JP2906687B2 - Method of forming composite ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forming method for forming a composite ceramic into a tape so that the ceramic can be used in a laminated state.

[0002]

2. Description of the Related Art Heretofore, as a method of forming a slurry or kneaded material containing composite ceramics, especially short fibers, whiskers, etc. into a tape shape, an extrusion molding method, a doctor blade method and the like are known.

In the extrusion molding method, a slurry is extruded through a flow path having a required cross-sectional area to form a tape, and in the doctor blade method, the slurry is formed into a tape with a required thickness by a blade. Things.

[0004]

However, in the above-mentioned conventional extrusion molding method, when the slurry is extruded in the flow channel, a shearing force acts only on the surface portion of the slurry that directly contacts the wall surface of the flow channel. Although the short fibers in the slurry are uniaxially oriented only at the surface of the slurry to which the shearing force acts, the short fibers and the like are not oriented at the center of the cross section of the tape-shaped one. In the doctor blade method, the orientation of short fibers in the slurry is seen at the surface layer of the slurry where the blade contacts, but the orientation is not seen over the entire cross section.

[0005] As described above, in both the conventional extrusion molding method and the doctor blade method, orientation can be performed only at the position where the shearing force acts on the surface layer. However, since the orientation is not positively oriented so as to cover the whole, High strength, high toughness ceramic parts could not be obtained.

Accordingly, an object of the present invention is to provide a method for forming a short fiber or the like so as to be uniaxially orientable in the longitudinal direction over the entire cross section of the formed tape.

[0007]

According to the present invention, in order to solve the above-mentioned problems, an orientation belt having wavy irregularities in the width direction on its surface is horizontally arranged and moved from one end to the other end.
The slurry is supplied from the upstream side to the surface of the alignment belt, and the supplied slurry is pre-dried, and then the alignment roll having wavy irregularities in the axial direction on the surface is moved at the moving speed of the alignment belt. Then, the slurry is formed into a tape shape by rotating the slurry at a different speed, and then the formed tape is dried and taken out.

[0008]

When the moving speed of the orientation belt and the rotation speed of the orientation roll are relatively changed, the slurry on the orientation belt is formed into a tape shape by the orientation roll over the entire cross section of the slurry. Shearing action occurs. This shearing action and the forming process between a series of uneven surfaces formed on the surface of the orientation belt in the longitudinal direction and the corresponding uneven surface formed on the surface correspond to the mixing in the slurry. The short fibers or the like are oriented and formed in the same axis as the flow direction of the slurry.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus for carrying out the method of forming a composite ceramic according to the present invention.
As shown in FIG. 1 (A), an endless orienting belt 3 hung on a driving roll 1 and a driven roll 2 has a cross-sectional shape having corrugations 3a in the width direction on the surface as shown in FIG. 1 (B). And the surface irregularities 3a are continuous in the longitudinal direction in a streak shape. At a position above the belt 3 between the driving roll 1 and the driven roll 2, a slurry supply device 4 and a dryer 5 for pre-drying the slurry are arranged in order from the upstream side to the downstream side as shown in FIG. As shown in FIG. 1B, the surface of the belt 3 has corrugations 6 corresponding to the irregularities 3a on the surface.
An orientation roll 6 having a shape in the axial direction and a dryer 7 for drying the tape 9 formed by the orientation roll 6 are arranged. The slurry 8 supplied to the orientation belt 3 from the slurry supply device 4 is a composite ceramic material mixed with short fibers or whiskers.

The driving roll 1 is driven to drive the orientation belt 3 at a speed U _V , and the orientation roll 6 is rotated at a speed U _R higher than U _V , with a speed difference of U _R -U _V = ΔU. Drive.

Under the above operating conditions, when the slurry 8 is supplied from the slurry supply device 4 onto the orientation belt 3,
The supplied slurry 8 is carried to the downstream side by the movement of the orientation belt 3. During this time, the slurry 8 is preliminarily dried by the dryer 5 so as to be in a state where fluidity is lost. In the molding method of the present invention, it is important for the uniaxial orientation of the short fibers and the like in the subsequent tape molding that the fluidity of the slurry 8 on the orientation belt 3 be eliminated.

