CN105133011A - Polycrystalline quartz crucible coating and preparation method thereof - Google Patents

Abstract

The invention provides a polycrystalline quartz crucible coating, which is characterized in that it is prepared from silicon nitride and a binder, the binder is selected from organic binders and/or inorganic binders, the The organic binder is selected from one or more of polyvinyl butyral, polyvinyl valerate and polyvinyl butyl acetal, and the inorganic binder is selected from nano silica, ceramic glue and nano One or more of silicon nitride. In the present invention, an organic binder and/or an inorganic binder is added as an additive to silicon nitride to prepare a coating, and one or more components in the organic binder and/or inorganic binder are used in combination to obtain a coating The layer of non-stick pan can enhance the bonding force of the coating, reduce the high-temperature sintering process and reduce energy consumption. The obtained coating has good compactness and mechanical strength.

Description

A kind of coating of polycrystalline quartz crucible and preparation method thereof

technical field

The invention belongs to the technical field of polycrystalline ingots, and in particular relates to a polycrystalline quartz crucible coating and a preparation method thereof.

Background technique

The polycrystalline ingot needs to use a quartz crucible as the ingot container, because the quartz will react with the polysilicon at high temperature and bond to cause impurities such as oxygen to enter the silicon material and the crucible will crack to cause the ingot to crack. Therefore, the quartz crucible needs to be sprayed with silicon nitride before ingot casting to avoid problems such as reaction between quartz and silicon material and bonding.

The spray coating of quartz crucible in solar polysilicon ingot adopts the sintering technology of sintering furnace to fully evaporate the water in the sprayed crucible, and finally make the coating dense, so as to prevent the molten silicon liquid from reacting with the quartz crucible during the ingot casting process. the goal of. At present, when spraying quartz crucibles, silicon nitride is directly used for spraying. Due to the poor bonding force between silicon nitride and quartz, problems such as sticking crucibles and ingots are prone to occur. Moreover, the sprayed coating in the prior art requires high-temperature sintering, and the sintering takes nearly 30 hours, which consumes a lot of energy, consumes a lot of equipment, and consumes a relatively large production cost.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a polycrystalline quartz crucible coating and a preparation method thereof. The quartz crucible coating provided by the present invention is free from sintering during the preparation process, and the coating does not stick to the pan.

The invention provides a polycrystalline quartz crucible coating, which is prepared from silicon nitride and a binder, the binder is selected from organic binders and/or inorganic binders, and the organic binder One or more selected from polyvinyl butyral, polyvinyl valerate and polyvinyl butyl acetal, and the inorganic binder is selected from nano silicon dioxide, ceramic glue and nano silicon nitride one or more of .

Preferably, the mass ratio of the silicon nitride to the binder is (400-1000):(10-200).

Preferably, the binder is a composite binder of an organic binder and an inorganic binder.

Preferably, the mass ratio of the organic binder and the inorganic binder in the composite binder is (15-40):(5-10).

The present invention also provides a kind of preparation method of polycrystalline quartz crucible coating, comprises the following steps:

A) mixing and stirring silicon nitride, binder and water to obtain a mixed slurry;

B) Spraying the mixed slurry on the surface of the polycrystalline quartz crucible to obtain a polycrystalline quartz crucible coating.

Preferably, the mass volume ratio of the silicon nitride, binder and water is (400-1000) g: (10-200) g: (800-2000) ml.

Preferably, the method of mixing and stirring is:

Stir for 5-30 minutes under the condition of 180-600 rpm, and stir for 5-15 minutes under the condition of 80-200 rpm.

Preferably, in step B), a sprayer is selected to spray the mixed slurry on the surface of the polycrystalline quartz crucible.

Preferably, the distance between the spray gun outlet of the spray coating machine and the surface of the polycrystalline quartz crucible is 10-60 cm; the pressure of the spray gun is 20-40 par.

Preferably, the spraying temperature is 20-120 degrees Celsius.

