JPS6036479B2 - Method of metal plating carbon fiber bundle or cloth - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of metal plating carbon formations, particularly carbon fibers or cloth, by electroless or electroplating.

Until now, when metal plating was applied to fibers in the form of a large number of single carbon fibers or woven fibers, the plating solution could not penetrate into the gaps between each single fiber, and the fiber bundles The carbon fibers near the center of the fiber cloth and the cross-joint parts of the fiber cloth are hardly plated, and the wettability of the metal plating to each carbon fiber is poor, resulting in insufficient adhesion and the metal plating peeling off easily. was.

In addition, in order to uniformize metal plating on carbon fibers or cloth, methods of immersing carbon fibers in aqueous solutions of solvents and surfactants are used to strengthen the plating during plating and to improve wettability. However, all of them were just imperfect metal plating.

Accordingly, an object of the present invention is to provide a method of providing a metal plating having a uniform thickness and good adhesion to a carbon fiber plate or cloth as described above.

In the method according to the present invention, when applying metal plating to a carbon formed product, in particular a carbon fiber or cloth made of a single fiber coated with a suitable sizing agent in advance, the carbon fiber or cloth is placed in air or an oxidizing atmosphere in advance. Perform a firing process, thereby
This is a plating method that makes it easier to unravel the carbon fibers during metal plating or between the carbon fibers that make up the cloth, making the thickness of the metal plating uniform and improving adhesion by improving curliness. More specifically, according to the present invention, a sizing agent or a sizing agent applied to increase the degree of concentration or bonding of carbon single fiber chicks by firing treatment in air or an oxidizing atmosphere, that is, in the presence of oxygen. The bonding agent is decomposed and then the carbon fiber itself is oxidized to cause roughening and activation of the single fibrous surface, thereby achieving uniform metal plating and dramatic improvement in adhesion.

Therefore, the firing processing conditions are very important, especially excessive firing will affect the properties of the carbon fiber itself and reduce the mechanical strength of the fiber or cloth, which will cause subsequent plating and post-processing. The workability of processing will be extremely deteriorated.

The firing treatment conditions are determined by the relationship between firing temperature and time, but based on various conditions, 200°C is the lower limit temperature, and if it is less than 200qC, sufficient uniformity and adhesion of metal plating cannot be obtained. The firing time also ranges from about 20 minutes to 200 minutes.

Practical methods for this firing treatment include leaving the material in a firing furnace for a predetermined period of time or passing it through a tube furnace at a predetermined speed. Any method to obtain it can be applied.

Next, the effects of the method according to the present invention will be explained by the following examples.

Example 1 Fiber East consisting of 300 single carbon fibers with an average diameter of 10 rm was treated with Hitachi Chemical HSIOIB type stock solution 6%, hydrochloric acid 32
%, in a catalyst aqueous solution having a liquid composition of 62% water at room temperature.
After soaking and crushing, it was thoroughly washed with water.

Next, after processing under the firing treatment conditions shown in Table 1, copper sulfate/pentahydrate 1/s, sodium ethylenediaminetetraacetate 3/s, formalli (30%) 10/s, hydroxide. A plated layer was formed by immersing it in an electroless steel plating solution with a solution composition of sodium 5/2 and a solution temperature of 50°C for 30 minutes, followed by sufficient water washing and drying. For the carbon fibers thus prepared, the uniformity of the plating thickness on the carbon fibers was determined using a cross-sectional microscope, and the adhesion and mechanical strength were determined using a bending test method. The judgment results are also shown in Table 1. Table 1○...Good △...
...Slightly inferior ×...Inferior As a result, the processing conditions that satisfy all three conditions, uniformity of plating thickness, adhesion, and mechanical strength, range from condition i to condition t, especially condition o.
, q and r.

Among these, in particular, the treatment temperature is 350 qo, the treatment time is 60~
FIG. 1 shows a cross section of the fiber east which was fired under treatment conditions q and r for 90 minutes. As shown in the figure, a copper laminate layer 2 of about 3 mm is uniformly formed around the carbon fiber 1 in the center, and the adhesion is also good. There was virtually no decrease in mechanical strength. Example 2 Carbon fibers made of 3,000 pieces of carbon fiber with an average diameter of loAm were fired in air at a treatment temperature of 350°C for a treatment time of 60 minutes to produce 5 g of cuprous cyanide/67 g of sodium cyanide. / In the evening, 1 female of sodium hydroxide was heated in an electric steel plating bath with the same bath composition for 3 minutes at a temperature of 50°C and a cathode current density of 4 A/d, while performing sufficient sea breaming. After plating, samples were prepared by thoroughly washing and drying, and the uniformity of plating thickness, adhesion, and mechanical strength were determined in the same manner as in Example 1. Both showed good characteristics.

As described above, according to the present invention, plating is performed after firing at a predetermined temperature and time as a pretreatment, so that the plating has a uniform thickness and good adhesion on each carbon single fiber lengthwise. It is possible to provide layers, and furthermore, it is possible to maintain mechanical strength equivalent to that of carbon fibers that have not been subjected to firing treatment.

Up to now, we have used carbon fiber east, which is made by concentrating carbon single fibers, as a sample, but compared to when plating carbon fiber cloth, this is because the area near the center of the east is the same as the outer twill. This was chosen because it is difficult to provide good plating, and it is clear that carbon fiber cloth can also be plated with good quality by a similar method. Furthermore, as is clear from the above description, the method according to the present invention can be applied to other formations such as single fibers, particles, chips, etc. as long as the material of the member to be plated is carbon.

Furthermore, although copper was used as the plating type in the above experiments, electroless plating uses nickel-phosphorous, cobalt-nickel-phosphorous, etc., while electroplating uses metals such as silver, nickel, gold, and tin. It will be easily understood that plating can be applied.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross section near the center of the carbon fiber plated by the method according to the present invention, observed under a microscope. 1... Carbon fiber, 2... Steel plating layer.

Claims (1)

[Claims] 1. A method for metal plating carbon fiber bundles or cloth, which comprises performing metal plating after firing a fiber bundle or cloth made of carbon single fibers coated with an appropriate sizing agent in an oxidizing atmosphere. . 2. The method of metal plating a carbon fiber bundle or cloth according to claim 1, wherein the firing treatment is performed at a temperature of 200° C. or higher. 3. The method of metal plating a carbon fiber bundle or cloth according to claim 2, wherein the firing treatment is performed for 20 minutes to 200 minutes. 4. The method of metal plating a carbon fiber bundle or cloth according to any one of claims 1 to 3, wherein the metal plating is performed by an electric plating method. 5. The method of metal plating a carbon fiber bundle or cloth according to any one of claims 1 to 3, wherein the metal plating is performed by an electroless plating method.