CN101746786B

CN101746786B - Method for preparing high-purity alpha-Al2O3 nano-crystalline material

Info

Publication number: CN101746786B
Application number: CN 200810072286
Authority: CN
Inventors: 卢灿忠; 常金晶
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Jianxi nano material technology R & D (Henan) Co.,Ltd.
Priority date: 2008-12-08
Filing date: 2008-12-08
Publication date: 2013-08-14
Anticipated expiration: 2028-12-08
Also published as: CN101746786A

Abstract

The invention relates to a method for preparing a high-purity pha-Al2O3 nano-crystalline material. Firstly, aluminum nitrate is dissolved in an organic solvent containing hydroxyl, then a polyhydroxy organic matter is added in the mixture, and the two kinds of organic matters generate hydroxyl condensation reaction to form a stable network-shaped metal complex. Then, the solution is continuously heated to form a loose large-volume organic precursor. Finally, ground precursor powder is calcined to obtain the uniform high-purity pha-Al2O3 nano-crystalline material. The method has the characteristics of simple process, low cost, short preparation period, high product purity, good repeatability, narrow grain size distribution and good crystallinity.

Description

High-purity α-the Al of a kind of preparation 2O 3The method of nano crystal material

[technical field]

The present invention relates to the high-purity α-Al of a kind of preparation ₂O ₃The method of nano crystal material belongs to crystalline material engineering field.

[background technology]

It is generally acknowledged that the grain fineness number size is referred to as nanocrystalline at the crystalline material of nanometer scale, because of its exclusive constitutional features, has good physico-chemical property and special light,, characteristics such as magnetic, nano crystal material has wide application prospect in many fields of functional materials and structured material, makes its preparation method receive much attention.Wherein, α-Al ₂O ₃Be exactly a kind of very important inorganic nanocrystal material, it is comprising microelectronic device, support of the catalyst, and optics, magneticsubstance, and the wide spectrum of high-strength material etc. all have good application potential.

Preparation nanometer α-Al ₂O ₃The traditional chemical method of material comprises gas-phase reaction method, the precipitator method, sol-gel method, alkoxide hydrolysis, hydro-thermal or solvent thermal process etc.People generally adopt these methods, at first generate hydrated aluminum oxide (AlOOH), under heating condition, AlOOH → β-Al take place then ₂O ₃→ γ-Al ₂O ₃→ α-Al ₂O ₃Transformation, the degree of this transformation then crucially depends on temperature and the soaking time of heating.Usually realize to α-Al ₂O ₃Transformation need carry out being higher than under 1200 ℃ the temperature condition, yet such high-temperature sintering process makes the size of crystal be difficult to control.

In addition, also there is the cost height in various traditional methods, and productive rate is low, and purity is low, complicated operation, equipment requirements height, the shortcomings and limitations of aspects such as contaminate environment.For example, gas-phase reaction method exists productive rate low, and it is difficult to collect, and reactant and gas import the restriction of the structure-design technique of control instability and reactor.Alkoxide hydrolysis and sol-gel method require very strict to reaction control, toxic organic solvent can pollute environment, is not suitable for industrial mass production.So in recent years, investigators attempt to seek the novel method of preparation high quality nano crystal material under mild conditions always.

[summary of the invention]

It is gentle, simple and practical, pollution-free that problem to be solved by this invention provides a kind of processing condition, α-Al that purity is high ₂O ₃The preparation method of nano crystal material, the shortcomings and limitations of solution traditional method.

α-Al provided by the invention ₂O ₃The preparation method of nano crystal material comprises the steps:

(1) with Al (NO ₃) ₃9H ₂O is dissolved in the deionized water of equal in quality, joins in the organic solvent of hydroxyl, forms mixture; The organic solvent of described hydroxyl has any one in following two kinds of basic structures:

The R representative contains the positive alkyl of 1～5 C atom in the general structure;

(2) add the network assistance agent in the mixture, be uniformly mixed into and be precursor solution; Described network assistance agent is the alcohols that contains a plurality of hydroxyls, aldehydes or ketone compounds;

(3) precursor solution is continued heat temperature raising to 180 ℃, constant temperature is naturally cooling after at least 0.5 hour, forms loose large-volume organism presoma;

(4) with the presoma dry grinding, under 1100 ℃ of conditions, calcined 2 hours afterwards, form the powdered product of white after cooling.

Organic solvent is trolamine or tetramethylolmethane described in the abovementioned steps (1).

Network assistance agent described in the abovementioned steps (2) is selected from a kind of in sorbyl alcohol, N.F,USP MANNITOL, pentitol, nucite, maltose or the fructose.

The present invention has following characteristics: the α-Al of the present invention's preparation ₂O ₃Nanocrystal has the pattern of pole shape, and length range is about 150～300nm, and diameter is mostly in 90nm～130nm scope.In the step (1), with Al (NO ₃) ₃9H ₂After the O dissolving, Al ³⁺Form the metal complex with network structure with the organic solvent of hydroxyl; In the step (2), the network assistance agent of adding, can with the condensation reaction of organic solvent generation hydroxyl, the effect of playing protection and strengthening for the network structure of presoma; In the step (4), the NO that forms in the calcination process ₂, NO, CO ₂, H ₂O gas can make the Al that at first forms ₂O ₃Nucleus is separated from each other, and is present in the network structure of presoma in the mode of " embedding "; The volatilization of gas is conducive to the system heat radiation, suppresses to form sintering between small-crystalline; With low cost, technology is simple, and preparation cycle is short, and equipment requirements is low, easy handling; The product purity height, good reproducibility, narrow diameter distribution, good crystallinity, less surface imperfection.The equal nontoxic pollution-free of reaction raw materials, intermediate product and final product.

