JPS6155579B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a ceramic-metal composite material with improved thermal conductivity and a method for producing the same.More specifically, the fracture surface of the composite material is enlarged and microscopically shows that each inner core is made of iron or iron and molybdenum metal. The present invention relates to a composite material in which the inner and outer skin surfaces of each of the inner and outer skins are coated with a forsterite-enstatite-based film and bonded together, and the outer surface of the material is coated with a forsterite-enstatite-based film layer, and a method for producing the same. Forsterite and similar enstatite ceramics have long been available, and these ceramics have excellent electrical insulation properties and good metallization properties, and their sintering temperatures are as low as 1,200 to 1,400 degrees Celsius, making them ideal for electronic components. It is suitable as an insulating material. However, the thermal conductivity of these ceramics is 1/1 that of alumina or magnesia ceramics.
5 to 1/10, poor heat dissipation, thick film IC
There were major restrictions on its use as a substrate or resistance substrate. The present invention has been made to solve the above-mentioned problems, and its gist is based on a ceramic-metal composite material and a manufacturing method thereof as set forth in the claims. The present invention aims to improve thermal conductivity without impairing the electrical insulation properties of ceramics by obtaining a sintered body in which the inner core is a metal and the outer surface of the core is made of ceramics. Since there is not much difference in the coefficient of thermal expansion between tellite and iron, it is easy to combine the two, and by adjusting the mixing ratio of iron and molybdenum, which has a small coefficient of thermal expansion, the difference in coefficient with forsterite can be reduced. It is made smaller and more complex. Additionally, test results have shown that iron compounds or iron compounds and molybdenum compounds/talcum type emulsions are more effective than other types of solid emulsifiers for creating composite particles of ceramics and metals. In addition, it must be taken into account that the above metal compounds are reduced to metals at temperatures below the sintering temperature of ceramics, and that they are dispersed or dissolved in water, and the melting point of the metals must be above the sintering temperature of porcelain. This is the selected one. An enlarged microscopic view of the fractured surface of the composite material created using the above method shows that each inner core is made of iron metal or iron and molybdenum metal, and the outer skin surface of each inner core is covered with a forsterite-enstatite ceramic film. To briefly explain the formation mechanism, turbid liquid A, which is made by adding water and polyethylene glycol to an iron compound or a mixture of an iron compound and a molybdenum compound, is poured into turbid liquid B, which is made by mixing and dispersing talc in a non-aqueous solvent. When strongly stirred while stirring, the turbid liquid A becomes fine particles and is dispersed in the nonaqueous solvent. In this case, talc acts as an emulsifier to stably disperse the fine particles of the turbid liquid A to prevent them from aggregating with each other, and the talcum surrounds the fine particles of the turbid liquid A. When this emulsion is granulated in a spray dryer, granules are formed in which the inner core is made of an iron compound or an iron compound and a molybdenum compound, and the outer surface is made of talc. When this granule powder is pressure-molded and sintered in a non-oxidizing atmosphere, 3MgO, 4SiO ₂ , H ₂ O of talcum is converted into forsterite 2MgO,
SiO ₂ and enstatite MgO/SiO ₂ become glassy, while Fe ₂ O ₃ is reduced to Fe,
MoO ₃ becomes Mo and the desired composite material is obtained. The fractured surface of this sintered body was observed with a scanning electron microscope, and the structure is shown in Fig. 1 in an enlarged microscopic view. It is a composite material that combines iron and molybdenum 2. The ceramic-metal composite material obtained by the present invention has a thermal conductivity of 0.10ca1/cm・at room temperature.
sec・℃, and the volume resistivity is 4×10 ¹³ at room temperature.
Ω・cm, forstellite 0.012ca1/
Thermal conductivity can be greatly improved compared to cm・sec・℃ and 8×10 ¹³ Ω・cm and enstatite's 0.006ca1/cm・sec・℃ and 3×10 ¹⁴ Ω・cm.
Despite this, the volume resistivity was not low, making it a highly practical material. Examples will be described below, but the present invention is not limited thereto within the scope of the gist of the present invention. Example Ferric oxide (Fe ₂ O ₃ , Hayashi Pure Chemical Industries, Ltd., Reagent 1
450 g of molybdenum oxide (MoO ₃ , Yoneyama Pharmaceutical Co., Ltd., reagent grade 1), 1400 c.c. of water, and 7 g of #4000 polyethylene glycol as a binder were mixed and ground in an alumina porcelain ball mill for 15 hours to form a turbid liquid. This turbid liquid is called A. Separately, 49 g of talc fine powder was placed in 2000 c.c. of ethylene tetrachloride (2Cc1 ₂ , Hayashi Pure Chemical Industries, reagent grade 1), stirred and mixed with a magnetic stirrer for 0.5 hours to form a turbid liquid, and this turbid liquid was Let it be B. While stirring this turbid liquid B using the above-mentioned apparatus, turbid liquid A was injected and emulsified and dispersed to prepare an emulsion of an iron compound and a molybdenum compound/talcum. At this time, the talcum surrounds the A liquid and acts as an emulsifier. Next, this emulsion was jet-dried and granulated under the conditions of a gas temperature of 160°C, a disk diameter of 105φmm, and 3600 rPm. This average particle size is granules of 100 μm,
It contained Fe ₂ O ₃ and MoO ₃ inside, and its outer surface was covered with talc. 1500 of this granule powder
13.5φ×1.35tmm and 75φ×4.5tmm with pressure force of Kg/ ^cm2
Two types of discs were molded. This is heated to 900℃ in the atmosphere.
Calcinate for 1 hour at 1300℃ in a hydrogen atmosphere to remove polyethylene glycol, and heat to a dew point of 30℃.
By sintering under these conditions, a composite was obtained with a skin of forsterite and enstatite containing iron and molybdenum. The characteristics of the above disk products were investigated, and forsterite and enstatite were investigated as comparison products and are shown below.

