CN104894648A - Preparation method of rod-like lithium disilicate crystal - Google Patents

Abstract

Disclosed is a preparation method of a rod-like lithium disilicate crystal. The method comprises: performing wet ball-milling, drying and sieving of lithium carbonate and silica powder; mixing the dried and sieved mixed powder of raw materials and Na2SO4 via wet ball-milling by using zirconia balls, and performing drying and sieving; loosely putting raw powder of crystal seeds into an alumina crucible for sintering; finally cooling the obtained product to a room temperature to obtain the crystal seeds, and taking the crystal seeds out; stirring the crystal seeds in deionized water at a temperature of 60 DEG C to enable the crystal seeds to be fully dissolved; filtering the obtained solution; performing corrosion with 5 vol% of HF for 1-3h; washing the obtained product with deionized water; and drying the resultant product to obtain the Li2Si2O5 crystal. The rod-like lithium disilicate crystal obtained in the invention is controllable in length-diameter ratio and high in purity, can be taken as an enhancement phase and a toughening phase to be added into a composite material matrix, and has the characteristic of improving mechanical properties of a composite material.

Description

A kind of preparation method of bar-shaped lithium bisilicate crystal

Technical field

The present invention relates to and a kind ofly can be used for the preparation technology that second-phase improves mechanical property, matrix material, particularly a kind of preparation method of bar-shaped lithium bisilicate crystal.

Background technology

Lithium bisilicate devitrified glass is the class stupalith that in biological ceramics, mechanical property and biological property are all relatively more outstanding.Its excellent mechanical property and perfect natural gloss, can reach the color close with natural teeth and outward appearance.And lithium bisilicate crystal itself has high-strength, high-ductility performance, make the theoretic wear resistance of this microcrystalline glass in series and enamel close, the excessive wear of natural teeth can not be caused.The aesthetics of its uniqueness and biological property are that metallic substance and macromolecular material are incomparable.In addition, the coefficient of expansion, the optical refractive index of lithium bisilicate rhabdolith are more suitable, and can reach mating of good thermodynamics and optics with glassy phase, be in All-ceramic restoration system, particularly the preferred material of leaf-comb reparation, shows wide application prospect in All-ceramic restoration field.

But in recent years, regulating and controlling its microstructure by controlling lithium bisilicate glass basis crystallization, reaching attractive in appearance, the satisfied of intensity and toughness be the subject matter of needs solution.Adopt traditional devitrification of glass or powder compact sintering to control matrix crystallization and cannot meet intensity and toughness mates this requirement, and do not affecting on the basis of its optical property, add tough phase to be just restricted, the selection of color makes it possible to the enhancing added, toughness reinforcing phase does not almost have, such as ZrO ₂particle, Si ₃n ₄rhabdolith, fiber etc., all can affect the light transmission of dental lithium bisilicate material.Therefore, lithium bisilicate rhabdolith self toughening glass-ceramic is developed, and the interpolation of this phase not only can not affect optical property, but also can improve the mechanical property of material.The application of lithium bisilicate rhabdolith is also not limited only to dental material, other need the pottery of highly malleablized or matrix material to add, at present, not only about lithium bisilicate rhabdolith as strengthening, the application aspect of toughness reinforcing phase rarely has report, and the preparation of lithium bisilicate rhabdolith also seldom finds or report, this also just for the preparation of lithium bisilicate rhabdolith, market application provide certain reference value, has considerable application prospect and economic worth.

Summary of the invention

In order to overcome the defect of above-mentioned prior art, the object of this invention is to provide a kind of preparation method of bar-shaped lithium bisilicate crystal, the bar-shaped lithium bisilicate crystal length-to-diameter ratio obtained is controlled, purity is high, can be used as wild phase and be toughness reinforcingly added in matrices of composite material, there is the feature of the mechanical property improving matrix material.

