CN100480438C - Monocrystal AIN nano chain - Google Patents

Abstract

Preparation of a single crystal AlN nano chain of new methods, which includes the following specific steps: (1) Al powder as raw materials, the introduction of 2 to 11 wt% nitric acid containing iron or iron nitrate crystal water as a catalyst; (2) mixtures After mixed evenly placed in the crucible; (3) will be placed crucible furnace atmosphere, all-or nitrogen and ammonia nitrogen gas mixture (4) in 1100 -1450 degree C reaction temperature range, for 2 to 8 hours; (5) With the furnace cooling to room temperature. Compared with the existing technology, the advantages of this invention lies in the preparation of nano-crystal AlN chain structure perfect, low cost, simple technology and equipment, and high-yield, high purity. This unique structure of low dimensional nanostructures used as a nano-device is expected to harsh working conditions in high-temperature environments such as light and thermal conductivity materials, as well as high-pressure environment of field emission source material.

Description

Single crystal AlN nano chain

Technical field

The present invention relates to a kind of preparation method of single crystal AlN nano chain, belong to technical field of material.

Technical background

Nano material is because its unique physics and chemical effect, the character of material will change a lot, produce many new various functional performances that are better than traditional material, have broad application prospects in fields such as fine ceramics, microtronics, biotechnology, chemical industry, medical science.In the research of nanometer material science, the preparation science of low-dimension nano material and structure occupies very consequence, and the microtexture and the performance of nano material had significant effects.And the controlledly synthesis of low-dimension nano material and structure is a major challenge of nanometer preparation science always.Realization will realize being the important foundation that follow-up nano-device successfully prepares to the physics of low-dimension nano material and structure and the microcosmic regulation and control of chemical property to regulation and control on the low-dimension nano material pattern and design.

Aluminium nitride (AlN) is the III-V family semiconductor material with wide forbidden band that paid attention to by people, has good physicals, has the potential application prospect in a lot of fields, as AlN very high thermal conductivity is arranged, good high-temperature insulating property and dielectric properties, heat shock resistance, hot strength is big, the hardness height, thermal expansivity is low, Heat stability is good, encapsulation, media isolated and the insulating material that can be widely used in electron device and unicircuit, be particularly suited for the high temperature high-power component, its energy gap is 6.2eV, is important blue light, ultra-violet light-emitting material.Having good piezoelectricity, high acoustic surface wave propagation speed and higher electromechanical coupling factor along the AlN of C axle orientation, is the preferred piezoelectric of GHz level surface acoustic wave device.In addition, the AlN nano material has excellent field emission performance, is expected to be applied in ultra-thin flat-panel monitor, microwave amplifier with on the valve tube.

Single crystal AlN nano chain is because its special pattern, thereby physical and chemical performance with uniqueness of some expections, this special low-dimensional nano structure is expected to be applied to fields such as some photoelectricity under the harsh working conditions as nano-device, as luminous and thermally conductive material in the hot environment and the field emission source material in the hyperbaric environment.The AlN nano chain rarely has report in the world, and the AlN nano chain output of prior art for preparing is little, and chain-like structure is imperfect, and is restive.

Summary of the invention

Technical problem to be solved by this invention provides the preparation method of the single crystal AlN nano chain that a kind of cost is low, technology is simple, productive rate is high.The equipment of method of the present invention and technology simple controllable, prepared monocrystalline chain-like structure is very perfect, any surface finish, length is 1～100um, width is 50～1000nm, each whisker is formed to hundreds of multiple six bipyramids of uniform size by tens, and each is six pyramids that bipyramid is a dodecahedro again.The single crystal AlN nano chain structure size of this method preparation is even, the purity height, and productive rate is big, has good repeatability.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: the preparation method of this single crystal AlN nano chain, and it comprises following concrete steps:

1) be raw material with the Al powder, the iron nitrate of introducing the iron nitrate of 2～11wt% or containing crystal water is as catalyzer;

2) said mixture is mixed, place crucible;

3) crucible is placed atmosphere furnace, feed reactant gases;

4), be incubated 2～8 hours in 1100～1450 ℃ of temperature range internal reactions;

5) cool to room temperature with the furnace.

In the described step (1), employed raw material is the Al powder, and employed catalyzer is iron nitrate or the iron nitrate that contains crystal water, also can use other magnesium-yttrium-transition metal and rare earth simple substance and compound thereof as catalyzer.

In the described step (2), the ball milling method that is adopted is a planetary ball mill, and mill is situated between and is agate ball, and ball grinder is the nylon resin jar, also can adopt grinding, stirs mill and waits other ways that catalyzer is dispersed in the Al powder.

In the described step (3), the crucible that is adopted is an alumina crucible, also can select other high-temperature crucibles such as graphite, BN for use.

In the described step (4), selected reactant gases is a nitrogen, also can select the mixed gas of nitrogen and ammonia for use.

