CN1736949A - Semitransparent nitride multiple phase ceramic and its preparation method - Google Patents

Abstract

The invention relates to semi-transparent nitride ceramic and preparation method. Wherein, the method comprises following steps: 1)selecting raw material according to weight proportion: AlN powder 50-70, alpha-Si3N4 powder 20-40, Y2O3 powder 3-10, Al2O3 powder 0-10; 2)mixing the material on ball grinder for 6-12h; 3)drying in vacuum; 4)putting into pulse current sintering furnace to sinter with axial pressure of 20-30MPa at N2 atmosphere of pressure of 0.01-0.1MPa and heating speed of 50-300Deg/min; 5)cutting, grinding, polishing to mirror face and obtain the product with lowest relative density larger than 97.5% near to theoretical value.

Description

A kind of semitransparent nitride multiple phase ceramic and preparation method thereof

Technical field

The present invention relates to a kind of semitransparent nitride pottery and preparation method thereof, belong to the field of Non-oxide Transparent Ceramics.

Background technology

Since the transparent alumina ceramics sixties in last century (U.S.P.3026210) came out, people had prepared a series of oxidic transparent ceramic materials, such as MgO, Y ₂O ₃(patent publication No. 1562886), YAG (patent publication No. 1562880) etc., and the mirror for taking photograph first-class field extensive use of under infrared window, high temperature window and high temperature or intense radiation conditions, working.Yet,, thereby more and more be difficult to satisfy requirement of actual application because mechanical property, the thermal shock resistance of oxidic transparent stupalith are relatively poor and thermal conductivity is lower along with science and technology development.

In recent years, nitride ceramics receives much attention because of its excellent comprehensive performances, and has successfully prepared transparent AlN pottery (Japanese ceramic industry association will, Vol.93, No.9,1985, pp517-522; Patent 1199036A).Silicon nitride ceramics has good high thermal resistance, thermal conductivity and the mechanical property more excellent than the AlN pottery, is important advanced structural ceramic material.Therefore in the AlN pottery, add the mechanical performance that silicon nitride helps to improve complex phase ceramic.Must possess conditions such as axle such as highly dense solidity, high purity, thing phase composition are simple, the enrichment of crystal boundary inclusion-free, crystal grain yet pottery is transparent.Bibliographical information shows (S.Hampshire and K.H.Jack, " The Kinetics of Densification and PhaseTransformation of Nitrogen Ceramics ", Proc.Br.Ceram.Soc., 31,37-49 (1981)), about 1600 ℃, wait the α-Si of axle ₃N ₄Particle changes the β-Si of long column shape into by dissolving-crystallization mechanism ₃N ₄Although particle is the β-Si of long column shape ₃N ₄But being formed with of particle helps improve the fracture toughness of material is difficult to reach crystalline ceramics for the microstructural requirement of material.Therefore, in high-temperature sintering process, suppress β-Si ₃N ₄The formation of particle is to obtain the having closely knit axle α-Si of grade ₃N ₄The compact structure that particle forms is the key of preparation transparent nitride complex phase ceramic.

Usually the preparation crystalline ceramics is to adopt with no pressure, hot pressed sintering, HIP sintering and the low temperature hot-press sintering technologies such as heat treatment afterwards.Yet ceramic crystal is often with the strong covalent bond combination, and its lattice diffusion coefficient is very low, and sintering is very difficult.Closely knit sintered body is the necessary condition of preparation crystalline ceramics owing to approach fully, adopts therefore that traditional preparation technology's sintering time long (several～tens hour), temperature height, energy consumption are big, complex process and manufacturing cost height.

Summary of the invention

The purpose of this invention is to provide semitransparent nitride multiple phase ceramic of a kind of highly dense solidity and preparation method thereof, this nitride multiple phase ceramic presents the optics translucence, and main phase consists of AlN and α-Si ₃N ₄Phase; This method can suppress β-Si in high-temperature sintering process ₃N ₄The formation of particle, have that sintering time is short, programming rate fast, energy consumption and the time consumption low characteristics.

The present invention is with AlN powder and α-Si ₃N ₄Powder is primary raw material, Y ₂O ₃, Al ₂O ₃Powder is additive, adopts the pulse electric current sintering technology, restrains long column shape β-Si by additive ₃N ₄The formation of particle also prepares the semitransparent silicon nitride complex phase ceramic fast.