For reaching above object, the present invention takes following technical scheme to be achieved:

A preparation method for bar-shaped lithium bisilicate crystal, is characterized in that, comprise the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=(1.5-2.5): 1, carry out mass conversion, take Quilonum Retard and silicon-dioxide powdery, add dehydrated alcohol, the mass ratio adding quality and raw material powder mix is 4:1, adopts zirconia ball wet ball grinding batch mixing at least 8h, then dries, sieves;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux Na ₂sO ₄powder is 1:(1-4 in mass ratio) carry out weighing mixing, add dehydrated alcohol, the total mass ratio of add-on and compound is 1.5:1, adopts zirconia ball wet ball grinding batch mixing at least 5h, then drying and screening;

(3) sinter: crystal seed fecula pine is loaded in alumina crucible, seals, be placed in air furnace, sinter at 900 DEG C-950 DEG C, be incubated at least 1h;

(4) step (3) is cooled to the crystal seed taking-up that room temperature obtains, the deionized water for stirring of 60 DEG C, make it fully dissolve, corrode 1-3h through filtration, 5vol.%HF, washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

Step (1) described raw material Li ₂cO ₃, SiO ₂be of a size of nanometer-micron order, micron order size is no more than 10 μm.

The flux selected described in step (2) is analytical pure anhydrous Na ₂sO ₄powder, purity>=99%, fusing point is 884 DEG C, close to the formation temperature of lithium bisilicate crystal.

Sinter at 900 DEG C-950 DEG C from being placed in air furnace in step (3), the temperature rise rate in its process is 3-10K/min.

The invention has the advantages that:

1, adopt the method for adding flux powder that raw material powder can be made to disperse better, can prepare that high purity, length-to-diameter ratio are controlled, the bar-shaped lithium bisilicate crystal of soilless sticking, technique is simple, cost is low.

2, flux powder Na ₂sO ₄fusing point be 884 DEG C, lower than but close to the synthesis temperature of lithium bisilicate crystal, when 900 DEG C ~ 950 DEG C sintering, the Na of melting ₂sO ₄the synthesis temperature of lithium bisilicate can be reduced significantly and shorten the reaction times of lithium bisilicate formation.

3, in sintering process, raw material mixed powder is solid phase, flux Na ₂sO ₄melting is liquid phase, and namely solid, liquid two-phase coexists, and in mixed powder, Quilonum Retard is decomposed to form LiO at about 618 DEG C ₂, SiO2 and LiO ₂there is certain solubleness in fused solution, Li ⁺, O ^2-mobility in the liquid phase and ion diffusion rates improve, with the SiO dissolved ₂fully and rapid reaction; Moreover, Na ₂sO ₄mixed powder wraps up and is filled in equably between powder by melt, accelerates the diffusion of ion and the carrying out of reaction, and mixed powder is reacted more fully with complete.

Accompanying drawing explanation

Fig. 1 is the invention process case 5 gained Li ₂si ₂o ₅crystal microstructure SEM photo.

Fig. 2 is the invention process case 5 gained Li ₂si ₂o ₅the XRD figure spectrum of crystal.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in further detail.

Embodiment 1

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=1.5, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.216, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 4.52g, nano high purity silicon-dioxide powdery (purity is 99.99%) 5.48g, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=4, adds dehydrated alcohol 75g, adopts zirconia ball wet ball grinding batch mixing 8h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by the crystal seed fecula pine after drying and screening, seal, be placed in air furnace, sinter at 900 DEG C, insulation 1h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, thus purity is very high; Average aspect ratio is 3, and crystal length is 2 ~ 4 μm, and wide is 0.5 ~ 1.2 μm.

Embodiment 2

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=1.5, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.216, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 9.04g, nano high purity silicon-dioxide powdery (purity is 99.99%) 10.96g, add dehydrated alcohol 80g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=2, adds dehydrated alcohol 90g, adopts zirconia ball wet ball grinding batch mixing 8h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by the crystal seed fecula pine after drying and screening, seal, be placed in air furnace, sinter at 900 DEG C, insulation 12h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅; Length-to-diameter ratio reaches more than 10, maximumly can reach 20, and crystal length is 10 ~ 20 μm, and wide is 0.47 ~ 2.48 μm.

Embodiment 3

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.62, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 6.18g, nano high purity silicon-dioxide powdery (purity is 99.99%) 3.82g, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=4, adds dehydrated alcohol 75g, adopts zirconia ball wet ball grinding batch mixing 8h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 920 DEG C, insulation 8h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 1h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, crystal purity is high, and average aspect ratio is 7, and crystal length is 8 ~ 10 μm, and wide is 0.8 ~ 1.56 μm.

