CN101717262A - Method for preparing nano mullite powder by sol-gel and solvothermal method - Google Patents

Abstract

The invention relates to a method for preparing nano mullite powder by sol-gel solvothermal method, including that tetraethoxysilane is dissolved in ethanol solution, distilled water is added in and hydrochloric acid is used for regulating pH value to be 2-4, then stirring by magnetic force is carried out to obtain mixed solution; then Al(NO3)3 9H2O is dissolved in distilled water to obtain Al(NO3)3 9H2O solution; the Al(NO3)3 9H2O solution is added into the mixed solution to be mixed to be uniform by magnetic force stirring, then ammonia water is used for regulating pH value to be 4.5-5.5 and the solution is dried to be dried gel in a drying oven, the dried gel is placed in a hydrothermal kettle and absolute alcohol is added in, treatment is carried out at 200 DEG for 12-16h, and sample is taken out to be dried in the drying oven; the dried sample is placed in an alumina crucible, the alumina crucible is placed in a muffle furnace to be heated to the temperature of 1150-1200 DEG C, and heat preservation is carried out for 2h, thus obtaining the nano mullite powder. In the invention, firstly sol-gel method is adopted to prepare mullite dried gel, then absolute ethanol is used as solvent, the solvent is preheated for a while and then placed in the muffle furnace to be calcined. The obtained mullite has even grain diameter distribution, controllable appearance, short reaction period and good repeatability.

Description

Collosol and gel-solvent-thermal method prepares the method for nano mullite powder

Technical field

The present invention relates to a kind of method for preparing nano mullite powder, be specifically related to the method that a kind of collosol and gel-solvent-thermal method prepares nano mullite powder.

Background technology

Mullite (mullite) is a kind of very practical 26S Proteasome Structure and Function material, have the good characteristic that other ceramic does not possess, as lower heat-conduction coefficient and thermal expansivity, high creep resistance and thermal shock resistance, excellent electric insulation, chemical stability and hot strength etc., can be used as high-temperature structural material, infrared transparent window, microelectronics base material also can be used as catalyst support material.Be widely used in making engineering materials, refractory materials and supercoat material, the Mullite porcelain that with the mullite is principal crystalline phase is then because the ideal material that low specific inductivity, low thermal expansivity and good electrical insulation properties are considered to modern novel computer component package.Mullite material (comprising mullite ceramic and based on mullite matrix material etc.) is that raw material makes with the mullite powder normally, and its performance depends on the quality of mullite powder.High-purity, superfine mullite powder can not only reduce the firing temperature of mullite material, and can improve the microstructure of material, improves its performance greatly.So preparation, especially the purity height of mullite powder, the preparation of the ultra-fine mullite powder of fine particles and hard aggregation-free just occupies crucial status in mullite material research.

Up to the present, the mullite nano crystalline substance is synthesized by several methods, as sol-gel method [Bulzar D, Lebdetter H, 3: 2 mullite of Crystal structure and compressibility of, American Mineralogist[J] .1993,78:1192-1196], coprecipitation method [Zhou M H, Jose M F, etal.Coprecipitation and processing ofmullite precursor phases[J] .J.Am.Ceram.Soc.1996,79 (7): 1756], hydrolysis-precipitator method [Xu Mingxia, Cui Feng, Deng. ultra micro mullite powdered preparation novel process [J]. silicate journal, 1991,19 (1): 80], hydrothermal crystallization method [Xue Rujun, Wang faithful and upright person, high China. the research [J] of hydro-thermal mullite synthesizing ultrafine powder particle stability. Anhui University of Science and Technology's journal, 2006,26 (2): 58-60], spray pyrolysis [Kanzaki S, Tabata H.Sintering and mechanicalproperties of stoichiometric mullite[J] .J.Am.Ceram.Soc., 1985,68 (1): C6] or the like.These methods or to the equipment requirements height, equipment and instrument are relatively more expensive; Very little to utilization ratio of raw materials; Perhaps complex process, preparation cycle is long, and is repeatable poor.In order to reach the purpose of practicability, the preparation technology of the nano mullite powder that necessary Development and Production cost is low, simple to operate, the cycle is short.

Summary of the invention

The object of the present invention is to provide and a kind ofly can reduce preparation cost, lack simple to operate, reaction time, collosol and gel-the solvent-thermal method of good reproducibility prepares the method for nano mullite powder, it is little that method of the present invention can be prepared particle diameter, narrow distribution range, the nano mullite powder that pattern is controlled.

