JP2011057505A - Porous ceramics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous ceramics, regarding one kind of porous ceramics, in which, particularly, the surface area of air contact is increased, and the heat radiation effect of a radiator can be improved. <P>SOLUTION: A resin is added to granular silicon carbide by a suitable proportion, thereafter, a solvent is added thereto, and mixing is caused so as to uniformly stir the mixture. In the kneading process, the resin covers the surface of the granular silicon carbide so as to form a colloid object, this colloid object is molded by extrusion molding, and the solid matter is sintered at the melting temperature of the silicon carbide. Since the melting temperature of the silicon carbide is extremely higher than that of the resin, the resin is perfectly burnt, and vacancies are formed in the spaces of the silicon carbide so as to form porous ceramics. Further, by altering the addition ratio of the resin, the size of the vacancies and the number of the vacancies, the proper conditions of the thermal conductivity and heat radiation in the porous ceramics can be adjusted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a kind of porous ceramics, and more particularly to a porous ceramic that can increase the surface area of air contact and improve the heat dissipation effect of a radiator.

Recently, the total heat generation of an electronic device increases with the miniaturization of electronic elements and the increase in the degree of integration per unit area, so it is necessary to improve the heat dissipation effect. In addition, it must be avoided that the electron ionization and thermal stress caused by the electronic element affect the overall stability and shorten the life of the electronic element. On the other hand, the conventional heat dissipation method using pure copper or aluminum alloy as a heat diffusion base material is no longer suitable for use. Therefore, in advanced technology, silicon carbide powder (SiC) powder is sintered into a porous silicon carbide ceramic body, and the heat release is accelerated by increasing the surface area of the air contact by the pores. .

However, this type of porous silicon carbide ceramic body has the following disadvantages when manufactured.

<I> When silicon carbide powder is sintered, vacancies are formed by the diffusion coefficient of silicon carbide itself, but the distribution of the vacancies is not uniform and the formation area of the vacancies cannot be accurately controlled. Therefore, the heat dissipation effect is limited.

<B> Before sintering silicon carbide, after adding water and a small amount of binder and bonding with silicon carbide, after stirring in a sludge form, water is evaporated and pressure-molded into a molded body, Provided for subsequent sintering. However, the hardness of silicon carbide is very high, and since the mold used for pressure molding comes into contact with silicon carbide, the wear of the mold is large, and a large pressure is required for molding the molded body.

Therefore, the main object of the present invention is to add the resin to the silicon carbide powder particles and sinter the silicon carbide. Then, the resin is completely burned and the function of forming pores is used to increase the resin addition rate. Providing a kind of porous ceramics by adjusting the size of pores after silicon carbide sintering and adjusting the number of pores with unit area by adjusting the optimal conditions for heat conduction and heat dissipation of porous ceramics There is to do.

Another object of the present invention is to provide a kind of porous ceramics that realizes energy saving and reduction in manufacturing cost by using a dielectric material as a bonding material between silicon carbide.

Another object of the present invention is to cover the resin on the surface of powdered silicon carbide, and when the mold is extruded by a mold, the mold comes into contact with a resin having low hardness, and the pressure required for molding is applied. An object of the present invention is to provide a kind of porous ceramics that can soften and reduce the wear of the mold.

Further, another object of the present invention is to cover the resin on the surface of powdered silicon carbide, and granulate these particles after pre-granulating and selecting a certain range of particle size before extrusion molding with a mold. It is an object of the present invention to provide a kind of porous ceramics in which the pores formed after the silicon carbide is sintered and the resin is completely burned are uniform.

In order to achieve the above object, the porous ceramic according to the present invention is manufactured by the following steps.

<I> Kneading, kneading powdered silicon carbide and dielectric material in an appropriate proportion, and adding a resin. Further, a solvent is added and uniformly stirred and mixed, so that the resin is covered on the surface of the powder particles in the course of kneading.

<B> Continue to stir until volatilization and solvent are completely volatilized

<C> Granulation and granulation of the kneaded product after the solvent has been volatilized, and selecting particles having a fixed particle size from the obtained granules.

<D> The molded and selected granules are put into a mold and extruded.

<E> Cured and extruded silicon carbide is heated to solidify the resin covered with silicon carbide to form silicon carbide into a solid.

<F> Sintering, heating the solid according to the melting point temperature of the dielectric material, melting the dielectric material and bonding it to silicon carbide, and then completely burning the resin to form pores, thereby producing porous ceramics. Finish.

As described above, main technical means by which the present invention can solve deficiencies and shortcomings of known techniques will be described as follows.

<I> In the present invention, the resin is covered with powdered silicon carbide and a silicon carbide base surface, and is contacted with the resin instead of silicon carbide when extrusion molding is performed by a mold. Since the hardness of the resin is softer than that of silicon carbide, molding can be performed with a low pressure, and the mold can avoid high wear due to contact with the silicon carbide having high hardness.

<B> The present invention completely burns the resin, leaving a space between the silicon carbides, and the silicon carbide is bonded by the silicon carbide base to form pores. Therefore, the size of the pores and the number of pores of the unit area can be adjusted to optimum conditions for heat conduction and heat dissipation of the porous ceramics by adjusting the resin addition rate.

<C> The present invention uses a dielectric material as a bonding material between silicon carbide, and since the melting temperature of the dielectric material is much lower than that of silicon carbide, lowering the combustion temperature realizes energy saving and reduced manufacturing costs In addition, different dielectric materials can be used according to various demands. For example, a dielectric material having a high melting temperature is used when used for a bearing, and a dielectric material having a low melting temperature is used when used for a heat sink.

