JPS6026834B2 - Outer blade for electric razor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an outer blade for an electric shaver that has excellent cutting properties and suppresses changes in metallographic structure at high temperatures.

Generally, outer blades for electric razors are made from an electrolytic solution containing nickel ions by the box method, by adding an organic brightener containing sulfur atoms, such as saccharin or sodium naphthalene trisulfonate, to the electrolytic solution. It imparts surface gloss to the formed outer blade and reduces internal stress to prevent peeling and deformation during deformation.

The use of such organic brighteners generally increases the hardness of the outer cutter, which has the advantage of preventing wear due to sliding of the opposing cutter (inner cutter). It has the disadvantage that it is susceptible to damage such as cracks and cracks due to strong impacts and is inferior in safety during use.

Through intensive studies by the inventors, an outer cutter made of a nickel-cobalt alloy electrodeposited material formed by impregnating an electrolytic solution containing nickel ions with cobalt ions and an inorganic brightener was found to be better than the conventional outer cutter. It has already been found that it has good balling properties.

In this existing outer cutter, instead of the conventional organic brightener containing sulfur atoms, the outer cutter has the same function as this brightener, that is, the function of imparting surface gloss and the function of reducing internal stress required for the outer cutter. By using an inorganic brightener with a Since the above-mentioned inorganic brightener has almost no function of increasing the hardness of the outer blade, the hardness is improved by incorporating cobalt ions into the electrolyte to form a nickel-cobalt alloy electrodeposit.

However, as is clear from the relationship between the cobalt atom content in the alloy electrodeposit and the Vickers hardness and elongation determined by the Eriksen test as an evaluation of rutting property shown in Table 1 below, if the cobalt atomic content is too high, rutting may occur. There is a certain point where the properties of the inorganic brightener gradually deteriorate and the inorganic brightener's function of reducing the internal stress of the outer blade can no longer be maintained.

Table 1 According to experiments conducted by the inventors, it has been recognized that the elongation by the Eriksen test requires at least two sides due to the rotational speed and hardness of the opposing blade. The content is usually 5% by weight in the total alloy.
It is preferable that the amount is as follows, and it has been found that within this range, the function of removing internal stress can be sufficiently maintained.

The present invention was made based on the above knowledge, and in subsequent research, it was discovered that when this type of alloy electrodeposit is brought to a high temperature, a thermal change occurs in the alloy microstructure, and this thermal change is greatly affected by the cobalt atomic content. This was done based on the finding that changes in the tissue structure can be suppressed by limiting the value to a specific range.

Figure 1 is an enlarged photograph (approximately 1,000x magnification) showing the cross-sectional structure of an outer blade made of a nickel-cobalt alloy electrodeposited material with a low amount of cobalt, for example, about 10 to 2% by weight.
Figure 1B is a photograph of the fractured surface of a piece that cracked during a practical test in which the above outer cutter was actually slid against a counter cutter for a certain period of time. A cross-sectional photograph of the object, FIG. 1C, is a cross-sectional photograph of the object before such practical tests and heat treatment. This figure shows that the cross-sectional structure changes during the practical test or heat treatment, and since the changes after the practical test and after the heat treatment are very similar, the cracking during the practical test is mainly due to this change in the microstructure. In addition, it can be seen that the thermal influence of sliding heat becomes noticeable at around 230 qC on the outer cutter made of the nickel-cobalt alloy electrodeposited material having a low cobalt atom content as described above.

FIG. 2 shows several types of nickel-cobalt alloy electrodeposit with Vickers hardness in the range of 450 to 550, which were formed in the presence of an inorganic brightener in the present invention, at 25 and 0.0, respectively. The graph shows the relationship between the amount of decrease (amount of change) in Vickers hardness and the cobalt atom content before and after the heat treatment, with the structural change due to this heat treatment being understood by the change in hardness.

As is clear from the figure, as the cobalt atom content increases, the amount of decrease in Vickers hardness decreases and thermal changes in the microstructure are suppressed. Approximately 29 degrees, then 35~
At 45% by weight, the decrease is suppressed to about 20-40%.

Figure 3 shows the relationship between actual Vickers hardness and cobalt atom content after heat treatment, and it shows that products with cobalt atom content exceeding 3% by weight can be used as outer blades for electric razors even after heat treatment. It can be seen that those with a Vickers hardness of 35% by weight or more have a Vickers hardness of around 480, which is sufficiently satisfactory for practical use, and the amount of decrease in Vickers hardness is very small.

As described above, the present invention is a nickel-cobalt alloy electrodeposited material formed by a turtle deposition method from an electrolytic solution containing nickel ions and cobalt ions and an inorganic brightener added thereto. By setting the cloud amount% to 35 to 5% by weight, preferably 35 to 45% by weight, it has improved porosity, and even at a high temperature of 250°C, there is little thermal change in the tissue structure and a decrease in hardness is suppressed. An outer blade for an electric razor was obtained.

The electrolytic solution applicable to the present invention includes various types of electrolytes known in the art, and representative ones include Watt's type and sulfamic acid type.