Embodiment 4

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.62, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 6.18g, nano high purity silicon-dioxide powdery (purity is 99.99%) 3.82g, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=4, adds dehydrated alcohol 75g, adopts zirconia ball wet ball grinding batch mixing 8h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 920 DEG C, insulation 5h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 1h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅; Average aspect ratio is 5, and crystal length is 3 ~ 6 μm, and wide is 0.3 ~ 0.9 μm.

Embodiment 5

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.62, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 12.36g, nano high purity silicon-dioxide powdery (purity is 99.99%) 7.64g, add dehydrated alcohol 80g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=2, adds dehydrated alcohol 90g, adopts zirconia ball wet ball grinding batch mixing 8h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 945 DEG C, insulation 3h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 1h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅; Average aspect ratio is 6 ~ 10, and average crystal length is 7 ~ 10 μm, and wide is 1 ~ 2 μm.(as shown in accompanying drawing 1, Fig. 2)

Embodiment 6

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.62, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 18.54g, nano high purity silicon-dioxide powdery (purity is 99.99%) 11.46g, add dehydrated alcohol 120g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=1, adds dehydrated alcohol 90g, adopts zirconia ball wet ball grinding batch mixing 5h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 920 DEG C, insulation 7h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 1h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, crystal purity is high, and average aspect ratio is 7, and average crystal length is 5 ~ 8 μm, and wide is 0.8 ~ 2 μm.

Embodiment 7

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2.5, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=2.03, take pure Lithium Carbonate powder (purity is 99.99%) 6.7g and silicon-dioxide powdery (purity is 99.99%) 3.3g that median size is 3 μm, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 8h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=1, adds dehydrated alcohol 30g, adopts zirconia ball wet ball grinding batch mixing 5h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 950 DEG C, insulation 2h, temperature rise rate is 3K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, crystal purity is high, and average aspect ratio is 3, and crystal length is 6 ~ 9 μm, and wide is 2.2 ~ 3 μm.

Embodiment 8

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2.5, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=2.03, take pure Lithium Carbonate powder (purity is 99.99%) 6.7g and silicon-dioxide powdery (purity is 99.99%) 3.3g that median size is 3 μm, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 8h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=1, adds dehydrated alcohol 30g, adopts zirconia ball wet ball grinding batch mixing 5h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 950 DEG C, insulation 10h, temperature rise rate is 3K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅; Average aspect ratio is 6, and crystal length is 9 ~ 15 μm, and wide is 2.48 ~ 3.52 μm.

Embodiment 9

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2.5, carry out mass conversion: mass ratio SiO2/Li ₂cO ₃=2.03, take pure Lithium Carbonate powder (purity is 99.99%) 6.7g and silicon-dioxide powdery (purity is 99.99%) 3.3g that median size is 3 μm, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 8h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=3, adds dehydrated alcohol 60g, adopts zirconia ball wet ball grinding batch mixing 5h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 935 DEG C, insulation 6h, temperature rise rate is 3K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, crystal purity is high, and average aspect ratio is 6 ~ 8, and crystal length is 8 ~ 20 μm, and wide is 2.3 ~ 3.24 μm.

Embodiment 10

A preparation method for bar-shaped lithium bisilicate crystal, comprises the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2.5, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=2.03, take pure Lithium Carbonate powder (purity is 99.99%) 6.7g and silicon-dioxide powdery (purity is 99.99%) 3.3g that median size is 3 μm, add dehydrated alcohol 40g, adopt zirconia ball wet ball grinding batch mixing 8h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄weighing mixing is carried out in powder/raw material powder mix=3, adds dehydrated alcohol 60g, adopts zirconia ball wet ball grinding batch mixing 5h, then revolves on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 950 DEG C, insulation 1h, temperature rise rate is 3K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 3h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

By obtained Li ₂si ₂o ₅crystal carries out SEM to be observed and XRD material phase analysis, records Li ₂si ₂o ₅crystal in crystal prototype only has Li mutually ₂si ₂o ₅, crystal purity is high, and average aspect ratio is 4, and crystal length is 5 ~ 8 μm, and wide is 1.6 ~ 2 μm.

Sample in extraction embodiment 5, as typical sample, carries out SEM and observes and XRD material phase analysis.