Technical scheme of the present invention is: a kind of semitransparent nitride multiple phase ceramic is characterized in that it is by AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃Powder raw material is prepared from, and the shared mass percent of each raw material is: AlN powder 50～70, α-Si ₃N ₄Powder 20～40, Y ₂O ₃Powder 3～10, Al ₂O ₃Powder 0～10.

A kind of preparation method of semitransparent nitride multiple phase ceramic is characterized in that it comprises the steps:

1). choose raw material: be by mass percentage: AlN powder 50～70, α-Si ₃N ₄Powder 20～40, Y ₂O ₃Powder 3～10, Al ₂O ₃Powder 0～10 is chosen AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder, Al ₂O ₃Powder is for subsequent use;

2). with AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder, Al ₂O ₃Powder ball mill mixing 6～12 hours on planetary ball mill, alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (is AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder, Al ₂O ₃Powder): the mass ratio of alcohol=(2～3): 1: (1.5～3);

3). with 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve;

4). the mixture after will sieving directly places graphite jig, puts into the pulse electric current sintering stove then, applies the axle pressure of 20～30MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.01～0.1MPa, and 50～300 ℃/min of heat-up rate when waiting to be warming up to 1750～1950 ℃ of sintering temperatures, cools to room temperature with the furnace behind insulation 0～15min;

5). the material with sintering obtains through cutting, grinding, be polished to minute surface, gets semitransparent nitride multiple phase ceramic.

Al ₂O ₃, Y ₂O ₃Be the sintering aid of the closely knit silicon nitride ceramics of preparation, pyroreaction can take place with the surface oxide layer of silicon nitride and generate liquid phase in these additive metal oxides about 1600 ℃, realize the liquid-phase sintering of silicon nitride ceramics, simultaneously α-Si ₃N ₄In liquid phase, take place to β-Si by dissolving-crystallization mechanism ₃N ₄The transformation of phase.Among the present invention, because the existence of AlN, the liquid phase that generates under the high temperature and AlN react compounds such as generating AlON and are consumed, and make α-Si ₃N ₄Be difficult to undergo phase transition by dissolving-crystallization mechanism.And the α-Si that in the AlN pottery, adds ₃N ₄Mass percent is 20～40, thus the AlN in the raw material enough with system in the liquid phase that produces react, reach supression α-Si ₃N ₄The purpose of phase transformation.

In addition, in conventional with no pressure or hot pressed sintering process, since for a long time insulation under sintering temperature, α-Si ₃N ₄Crystal grain can change β-Si fully into ₃N ₄Crystal grain, and the β-Si that generates ₃N ₄It is Elongated grain that crystal grain has time enough and Growth In Space.The present invention adopts the pulse electric current sintering technology and since exist pulse current with and the new mechanism such as the various field-effect effects of inducing, can realize that sintering time is short, programming rate is fast, energy consumption and the time consumption low.In the pulse electric current sintering process, the densified of nitride multiple phase ceramic finished in several minutes, α-Si ₃N ₄Crystal grain has little time to change into fully β-Si ₃N ₄Crystal grain, the β-Si that generates simultaneously ₃N ₄Crystal grain material before being grown to Elongated grain has reached high packing, and its growth time and space are all limited greatly.Therefore can prepare to wait axle AlN and wait axle α-Si by the pulse electric current sintering technology ₃N ₄Be the closely knit nitride multiple phase ceramic material of main phase mutually.In sintering process, the oxidesintering auxiliary agent of introducing is because of the garnet of the axles such as mutual pyroreaction generation, and these compounds not only have optical transparence but also can restrain AlN and α-Si ₃N ₄The growth of crystal grain, thus obtain even grain size, the axle AlN such as tiny and etc. axle α-Si ₃N ₄Be principal phase mutually, wait the in the inner closely knit silicon nitride ceramic material with optics translucence of section of axle garnet disperse.

The minimum relative density of the semitransparent nitride multiple phase ceramic that preparation method of the present invention obtains is greater than 97.5%, and average relative density is near solid density, and uniform crystal particles is tiny, to wait axle AlN and α-Si ₃N ₄Xiang Weizhu, infrared transmittivity are 30%～55%.

