CN101700980A - Method for preparing nano-mullite powder by sol-gel-hydrothermal method - Google Patents

Abstract

The invention provides a method for preparing nano-mullite powder by a sol-gel-hydrothermal method. The technical scheme is as follows: tetraethoxysilane is dissolved in ethanol solution, then distilled water is added into the solution and hydrochloric acid is used for regulating the pH value between 2-4, and then mixed solution is obtained through magnetic stirring; the Al (NO3)3.9H2O is dissolved in the distilled water to obtain Al (NO3)3.9H2O solution; the Al (NO3)3.9H2O solution is added into the mixed solution to be mixed evenly through magnetic stirring, and then ammonia water is used for regulating the pH value of the solution between 4.5-5.5 and the solution is placed into a drying oven to be dried to obtain dried gel, the dried gel is placed into a hydrothermal reactor and the distilled water is added into the hydrothermal reactor, then processing is carried out at 200 DEG C for 12-16h, and the samples are taken out and placed into a drying oven to be dried; the dried samples are placed into an alumina crucible and then are placed into a muffle furnace to be heated to 1150-1200 DEG C and the heat is preserved for 2h, thus finally obtaining the nano-mullite powder. The method first adopts the sol-gel method to prepare the mullite dried gel and then selects water as the solvent, and the dried gel is calcined in the muffle furnace after a certain period of hydrothermal processing. The obtained nano-mullite has evenly distributed grain size, controllable shape, short reaction period and good repeatability, thus having extensive development prospect.

Description

The method of collosol and gel-Hydrothermal Preparation 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 for a kind of collosol and gel-Hydrothermal Preparation 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, Crystal structure and compressibility of 3:2 mullite, American Mineralogist[J] .1993,78:1192-1196], coprecipitation method [Zhou M H, Jose MF, etal.Coprecipitation and processing of mullite 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, the method for the collosol and gel of good reproducibility-Hydrothermal Preparation nano mullite powder, and 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 distilled water 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 water then for use is solvent, and hydrothermal treatment consists 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 distilled water 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 distilled water 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 distilled water 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 impurity peaks to occur, and be pure mullite powder, 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. the method for collosol and gel-Hydrothermal Preparation nano mullite powder 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 distilled water 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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