Preparation method of micron-sized hafnium carbide powder

Abstract

The invention provides a preparation method of micron-sized hafnium carbide powder, the micron-sized hafnium carbide powder is prepared by calcining powder obtained by ball-milling and uniformly mixing graphite powder or carbon black and hafnium dioxide, and the used graphite or carbon black is micron-sized; the hafnium oxide is monoclinic hafnium oxide of 3-5 microns, the raw materials are uniformly mixed through a planetary ball mill, and the mixture is subjected to a solid-solid reaction through high-temperature calcination. According to the method, the complexity of the previous technological process is greatly reduced, and the prepared hafnium carbide powder is small in particle size, high in purity and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic powder preparation, and in particular relates to a method for preparing micron-sized hafnium carbide powder. Background Art

[0002] Hafnium carbide is a typical "NaCl" type face-centered cubic crystal with a hexagonal crystal form, gray crystal, cubic system, density 12.6 g / cm3, melting point about 3890 °C, softening temperature 1700-2500 °C, insoluble in water, and chemical properties similar to zirconium carbide.

[0003] At present, hafnium carbide powder is mainly produced by the carbon thermal reduction method of hafnium dioxide, and the reaction equation is: HfO2+3C=HfC+2CO↑ It is divided into two steps: Step 1: HfO2+2C=HfCO+CO↑ Step 2 HfCO+C=HfC+CO↑ The above reaction process is a solid-solid reaction type, and the reaction progress is controlled by material diffusion; currently most of the synthesis methods are to react a precursor carbon source with hafnium oxide to prepare hafnium carbide, and the process is complicated and has poor controllability. Summary of the invention

[0004] The present invention aims to overcome the complexity of the prior art and provide a method for preparing micron-sized hafnium carbide powder.

[0005] The present invention adopts the following technical solutions to achieve the above-mentioned purpose: A method for preparing micron-sized hafnium carbide powder is provided, wherein the powder is calcined after being mixed by ball milling graphite powder or carbon black and hafnium dioxide, wherein the graphite or carbon black used is micron-sized; the hafnium dioxide is monoclinic 3-5 μm hafnium dioxide, the raw materials are mixed by a planetary ball mill, and calcined at high temperature to cause a solid-solid reaction; the method specifically comprises the following steps: S1. Weighing: weigh the raw material powder according to the molar ratio; the molar ratio is consistent with the ratio of the chemical equation; S2, mixing: put the powder in S1 into a ball mill, add anhydrous ethanol, and add Si3N4 grinding balls of two diameters, and ball mill on a planetary ball mill; S3, drying: placing the slurry in S2 on a tray and placing it in a drying oven; S4, synthesis: take out the dry powder in S3 and place it in a graphite crucible, perform high-temperature synthesis in a vacuum graphite furnace, and obtain high-purity micron-grade hafnium carbide powder after cooling.

[0006] The diameters of the two Si3N4 ball milling balls are φ15 and φ10 respectively, the mass ratio thereof is 2:1, 3:1 or 4:1, and the ball milling time is 4 to 6 hours.

[0007] The temperature of the drying oven in S3 is set to 40 ℃ ~ 70 ℃.

[0008] Furthermore, the atmosphere used for the high temperature synthesis in S4 is an inert atmosphere or a reducing atmosphere, and the synthesis temperature is 1600-2300°C.

[0009] The invention provides a method for preparing micron-sized hafnium carbide powder, which greatly reduces the complexity of the previous process of preparing hafnium carbide from a precursor carbon source. The hafnium carbide powder prepared by the invention has a small particle size, high purity and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 XRD pattern of the synthesized pure phase hafnium carbide.

