JPH0672274B2 - Method for producing fiber molded body and method for producing fiber reinforced composite material using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a fiber molded body and a method for producing a fiber reinforced composite material (FRM) using the same.

[Prior Art] As a method for producing a fiber-reinforced composite material using inorganic fibers or the like as a reinforcing material, a so-called pressurization in which a matrix metal melt is press-fitted, impregnated and solidified into an inorganic fiber molded body (molded body) of the reinforcing material. Casting methods are known.

Conventionally, the fiber molded body used in this method is placed in a furnace kept in an inert gas atmosphere or an air atmosphere and preheated near the melting point of the matrix metal, as is usually done in the pressure casting method. In this case, the molded product is stored in a container that will not be damaged when it is pressurized and impregnated with the molten matrix metal, or the molded product is impregnated with an inorganic binder such as colloidal silica and dried to retain the molded product. The shape is adopted. Then, these molded bodies are placed in a cavity of a mold, a matrix metal is poured into the cavity, and this is pressed to impregnate and solidify the molded body to manufacture a fiber reinforced composite material.

[Problems to be Solved by the Invention] However, in the above-mentioned method, it is necessary to take out the molded body storage container after manufacturing the composite material, which increases the number of manufacturing steps and causes a high cost. . Furthermore, it is impossible to reinforce only a part of the member with inorganic fibers.

On the other hand, in the method of 1, although the above-mentioned problems are solved, the inorganic binder such as colloidal silica impregnated in the molded body, silicic acid is accompanied by the movement of water in the inorganic binder during drying to the outer peripheral portion. Since it is carried, the distribution of silicic acid in the molded body becomes non-uniform, and as a result, the properties of the composite material produced differ from place to place, which causes variations in properties.

After manufacturing the composite material, the outer peripheral portion may be removed by cutting or the like, but the number of steps is increased and the yield is poor, which causes a high cost. Furthermore, there is a problem that the outer shape of the molded body may be unevenly contracted due to the movement of water during the drying of the inorganic binder, so that the molded body having a desired shape cannot be obtained.

[Means for Solving the Problem] The present invention aims to solve the above problems. According to the present invention, at least one metal alkoxide selected from the alkoxides of Si, Al, Ti, Zr, and Na is hydrolyzed, and a gelling accelerator is added to this to obtain 0.2
The solution adjusted to gel within 60 minutes is used as a binder for forming a fiber molded body for a fiber reinforced composite material. Then, a molten metal of the matrix metal is poured into the mold in the mold, the fiber molding formed by the solution is placed in the cavity of the mold, and by the pressurizing plunger engaging with the mold, This is achieved by pressurizing and solidifying the molten matrix metal.

[Operation] According to this method, the above-mentioned binder is not contained in the fiber molded body.
Since it is solidified in the process of gelling in 2 to 60 minutes, it does not accompany the migration of silicic acid generated during the drying of the above colloidal silica or the like. Therefore, the manufactured fiber-reinforced composite material has a uniform structure and is a highly reliable material with stable characteristics. Further, similarly, since the deformation of the molded body does not occur in the gelling process, the dimensional accuracy and the yield of the fiber molded body are improved. The metal alkoxide according to the present invention includes, for example, Si (OC ₂ H ₅ ) ₄ , n = 0,1,2 ...... n Si (OCH 3) 4, Al (OC 3 H 7) 3, Al (OC 4 H 7) 3, Ti (OC 3 H 7) 4, Zr (OC 3 H 7 ) ₄ , Zr (OCH ₃ ) ₄ and NaOCH ₃ are preferred.

In addition, Si (OC ₂ H ₅ ) ₄ , The hydrolysis reaction of n = 0,1,2 ... n includes an acidic method and an alkaline method, but the acidic method is preferable because the gel is dense and has a binding force. Further, as the gelling accelerator in this case, a 10% (NH ₄ ) ₂ CO ₃ aqueous solution is preferable.

As mentioned above, the gelling time is preferably 0.2 to 60 minutes, and if it is longer than this, the production efficiency is lowered. On the other hand, if the gelation is carried out instantly, the hydrolyzed solution is gelated before it is sufficiently impregnated into the fiber molded body, and the gel distribution in the fiber molded body becomes uneven, which is not preferable. For the method of impregnating the binder, immerse the fiber molding in the binder solution,
Alternatively, the binder may be atomized and sprayed onto the fiber molded body, which is not particularly limited. The fibers that can be used in the present invention include Al ₂ O ₃ fibers and Al ₂ O ₃ -Si
O ₂ fibers, B fibers, C fibers, SiC fibers, inorganic long fibers such as Si-Ti-CO fibers, metal fibers such as stainless steel, or chopped short fibers of these, or SiC, Si ₃ N ₄ And whiskers.

As the matrix metal, Al-based (Al alone or Al
Alloy), Mg-based (Mg simple substance and Mg alloy), Zn-based (Zn simple substance and Zn alloy) and the like are used, but not limited thereto.

EXAMPLES Example 1 The present invention will be described below based on some examples with reference to the accompanying drawings.

