JPS6214031B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a surface treatment method,
More specifically, the present invention particularly relates to a surface treatment method for a tape guide member.

Conventionally, tape guide members such as capstans used in audio and video equipment have been treated by mechanical methods such as sandblasting, liquid honing, and ceramic coating, or by chemical methods such as etching. Mechanical methods are easy to operate, but problems arise in maintaining a constant surface roughness and in keeping the roundness below 0.5 μm, which is considered not to cause distortion in the sound. As for the etching method, which is a chemical method, it is known that a ferric chloride solution is used as an etching solution. When the material was etched to a certain extent, the intergranular corrosion of the material was severe, and rust easily occurred in the salt spray test (JIS-Z2301). In addition, when assembled into a tape recorder and used, the tape could be driven stably at the beginning of use, but as the usage time increases, the surface roughness changes due to friction with the tape and the initial characteristics are maintained. I couldn't do it anymore.

Therefore, the present invention provides a new surface treatment method that can improve the various drawbacks of the prior art.

The surface treatment method according to the present invention comprises surface treating a tape guide member with an etching agent containing nitrophenols represented by the following general formula, alcohol, and hydrochloric acid as main components.

The nitrophenols contained in the etching agent used in this invention have the general formula: (In the formula, R ₁ , R ₂ and R ₃ are all hydrogen atoms or NO ₂ groups, and at least one of them is
(one is always NO ₂ ). These nitrophenols are approximately 1
It is preferable to use it in the range of g/ to 20 g/.

Furthermore, examples of the alcohols used include methyl alcohol and ethyl alcohol. Conveniently, the amount used is about 500 c.c./950 c.c./. Furthermore, the hydrochloric acid used is approx.
It is best to use it within the range of 0.01 to 2.

Etching agents that can be used include:
In order to lower the surface tension of the treatment liquid, additives such as carboxymethyl cellulose and carboxyethyl cellulose can be added as surfactants and viscosity modifiers. It is convenient to use the surfactant and viscosity modifier in an amount within the range of about 0.01 to 1 g/g.

Among the etching treatment conditions in the method according to the present invention, the etching temperature is not particularly limited, but is preferably within the range of about 10°C to 50°C. Further, the etching treatment time is not particularly limited, and can be appropriately selected depending on the degree of surface roughness caused by etching, but generally it is about 10 seconds to 20 minutes, preferably. It may be for 30 seconds to 5 minutes.

The method according to the present invention is particularly suitable for surface treatment of tape guide members such as capstans, and the tape guide members treated as described above have good roundness and stable surface roughness. are doing. Furthermore, grain boundary corrosion is significantly less than when treated with an etching agent containing ferric chloride as a main component, and good results can be obtained in the salt spray test. Further, when the tape guide member processed according to the present invention is assembled into a tape recorder to drive the tape, it can maintain its initial characteristics even if it is continuously run for a long time.

Hereinafter, this invention will be explained in detail with reference to Examples.

Example After removing oil and fat from a stainless steel cylindrical tape guide member containing 10% or more of Cr with trichloride, it was treated with 10 g of picric acid/
Etching treatment was performed by immersing it in a solution consisting of 0.6 NHC and about 950 c.c. of ethanol at 25° C. to 30° C. for 2 minutes, and a tape guide member having a surface roughness of about 1 to 3 μm was obtained.

When the surface of this surface-treated tape guide member was observed using a scanning electron microscope, it was found that intergranular corrosion was significantly less in the case of ferric chloride. Good results were also obtained in the salt spray test according to JIS-Z2301. Furthermore, in a continuous tape running test in which this member was incorporated into a tape recorder, its initial characteristics did not change even after more than 1,500 hours had passed.

Comparative Example In the same manner as in the example, the surface was treated with a 40° Baumé ferric chloride aqueous solution. After 50 hours, the component thus obtained had almost doubled its initial properties, especially its wow and flutter.

Claims (1)

[Claims] 1. General formula: _{Nitrophenols , alcohols and _} A surface treatment method comprising surface treating a tape guide member with an etching agent containing hydrochloric acid as a main component.