[description of drawings]

Fig. 1 is the embodiment of the invention 1,2, the infrared spectrogram of 3 three kinds of precursor compounds;

Fig. 2 is the powder x-ray diffraction figure of the embodiment of the invention 1 calcining products therefrom, shows that product is single tripartite phase;

Fig. 3 is the SEM organization chart of the embodiment of the invention 1 calcining products therefrom, and magnification is 100000, shows that product is the pole shape, and three-dimensional dimension is about 100nm * 100nm * 300nm.

[embodiment]

A kind of preparation purity height, particle diameter is even, the α-Al of good crystallinity ₂O ₃The method of nano crystal material.Use the organic solvent of aluminum nitrate and hydroxyl to be raw material, and the poly-hydroxy organism is the network assistance agent.At first, Al ³⁺Form the metal complex presoma with network structure with the organic solvent of hydroxyl, the poly-hydroxy organism network assistance agent of adding, can with the condensation reaction of organic solvent generation hydroxyl, the effect that network structure is played protection and strengthens.Through the presoma after the dry grinding, calcining is 2 hours under 1100 ℃ of air conditionses, obtains α-Al behind the naturally cooling ₂O ₃Nano crystal material.

Fig. 2 is the powder x-ray diffraction figure of embodiment 1 calcining products therefrom, meets trigonal system α-Al fully ₂O ₃Characteristic diffraction peak, do not find other aluminum oxide crystal formation characteristic of correspondence diffraction peak.Fig. 3 is the SEM microtexture pattern of embodiment 1 calcining products therefrom, the α-Al of pole shape ₂O ₃Crystal particle diameter is even, good crystallinity, and there is interconnected phenomenon in intercrystalline, is α-Al ₂O ₃The typical organization of crystal.

Below be specific embodiment:

Embodiment 1:

Take by weighing 1.36g tetramethylolmethane powder, be dissolved in the deionized water, being mixed with concentration is the tetramethylolmethane solution of 0.05g/mL.Take by weighing 1.86g Al (NO ₃) ₃9H ₂The O powder is dissolved in the deionized water of equivalent, joins then in the tetramethylolmethane solution.Take by weighing 1.71g sucrose, join in the mixing solutions, magnetic agitation 20min, speed is 500r/min, becomes precursor solution, the pH value is 3.0～4.0.It is persistently overheating to 180 ℃ that this forerunner's liquid solution is put into process furnace, constant temperature 0.5 hour, treat naturally cooling after, formed the loose large-volume organic precursor.This presoma is dry grinded in agate stone mortar, put into the globars process furnace then, under air ambient, be warming up to 1100 ℃ with the speed of 8～10 ℃/min, calcination time is 2 hours.Gained bright white powder product is pole shape α-Al ₂O ₃Nanocrystal, three-dimensional dimension are about 100nm * 100nm * 300nm.

Embodiment 2:

Take by weighing 1.36g tetramethylolmethane powder, be dissolved in the deionized water, being mixed with concentration is the tetramethylolmethane solution of 0.05g/mL.Take by weighing 1.86g Al (NO ₃) ₃9H ₂The O powder drops in the tetramethylolmethane solution.Take by weighing 1.82g N.F,USP MANNITOL, join in the mixing solutions, magnetic agitation 20min, speed is 500r/min, becomes lurid precursor solution, the pH value is 3.0～4.0.It is persistently overheating to 180 ℃ that this forerunner's liquid solution is put into process furnace, constant temperature 0.5 hour, treat naturally cooling after, formed pale brown look loose large-volume organic precursor.This presoma is dry grinded in agate stone mortar, put into the globars process furnace then, under air ambient, be warming up to 1100 ℃ with the speed of 8～10 ℃/min, calcination time is 2 hours.Gained bright white powder product is pole shape α-Al ₂O ₃Nanocrystal, three-dimensional dimension are about 110nm * 110nm * 300nm.

Embodiment 3:

Take by weighing 1.86g Al (NO ₃) ₃9H ₂The O powder is dissolved in the deionized water of equivalent, joins then in the trolamine solvent.Take by weighing the 1.82g sorbyl alcohol, join in the mixing solutions, magnetic agitation 20min, speed is 500r/min, becomes precursor solution, the pH value is 3.0～4.0.It is persistently overheating to 180 ℃ that this forerunner's liquid solution is put into process furnace, constant temperature 0.5 hour, treat naturally cooling after, formed the loose large-volume organic precursor.This presoma is dry grinded in agate stone mortar, put into the globars process furnace then, under air ambient, be warming up to 1100 ℃ with the speed of 8～10 ℃/min, calcination time is 2 hours.Gained bright white powder product is pole shape α-Al ₂O ₃Nanocrystal, three-dimensional dimension are about 120nm * 120nm * 300nm.

Claims

1. one kind prepares high-purity α-Al ₂O ₃The method of nano crystal material comprises the steps:

(1) with A1 (NO ₃) ₃.9H ₂O is dissolved in the deionized water of equal in quality, joins in trolamine or the tetramethylolmethane, forms mixture;

(2) add the network assistance agent in the mixture, magnetic agitation 20min, speed is 500r/min, becomes the pH value and be 3.0～4.0 precursor solution; Described network assistance agent is selected from a kind of in sorbyl alcohol, N.F,USP MANNITOL, pentitol, nucite, maltose or the fructose;

(3) precursor solution is continued to be heated to 180 ℃, and constant temperature at least 0.5 hour, naturally cooling forms loose large-volume organism presoma then;

(4) with the presoma dry grinding, afterwards 1100 ℃ of calcinings 2 hours, form the powdered product of white after cooling.