The slurry 8 pre-dried by the dryer 5
Is formed into a tape shape by the orientation roll 6.
At this time, since the rotation speed U _R of the orientation roll 6 is higher than the moving speed U _V of the orientation belt 3, a shearing force acts on the entire cross section of the slurry as shown by an arrow a in FIG. Due to the shearing force acting on the slurry 8 and the corrugated action of the irregularities on the surface of the orientation belt 3 and the irregularities on the surface of the orientation roll 6, the slurry 8 is mixed in the slurry.
BR> short fibers and the like are arranged in the same direction as the flow direction, and a uniaxial orientation is achieved over the entire cross section. In this case, the irregularities formed on the surface of the alignment belt 3 and the surface of the alignment roll 6 can prevent short fibers and the like from moving in the belt width direction, and thus can improve the uniaxial orientation. There is.

Tape 9 formed by orientation roll 6
Is dried by a dryer 7 and taken out. The tape 9 taken out has short fibers or the like uniaxially oriented over the entire cross section as shown in FIG. In FIG. 3, reference numeral 10 denotes a short fiber. The tape 9 is a material, and when forming a molded product, the tape 9 is appropriately cut, laminated, and formed into an arbitrary shape. Since short fibers and the like are uniaxially oriented in the laminated tape 9, the molded product itself has high strength and high toughness.

In the forming process using the above-described orientation roll 6, the rotation speed U _R of the orientation roll 6 and the orientation belt 3
Of the speed difference ΔU from the moving speed U _V of the slurry 8
The viscosity should be adjusted depending on the viscosity of the slurry. Generally, it is effective to increase ΔU for a slurry of high concentration (kneaded material).
The thickness of the tape 9 is generally considered to be related to the length of the short fibers and the like. However, in the molding method of the present invention, the short fibers and the like are arranged uniaxially by applying a shearing force to the entire cross section. There is no restriction on the thickness.

The present invention is not limited to only the above embodiment. For example, the dryer 5 for pre-drying the slurry 8 is for eliminating the fluidity of the slurry 8, However, it is not preferable that the hot air is blown because the slurry 8 is foamed, and the heat transfer heater type is effective.
Further, the dryer 5 may be provided below the orientation belt 3, the orientation belt 3 may not be endless, and the moving speed of the orientation belt 3 may be higher than the peripheral speed of the orientation roll. Of course, it may be faster.

[0017]

As described above, according to the method for forming a composite ceramic of the present invention, the slurry supplied onto the alignment belt having a cross-sectional shape having corrugations on the surface in the width direction is preliminarily dried by a dryer. After the liquidity is lost
Applying a speed difference between the rotation speed of the alignment roll having wavy irregularities in the axial direction on the surface and the moving speed of the alignment belt, forming the tape into a tape shape, and drying and removing the tape Therefore, the following excellent effects can be obtained. (i) As a molded composite ceramic tape, a tape in which short fibers and the like are uniaxially oriented over the entire cross section is obtained. (ii) Since a tape is formed between the alignment belt and the alignment roll, a tape having a large width can be formed. (iii) Applicable to slurries with a wide range of viscosities. (iv) The obtained tape is cut and laminated to form a molded article having an arbitrary shape, which facilitates the formation of a ceramic component, and provides a ceramic component having high strength and high toughness.

[Brief description of the drawings]

FIG. 1 shows an example of an apparatus for carrying out a molding method of the present invention, wherein (A) is a side view and (B) is a front view of a part.

FIG. 2 is a diagram illustrating a shearing force generated between an orientation belt and an orientation roll.

FIG. 3 is a diagram of a tape obtained according to the present invention.

[Explanation of symbols]

 3 Orientation Belt 3a Irregularity 4 Slurry Supply Device 5 Dryer 6 Orientation Roll 6a Irregularity 7 Dryer 8 Slurry 9 Tape

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-168001 (JP, A) JP-A-63-214405 (JP, A) JP-A-62-297107 (JP, A) JP-A-54-214 43227 (JP, A) Japanese Utility Model Showa 54-47810 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B28B 1/52 B28B 1/30 101 B28B 3/16

Claims (1)

(57) [Claims] 1. An alignment belt having a cross-sectional shape having wavy irregularities in the width direction on its surface is horizontally arranged, moved from one end to the other end, and the slurry supplied on the alignment belt is pre-dried. After that, the orientation roll having irregularities in the form of a wave in the axial direction on the surface is rotated at a speed different from the moving speed of the orientation belt to form the slurry into a tape,
Thereafter, a molding tape is dried and taken out to obtain a composite ceramics molding method.