Typical inorganic brighteners added to this electrolyte include nickel formate and magnesium sulfate.

The amount of brightener used varies depending on the type of brightener, but for example, it is sufficient to use nickel formate in an amount of usually 10 days/Z or more, and magnesium sulfate in an amount of 30 days/Z or more.

Further, an appropriate cobalt salt depending on the type of electrolytic solution is added to and dissolved in such an electrolytic solution, so that cobalt ions are included in the electrolytic solution.

As an example, Fig. 4 shows the additive reef U combination of cobalt sulfamate (percentage of the total amount with nickel sulfamate) in a sulfamic acid bath with constant electrodeposition conditions such as current density, electroplating time, and rope conditions. This figure shows the relationship with the cobalt source content in the alloy electrodeposit.As is clear from the figure, the cobalt source content in the alloy electrodeposit depends on the ratio of cobalt ions to nickel ions contained in the electrolyte. do. Therefore, in the present invention, when obtaining various forms of outer blades for electric razors from the above-mentioned electrolytic solution using a known electrodeposition method, first, the copalty in the electrolytic solution,
By appropriately setting the on-ratio and variously changing the current density, oxidation conditions, etc., the cobalt atom content of the resulting outer cutter can be adjusted to a desired ratio.

Next, the outer cutter for an electric shaver of the present invention will be specifically described based on examples.

Examples Nickel sulfamate 400 / Cobalt tough mate 45 Nickel bromide
3 Boric acid
40″ Nickel Formate 25
``Formalin 2'' / Surfactant 3 PH
4.0 common warmth
50~55℃ current density
6A/d〆A nickel-cobalt alloy electrodeposited product with a thickness of 120 cm and a cobalt atomic weight of 40 wt. % outer blade for electric razor was obtained.

When forming such an outer cutter, we changed the addition ratio of cobalt sulfamate in the electrolytic solution (percentage of the total amount with nickel sulfamate) and investigated the relationship between this addition ratio and the cobalt atom content of the resulting outer cutter. , as shown in FIG.

In addition, the Eriksen test (JISZ-2247) was used to evaluate the initial Vickers hardness and toughness of various electric razor outer blades with different cobalt atom contents obtained in this way.
The results of the examination of the elongation due to the above-mentioned conditions were as shown in Table 1 above.

Furthermore, each outer cutter is 250qo and 0. The hardness difference before and after the heat treatment was taken as the amount of decrease in hardness, and the relationship between this amount of decrease and the cobalt content is shown in FIG.

In addition, the relationship between the hardness after heat treatment and the cobalt atom content was
Shown in the figure. Next, an outer blade made of a nickel-cobalt alloy electrodeposit containing 10% by weight of cobalt atoms was formed in the same manner as described above. When a practical test was conducted by sliding this outer cutter against an opposing cutter for a certain period of time, cracking occurred during the test.

A photo of the fractured surface of the outer blade where this crack occurred, showing 23 pieces of the same type of outer blade.
The cross-sectional photograph of the specimen heat-treated at 0 qo and the cross-sectional photograph before heat treatment are as shown in FIG. 1 A, B, and C, respectively. For reference, an outer blade for an electric razor made of nickel alone was obtained in the same manner as in the example using the following electrolyte and packaging conditions. Vickers hardness was 540.

Further, when this outer cutter was heat treated at 230oC for 30 minutes and the Vickers hardness after the heat treatment was examined, cracks occurred during hardness measurement. Reference example Nickel sulfamate 450/Nickel bromide 3 Boric acid
40 〃Naphthalene trisulfonic acid sodium 20 〃2butyne 1,4 diol
0.1″pH
4.0 rating
50-55q0 current density
ship/d elbow

[Brief explanation of drawings]

Figures A, B, and C are enlarged photographs showing the cross-sectional structure of an outer cutter made of a nickel-cobalt alloy electrodeposit with a cobalt atom content of 1% by weight after a practical test, after heat treatment, and before heat treatment (magnification: approximately 1,000 yen). Figure 2 is a characteristic diagram showing the relationship between the amount of decrease in Vickers hardness and the cobalt atomic content when the outer blade for an electric razor of the present invention is heat treated at 250 oo.
Figure 3 is a characteristic diagram showing the relationship between the Vickers hardness and cobalt atom content after the above heat treatment, and Figure 4 shows the relationship between the proportion of cobalt salt in the electrolyte and the cobalt atom content of the outer cutter obtained from this. It is a characteristic diagram. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A nickel-cobalt alloy electrodeposit formed by an electrodeposition method from an electrolytic solution containing nickel ions and cobalt ions and an inorganic brightener added thereto, wherein the cobalt atomic content is completely eliminated. An outer blade for an electric razor, characterized in that the proportion of the alloy is 35 to 50% by weight. 2. The outer cutter for an electric razor according to claim 1, wherein the cobalt atom content is 35 to 45% by weight in the total alloy. 3. The outer blade for an electric razor according to claim 1 or 2, wherein the inorganic brightener is selected from nickel formate and magnesium sulfate.