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In situ reaction heat pressing synthesized V2AlC bulk ceramic and preparation thereof

An in-situ reaction and bulk technology, applied in the field of single-phase bulk ceramics and its preparation, can solve the problems of time-consuming and labor-consuming, complex process, unfavorable rapid production, etc., and achieve controllable grain size, simple process, and good damage The effect of tolerance

Inactive Publication Date: 2009-07-22
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Gupta used hot isostatic pressing technology to prepare V with vanadium powder, aluminum powder and graphite powder as raw materials. 2 AlC, the process is complex and time-consuming and labor-intensive (insulated at 1600°C for 8 hours, and the applied pressure is 100MPa), and the synthesized sample also contains ~2vol.% Al 2 o 3 Impurities (Journal of the Electrochemical Society, J.Electrochem.Soc.151(2004)D24)
This complex synthesis method is not conducive to rapid production

Method used

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  • In situ reaction heat pressing synthesized V2AlC bulk ceramic and preparation thereof
  • In situ reaction heat pressing synthesized V2AlC bulk ceramic and preparation thereof
  • In situ reaction heat pressing synthesized V2AlC bulk ceramic and preparation thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1 (V1400)

[0022] With 30.54 grams of vanadium powder, 9.72 grams of aluminum powder, and 3.24 grams of graphite powder as raw materials (the molar ratio is 2:1.2:0.9, and the particle size of the raw material powder is 200 mesh), ball milling in a resin tank under dry conditions for 24 hours, after sieving Put it into a graphite mold for cold pressing (10MPa), sinter in a hot-press furnace with argon gas, the heating rate is 15°C / min, sinter at 1400°C, the holding time is 60 minutes, and the applied pressure is 35MPa. The density measured by the Archimedes method is 4.02g / cm 3 , 99% of the theoretical density. X-ray diffraction analysis is all V 2 AlC. The average grain size is 49 μm in length and 19 μm in width. Determination of V 2 The Vickers hardness of AlC bulk ceramics is 2.9GPa, the bending strength is 263MPa, and the fracture toughness is 5.26MPa m 1 / 2 , The compressive strength is 742MPa.

Embodiment 2

[0023] Example 2 (V1500)

[0024] The difference from Example 1 lies in that the molar ratio of raw material powder is different, and the sintering temperature, holding time and applied pressure are different.

[0025] With 30.54 grams of vanadium powder, 9.72 grams of aluminum powder, and 3.6 grams of graphite powder as raw materials (the molar ratio is 2:1.2:1, and the particle size of the raw material powder is 300 mesh), ball milling in a resin tank under dry conditions for 12 hours, after sieving Put it into a graphite mold for cold pressing (10MPa), sinter in a hot-press furnace with argon gas, the heating rate is 15°C / min, sinter at 1500°C, the holding time is 30 minutes, and the applied pressure is 30MPa. The density measured by the Archimedes method is 4.03g / cm 3 , 99% of the theoretical density. X-ray diffraction analysis is all V 2 AlC. The average grain size is 108 μm in length and 37 μm in width. Determination of V 2 The Vickers hardness of AlC bulk ceramics...

Embodiment 3

[0026] Example 3 (V1600)

[0027] The difference from Example 1 is that the molar ratio of raw material powder is different, and the sintering temperature, heating rate, holding time and applied pressure are all different.

[0028] With 30.54 grams of vanadium powder, 8.91 grams of aluminum powder, and 2.88 grams of graphite powder as raw materials (the molar ratio is 2:1.1:0.8, and the particle size of the raw material powder is 400 mesh), ball milling in a resin tank under dry conditions for 12 hours, after sieving Put it into a graphite mold for cold pressing (5MPa), sinter in a hot-press furnace with argon gas, the heating rate is 10°C / min, sinter at 1600°C, the holding time is 30 minutes, and the applied pressure is 25MPa. The density measured by the Archimedes method is 4.01g / cm 3 , 99% of the theoretical density. X-ray diffraction analysis is all V 2 AlC. The average grain size is 119 μm in length and 47 μm in width. Determination of V 2 The Vickers hardness of Al...

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Abstract

The invention relates to single-phase block ceramic and a preparation method thereof, in particular to V2AlC block ceramic synthesized by reaction in-situ and heat pressing and a preparation method thereof. The V2AlC block ceramic comprises single-phase V2AlC; the relative density of the single-phase V2AlC prepared by the reaction in-situ and hot pressing technology is 98 to 99 percent; the average crystal grain size length range of the prepared sample is between 49 and 405 Microns; the width range is between 19 and 106 Microns. Vanadium powder, aluminum powder and black lead powder are used as the materials and grinded for 12 to 24 hours in a resin jar under a drying condition, screened and arranged into a black lead die for cold press forming, then sintered in a hot pressing furnace which is vacuum or pumped with argon; the temperature rising speed is 10 to 15 DEG C / min; the sintering temperature is between 1400 and 1700 DEG C; the heat preservation time is between 30 and 60 minutes; and the applied pressure is between 25 and 35MPa, thereby preparing the V2AlC single-phase ceramic. The invention can prepare the V2AlC block ceramic containing the crystal grains of different sizes under different sintering technique conditions; and the synthesized sample has the characteristics of simple technique, high purity, high density, and good high temperature rigidity.

Description

technical field [0001] The invention relates to single-phase bulk ceramics and a preparation method thereof, in particular to an in-situ reaction hot-pressing synthesis V 2 AlC bulk ceramics and methods for their preparation. Background technique [0002] m n+1 AX n (M is a transition group metal, A is a group A element, X is C or N, n=1-3) has a layered hexagonal structure. Since M.W.Barsoum et al. (Journal of the American Ceramic Society, J.Am.Ceram.Soc.79(1996)1953) synthesized bulk Ti for the first time by reactive hot pressing technique 3 SiC 2 Since, M n+1 AX n With its unique performance, it has attracted the attention of more and more scientific researchers in the world. Briefly, M n+1 AX n The phase has the characteristics of both ceramics and metals: low density, low hardness, high modulus, high fracture toughness, good thermal shock resistance, good electrical and thermal conductivity, and has become a structural material for high-temperature applications...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/56C04B35/645
Inventor 周延春胡春峰包亦望
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI