A mask jig 1 which engages with the strap 1.
0 indicates that the base of a large number of tube-shaped tubular members 11 arranged so as to correspond to the intervals between the springs 3 is the support plate 12
, And the slits 13 are formed on the tip end side of these cylindrical bodies 11 to form a half-split shape. Further, as shown in FIG. 2, each of the cylindrical bodies 11 has an insulating material 11b applied to the outer surface of a conductive material 11a. Then, with the tubular bodies 11 of the mask jig 10 aligned with the non-plated portions 4 of the strap 1, the tubular bodies 1 are
The strap 1 is inserted into the slit 13 of 1. Thereby, the tubular bodies 11 are attached so as to surround the non-plated portion 4 of the strap 1 in a non-contact state. Then, as shown in FIG. 4, when a plurality of mask jigs 10 to which the strap 1 is attached are assembled,
By immersing in the i-plating bath 20 and electroplating, only the plated portion 6 of the strap 1 (within a width range of about 5 mm indicated by a in FIG. 5) is Ni-plated. In this case, in the non-plated portion 4 of the strap 1 housed in the tubular body 11, since the current density in the tubular body 11 is low, it is not easily plated and the dimple 2
Also, the adhesion of Ni to the spring 3 can be significantly suppressed. Further, since each of the cylindrical bodies 11 is formed by applying the insulating agent 11b to the outer surface of the conductive material 11a,
The outer surface of the cylindrical body 11 is prevented from being plated,
As a result, the current density between the tubular bodies 11 is increased, the plating process of the brazing part (plating part) 6 requiring plating is promoted, and the plating thickness of the plating part 6 is further increased. be able to. The strap 1 thus obtained was measured for plating thickness using a fluorescent X-ray film thickness meter. As a result, the thickness of the non-plated portion 4 was 0 to 0.04 μm, while the thickness of the plated portion 6 was about 0 to 0.04 μm. A plating thickness of 0.9-2.3 μm was obtained.

[0010]

As described above, according to the first aspect of the present invention.
Is attached to a mask jig that encloses the non-plated portion of the plate-like body in a non-contact state, the plate-like body is detachably attached, the plate-like body is plated, and then the plate is removed from the mask jig. Since the plate-shaped body is removed, the non-plated portion of the plate-shaped body is surrounded by a mask jig in a non-contact state, and the plate-shaped body is attached to the mask jig to perform partial plating. It is not necessary to use a masking agent, the non-plated part in the mask jig is not protected and plated, and smooth and reliable partial plating can be performed. Can prevent damage. Further, a second aspect of the present invention is a mask jig that surrounds a non-plated portion of a plate-shaped body in a non-contact state, and a slit is formed in the tubular body to sandwich the plate-shaped body. ,
By sandwiching the plate-like body in the slit of the cylinder-like body, the non-plated portion of the plate-like body can be completely housed and protected in the cylinder-like body, and the plate-like body with respect to the cylinder-like body before and after the plating process. Can be easily engaged and disengaged. Further, according to claim 3 of the present invention, the tubular body has a two-layer structure, and the outer layer portion is formed of an insulating material and the inner layer portion is formed of a conductive material. The insulating material forming the portions can prevent the outer surface of the tubular body from being plated, and can increase the current density between the tubular bodies, and only the plated portion requiring plating can be The plating can be intensively performed, and the plating thickness can be further increased.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a perspective view showing an example of a strap.

FIG. 4 is an explanatory diagram showing a state of being immersed in a Ni plating bath.

FIG. 5 is a front view showing an example of a partially plated strap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Strap 4 Non-plated part 10 Mask jig 11 Cylindrical body 11a Conductive material 11b Insulating agent (insulating material) 13 Slit

Claims (3)

[Claims] 1. A mask jig that encloses a non-plated portion of a plate-shaped member in a non-contact state, the plate-shaped member is detachably attached, and the plate-shaped member is subjected to a plating treatment, and then the mask treatment is performed. A method for partially plating a plate-shaped body, comprising removing the plate-shaped body from the tool. 2. A mask jig which surrounds a non-plated portion of a plate-shaped body in a non-contact state, wherein a slit is formed in the cylindrical body for sandwiching the plate-shaped body. 3. The mask jig according to claim 2, wherein the tubular body has a two-layer structure, the outer layer portion of which is made of an insulating material and the inner layer portion of which is made of a conductive material.