[Table] The above thermal conductivity was measured using a thermal constant measuring device TLP-1000 manufactured by Miki Engineering Co., Ltd., and the volume specific resistance was measured using an electrometer TR-8651 manufactured by Takeda Riken Co., Ltd. Although the above embodiments described pressure molding of powder, sheet molding by casting is also possible by adding one to three other binders. As described above, the composite material of the present invention has a thermal conductivity comparable to that of magnesia ceramics, so it can be used as an insulating material for electronic components such as thick-film IC boards and resistance boards, and as a magnetic stirrer. It is the material.

[Brief explanation of the drawing]

FIG. 1 shows an enlarged macroscopic structure of the fracture surface. 1...Forsterite-enstatite ceramic coating layer, 2...Iron or iron and molybdenum.

Claims (1)

[Scope of Claims] 1 The fracture surface of the composite material is enlarged and microscopically shows that each inner core is made of iron metal or iron and molybdenum metal, and the outer skin surface of each inner core is covered with a forsterite-enstatite ceramic film. A composite material of ceramic and metal that is bonded together and whose outer surface consists of a forsterite-enstatite film layer. 2 Water and polyethylene glycol are added to an iron compound or a mixture of an iron compound and a molybdenum compound, mixed and ground to obtain a turbid solution A, and talcum is mixed and dispersed as an emulsifier in a non-aqueous solvent that is not compatible with water to obtain a turbid B. As a liquid, the above-mentioned turbid liquid A is poured into the turbid liquid B while stirring to emulsify and disperse it, and this is granulated in a spray dryer to form an emulsion of an iron compound or an iron compound and a molybdenum compound/talcum, and the inner core is formed. Granules are made of an iron compound or an iron compound and a molybdenum compound, and the outer surface is made of talcum. After the granules are press-formed into a predetermined shape, they are sintered at 1200 to 1400℃ in a non-oxidizing atmosphere. Then, the inner core is made of iron metal or iron metal and molybdenum metal, and the outer skin surface is covered with a forsterite-enstatite ceramic film and bonded,
A method for producing a composite material of ceramic and metal, characterized in that the outer surface of the sintered body is composed of a forsterite-enstatite film layer. 3. A method for producing a composite material of ceramic and metal, characterized in that the non-aqueous solvent according to claim 2 is ethylene tetrachloride.