CN108301041A - A kind of crucible used for polycrystalline silicon ingot casting and preparation method thereof - Google Patents

Abstract

The present invention relates to a kind of crucible used for polycrystalline silicon ingot casting and preparation method thereof, including vitreous silica and Thermal conductive additives, the weight ratio of the compounding of one or both of the Thermal conductive additives for silicon carbide, in aluminium oxide, the vitreous silica and Thermal conductive additives is (1~3)：1.The beneficial effects of the invention are as follows：Crucible provided by the invention has good heat conductivility, and compared with the fused silica crucible on existing market, thermal conductivity improves 40% or more, not only improves the quality of long crystalline substance, and shortens the long brilliant period, and the ingot casting production capacity of ingot furnace greatly improved.

Description

A kind of crucible used for polycrystalline silicon ingot casting and preparation method thereof

Technical field

The present invention relates to a kind of crucible and preparation method thereof more particularly to a kind of crucible used for polycrystalline silicon ingot casting and its preparation sides Method belongs to solar-photovoltaic technology field.

Background technology

Photovoltaic generation is one of currently the most important clean energy resource, has great development potentiality.Restrict photovoltaic industry hair On the one hand the key factor of exhibition is that electricity conversion is low, is on the other hand high expensive.Photovoltaic silicon wafer is production solar-electricity The basic material in pond and component, for produce photovoltaic silicon wafer polysilicon purity must (i.e. non-silicon impurities always contain at 6N grades or more Amount is in 1ppm or less), otherwise the performance of photovoltaic cell will be by prodigious negative effect.

Existing usually used polysilicon ingot crucible is the fused silica crucible that purity is 99.9%, and vitreous silica is high The pure silica high viscosity silica glass that chilling obtains after high-temperature fusion, is a kind of high-energy amorphous state substance, has The features such as coefficient of thermal expansion is small, conductance hot property is low, good thermal shock, meanwhile, it is prepared by primary raw material of vitreous silica particle Fused quartz ceramic crucible because there are the intergranular micro-pore of a large amount of vitreous silica, can avoid or reduce vitreous silica The harm of surface tensile stress crack propagation in crystallization process caused by bulk effect, further improves the safe to use of material Property.

But there are one notable disadvantages for existing fused silica crucible：The thermal conductivity of quartz is very poor, polycrystalline silicon ingot casting mistake Silicon material heating is highly difficult in journey, and long crystalline substance process heat dissipation is slow and Vertical Temperature Gradient is difficult to pull-up, increases temperature during ingot casting The difficulty of gradient control, is unfavorable for the oriented growth of silicon crystal, and the crystal growth quality to influence silicon ingot finally influences battery efficiency, Thus how to improve silica crucible thermal conductivity is the key that need to solve the problems, such as this.

Invention content

The present invention provides a kind of polycrystalline silicon ingot casting for deficiency existing for existing polycrystalline silicon ingot casting fused silica crucible With crucible and preparation method thereof.

The technical solution that the present invention solves above-mentioned technical problem is as follows：

A kind of crucible used for polycrystalline silicon ingot casting, including vitreous silica and Thermal conductive additives, the Thermal conductive additives are silicon carbide, oxidation The weight ratio of the compounding of one or both in aluminium, the vitreous silica and Thermal conductive additives is (1~3)：1.

Further, the impurity content control of the vitreous silica is as follows：Iron oxide<40ppm, aluminium oxide<1000ppm, alkali Tenor<50ppm；The impurity content control of the silicon carbide is as follows：Iron oxide<40ppm, alkali metal content<50ppm；Institute The impurity content control for stating aluminium oxide is as follows：Iron oxide<40ppm, alkali metal content<50ppm.

The preparation method of above-mentioned crucible used for polycrystalline silicon ingot casting is also claimed in the present invention, includes the following steps：

1) Thermal conductive additives are added into raw material as raw material for the tekite sand using granularity within 500 μm, and the heat conduction helps The weight ratio of the compounding of one or both of the agent for silicon carbide, in aluminium oxide, the vitreous silica and Thermal conductive additives is (1~3)： 1, crucible green compact are obtained using casting molding technique afterwards, it is dry；

2) be sintered in the environment of the green compact after drying being placed in 1000~1400 DEG C 10~56 hours to get.