For achieving the above object, the technical solution used in the present invention is:

1) at first, getting the 5-10ml tetraethoxy is dissolved in the analytically pure ethanolic soln, get solution A to wherein adding distilled water again, tetraethoxy wherein: ethanol: the volume ratio of distilled water is 1: 4: 2～4, transferring the pH value of solution A with hydrochloric acid is 2～4, solution A after will regulating with hydrochloric acid then places the beaker that seals with preservative film, and magnetic agitation makes tetraethoxy prehydrolysis obtain mixing solutions B at normal temperatures;

2) then, according to Si: the mol ratio of Al is that 1: 3 ratio is got analytically pure Al (NO ₃) ₃9H ₂O puts into beaker, and adds the distilled water of 10-20ml in beaker, and magnetic agitation makes Al (NO at normal temperatures ₃) ₃9H ₂O dissolve fully Al (NO ₃) ₃9H ₂O solution;

3) with Al (NO ₃) ₃9H ₂Magnetic agitation mixes in the O solution adding solution B, and regulating the pH value with ammoniacal liquor then is that 4.5-5.5 gets mixed solution C;

4) mixed solution C is placed baking oven, drying down at 60-80 ℃ is xerogel, xerogel is placed water heating kettle again, in water heating kettle, add dehydrated alcohol again, add to water heating kettle volumetrical 1/2-2/3 place, then handle 12h-16h down, take out sample and place baking oven to dry at 200 ℃;

5) sample after will drying places alumina crucible, places retort furnace, and it is 5 ℃/min that temperature rise rate is set, and makes it be warming up to 1150-1200 ℃, insulation 2h, then at the stove internal cooling to room temperature, promptly finally obtain nano mullite powder.

The present invention goes out the mullite xerogel with Prepared by Sol Gel Method earlier, and selecting dehydrated alcohol then for use is solvent, and solvent heat treatment places retort furnace to calcine after for some time again.Gained nano mullite size distribution is even, and pattern is controlled, and reaction time is short, and therefore good reproducibility has vast potential for future development.

Description of drawings

Fig. 1 is the XRD figure spectrum of the nano mullite powder that makes of the present invention;

Fig. 2 is the SEM picture of the nano mullite powder that makes of the present invention.

Embodiment

Embodiment 1:

1) at first, getting the 5ml tetraethoxy is dissolved in the analytically pure ethanolic soln, get solution A to wherein adding distilled water again, tetraethoxy wherein: ethanol: the volume ratio of distilled water is 1: 4: 2, transferring the pH value of solution A with hydrochloric acid is 4, solution A after will regulating with hydrochloric acid then places the beaker that seals with preservative film, and magnetic agitation makes tetraethoxy prehydrolysis obtain mixing solutions B at normal temperatures;

2) then, according to Si: the mol ratio of Al is that 1: 3 ratio is got analytically pure Al (NO ₃) ₃9H ₂O puts into beaker, and adds the distilled water of 10ml in beaker, and magnetic agitation makes Al (NO at normal temperatures ₃) ₃9H ₂O dissolve fully Al (NO ₃) ₃9H ₂O solution;

3) with Al (NO ₃) ₃9H ₂O solution adds that magnetic agitation mixes in the solution B, and regulating pH value with ammoniacal liquor then is 4.5 must mixed solution C;

4) mixed solution C is placed baking oven, drying down at 60 ℃ is xerogel, xerogel is placed water heating kettle again, in water heating kettle, add dehydrated alcohol again, add to water heating kettle volumetrical 1/2-2/3 place, then handle 12h down, take out sample and place baking oven to dry at 200 ℃;

5) sample after will drying places alumina crucible, places retort furnace, and it is 5 ℃/min that temperature rise rate is set, and makes it be warming up to 1150 ℃, insulation 2h, then at the stove internal cooling to room temperature, promptly finally obtain nano mullite powder.

Embodiment 2:

1) at first, getting the 8ml tetraethoxy is dissolved in the analytically pure ethanolic soln, get solution A to wherein adding distilled water again, tetraethoxy wherein: ethanol: the volume ratio of distilled water is 1: 4: 3, transferring the pH value of solution A with hydrochloric acid is 3, solution A after will regulating with hydrochloric acid then places the beaker that seals with preservative film, and magnetic agitation makes tetraethoxy prehydrolysis obtain mixing solutions B at normal temperatures;

2) then, according to Si: the mol ratio of Al is that 1: 3 ratio is got analytically pure Al (NO ₃) ₃9H ₂O puts into beaker, and adds the distilled water of 15ml in beaker, and magnetic agitation makes Al (NO at normal temperatures ₃) ₃9H ₂O dissolve fully Al (NO ₃) ₃9H ₂O solution;