Compared with prior art, the invention has the advantages that:

1) the prepared very perfection of single crystal AlN nano chain structure of the present invention;

2) the prepared single crystal AlN nano chain structure productive rate height of the present invention can reach 60%;

3) technology and equipment are simple, and is with low cost;

4) synthetic product purity height, institute synthesis of nano chain surface is bright and clean, does not pollute.

Description of drawings

Fig. 1 is low power scanning electron microscope (SEM) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 2 is high power scanning electron microscope (SEM) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 3 is high power scanning electron microscope (SEM) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 4 is X-ray diffraction (XRD) collection of illustrative plates of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 5 is transmission electron microscope (TEM) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 6 is selected diffraction (SAED) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 7 is high-resolution-ration transmission electric-lens (HRTEM) figure of the prepared AlN nano chain of the embodiment of the invention one.

Fig. 8 is high power scanning electron microscope (SEM) figure of the prepared AlN nano chain of the embodiment of the invention two.

Fig. 9 is high power scanning electron microscope (SEM) figure of the prepared AlN nano chain of the embodiment of the invention three.

Embodiment

The present invention is described in further detail below in conjunction with accompanying drawing embodiment.

Embodiment one

Take by weighing Al powder (99% chemical pure, 100～300 orders) and Fe (NO ₃) ₃.9H ₂O (corresponding Fe (NO ₃) ₃The introducing amount be 8wt%, 99% chemical pure) 10g altogether, planetary ball mill is 2 hours in the nylon resin ball grinder of packing into, mixes to be placed in the alumina-ceramic crucible, atmosphere furnace is evacuated to～10Pa, at the 99.99%N of～0.1MPa ₂In the tubular type atmosphere sintering furnace, be warming up to 1350 ℃ from room temperature under the atmosphere, and under this temperature, be incubated 4 hours, cool to room temperature then with the furnace, in crucible, promptly get high-purity in a large number AlN nano chain, as shown in Figure 1 with 15 ℃/min.The length of AlN nano chain is 1～100um, width is 50～1000nm, each nano chain is formed to multiple six bipyramids of hundreds of by tens, each multiple six pyramid that bipyramid is a dodecahedro, size evenly between the ditrigonal bipyramids, chain-like structure is very perfect, and any surface finish is shown in Fig. 2 and 3.The phase composite of the synthetic AlN of institute nano chain is highly purified single wurtzite-type, as shown in Figure 4.Fig. 5,6 and 7 is respectively the TEM of prepared AlN nano chain, and SAED and HRTEM figure show that whole AlN nano chain is a monocrystalline, the crystalline structure perfection.

Embodiment two

Take by weighing Al powder (99% chemical pure, 100～300 orders) and Fe (NO ₃) ₃(introducing amount 4w%, 99% chemical pure) be 10g altogether, and planetary ball mill is 3 hours in the nylon resin ball grinder of packing into, mixes to be placed in the alumina-ceramic crucible, atmosphere furnace is evacuated to～10Pa, at the 99.99%N of～0.1MPa ₂And NH ₃Mixed gas (ammonia accounts for 4vol%) atmosphere under in the tubular type atmosphere sintering furnace, be warming up to 1400 ℃ from room temperature with 15 ℃/min, and under this temperature, be incubated 3 hours, cool to room temperature then with the furnace, promptly get high-purity in a large number AlN nano chain in crucible, its typical pattern as shown in Figure 8.

Embodiment three

Take by weighing Al powder (99% chemical pure, 100～300 orders) and Fe (NO ₃) ₃(introducing amount 4wt%, 99% chemical pure) be 10g altogether, and planetary ball mill is 2 hours in the nylon resin ball grinder of packing into, mixes to be placed in the alumina-ceramic crucible, atmosphere furnace is evacuated to～10Pa, at the 99.99%N of～0.1MPa ₂Be warming up to 1350 ℃ with 15 ℃/min from room temperature under the atmosphere in the tubular type atmosphere sintering furnace, and be incubated 6 hours under this temperature, cool to room temperature then with the furnace, promptly get high-purity in a large number AlN nano chain in crucible, its typical pattern as shown in Figure 9.

The present invention has prepared single crystal AlN nano chain first, compares with the work of having reported, method of the present invention is synthesized AlN nano chain perfect structure, cost is low, equipment and process is simple, productive rate is high, the purity height. The low-dimensional nano junction of this uniqueness Structure is expected to be applied to some photoelectric fields under the harsh condition of work as nano-device, such as the luminous and heat conduction material in the hot environment Field emission source material in material and the hyperbaric environment.

Claims (2)

1, a kind of preparation single crystal AlN nano chain of new methods, it comprises following concrete steps:

1) be raw material with the Al powder, the iron nitrate of introducing the iron nitrate of 2～11wt% or containing crystal water is as catalyzer;

2) said mixture is mixed, place crucible;

3) crucible is placed atmosphere furnace, feed reactant gases;

4), be incubated 2～8 hours in 1100～1450 ℃ of temperature range internal reactions;

5) cool to room temperature with the furnace.

2, the method for preparing single crystal AlN nano chain according to claim 1 is characterized in that: in the described step (3), selected reactant gases is the mixed gas of nitrogen or nitrogen and ammonia.

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