Embodiment

Embodiment 1:

With AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃The mixture of powder is raw material, wherein the mass content of AlN powder be 50%, α-Si ₃N ₄The mass content of powder is 35%, Y ₂O ₃The mass content of powder is 8%, Al ₂O ₃The mass content of powder is 7%.Ball mill mixing is 10 hours on planetary ball mill, and alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃Powder): alcohol quality ratio=2: 1: 3.With 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve; Put into circular graphite jig then, the mould internal diameter is 20mm.Then graphite jig is put into the pulse electric current sintering stove, apply the axle pressure of 25MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.05MPa, and 150 ℃/min of heat-up rate when waiting to be warming up to 1800 ℃ of sintering temperatures, cools to room temperature with the furnace behind the insulation 10min, the material that sintering is obtained, and through cut, grinds, is polished to minute surface, must semitransparent nitride multiple phase ceramic; The relative compaction of this semitransparent nitride multiple phase ceramic is 98.5%, and maximum infrared transmittivity is 41%.Silicon nitride phase composition ratio in the semitransparent nitride multiple phase ceramic is: α-Si ₃N ₄81%, β-Si ₃N ₄19%.

Embodiment 2:

With AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃The mixture of powder is raw material, wherein the mass content of AlN powder be 65%, α-Si ₃N ₄The mass content of powder is 25%, Y ₂O ₃The mass content of powder is 5%, Al ₂O ₃The mass content of powder is 5%.Ball mill mixing is 10 hours on planetary ball mill, and alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃Powder): alcohol quality ratio=2: 1: 3.With 83～87 ℃ of dryings under the mixture vacuum behind ball 3. mills, 100 mesh sieves sieve; Put into circular graphite jig then, the mould internal diameter is 20mm.Then graphite jig is put into the pulse electric current sintering stove, apply the axle pressure of 30MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.05MPa, and 100 ℃/min of heat-up rate when waiting to be warming up to 1850 ℃ of sintering temperatures, cools to room temperature with the furnace behind the insulation 15min, the material that sintering is obtained, and through cut, grinds, is polished to minute surface, must semitransparent nitride multiple phase ceramic.After measured, the relative compaction of this semitransparent nitride multiple phase ceramic is 99.3%, and maximum infrared transmittivity is 53%.Silicon nitride phase composition ratio is in the semitransparent nitride multiple phase ceramic: α-Si ₃N ₄88%, β-Si ₃N ₄12%.

Embodiment 3:

With AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃The mixture of powder is raw material, wherein the mass content of AlN powder be 55%, α-Si ₃N ₄The mass content of powder is 35%, Y ₂O ₃The mass content of powder is 4%, Al ₂O ₃The mass content of powder is 6%.Ball mill mixing is 10 hours on planetary ball mill, and alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃Powder): alcohol quality ratio=2: 1: 3.With 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve; Put into circular graphite jig then, the mould internal diameter is 20mm.Then graphite jig is put into the pulse electric current sintering stove, apply the axle pressure of 25MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.05MPa, and 300 ℃/min of heat-up rate when waiting to be warming up to 1900 ℃ of sintering temperatures, cools to room temperature with the furnace behind the insulation 10min, the material that sintering is obtained, and through cut, grinds, is polished to minute surface, must semitransparent nitride multiple phase ceramic.After measured, the relative compaction of semitransparent nitride multiple phase ceramic is 98.9%, and maximum infrared transmittivity is 45%.Silicon nitride phase composition ratio is in the semitransparent nitride multiple phase ceramic: α-Si ₃N ₄83%, β-Si ₃N ₄17%.

Embodiment 4:

A kind of preparation method of semitransparent nitride multiple phase ceramic, it comprises the steps:

1). choose raw material: be by mass percentage: AlN powder 50, α-Si ₃N ₄Powder 40, Y ₂O ₃Powder 10 is chosen AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder is for subsequent use;

2). with AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder ball mill mixing 6 hours on planetary ball mill, alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (is AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder): the mass ratio of alcohol=2: 1: 1.5;

3). with 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve;

4). the mixture after will sieving directly places graphite jig, puts into the pulse electric current sintering stove then, applies the axle pressure of 20MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.01MPa, and 50 ℃/min of heat-up rate when waiting to be warming up to 1750 ℃ of sintering temperatures, behind the insulation 0min, cools to room temperature with the furnace;

5). the material with sintering obtains through cutting, grinding, be polished to minute surface, gets semitransparent nitride multiple phase ceramic.After measured, the relative compaction of semitransparent nitride multiple phase ceramic is 97.8%, and maximum infrared transmittivity is 32%.Silicon nitride phase composition ratio is in the semitransparent nitride multiple phase ceramic: α-Si ₃N ₄92%, β-Si ₃N ₄8%.