3) with Al (NO ₃) ₃9H ₂O solution adds that magnetic agitation mixes in the solution B, and regulating pH value with ammoniacal liquor then is 5 must mixed solution C;

4) mixed solution C is placed baking oven, drying down at 70 ℃ is xerogel, xerogel is placed water heating kettle again, in water heating kettle, add dehydrated alcohol again, add to water heating kettle volumetrical 1/2-2/3 place, then handle 14h down, take out sample and place baking oven to dry at 200 ℃;

5) sample after will drying places alumina crucible, places retort furnace, and it is 5 ℃/min that temperature rise rate is set, and makes it be warming up to 1170 ℃, insulation 2h, then at the stove internal cooling to room temperature, promptly finally obtain nano mullite powder.

Embodiment 3:

1) at first, getting the 10ml tetraethoxy is dissolved in the analytically pure ethanolic soln, get solution A to wherein adding distilled water again, tetraethoxy wherein: ethanol: the volume ratio of distilled water is 1: 4: 4, transferring the pH value of solution A with hydrochloric acid is 2, solution A after will regulating with hydrochloric acid then places the beaker that seals with preservative film, and magnetic agitation makes tetraethoxy prehydrolysis obtain mixing solutions B at normal temperatures;

2) then, according to Si: the mol ratio of Al is that 1: 3 ratio is got analytically pure Al (NO ₃) ₃9H ₂O puts into beaker, and adds the distilled water of 20ml in beaker, and magnetic agitation makes Al (NO at normal temperatures ₃) ₃9H ₂O dissolve fully Al (NO ₃) ₃9H ₂O solution;

3) with Al (NO ₃) ₃9H ₂O solution adds that magnetic agitation mixes in the solution B, and regulating pH value with ammoniacal liquor then is 5.5 must mixed solution C;

4) mixed solution C is placed baking oven, drying down at 80 ℃ is xerogel, xerogel is placed water heating kettle again, in water heating kettle, add dehydrated alcohol again, add to water heating kettle volumetrical 1/2-2/3 place, then handle 16h down, take out sample and place baking oven to dry at 200 ℃;

5) sample after will drying places alumina crucible, places retort furnace, and it is 5 ℃/min that temperature rise rate is set, and makes it be warming up to 1200 ℃, insulation 2h, then at the stove internal cooling to room temperature, promptly finally obtain nano mullite powder.

Referring to Fig. 1, prepared as seen from Figure 1 sample does not have the impurity phase, prove that prepared powder is purer, and the peak type is sharp-pointed, and crystal property is better.

Referring to Fig. 2, prepared as seen from Figure 2 sample topography is a club shaped structure, and it is more serious to reunite, and this has proved that also particle size is smaller, and the size distribution of powder is more even.

Claims (1)

1. collosol and gel-solvent-thermal method prepares the method for nano mullite powder, it is characterized in that:

1) at first, getting the 5-10ml tetraethoxy is dissolved in the analytically pure ethanolic soln, get solution A to wherein adding distilled water again, tetraethoxy wherein: ethanol: the volume ratio of distilled water is 1: 4: 2～4, transferring the pH value of solution A with hydrochloric acid is 2～4, solution A after will regulating with hydrochloric acid then places the beaker that seals with preservative film, and magnetic agitation makes tetraethoxy prehydrolysis obtain mixing solutions B at normal temperatures;

2) then, according to Si: the mol ratio of Al is that 1: 3 ratio is got analytically pure Al (NO ₃) ₃9H ₂O puts into beaker, and adds the distilled water of 10-20ml in beaker, and magnetic agitation makes Al (NO at normal temperatures ₃) ₃9H ₂O dissolve fully Al (NO ₃) ₃9H ₂O solution;

3) with Al (NO ₃) ₃9H ₂Magnetic agitation mixes in the O solution adding solution B, and regulating the pH value with ammoniacal liquor then is that 4.5-5.5 gets mixed solution C;

4) mixed solution C is placed baking oven, drying down at 60-80 ℃ is xerogel, xerogel is placed water heating kettle again, in water heating kettle, add dehydrated alcohol again, add to water heating kettle volumetrical 1/2-2/3 place, then handle 12h-16h down, take out sample and place baking oven to dry at 200 ℃;

5) sample after will drying places alumina crucible, places retort furnace, and it is 5 ℃/min that temperature rise rate is set, and makes it be warming up to 1150-1200 ℃, insulation 2h, then at the stove internal cooling to room temperature, promptly finally obtain nano mullite powder.

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