JPS6021237B2 - damping material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a material for highly attenuating vibrations and the like.

The present inventors previously proposed a material with a depth of 5
We have proposed an invention that dramatically improves the damping capacity of materials by creating a large number of willow cracks with a crack clearance of 0 to 200 rm, a crack clearance of 5 mm or less, and a spacing between cracks of 0.1 to 5 mm.

However, in order to generate a large number of cracks on the surface of this damping material, not only the material is limited, but the method for producing it is also subject to many limitations. For this reason, although there are many materials that appear to be advantageous from the standpoint of cost, mechanical properties, and chemical properties,
At present, it is difficult to generate many cracks on the surface. Furthermore, in the method proposed earlier, it may be difficult to maintain a constant crack depth. Moreover, when used under high stress, it is increasingly seen that the cracks created in advance become the starting point for the material to break.
The present invention has been made to solve the above-mentioned problems, and is characterized by forming a plating layer on the surface of the material and causing cracks in the plating layer. The size of the crack depends on the plating layer, but the approximate depth is 10 to 100.
0rm, crack clearance: 0.1 to 10 m, and interval between cracks: 0.1 to 5000 mm.

The lower limit value of depth (loAm) affects the attenuation ability, below which the attenuation effect decreases, and the upper limit value (1000
1m) is a value that depends on the method of forming the plating.

In addition, the lower limit of the crack clearance (0.1 m) is a value that is inevitably generated, and the upper limit (10 rm) is that if the clearance is larger than this, the damping effect will be small for minute vibrations of the damping material. It is a value. Lower limit of interval between cracks (0
．． 1mm) is a value that is restricted from the manufacturing perspective, and the upper limit value (
5000 m) affects the damping effect, and above this value the damping effect decreases. The present invention will be explained in detail below.

The plating layer to be formed on the surface of the material must have a thickness of several tens to several layers, and suitable methods for this purpose include hot-dip plating, thermal spray plating, and electroplating.

The method for generating cracks in the plating layer produced by these methods is as follows. (i) A method that utilizes the internal stress of the plating layer.

It is generally known that when a material is plated with a plating material that has a large lattice constant, a significantly large tensile residual stress is generated in the plating layer, and this stress is used to create numerous hexagonal-shaped cracks in the plating layer. generate. The stress can be increased by appropriately selecting the plating material, plating conditions, plating thickness, and the like. In this case, if the surface of the material is processed to provide protrusions with a small curvature, the tensile stress of the plating layer attached to the surface of the protrusions will further increase due to the curvature, resulting in clear cracks. . Furthermore, after forming a thin plating layer on the surface of the material, bending the material causes many cracks.

If plating is continued thereafter, epitaxial growth will be less likely to occur at the cracked location, making cracks more likely to occur. It is also effective to perform porous plating by changing the sacrifice during plating. Alternatively, hydrogen may be occluded in the plating layer by an electrolytic method to increase the internal stress of the plating layer, and then an external force may be applied to cause cracks.

(ii) A method of applying external force to the plating layer.

A large number of cracks can be generated on the surface of the material by forming a plating layer using a method similar to the above item (i), bending the material as necessary, and then subjecting it to shot peening.

(iii) A method in which after alloy plating or multilayer plating is performed, phosphorous annealing is performed to generate cracks as the composition is likely to cause cracks.

After the surface of the material is plated with a multilayer of Cr and Ni, for example, it is carburized, followed by diffusion sintering and sensitization treatment, followed by a known intergranular corrosion treatment.

Further, after the surface of the material is plated with an alloy of Ni and Sn, thermal shock is applied. In this way, many cracks can be generated in the plating layer on the surface of the material. Next, examples of the present invention will be described.

{Protrusions with a height of 1 column, a width of 0.5 mm, and a curvature of 0.250 at the tip are formed in stripes at intervals of 3 fences by machining on the surface of a 1'S3 length board (thickness 3 side). .

After that, hard chrome plating with a thickness of 0.5 mm was applied using a known method, and the surface of the plating layer had a depth of about 0.5 mm.
Many microscopic cracks in the ribs occurred. ■ After forming a plating layer on the surface of the material in the same manner as in [1] above, shot peening was applied to the surface of the plating layer for 5 minutes. Many cracks occurred.

'3} Cr on the surface of 1$r stainless steel (3 mm thick)
After plating was applied to a thickness of 0.2, two layers of Cr and Ni plating were applied alternately to give a total thickness of 0.2.

Next, C powder was applied to this surface, and heat treatment was performed by air cooling at 1100 qo×water r and furnace cooling at 650° C.×r. Further, this material was subjected to intergranular corrosion for 2 hours in a solution of 10% 4S04 and 10% C ship 04. As a result, many fine cracks (depth 0.2 bars) were generated on the surface. ■ Hard chrome plating on the surface of 18-8 stainless steel (2.5 mm thick)
．． 4 enemies were refuted.

This material was mixed in 0.5% acetic acid + 2 Komisaki AS203 solution for 1 to 2 hours. After 5 minutes of electrolysis with Kareme, bending stress was applied and many cracks were created. A test piece (2×5×1IW cape) was taken from the material of Example 1} to '41 above, and the damping capacity was measured by the transverse vibration method, and the results shown in the table below were obtained.

It is clear from the table that the damping material of the present invention has a higher damping ability than the raw material. In addition, the depth of the cracks that occurred in Example (2) stopped at the boundary between the material and the chromium layer, so it remained almost constant, and there were almost no cases where cracks penetrated into the material. In addition, the test piece of Example '4' (2 x 5
An electromagnetic and bioscillatory fatigue test was conducted using As a result, the fatigue limit at N=1 pi was 16k9/boil. On the other hand, 19-8 stainless steel material (thickness 1.6 fence)
The fatigue limit under the same load was 16.1k9/piece. Further, even if a crack exists in the hard chrome plating layer, if there is a soft 18-8 stainless steel base material underneath, the notch effect due to the presence of the crack is small. Therefore, the presence of cracks in the chromium plating layer is unlikely to become a starting point for cracks due to fatigue. In this example described above, a plating layer was formed on the surface of the material, but if a plating layer was already formed on the surface of the material, fine cracks were directly formed on the plating layer by the same method as in this example. It goes without saying that this will occur.

Claims (1)

[Claims] 1. A damping material characterized in that a plating layer is formed on the surface of the material, cracks are generated in the plating layer, and the interface of the cracks rubs when the material vibrates.