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High-toughness Si3N4 ceramic preparation method

A high-toughness, -si3n4 technology, applied in the field of preparation of high-toughness Si3N4 ceramics, to achieve the effect of improving fracture toughness, excellent comprehensive mechanical properties, and improving fracture toughness

Inactive Publication Date: 2015-09-23
GUANGDONG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Then, what kind of morphology of β-Si 3 N 4 Seeding can maximize Si 3 N 4 The fracture toughness of ceramics has not been specifically reported in this regard.

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0032] The high toughness Si of the present invention 3 N 4 The preparation method of pottery, comprises the steps:

[0033] (1) with Si 3 N 4 Powder as raw material, with β-Si 3 N 4 as the seed crystal, with Re 2 o 3 is a sintering aid, in which β-Si 3 N 4 The seed crystal is self-made β-Si with specific morphology 3 N 4 Seed, its aspect ratio is 3.0-5.0, diameter is 0.30-0.60μm, Re=Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , any of Yb, Lu, Si 3 N 4 Powder, β-Si 3 N 4 Seed and Re 2 o 3 The mass fraction ratio of is:

[0034] Si 3 N 4 Powder 75-98wt%

[0035] β-Si 3 N 4 Seed 1-10wt%

[0036] Re 2 o 3 1-15wt%

[0037] (2) Si 3 N 4 Powder, β-Si 3 N 4 Seed and Re 2 o 3 To mix:

[0038] (3) After drying and high-temperature hot-pressing sintering, Si with high toughness can be obtained. 3 N 4 ceramics.

[0039] In this example, Re=Lu, the preparation of high toughness Si 3 N 4 The specific method of ceramics is as follows:

...

Embodiment 2

[0044] In this example, Re=Lu, the preparation of high toughness Si 3 N 4 The specific method of ceramics is as follows:

[0045] β-Si with a self-made aspect ratio of 4.2 and a diameter of 0.44 μm 3 N 4 as the seed crystal, with Lu 2 o 3 (99.9% purity) is a sintering aid according to Si 3 N 4 Powder mass fraction is 75wt%, β-Si 3 N 4 The seed mass fraction is 10wt%, Lu 2 o 3 The mass fraction ratio is 15wt% to carry out batching, prepares Si according to embodiment 1 method 3 N 4 ceramics. The relative density of the prepared ceramic material is 97%, the Vickers hardness is 14.3GPa, and the fracture toughness measured by indentation method is 8.5MPa m 1 / 2 , The three-point bending strength is 685Mpa.

Embodiment 3

[0047] In this example, Re=Lu, the preparation of high toughness Si 3 N 4 The specific method of ceramics is as follows:

[0048] β-Si with a self-made aspect ratio of 4.2 and a diameter of 0.44 μm 3 N 4 as the seed crystal, with Lu 2 o 3 (99.9% purity) is a sintering aid according to Si 3 N 4 Powder mass fraction is 90wt%, β-Si 3 N 4 The seed mass fraction is 1wt%, Lu 2 o 3 The mass fraction ratio is 9wt% to carry out batching, prepares Si according to embodiment 1 method 3 N 4 ceramics. The relative density of the prepared ceramic material is 99%, the Vickers hardness is 17.3GPa, and the fracture toughness measured by indentation method is 8.7MPa m 1 / 2 , The three-point bending strength is 860Mpa.

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Abstract

The invention discloses a high-toughness Si3N4 ceramic preparation method. The high-toughness Si3N4 ceramic preparation method comprises the following steps: (1) adopting Si3N4 powder as a raw material, beta-Si3N4 as seed crystals and Re2O3 as a sintering additive, wherein beta-Si3N4 seed crystals are self-made beta-Si3N4 seed crystals in specific shapes, and are 3.0-5.0 in length-diameter ratio and 0.30-0.60 [mu]m in diameter, Re is any one of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and the mass fractions of Si3N4 powder, beta-Si3N4 crystals and Re2O3 are respectively 75-98 wt%, 1-10 wt% and 1-15 wt%; (2) mixing Si3N4 powder, beta-Si3N4 seed crystals and Re2O3; (3) performing drying and high-temperature hot-press sintering on the mixture to obtain the high-toughness Si3N4 ceramic, wherein the sintering temperature is 1700-1900 DEG C and kept for 0.5-4 h. The high-toughness Si3N4 ceramic has the relatively density being equal to or higher than 95%, the fracture toughness measured by the indentation method is 5-10 MPa.m<1 / 2>, and the excellent comprehensive mechanical properties of high hardness and bending strength and the like are maintained.

Description

technical field [0001] The invention relates to the field of non-oxide-based ceramic materials, and specifically discloses a high-toughness Si 3 N 4 Methods of preparation of ceramics. Background technique [0002] Si 3 N 4 Ceramics have excellent properties such as wear resistance, high temperature resistance, and high thermal conductivity, and are widely used in LED heat dissipation substrates, high-speed cutting tools, and key engine parts. However, the inherent high brittleness and low toughness greatly limit the Si 3 N 4 Ceramic applications. [0003] In order to improve Si 3 N 4 For the fracture toughness of ceramics, researchers mainly study from the aspect of "microstructure design". 3 N 4 Ceramics form long rod-shaped grains, realize self-toughening, and obtain high toughness Si 3 N 4 ceramics. There are two main methods to achieve self-toughening structure: (1) in Si 3 N 4 Add appropriate Re to the powder 2 o 3 (Re=Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/596C04B35/593
Inventor 郭伟明熊明伍尚华蒋强国古尚贤
Owner GUANGDONG UNIV OF TECH
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