Method for preparing AlN ceramic powder by carbothermal reduction nitridation method

A technology of ceramic powder and nitriding method, which is applied in chemical instruments and methods, nitrogen compounds, inorganic chemistry, etc., can solve the problems of hindering the reaction process, high pressure, high CO concentration, etc., and achieve increased production, small crystal grains, and reduced Effect of O content

Active Publication Date: 2020-02-14
DALIAN MARITIME UNIVERSITY
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Problems solved by technology

It can be seen from the reaction equation that the carbothermal reduction nitriding reaction consumes N 2 The simultaneous generation of 3 times the N 2 The number of moles of CO, that is, the area of ​​the powder layer where the reaction occurs, especially the pressure inside the powder layer is relatively high, and the concentration of CO is relatively high, so that the gas N required for the reaction to proceed 2 Difficult to enter deep into the powder layer, hindering the reaction process

Method used

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  • Method for preparing AlN ceramic powder by carbothermal reduction nitridation method
  • Method for preparing AlN ceramic powder by carbothermal reduction nitridation method
  • Method for preparing AlN ceramic powder by carbothermal reduction nitridation method

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Experimental program
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Effect test

Embodiment 1

[0049] γ-Al with an average particle size of 20nm 2 o 3 AlN ceramic powder was synthesized by carbothermal reduction nitriding method in a nitrogen environment with activated carbon as raw material. The main steps include:

[0050] ①Ingredients: Weigh γ-Al according to the carbon content (the mass percentage of activated carbon in the mass percentage of the mixed powder) is 36% 2 o 3 Mix powder with activated carbon, place the weighed powder in a high-energy ball mill tank equipped with alumina balls, inject deionized water as the ball mill medium (the ratio of ball to material is 10:1, and the ratio of liquid to solid is 4:1) , with 300rpm ball milling for 5h, using a spray dryer to dry and granulate the slurry;

[0051] ②Charging and pulse air pressure control: Lay graphite paper around and at the bottom of the graphite material box, put the mixed powder obtained in step ① into the above graphite material box, the height of the mixed powder is 27mm, and place the graphit...

Embodiment 2

[0059] Embodiment 2 is according to the method for embodiment 1, and difference is that the lower limit of pressure in the furnace is made as 2.0kPa, and the upper limit pressure is made as 4kPa, and the cycle period is 4.4min; Step 3. heating rate is 5 ℃ / min. The XRD results of the synthesized powders located at different positions of the powder layer (upper surface, middle part, lower surface and side surface) are shown in Figure 6 , are pure phase AlN; the oxygen content of the powder is 1.02%; Figure 7 (a), the particle morphology after ball milling is shown in Figure 7 (b); the particle size distribution of AlN ceramic powder after ball milling is shown in Figure 8 , with an average particle size of about 1 μm.

Embodiment 3

[0061] Example 3 According to the method of Example 1, the difference is that step ③ synthesis temperature is 1650°C. The XRD results of the powders synthesized at different positions of the powder layer (upper surface, middle part, lower surface and side surface) are shown in Figure 9 , indicating that the phase composition of the powder prepared by this method is pure phase AlN; the oxygen content of the powder is 0.92%; the crystal grains of the synthesized AlN ceramic powder are small, and the particle morphology Figure 10 (a), the particles of the powder after ball milling are fine, and the appearance can be seen in Figure 10 (b); the particle size distribution of AlN ceramic powder after ball milling at 210rpm is shown in Figure 11 , the average particle size is about 0.9 μm.

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Abstract

The invention relates to a method for preparing AlN ceramic powder through a carbothermal reduction nitridation method, and belongs to the field of ceramic material preparation. The method is carriedout in an atmosphere synthesis device by taking aluminum oxide powder, carbon powder and nitrogen gas as raw materials, in the preparation process, nitrogen gas is continuously or intermittently introduced into the atmosphere synthesis device, and the gas pressure in the atmosphere synthesis device is controlled to generate pressure difference by adjusting the gas charging rate and the gas discharging rate, so that the atmosphere synthesis device has the pulse type characteristics of slow charging and quick discharging and is dynamically changed in real time in a periodic circulation manner, and the circulation period is 0.1-20 minutes. According to the invention, under the condition of no additive, pulse-type periodically-circulating real-time-changing air pressure is formed by utilizingan air pressure regulation and control technology, so that exchange of gas inside and outside a powder layer is promoted, pure-phase AlN can still be obtained under the condition of increasing the thickness of the powder layer, and the quality of AlN powder is guaranteed.

Description

technical field [0001] The invention relates to a method for preparing AlN ceramic powder by a carbothermal reduction nitriding method, which belongs to the field of ceramic material preparation. Background technique [0002] AlN has good chemical stability and thermal stability, as well as excellent thermal conductivity, high mechanical strength and low dielectric constant. Its thermal expansion coefficient is close to that of silicon, and it is easy to be compatible with other semiconductor materials. It is a large-scale integration technology. It is one of the preferred materials for circuit insulation and heat dissipation packaging and semiconductor substrates, and is widely used in the fields of electronic components and optical devices. [0003] High-purity AlN ceramic powder is an essential raw material for the preparation of high-performance devices. At present, the methods for preparing AlN ceramic powder include carbothermal reduction nitriding method, direct nitr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/072
CPCC01B21/0726
Inventor 单英春徐久军徐锦海
Owner DALIAN MARITIME UNIVERSITY
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