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Semitransparent silicon nitride ceramics and its preparation method

A silicon nitride ceramic, translucent technology, applied in the field of translucent silicon nitride ceramics and its preparation, can solve the problems of long sintering time (several to tens of hours, high energy consumption, high manufacturing cost, etc.

Inactive Publication Date: 2007-05-23
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, ceramic crystals are often bound by strong covalent bonds, and their lattice diffusion coefficient is very low, making sintering very difficult.
Since obtaining a nearly completely dense sintered body is a necessary condition for the preparation of transparent ceramics, the traditional preparation process must face difficulties such as long sintering time (several to tens of hours), high temperature, high energy consumption, complex process and high manufacturing cost.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] α-Si 3 N 4 powder, MgO powder, Y 2 o 3 Powder and Al 2 o 3 Powder mixture is the raw material, where α-Si 3 N 4The mass content of powder is 83%, the mass content of MgO powder is 6%, Y 2 o 3 The mass content of powder is 3%, Al 2 o 3 The mass content of powder is 8%. Ball mill the mixture for 10 hours on a planetary ball mill, alcohol is the ball milling medium, Al 2 o 3 The ball is a milling ball, Al 2 o 3 Ball: Material (α-Si 3 N 4 powder, MgO powder, Y 2 o 3 Powder and Al 2 o 3 powder): alcohol mass ratio=2:1:3. The mixed material after ball milling is dried under vacuum at 83-87°C, sieved through a 100-mesh sieve, and then put into a circular graphite mold with an inner diameter of 20mm. Put the graphite mold into the pulse current sintering furnace, apply an axial pressure of 25MPa, and the 2 Sintering under atmosphere, N 2 The gas pressure is 0.05MPa, and the heating rate is 150°C / min. When the temperature rises to the sintering temperature...

Embodiment 2

[0020] α-Si 3 N 4 powder, MgO powder and Al 2 o 3 Powder mixture is the raw material, where α-Si 3 N 4 The mass content of powder is 90%, the mass content of MgO powder is 5%, Al 2 o 3 The mass content of powder is 5%. Ball mill the mixture for 10 hours on a planetary ball mill, alcohol is the ball milling medium, Al 2 o 3 The ball is a milling ball, Al 2 o 3 Ball: Material (α-Si 3 N 4 powder, MgO powder and Al 2 o 3 powder): alcohol mass ratio=2:1:3. The mixed material after ball milling is dried under vacuum at 83-87°C, sieved through a 100-mesh sieve, and then put into a circular graphite mold with an inner diameter of 20mm. Put the graphite mold into the pulse current sintering furnace, apply an axial pressure of 30MPa, and the 2 Sintering under atmosphere, N 2 The gas pressure is 0.05MPa, and the heating rate is 150°C / min. When the temperature rises to the sintering temperature of 1850°C, it is kept for 15 minutes and then cooled to room temperature with ...

Embodiment 3

[0022] α-Si 3 N 4 powder, MgO powder, Y 2 o 3 Powder and Al 2 o 3 Powder mixture is the raw material, where α-Si 3 N 4 The mass content of powder is 86%, the mass content of MgO powder is 4%, Y 2 o 3 The mass content of powder is 2%, Al 2 o 3 The mass content of powder is 8%. Ball mill the mixture for 10 hours on a planetary ball mill, alcohol is the ball milling medium, Al 2 o 3 The ball is a milling ball, Al 2 o 3 Ball: Material (α-Si 3 N 4 powder, MgO powder, Y 2 o 3 Powder and Al 2 o 3 powder): alcohol mass ratio=2:1:3. The mixed material after ball milling is dried under vacuum at 83-87°C, sieved through a 100-mesh sieve, and then put into a circular graphite mold with an inner diameter of 20mm. Put the graphite mold into the pulse current sintering furnace, apply an axial pressure of 25MPa, and the 2 Sintering under atmosphere, N 2 The gas pressure is 0.05MPa, and the heating rate is 300°C / min. When the temperature rises to the sintering temperatur...

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Abstract

The invention relates to semi-transparent silicon nitride ceramic, which is characterized in that it comprises raw material with their mass proportion as alpha-Si3N4 powder 82-95, Al2O3 powder 2-8, and MgO powder or the mixture of MgO powderand Y2O3 powder 2-10; wherein, when using MgO powder and Y2O3 powder, the added mass of Y2O3 is more than zero but not larger than half total mass of MgO powder and Y2O3 powder. This product has lowest relative density larger than 97% near to theoretical value; the particle has even size with equiaxed alpha-Si3N4 phase as main, and the infrared permeance rate is 30%-45%.

Description

technical field [0001] The invention relates to a translucent silicon nitride ceramic and a preparation method thereof, belonging to the field of non-oxide transparent ceramics. Background technique [0002] Since the advent of transparent alumina ceramics (U.S.P.3026210) in the 1960s, people have prepared a series of oxide transparent ceramic materials, such as MgO, Y 2 o 3 (patent 1562886), YAG (patent 1562880), etc., and are widely used in infrared windows, high temperature windows, and photographic lenses working under high temperature or strong radiation conditions. However, with the development of science and technology, due to the poor mechanical properties, thermal shock resistance and low thermal conductivity of oxide transparent ceramic materials, it is increasingly difficult to meet the requirements of practical applications. [0003] In recent years, nitride ceramic materials have attracted attention because of their excellent com...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/584C04B35/622
Inventor 王皓傅正义王为民王玉成张金咏张清杰
Owner WUHAN UNIV OF TECH
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