Further, the casting molding technique is using acrylamide gels system.

Further, the tekite sand be purity 99.9% or more varigrained quartz powder materials mixture.

The beneficial effects of the invention are as follows：

Crucible used for polycrystalline silicon ingot casting provided by the invention has good heat conductivility, with the vitreous silica on existing market Crucible is compared, and thermal conductivity improves 40% or more, not only improves the quality of long crystalline substance, and shortens the long brilliant period, is substantially carried The high ingot casting production capacity of ingot furnace.

Specific implementation mode

Principles and features of the present invention are described below in conjunction with example, the given examples are served only to explain the present invention, and It is non-to be used to limit the scope of the present invention.

The impurity content control of tekite sand used in the embodiment of the present invention is as follows：Iron oxide<40ppm, aluminium oxide< 1000ppm, alkali metal content<50ppm；The impurity content control of silicon carbide is as follows：Iron oxide<40ppm, alkali metal content< 50ppm；The impurity content control of aluminium oxide is as follows：Iron oxide<40ppm, alkali metal content<50ppm.

Embodiment 1：

A kind of crucible used for polycrystalline silicon ingot casting, including vitreous silica and Thermal conductive additives, Thermal conductive additives are silicon carbide, vitreous silica Weight ratio with silicon carbide is 3：1.

The preparation method of above-mentioned crucible is as follows：

Will 50 parts by weight blout sand input ball mill in carry out wet ball grinding, size controlling within 10 microns, Then 50~100 microns of addition, 250~350 microns of each 20 parts of vitreous silica after ageing 10 days, 30 parts of silicon carbide are added single Body acrylamide, crosslinking agent methylene-bisacrylamide and initiator ammonium persulfate are sufficiently stirred, and are sufficiently stirred until slurry temperature Degree reaches 30 DEG C, and froth in vacuum after physical and chemical index detection is qualified, rear pressure injects stainless steel mould, while being aided with slight vibrations, Vibration frequency is 30 beats/min, 3 millimeters of amplitude.15~30 minutes are stood after casting complete, is placed in 60 DEG C of sea water bath, 1 It is taken out after hour and demoulds to obtain green compact, it is 12 hours dry in the environment of green compact are placed in humidity more than 80%, then in 90 DEG C of ring It is 24 hours dry under border.Green compact after drying are put into kiln to fire, are first fired 20 hours in 1000 DEG C under oxidizing atmosphere, and 36 hours are fired to get 1# composite ceramics crucibles in 1200 degree under reducing atmosphere afterwards.

Embodiment 2：

A kind of crucible used for polycrystalline silicon ingot casting, including vitreous silica and Thermal conductive additives, Thermal conductive additives are aluminium oxide and silicon carbide According to mass ratio 5：The weight ratio of mixture made of 3 compoundings, vitreous silica and Thermal conductive additives is 11：8.

The preparation method of above-mentioned crucible is as follows：

Will 45 parts by weight blout sand input ball mill in carry out wet ball grinding, size controlling within 10 microns, Ageing is added 50~100 microns of 10 parts of tekite sand after 10 days, and 15 parts 50~100 microns of silicon carbide, 25 part 250~ Then monomeric acrylamide, crosslinking agent methylene-bisacrylamide and initiator ammonium persulfate is added in 350 microns of aluminum oxide sand It is sufficiently stirred, is sufficiently stirred until slurry temperature reaches 40 DEG C, froth in vacuum after physical and chemical index detection is qualified, rear pressure injection is not Rust steel mold, while being aided with slight vibrations, vibration frequency is 30 beats/min, 3 millimeters of amplitude.15~30 are stood after casting complete Minute, it is placed in 50 DEG C of drying chamber and places 3 hours, rear take out demoulds to obtain green compact, and green compact are placed in the ring that humidity is more than 80% It is 8 hours dry under border, it is then 24 hours dry in the environment of 180 DEG C.Green compact after drying are put into kiln to fire, first in oxygen Change and fired in 1000 DEG C under atmosphere 15 hours, then fires 10 hours in 1400 degree to get 2# composite ceramics earthenwares under reducing atmosphere Crucible.

