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Silicon nitride ceramic and preparation method thereof

A technology of silicon nitride ceramics and phase silicon nitride, which is applied in the field of ceramic materials, can solve the problems of unimproved wear resistance, high fracture toughness, and unavailability, and achieve improved wear resistance, toughness, and high strength. Effect

Active Publication Date: 2015-11-04
GUANGDONG UNIV OF TECH
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

For example, U.S. Patent US8652981B2 discloses a method of improving the mechanical and thermal properties of silicon nitride ceramics by using metal oxides and complex rare earths, but its wear resistance has not been improved.
And U.S. Patent US7056850 discloses a method of using rare earth and wear-resistant additives to improve the wear resistance and bending strength of silicon nitride ceramics, but the cost of this method is that high fracture toughness and high thermal conductivity cannot be obtained

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  • Silicon nitride ceramic and preparation method thereof
  • Silicon nitride ceramic and preparation method thereof
  • Silicon nitride ceramic and preparation method thereof

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preparation example Construction

[0022] The preparation method of the silicon nitride ceramics of embodiment 1-4 is as follows:

[0023] (1) Mixing: add metal oxides, rare earth oxide mixtures and wear-resistant additives (if wear-resistant additives are used) into absolute ethanol; then ultrasonic (power 200-1000w, frequency 20-60KHz) dispersion 10min; then add silicon nitride grinding balls whose mass is 3 times the total mass of metal oxide, rare earth oxide mixture and wear-resistant additive to the mixture, and ball mill for 2h; continue to add α-phase silicon nitride powder to the mixture, and then Ultrasonic (power 200-1000w, frequency 20-60KHz) dispersed for 10 minutes, and then ball milled for 12 hours. If β-phase silicon nitride crystals are added, continue to add β-phase silicon nitride crystals to the mixture at this time, and continue ball milling for 2 hours. The components are fully mixed uniformly to obtain a slurry. The mass of absolute ethanol is 1-5 times of the total mass of components f...

Embodiment 5

[0038] Compared with Example 4, the present embodiment is different in that: by 5.56gYb 2 o 3 and 5.56gLa 2 o 3 The composition of the rare earth oxide mixture was changed to 11.12g of Yb 2 o 3 . Other components and amounts, and the method of preparation are exactly the same.

[0039] The above Examples 1-5 are all sintered by hot pressing sintering, and in other embodiments, sintering can also be carried out by using the above-mentioned pressureless sintering, air pressure sintering, hot isostatic pressing sintering and other methods.

[0040] The silicon nitride ceramics prepared in Examples 1-5 were respectively processed with diamond tools, and a plurality of 3mm×4mm×45mm splines were made from the silicon nitride ceramics of each example. The spline made of the silicon nitride ceramics of Example 1 is marked as No. 1 spline, and the splines made of the silicon nitride ceramics of Examples 2-5 are correspondingly marked as No. 2-5 splines. No. 1-5 specimens are use...

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Abstract

The invention relates to the technical field of ceramic materials, in particular to a silicon nitride ceramic and a preparation method thereof. The preparation method comprises the steps that a rare earth oxide mixture, a beta-phase silicon nitride crystal and a wear-resisting additive are added in an alpha-phase silicon nitride powder, mixing, drying, forming and sintering are carried out, and therefore the silicon nitride ceramic with high tenacity, strength, heat conductive rate and wear resistance is obtained. Due to the fact that the rare earth oxide mixture is added into silicon nitride, the crystal boundary can be effectively weakened, and the silicon nitride ceramic tenacity, strength and heat conductivity are significantly improved; then the beta-phase silicon nitride crystal is added, so that the bimodal distribution structure of silicon nitride crystal particles is obtained at the same time, and the silicon nitride ceramic tenacity, strength and heat conductivity are further improved; the wear-resisting additive is added, so that the silicon nitride ceramic wear resistance is significantly improved, the silicon nitride ceramic tenacity, strength and heat conductivity are not affected, and the silicon nitride ceramic has the high tenacity, strength, heat conductive rate and wear resistance at the same time.

Description

technical field [0001] The invention relates to the technical field of ceramic materials, in particular to silicon nitride ceramics and a preparation method thereof. Background technique [0002] Structural ceramics have been widely studied and applied due to their high hardness, low density, high strength, corrosion resistance, high temperature resistance and many other advantages. They are mainly used in extreme environments such as high temperature, corrosion, strong wear and some electronic components, such as ceramics Engine turbines, cast aluminum crucibles, knives, bearing balls, heat dissipation substrates, etc. However, the brittleness of ceramic materials greatly limits its application in these fields. Researches in recent decades have toughened ceramics through various methods, such as particle dispersion toughening, phase transformation toughening, whisker toughening, self-toughening, etc., which have improved the toughness of ceramics to a certain extent, but t...

Claims

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Application Information

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IPC IPC(8): C04B35/584C04B35/622
Inventor 伍尚华蒋强国郭伟明熊明秦杰古尚贤付君宇童文欣
Owner GUANGDONG UNIV OF TECH
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