<D> In the present invention, the resin is coated on the surface of powdered silicon carbide, granulated in advance before extrusion molding with a mold, and after selecting a certain range of particle diameter, these granules are molded into a mold. The entire heat dissipation effect can be made uniform by carrying out extrusion molding and making the pores formed after the silicon carbide is sintered and the resin is completely burned.

The porous ceramic according to the present invention is based on silicon carbide (SiC), and when a porous ceramic is manufactured, after adding an appropriate proportional thermosetting resin to powdered silicon carbide in advance, A solvent such as acetone is added, and the mixture is uniformly stirred and mixed with silicon carbide. The resin is dissolved in a liquid state with a solvent, and the resin is continuously stirred in the course of kneading until the surface of the powdered silicon carbide is covered and the solvent is completely volatilized to become a glue.

Subsequently, after granulating this colloid and selecting a certain particle size range among the obtained granules, this granule is put into a mold and extruded to form the desired shape of the product. The resin is cured to form a solid by a low-temperature heating (about 180 degrees Celsius) method.

Further, the solid is heated by the melting point temperature of silicon carbide (about 2000 to 2600 degrees Celsius) to sinter silicon carbide into ceramics. Since the melting point of silicon carbide far exceeds that of the resin, the resin burns completely during the sintering process, and the occupied volume is lost, forming voids and forming porous ceramics.

From the above description, it can be seen that the pores of the porous ceramics are pores left after the resin is completely burned. Therefore, adjusting the size of the pores or the number of pores per unit area can be realized by adjusting the resin addition rate, and various types of porous ceramics can be produced as necessary.

The melting point of silicon carbide is very high, and the heat resistance temperature of the produced porous ceramics is also very high. Therefore, when using at a heat resistance temperature that is not too high, a dielectric material with a low melting point is added as a bonding substance between silicon carbides, and the combustion temperature is lowered and sintered at the melting point of the dielectric material. , Energy saving and manufacturing cost reduction can be realized.

Further, the dielectric material is a silicon oxide based melt (Silicon Oxide Based Meltings, melting temperature about 1000 degrees Celsius), and before adding the dielectric material to the process, the powdered silicon carbide and dielectric The ingredients are mixed in appropriate proportions and the resin is added. At this time, a thermosetting resin is used as the resin, and the addition proportion of the powdered silicon carbide, the dielectric material, and the resin is about 8: 1: 1. Further, a solvent is added, and the mixture is stirred and kneaded until uniform. At this time, acetone or the like is used as the solvent. The resin solution is dissolved in a liquid by the solvent, and the resin is continuously stirred in the kneading process until the powdered silicon carbide and the surface of the dielectric material are covered and the solvent is completely volatilized and becomes a colloid. Along with this, a certain particle size range is selected from the granules obtained by granulating this colloid, and these granules are put into a mold and extruded, and then heated at a low temperature (about 180 degrees Celsius). To cure the resin and form a solid.

Further, the solid material is heated according to the melting temperature of the dielectric material, and the dielectric material is melted and bonded to silicon carbide. Since the melting point of the dielectric material is much higher than that of the resin, after the resin is completely burned, the volume occupied so far is lost and porous ceramics are formed.

Claims (5)

It is a porous ceramic that increases the surface area of air contact and improves the heat dissipation effect of the radiator,
The porous ceramic is based on silicon carbide (SiC). Before the porous ceramic is molded, a resin is added to the silicon carbide in powder form in an appropriate proportion, and then a solvent is added. Stir uniformly, the resin is dissolved in a liquid state by the solvent, and the resin covers the surface of the powdered silicon carbide in the kneading process, and is continuously stirred until the solvent is completely volatilized and becomes a glue. Then, after the colloid is formed by extrusion molding, the resin is subsequently cured by low-temperature heating, the formed colloid forms a solid, and is sintered at the melting temperature of silicon carbide. Fired into ceramics, the melting point of silicon carbide is much higher than that of the resin, so the resin is completely burned in the sintering process, and the volume it has occupied so far Lost to form pores, characterized in that the porous ceramic is completed, the porous ceramics. After the powdered silicon carbide and the resin are formed into a colloid, granulation is performed to select granules having a certain particle size range, and then the selected granules are extruded. The porous ceramic according to claim 1. A porous ceramic that increases the surface area of air contact and improves the heat dissipation effect of a radiator, wherein the porous ceramic is based on silicon carbide (SiC) and bonded by a dielectric material, and the porous ceramic is molded Before being mixed, the powdered silicon carbide and dielectric material are mixed in an appropriate proportion, and after adding a resin, a solvent is added and stirred uniformly, and the resin is dissolved in a liquid by the solvent. In the kneading process, the resin covers the surface of the powdered silicon carbide, and is continuously stirred until the solvent is completely volatilized into a gelatinous substance. The resin is cured by the above, and the formed gelatinous substance is formed into a solid substance, and then the solid substance is heated by the melting temperature of the dielectric material. Because it melts and bonds to silicon carbide and the melting point of the dielectric material is much higher than that of the resin, the resin is completely burned in the sintering process, losing the previously occupied volume, and the silicon carbide space Porous ceramics characterized in that pores are formed in the porous ceramics. After the powdered silicon carbide, dielectric material, and resin are formed into a glue, granulation is performed to select granules having a certain particle size range, and then the selected granules are extruded. The porous ceramic according to claim 3, wherein: The porous ceramic according to claim 3, wherein the dielectric material is based on silicon oxide based melting.