Li is measured by SEM ₂si ₂o ₅the microstructure morphology of crystal, XRD tests the thing phase in sample, the phase composite of analytic sample thing.Figure 1 shows that Li ₂si ₂o ₅the SEM photo of crystal, Fig. 2 is Li ₂si ₂o ₅the XRD figure spectrum of crystal.

Li as can be seen from Figure 1 ₂si ₂o ₅crystal is club shaped structure, and crystal length-to-diameter ratio is about 4 ~ 10, and crystallographic dimension has bimodal character, and namely size dimension is evenly interspersed, and this is conducive to the toughness improving material.As can be seen from Figure 2, Li is only had in sample ₂si ₂o ₅crystal phase.Li prepared by the method is described ₂si ₂o ₅crystal has the high feature of purity, and length-to-diameter ratio is controlled.

Claims (5)

1. a preparation method for bar-shaped lithium bisilicate crystal, is characterized in that, comprise the following step:

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=(1.5-2.5): 1, carry out mass conversion, take Quilonum Retard and silicon-dioxide powdery, add dehydrated alcohol, the mass ratio adding quality and raw material powder mix is 4:1, adopts zirconia ball wet ball grinding batch mixing at least 8h, then dries, sieves;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux Na ₂sO ₄powder is 1:(1-4 in mass ratio) carry out weighing mixing, add dehydrated alcohol, the total mass ratio of add-on and compound is 1.5:1, adopts zirconia ball wet ball grinding batch mixing at least 5h, then drying and screening;

(3) sinter: crystal seed fecula pine is loaded in alumina crucible, seals, be placed in air furnace, sinter at 900 DEG C-950 DEG C, be incubated at least 1h;

(4) step (3) is cooled to the crystal seed taking-up that room temperature obtains, the deionized water for stirring of 60 DEG C, make it fully dissolve, corrode 1-3h through filtration, 5vol.%HF, washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.

2. the preparation method of a kind of bar-shaped lithium bisilicate crystal according to claim 1, is characterized in that, step (1) described raw material Li ₂cO ₃, SiO ₂be of a size of nanometer-micron order, micron order size is no more than 10 μm.

3. the preparation method of a kind of bar-shaped lithium bisilicate crystal according to claim 1, it is characterized in that, the flux selected described in step (2) is analytical pure anhydrous Na ₂sO ₄powder, purity>=99%, fusing point is 884 DEG C, close to the formation temperature of lithium bisilicate crystal.

4. the preparation method of a kind of bar-shaped lithium bisilicate crystal according to claim 1, is characterized in that, sinter at 900 DEG C-950 DEG C from being placed in air furnace in step (3), the temperature rise rate in its process is 3-10K/min.

5. the preparation method of a kind of bar-shaped lithium bisilicate crystal according to claim 1, is characterized in that,

(1) acquisition of raw material powder mix: according to mol ratio SiO ₂/ Li ₂cO ₃=2, carry out mass conversion: mass ratio SiO ₂/ Li ₂cO ₃=1.62, taking median size is 5 μm of pure Lithium Carbonate powders (purity is 99.99%) 12.36g, nano high purity silicon-dioxide powdery (purity is 99.99%) 7.64g, add dehydrated alcohol 80g, adopt zirconia ball wet ball grinding batch mixing 10h, mix, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(2) acquisition of crystal seed fecula: by the raw material powder mix after drying and screening and interpolation flux analytical pure Na ₂sO ₄powder (purity>=99%), is: Na in mass ratio ₂sO ₄powder/raw material powder mix=2, carry out weighing mixing, add dehydrated alcohol 90g, adopt zirconia ball wet ball grinding batch mixing 8h, then revolve on a rotary evaporator to steam and loft drier 80 DEG C of drying and screening are put in alcohol oven dry, taking-up;

(3) sinter: loaded in alumina crucible by crystal seed fecula pine, seal, be placed in air furnace, sinter at 945 DEG C, insulation 3h, temperature rise rate is 5K/min, cools to room temperature with the furnace;

(4) crystal seed block step (3) obtained takes out, and the deionized water for stirring of 60 DEG C, makes it fully dissolve, and corrodes 1h through filtration, 5vol.%HF, and washed with de-ionized water is clean, dries and obtains Li ₂si ₂o ₅crystal.