Embodiment 5:

A kind of preparation method of semitransparent nitride multiple phase ceramic, it comprises the steps:

1). choose raw material: be by mass percentage: AlN powder 70, α-Si ₃N ₄Powder 20, Y ₂O ₃Powder 10 is chosen AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder is for subsequent use;

2). with AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder ball mill mixing 12 hours on planetary ball mill, alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (is AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder): the mass ratio of alcohol=3: 1: 3;

3). with 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve;

4). the mixture after will sieving directly places graphite jig, puts into the pulse electric current sintering stove then, applies the axle pressure of 30MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.1MPa, and 300 ℃/min of heat-up rate when waiting to be warming up to 1950 ℃ of sintering temperatures, cools to room temperature with the furnace behind the insulation 15min;

5). the material with sintering obtains through cutting, grinding, be polished to minute surface, gets semitransparent nitride multiple phase ceramic.After measured, the relative compaction of semitransparent nitride multiple phase ceramic is 99%, and maximum infrared transmittivity is 42%.Silicon nitride phase composition ratio is in the semitransparent nitride multiple phase ceramic: α-Si ₃N ₄78%, β-Si ₃N ₄22%.

Embodiment 6:

A kind of preparation method of semitransparent nitride multiple phase ceramic, it comprises the steps:

1). choose raw material: be by mass percentage: AlN powder 60, α-Si ₃N ₄Powder 37, Y ₂O ₃Powder 3 is chosen AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder is for subsequent use;

2). with AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder ball mill mixing 8 hours on planetary ball mill, alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material (is AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder): the mass ratio of alcohol=2.5: 1: 2;

3). with 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve;

4). the mixture after will sieving directly places graphite jig, puts into the pulse electric current sintering stove then, applies the axle pressure of 25MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.05MPa, and 200 ℃/min of heat-up rate when waiting to be warming up to 1850 ℃ of sintering temperatures, cools to room temperature with the furnace behind the insulation 10min;

5). the material with sintering obtains through cutting, grinding, be polished to minute surface, gets semitransparent nitride multiple phase ceramic.After measured, the relative compaction of semitransparent nitride multiple phase ceramic is 99.4%, and maximum infrared transmittivity is 55%.Silicon nitride phase composition ratio is in the semitransparent nitride multiple phase ceramic: α-Si ₃N ₄86%, β-Si ₃N ₄14%.

Claims (2)

1. a semitransparent nitride multiple phase ceramic is characterized in that it is by AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder and Al ₂O ₃Powder raw material is prepared from, and the shared mass percent of each raw material is: AlN powder 50～70, α-Si ₃N ₄Powder 20～40, Y ₂O ₃Powder 3～10, Al ₂O ₃Powder 0～10.

2. the preparation method of a semitransparent nitride multiple phase ceramic is characterized in that it comprises the steps:

1). choose raw material: be by mass percentage: AlN powder 50～70, α-Si ₃N ₄Powder 20～40, Y ₂O ₃Powder 3～10, Al ₂O ₃Powder 0～10 is chosen AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder, Al ₂O ₃Powder is for subsequent use;

2). with AlN powder, α-Si ₃N ₄Powder, Y ₂O ₃Powder, Al ₂O ₃Powder ball mill mixing 6～12 hours on planetary ball mill, alcohol is ball-milling medium, Al ₂O ₃Ball is the ball milling ball, Al ₂O ₃Ball: material: the mass ratio of alcohol=2～3: 1: 1.5～3;

3). with 83～87 ℃ of dryings under the mixture vacuum behind the ball milling, 100 mesh sieves sieve;

4). the mixture after will sieving directly places graphite jig, puts into the pulse electric current sintering stove then, applies the axle pressure of 20～30MPa, at N ₂Carry out sintering, N under the atmosphere ₂Atmospheric pressure is 0.01～0.1MPa, and 50～300 ℃/min of heat-up rate when waiting to be warming up to 1750～1950 ℃ of sintering temperatures, cools to room temperature with the furnace behind insulation 0～15min;

5). the material with sintering obtains through cutting, grinding, be polished to minute surface, gets semitransparent nitride multiple phase ceramic.