JPS624225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a composite mechanical part in which a ceramic brittle material is bonded and coated to a base material to be bonded such as metal or plastic.

Ceramic is a material that exhibits excellent properties as a heat-resistant, corrosion-resistant, and wear-resistant material.
In recent years, attempts have been made to combine them with other materials, such as metals and plastics.

Examples of composite methods include (1) mixing ceramic powder materials such as resin, (2) melting and coating ceramic powder by thermal spraying, and (3) bonding and coating ceramic sintered bodies. These are used as appropriate depending on the intended use.

Among these methods, for wear resistance, (3)
The method described above is the best, but this method tends to result in unreliable joints.

This is mainly due to the following reasons.

(1) Because the coefficient of thermal expansion is different from that of the materials to be joined, such as metals and plastics, repeated temperature changes may cause the joint to separate, even if the range of temperature change is small.

(2) Because the material constants (elasticity values, etc.) are different from those of the material to be joined, the deformation behavior in response to stress is different, and separation may occur.

Due to the above-mentioned reasons (1) and (2), ceramic materials adhered or bonded to metal or plastic surfaces often suffer from problems such as peeling and have the drawback of lacking reliability in bonding and adhesion.

In view of the above points, the inventor of the present invention has made the following findings as a result of intensive research into adhesive structures that can provide perfect bonding and adhesion, and has previously filed an application for an invention. There is.

This method involves interposing a rubbery elastic membrane with a thickness of 0.3 mm or less between the base material and ceramic material, which solves the above-mentioned problems. .

This solves the conventional problems all at once, and
This gave a sufficient reinforcing effect to the ceramic layer.

However, the problem with this technology is that although it was certainly effective in the above points, the ceramic layer is placed on top of the rubber film, so the force is applied even though it is a very small amount. When applied, displacement or flow occurred. For this reason, it has been difficult to apply it to precision instruments that cannot tolerate even the slightest displacement.

The present invention solves the technical problems of the inventor's previous invention as described above, and the gist thereof is to provide a composite mechanical component in which a ceramic brittle material is adhesively coated on a base material to be joined. The brittle material and the base material are bonded to each other via a composite rigid-elastic membrane that exhibits rigidity against compressive loads and elasticity against lateral displacement. This is the structure of a composite mechanical part that is adhesively coated with a brittle ceramic material.

The composite rigid-elastic membrane of the present invention basically acts as a rigid body against compressive loads, and also acts as a rigid body when subjected to compressive loads, and also acts as a rigid body against compressive loads, and also acts as a rigid body against compressive loads, and also acts as a rigid body against compressive loads.
Since it is necessary to act as an elastic body that freely adapts and absorbs relative displacement in the lateral direction, there are several composite forms of elastic bodies and rigid bodies for this purpose. The following form is possible.

Two of the most typical examples will be explained using the drawings.

The example of FIG. 1 is in the form of a so-called composite, in which rigid particles (eg, metal, ceramic, plastic) are dispersed in a rubber-like elastic body.

In the example shown in FIG. 2, fine mesh-like through holes are formed in an elastic membrane (elastic sheet), and these through holes are filled with a rigid body.

First, the example shown in FIG. 1 will be explained.

FIG. 1 is an explanatory diagram of a cross-sectional structure when a composite type rigid elastic membrane is used.

1 is a ceramic layer, 2 is a base material, and 3 is a composite rigid elastic membrane.

The rigid elastic membrane 3 is made of a composite material in which rigid particles 5 are dispersed or embedded in a rubber-like elastic body 4, and is adhered to both the ceramic layer and the base material.

Rubber-like elastic materials have the property of being able to freely adapt to any force, but because they are soft, when a compressive load is applied to the ceramic layer, they may sink, even if only by a small amount. . By dispersing the rigid particles, the particles are interposed between the ceramic layer and the base material to support this load and prevent the ceramic layer from sinking. The rigidity of the rigid particles holds the ceramic layer in place unless the particles are broken.

On the other hand, in the lateral direction (parallel to the base material and shellac layer)
With respect to the displacement, the rubber-like elasticity is exhibited as is, and the relative misalignment between the base material and the ceramic is eliminated. Therefore, no internal stress is generated between the ceramic layer and the base material due to the difference in elongation rate.
No problems such as peeling occur.

As described above, a rigid elastic membrane has the property of exhibiting both rigidity and elasticity depending on the direction of force.

The material of the rigid particles can be metal, ceramic, plastic, or other rigid bodies, and is appropriately selected depending on the conditions of use (taking pressure and atmosphere into consideration).

The specific construction method in this example is as follows.

Bonding material: Alumina plate and stainless steel plate (100mm x 100
mm x 10mm) Adhesive: Elastomer adhesive Rigid particles: Alumina powder with an average particle size of 100mm Bonding operation: Add approximately 20% alumina powder to elastomer adhesive
The mixture was mixed and applied to the adhesive surface, and the surfaces to be joined were placed on top of each other and pressure was applied from above with a force of approximately 100 kg to adhere the two.

