JPS60186479A - Manufacture of high heat conductivity aluminum nitride sintered body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing an aluminum nitride sintered body having high thermal conductivity.

[Technical background of the invention and its problems]

Aluminum nitride is known as a ceramic that is insulating and has excellent thermal conductivity.

However, aluminum nitride powder, which is a raw material for aluminum nitride sintered bodies, usually contains impurities such as oxygen. For this reason, the raw material powder is sintered in a process that prevents the contamination of impurities as much as possible, for example at 1600℃.
Even if pressure sintering is performed at ~1900°C, there is a problem that the thermal conductivity of the obtained sintered body remains at a value of about 40 to 45 w/Im-K, and there is a demand for higher thermal conductivity. Ta.

[Purpose of the invention]

The present invention aims to improve the above-mentioned problems and provide a method for producing an aluminum nitride sintered body with excellent thermal conductivity.

[Summary of the invention]

In order to achieve the above-mentioned object, the present inventors added 0.05 to 2% by weight of aluminum nitride raw material powder with an average particle size of 3 or less.
It has been found that it is extremely effective to pressure sinter powder mixed with carbon or a compound that decomposes to form the same amount of carbon.

In practice, the higher the pressure during sintering, the higher the densification of the sintered body, the improvement of thermal conductivity, and the strength of the container used during sintering.
The range of 0 to 600 ψ- is preferable.

If the temperature during sintering is less than 1,700°C, the sintered body will not become dense, and if it exceeds 2,100°C, the evaporation of aluminum nitride will be noticeable and a good sintered body will not be obtained.
The temperature range is 700°C to 2100°C. If the amount of carbon added is excessive, it may remain in the sintered body and cause a decrease in thermal conductivity, so it is necessary to keep the amount in the range of 0.05 to 2*. Further, if the A/N powder exceeds 3 μm, the density and thermal conductivity will decrease, so the thickness should be 3 μm or less.

〔Effect of the invention〕

The aluminum nitride sintered body of the present invention improves the thermal conductivity of the sintered body through a simple operation by sintering aluminum nitride powder with a predetermined amount of carbon or a compound that decomposes into carbon. can do. In addition, since the only additive is carbon, and the added carbon removes oxygen contained in the aluminum nitride powder, the sintered body after sintering has extremely high purity, which is required. It can also be used in aluminum melting crucibles, etc., and other effects can be expected.

Examples of the invention] This will be explained in detail below using examples.

Example 1 Aluminum nitride powder 100y1 with an average particle size of 3 μm or less
This amorphous carbon (particle size 1 μm or less) 0. Add IP and wet mix in a ball mill for 4 hours. After drying, use a mold press to pressure mold 3QQKy'm' to approximately 3Q7WX.
A green compact of 30m×12M was obtained.

The green compact was placed in a carbon mold and subjected to pressure sintering at 300° C. and 1800° C. for 1 hour in a nitrogen gas atmosphere. The obtained sintered body has a diameter of 10 mm and a thickness of 4 mm.
When a circular plate of R was cut out and its thermal conductivity was measured by the laser flash method, a value of 55 w/m was obtained.

The density of the sintered body was 3.26V (ld).

Example 2-9 Table 1 shows the thermal conductivity measurement results of aluminum nitride sintered bodies obtained using the same aluminum nitride powder and carbon as in Example 1 but varying the carbon concentration and sintering temperature and pressure. Ta.

Table 1 Example Work 1 Aluminum nitride powder with an average particle size of 2 μm or less 100)
One portion of sugar was added as a carbon source, and dry mixing was carried out in a ball mill for 24 hours. This mixed powder was pressure-molded to a size of 3QQvd using a mold press, approximately 30m x 3Qm.
A green compact of x 12 m was obtained. The green compact was placed in a carbon mold and heated to 300 in a nitrogen gas atmosphere on 9/ad-18.
Pressure sintering was performed at 00°C for 30 minutes. A disk with a diameter of IQm and a thickness of 4m was cut out from the obtained sintered body and its thermal conductivity was measured using a laser flash method.It was 55w.
/mK values were obtained. The density of the sintered body was 3.26Pβ.

Comparative Examples 1 to 5 Thermal conductivity measurement results of aluminum nitride sintered bodies obtained by using the same aluminum nitride powder and carbon as in Examples 1-9 and changing the carbon concentration and sintering temperature and pressure are shown in Table 2 f. This is the proof.

Agent: Kensuke Chika (and 1 other person) Continued from page 1 0 Inventor: Akihiko Tsuge Tokyo Shibaura Electric Co., Ltd. General Research A^^

Claims (2)

[Claims] (1) The carbon plan is made into A/N powder with an average particle size of 3 IJrn or less, and the compound that decomposes to become carbon is 0.05 in terms of carbon.
A method for producing a highly thermally conductive aluminum nitride sintered body, characterized in that it is obtained by sintering a mixed powder containing 2% by weight or more and 2% by weight or less. (2) The highly thermally conductive aluminum nitride sintered body according to claim 1, wherein the sintering is performed at a temperature range of 1,700°C to 2,100°C and a pressure of 50°C or more. Production method.