As shown in Fig. 1, the continuous Si-Ti-CO fiber 1 is arranged in one direction to have a width of 80 mm, a thickness of 10 mm, and a length of 150 mm, and is divided into a pair of vinyl chloride containers 2a and 2b. The volume ratio is 50%. Then, with a solution having the following composition, Si (OC ₂ H ₅ ) ₄ … 1000g C ₂ H ₅ OH… 550g H ₂ O… 100g 1N-HCl… 17g Si (OC ₂ H ₅ ) ₄ at room temperature for 12 hours Hydrolysis reaction is performed to prepare silicic acid sol, and 30 g of 10% (NH ₄ ) ₂ CO ₃ aqueous solution is added to this so that gelation is completed in about 10 minutes. -Dip the vinyl chloride container with the Ti-CO fiber in it, remove it from the solution after 8 minutes, and after 10 minutes, after the gelation is complete, remove the vinyl chloride container and
A plate-like fiber molded body 3 having a width of 80 mm, a thickness of 10 mm and a length of 150 mm as shown in the figure was obtained. Furthermore, the fiber molded body 3 is heated to 650 ° C. in a furnace kept in the air atmosphere, and as shown in FIG.
Molten aluminum 4 at 750 ℃ in mold 5 (JIS standard 107
After pouring 0), the fiber molded body 3 was placed in the mold 5. Then, as shown in FIG. 4, the pressurizing plunger 6
And pressurize the aluminum melt 4 to 1000 kg / cm ² ,
The molten metal 4 is impregnated into the fiber molding 3 and solidified to form continuous Si-Ti-
A CO fiber reinforced composite material was manufactured. The fiber-reinforced composite material was taken out and the cross-sectional structure was observed. As a result, there were no casting defects such as voids, there was no disturbance in the orientation of the fibers, and the external dimensions and shape and the volume ratio of the fibers were also compared to those of the molded body. There was no change. It was also confirmed that the silicic acid in the composite material was uniformly dispersed.

Furthermore, when the bending strength in the fiber orientation direction was measured for this composite material, a high value of 120 kg / mm ² was obtained,
It was found that the effect of silicic acid in the composite was very small.

Example 2 As shown in FIG. 1, continuous Al ₂ O ₃ fibers 1 were unidirectionally 50 m wide.
Aligned to m, thickness 5 mm, and length 100 mm, they were placed in a pair of vinyl chloride containers 2a and 2b divided into two so that the volume ratio would be 50%.

Then, a solution having the following composition Ti (OC ₃ H ₇ ) ₄ ... 1 mol C ₃ H ₇ OH ... 2.5 mol is mixed, and a mixed solution of C ₃ H ₇ OH ... 2.5 mol H ₂ O ... 1 mol is added, Hydrolysis reaction is performed to prepare titanic acid sol, and HCl is adjusted to 0.0 to complete gelation in about 5 minutes.
The vinyl chloride container in which the Al ₂ O ₃ fiber is arranged is immersed in the solution added with 03 mol, and after 8 minutes, it is taken out of the solution and after 10 minutes, the gelation is completed, and then the vinyl chloride container. The width 50mm, thickness 5mm, length 100 as shown in Fig. 2.
A plate-shaped fiber molding 3 having a size of mm was obtained. Further, the fiber molded body 3 is heated to 700 ° C. in a furnace kept in the air atmosphere, and as shown in FIG.
After pouring (JIS standard 1070), the fiber molded body 3 was placed in the mold 5. Then, as shown in FIG. 4, the aluminum melt 4 is heated to 800 kg / cm by a pressurizing plunger 6.
^The molten metal 4 was impregnated into the fiber compact 3 and solidified by pressurizing to ² to produce an Al ₂ O ₃ fiber reinforced composite material. When the composite material was taken out and the cross-sectional structure was observed, there were no casting defects such as voids, there was no disturbance in the orientation of the fibers, and there was no change in the external shape and shape and the volume ratio of the fibers as compared with those in the molded body. It was It was also confirmed that the titanic acid in the composite material was uniformly dispersed. Furthermore, when the bending strength of the composite material in the fiber orientation direction was measured, a high value of 100 kg / mm ² was obtained, and it was found that the influence of titanic acid in the composite material was very small.

[Effects of the Invention] As described above, according to the present invention, a homogeneous fiber-reinforced composite material can be provided in a composite material by using a fiber molded body that is shaped by a gel uniformly dispersed in the fiber molded body. It can be manufactured without remaining.

Therefore, the whole or a part of the member can be arbitrarily made into a fiber-reinforced composite material.

[Brief description of drawings]

FIG. 1 is a perspective view showing a molded article for fiber reinforced composite material in a first embodiment of the method for producing fiber reinforced composite material according to the present invention, and FIG. 2 is a method for manufacturing the fiber reinforced composite material according to the present invention. FIG. 3 is a perspective view showing a fiber molded body for a fiber-reinforced composite material according to the first embodiment, and FIGS. 3 and 4 are longitudinal sectional views showing a casting step in a method for producing a fiber-reinforced composite material according to the first embodiment. . 1 ... Continuous inorganic fiber, 2 ... Split container made of vinyl chloride divided into 2 (2a, 2b), 3 ... Continuous inorganic fiber molded body, 4 ... Aluminum melt, 5 ... Mold, 6 ... ... a plunger for pressurization.

Claims (2)

[Claims] 1. At least one metal alkoxide selected from alkoxides of Si, Al, Ti, Zr and Na is hydrolyzed, and a gelation accelerator is added to this to gel in 0.2 to 60 minutes. A method for producing a fiber molded body, which comprises using the solution thus prepared as a binder for molding the fiber molded body. 2. A molten metal of a matrix metal is poured into a mold of a mold, and the fiber molded body manufactured by the manufacturing method according to claim 1 is installed in a cavity of the mold to engage with the mold. A method for producing a fiber-reinforced composite material, characterized in that the molten metal of the matrix metal is pressed and solidified by a pressing plunger.