After bonding, we measured the displacement of the bonded surface against the load, and found that there was no displacement in the vertical direction even with a force of 100 kg, but there was free elastic displacement in the parallel direction.

Next, the case of FIG. 2 will be explained.

In FIG. 2, an elastic sheet 4 is used as the elastic body,
Fine mesh-like through holes are formed in this, and these through holes are filled with a rigid body 5.

In this example as well, this rigid filling body exhibits rigidity against compressive loads and prevents the ceramic layer from sinking. Further, even in the case of lateral displacement, the rubber-like elasticity eliminates any stress without any residual stress, as in the previous example. For this reason, troubles such as peeling do not occur in this example as well.

A method such as punching can be used to create a fine mesh-like sheet.

Next, as a method of filling this mesh-shaped through hole with a rigid body, for example, when this mesh sheet is bonded to a base material, this adhesive for bonding may be filled together, or this sheet may be filled with a rigid body. This adhesive may be filled at the same time as bonding the ceramic layer. In any case, the simplest method is to simultaneously fill the through hole with adhesive and solidify it when bonding the base material or ceramic layer. Moreover, when pressure is applied during this bonding, elastic flow occurs in the elastic sheet and closer contact is obtained, and when solidified in this state, the relative bonding strength increases due to this elastic activity. This also applies to the composite type shown in FIG. 1, and it is preferable to apply pressure during adhesion and joining as much as possible (unless it is difficult due to shape problems, etc.).

In this case, in the case of the method in which the adhesive is filled at the same time, after solidification, a bridge of the hardened adhesive is formed between the ceramic layer and the base material through this through hole.

If this bridge part between the shellac layer and the base material is not bonded, the relative sliding between the two will be smooth, but if they are bonded, they may become constrained. This binding may cause the adhesive layer at the bridge part to peel off, but since the two are tightly adhered to each other at the elastic sheet part,
There is no possibility that the two will separate. It is rather preferable for the bridge portion to be non-adhesive or peeled off. However, it is not necessary to deliberately peel off this part, and any material that peels off naturally during use is fine.

As a method for filling the rigid body, in addition to the above-mentioned method, there is also a method of inserting pre-processed rigid particles or fine button-shaped rigid bodies into the through hole, although it is a time-consuming method.

There is also a method in which the through holes of a rigid punched sheet are filled with a rubber-like elastic material and bonded, which is completely opposite to the case of this example.

The specific construction method in this example is as follows.

Holes with a diameter of approximately 500 mm are punched into a 100 mm thick rubber sheet at a rate of 5 holes per ¹ cm2.
After filling this hole with epoxy adhesive, it was inserted into the bonding surface of the alumina plate and S45C steel, and the adhesive was bonded under pressure (approximately 1 Kg/cm ² ).

After bonding, the displacement of the bonded surface against the load was measured.

On a vertical plane, even if a load of 100 kg is applied to 1 cm ² , the displacement is zero.
It was freely elastically deformed in the parallel direction.

The thickness of the rigid elastic membrane must be extremely thin, 0.3 mm or less (preferably 0.15 mm or less), in order to have the effect of reinforcing the base material against the ceramic layer. In this state, both will begin to behave as one in response to external forces.

Although it depends on the composite form of the rigid body in the rubber elastic body and the area ratio of this rigid body, as the intermediate film becomes thicker, the reinforcing effect becomes smaller.

In order to simplify the explanation in FIGS. 1 and 2, the ceramic layer is shown as a flat plate, but in the present invention,
The present invention is not limited to this, and can be applied to any shape.

For complex curved surfaces, ceramic pieces divided into small pieces are closely glued together without any gaps to create a shape as close to the curved surface as possible, and then polished if necessary.

Furthermore, a method of fitting a pre-processed ceramic sleeve into the inner circumferential surface of the cylinder can also be adopted.

The ceramic material used in the present invention refers to fired ceramics and glass materials in general, and ceramics include oxides such as alumina,
These include carbides and nitrides.

A promising field of application of the present invention is wear-resistant precision parts that are used at relatively low temperatures near room temperature.

The ceramic material of the present invention is sintered and has better wear resistance than conventional thermal spray coatings or ceramic coatings made by other methods. Further, it is possible to avoid distortion of the base material due to adhesion, and to obtain complete and reliable adhesion. Furthermore, there are no restrictions on the material of the base material, and all kinds of materials such as metal, plastic, and wood can be used.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a cross-sectional structure when a composite type rigid elastic membrane is used. FIG. 2 is an explanatory diagram of a cross-sectional structure when a fine mesh-like elastic sheet whose through holes are filled with a rigid body is used as the rigid elastic membrane.

Claims (1)

[Claims] 1 A rubber-like elastic sheet with countless through-holes perforated on its surface, filled with a rigid material, or a rubber-like elastic sheet with rigid particles dispersed therein, is inserted into the bonding surface, and the ceramic is bonded through the sheet. A composite mechanical part made of adhesively bonded ceramics.