[0011] Figure 2 SEM image of the synthesized micron-scale pure phase hafnium carbide. DETAILED DESCRIPTION

[0012] The present invention is described in detail with reference to the accompanying drawings and specific embodiments: Embodiment 1:

[0013] A simple preparation method of micron-sized hafnium carbide, the process is: S1, weighing: weighing the raw material powder according to the molar ratio; S2, mixing: put the powder in S1 into a ball mill, add anhydrous ethanol, add two kinds of grinding balls (Si3N4) φ15 / φ10, the mass ratio is 2:1, and ball mill on a planetary ball mill for 4h; S3, drying: the slurry in S2 is placed on a tray and placed in a drying oven with the temperature set at 40°C; S4, synthesis: take out the dry powder in S3 and place it in a graphite crucible, and keep it at 1600°C for 2 hours in a vacuum graphite furnace for high-temperature synthesis. After cooling, high-purity micron-sized hafnium carbide powder is obtained. Embodiment 2:

[0014] A simple preparation method of micron-sized hafnium carbide, the process is: S1, weighing: weighing the raw material powder according to the molar ratio; S2, mixing: put the powder in S1 into a ball mill, add anhydrous ethanol, add two kinds of grinding balls (Si3N4) φ15 / φ10, the mass ratio is 3:1, and ball mill on a planetary ball mill for 5h; S3, drying: the slurry in S2 is placed on a tray and placed in a drying oven with the temperature set at 50°C; S4, synthesis: take out the dry powder in S3 and place it in a graphite crucible, and keep it at 1900°C for 4 hours in a vacuum graphite furnace for high-temperature synthesis. After cooling, high-purity micron-sized hafnium carbide powder is obtained. Embodiment 3:

[0015] A simple preparation method of micron-sized hafnium carbide, the process is: S1, weighing: weighing the raw material powder according to the molar ratio; S2, mixing: put the powder in S1 into a ball mill, add anhydrous ethanol, add two kinds of grinding balls (Si3N4) φ15 / φ10, the mass ratio is 4:1, and ball mill on a planetary ball mill for 6h; S3, drying: the slurry in S2 is placed on a tray and placed in a drying oven with the temperature set at 60°C; S4, synthesis: take out the dry powder in S3 and place it in a graphite crucible, and keep it in a vacuum graphite furnace at 2200°C for 6 hours for high-temperature synthesis. After cooling, high-purity micron-sized hafnium carbide powder is obtained.

Claims

1. A method for preparing micron-sized hafnium carbide powder, characterized in that: The method is prepared by calcining the powder after mixing graphite powder or carbon black with hafnium dioxide by ball milling, wherein the graphite or carbon black used are both micron-sized; the hafnium dioxide is monoclinic 3-5 μm hafnium dioxide, the raw materials are mixed by a planetary ball mill, and calcined at high temperature to cause a solid-solid reaction; the method specifically comprises the following steps: S1. Weighing: weigh the raw material powder according to the molar ratio; the molar ratio is consistent with the ratio of the chemical equation; S2, mixing: put the powder in S1 into a ball mill, add anhydrous ethanol, and add Si3N4 grinding balls of two diameters, and ball mill on a planetary ball mill; S3, drying: placing the slurry in S2 on a tray and placing it in a drying oven; S4, synthesis: take out the dry powder in S3 and place it in a graphite crucible, perform high-temperature synthesis in a vacuum graphite furnace, and obtain high-purity micron-grade hafnium carbide powder after cooling.

2. The method for preparing micron-sized hafnium carbide powder according to claim 1, characterized in that: The diameters of the two Si3N4 ball milling balls are φ15 and φ10 respectively, the mass ratio thereof is 2:1, 3:1 or 4:1, and the ball milling time is 4 to 6 hours.

3. The method for preparing micron-sized hafnium carbide powder according to claim 1, characterized in that: The temperature of the drying oven in S3 is set to 40 ℃ ~ 70 ℃.

4. The method for preparing micron-sized hafnium carbide powder according to claim 1, characterized in that: The atmosphere used for high temperature synthesis in S4 is an inert atmosphere or a reducing atmosphere, and the synthesis temperature is 1600-2300°C.

Images