Embodiment 3：

A kind of crucible used for polycrystalline silicon ingot casting, including vitreous silica and Thermal conductive additives, Thermal conductive additives are aluminium oxide, vitreous silica Weight ratio with aluminium oxide is 1：1.

The preparation method of above-mentioned crucible is as follows：

Will 40 parts by weight blout sand input ball mill in carry out wet ball grinding, size controlling within 10 microns, 50~100 microns of 40 parts by weight of alumina powder are added in ageing after 10 days, monomeric acrylamide, crosslinking agent methylene is then added Bisacrylamide and initiator ammonium persulfate are sufficiently stirred, and are sufficiently stirred until slurry temperature reaches 45 DEG C, physical and chemical index detects Froth in vacuum after qualification, rear pressure injects stainless steel mould, while being aided with slight vibrations, and vibration frequency is 30 beats/min, amplitude 3 millimeters.15~30 minutes are stood after casting complete, is placed in 50 DEG C of drying chamber and places 2 hours, rear take out demoulds to obtain green compact, It is 8 hours dry in the environment of green compact are placed in humidity more than 80%, it is then 24 hours dry in the environment of 100 DEG C.It will dry Green compact afterwards are put into kiln firing, are first fired in 1200 DEG C under oxidizing atmosphere 4 hours, then in 1400 degree of burnings under reducing atmosphere 6 hours are made to get 3# composite ceramics crucibles.

Comparative example 1：

One kind crucible used for polycrystalline silicon ingot casting made of vitreous silica, difference lies in raw materials with embodiment 1 for preparation method In be added without silicon carbide, obtain 4# composite ceramics crucibles.

1~4# composite ceramics crucible of 1 gained of Examples 1 to 3 and comparative example has been carried out performance test by us, as a result such as Shown in table 1.

The main performance index of table 1 1~4# composite ceramics crucibles

1# composite ceramics crucibles are carried out polycrystalline silicon ingot casting by us, and the long brilliant time of ingot casting was shortened to by original 40 hours 32 hours, the ingot casting period was shortened to 70 hours by 78 hours, the separate unit ingot furnace moon ingot casting quantity be promoted to by 9.2 original stoves 10.3 stoves, ingot furnace production capacity promotes 12%, and the square ingot plagioclase crystal in the areas silicon ingot A, B disappears substantially, and silicon ingot improved efficiency is about 0.05%.

The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all the present invention spirit and Within principle, any modification, equivalent replacement, improvement and so on should all be included in the protection scope of the present invention.

Claims (5)

1. a kind of crucible used for polycrystalline silicon ingot casting, which is characterized in that include vitreous silica and Thermal conductive additives, the Thermal conductive additives are carbon The weight ratio of the compounding of one or both in SiClx, aluminium oxide, the vitreous silica and Thermal conductive additives is (1~3)：1.

2. crucible used for polycrystalline silicon ingot casting according to claim 1, which is characterized in that the impurity content control of the vitreous silica System is as follows：Iron oxide<40ppm, aluminium oxide<1000ppm, alkali metal content<50ppm；The impurity content of the silicon carbide controls It is as follows：Iron oxide<40ppm, alkali metal content<50ppm；The impurity content control of the aluminium oxide is as follows：Iron oxide<40ppm, Alkali metal content<50ppm.

3. a kind of preparation method of crucible used for polycrystalline silicon ingot casting as claimed in claim 1 or 2, which is characterized in that including walking as follows Suddenly：

1) Thermal conductive additives are added into raw material as raw material for the tekite sand using granularity within 500 μm, and the Thermal conductive additives are The weight ratio of the compounding of one or both in silicon carbide, aluminium oxide, the vitreous silica and Thermal conductive additives is (1~3)：1, after Crucible green compact are obtained using casting molding technique, it is dry；

2) be sintered in the environment of the green compact after drying being placed in 1000~1400 DEG C 10~56 hours to get.

4. preparation method according to claim 3, which is characterized in that the casting molding technique is using acrylamide Gel rubber system.

5. preparation method according to claim 3 or 4, which is characterized in that the tekite sand is purity 99.9% The mixture of above varigrained quartz powder materials.