Compared with the prior art, the present invention provides a polycrystalline quartz crucible coating, which is characterized in that it is prepared from silicon nitride and a binder, and the binder is selected from organic binders and/or Inorganic binder, the organic binder is selected from one or more of polyvinyl butyral, polyvinyl valerate and polyvinyl butyl acetal, and the inorganic binder is selected from nanometer One or more of silicon oxide, ceramic glue and nano-silicon nitride. In the present invention, an organic binder and/or an inorganic binder is added as an additive to silicon nitride to prepare a coating, and one or more components in the organic binder and/or inorganic binder are used in combination to obtain a coating The layer of non-stick pan can enhance the bonding force of the coating, reduce the high-temperature sintering process and reduce energy consumption. The obtained coating has good compactness and mechanical strength.

The results show that the elastic modulus of the coating of the polycrystalline quartz crucible provided by the present invention is ≥63.8Gpa, the bending strength is ≥692MPa, and the coating density is ≥3.51g/cm ³ .

Description of drawings

Fig. 1 is the electron micrograph of the polycrystalline quartz crucible coating that embodiment 1 prepares;

Fig. 2 is the electron micrograph of the polycrystalline quartz crucible coating that embodiment 1 prepares;

Fig. 3 is the electron micrograph of the polycrystalline quartz crucible coating that comparative example 1 prepares;

FIG. 4 is an electron microscope image of the polycrystalline quartz crucible coating prepared in Comparative Example 1.

Detailed ways

The invention provides a polycrystalline quartz crucible coating, which is characterized in that it is prepared from silicon nitride and a binder, the binder is selected from organic binders and/or inorganic binders, the The organic binder is selected from one or more of polyvinyl butyral, polyvinyl valerate and polyvinyl butyl acetal, and the inorganic binder is selected from nano silica, ceramic glue and nano One or more of silicon nitride.

The polycrystalline quartz crucible coating provided by the invention is prepared from silicon nitride and a binder. The mass ratio of the silicon nitride to the binder is (400-1000):(10-200), preferably (500-900):(50-150). Wherein, the present invention has no special limitation on the specific source of the silicon nitride, which is generally commercially available. In the present invention, it is preferable to use silicon nitride powder to prepare the coating, and the mesh size of the silicon nitride powder is preferably 300-2500 mesh, more preferably 500-1000 mesh.

The polycrystalline quartz crucible coating provided by the present invention also includes a binder. In the present invention, the binder is an organic binder and/or an inorganic binder, wherein the organic binder is selected from One or more of polyvinyl butyral, polyvinyl pental and polyvinyl butyl acetal. The present invention has no special limitation on the source of the above-mentioned organic binder, which is generally commercially available.

The inorganic binder in the present invention is selected from one or more of nano silicon dioxide, ceramic glue and nano silicon nitride. In the present invention, there is no special limitation on the source of the above-mentioned inorganic binder, which is generally commercially available. In the present invention, the particle size of the nano silicon dioxide is preferably 1-100 nm, more preferably 15-45 nm; the particle size of the nano-silicon nitride is preferably 100-1300 nm, more preferably 400-900 nm.

The binding agent described in the present invention can be organic binding agent, also can be inorganic binding agent, also can be the composite binding agent of organic binding agent and inorganic binding agent, wherein, in the described composite binding agent The mass ratio of the organic binder to the inorganic binder is (15-40):(5-10), preferably (20-35):(6-9).

The polycrystalline quartz crucible coating of the present invention has a thickness of 80-700 μm, preferably 150-480 μm.

The present invention also provides a kind of preparation method of polycrystalline quartz crucible coating, comprises the following steps:

A) mixing and stirring silicon nitride, binder and water to obtain a mixed slurry;

B) Spraying the mixed slurry on the surface of the polycrystalline quartz crucible to obtain a polycrystalline quartz crucible coating.

In the present invention, silicon nitride, binder and water are first mixed and stirred to obtain a mixed slurry, wherein the mass volume ratio of the silicon nitride, binder and water is preferably (400-1000) g: (10- 200) g: (800-2000) ml, more preferably (500-900) g: (50-150) g: (900-1800) ml.

The present invention has no special limitation on the specific method of mixing and stirring the silicon nitride, the binder and water, and the mixing and stirring methods known to those skilled in the art will suffice. In the present invention, it is preferred to mix and stir according to the following method:

Stir for 5-30 minutes under the condition of 180-600 rpm, and stir for 5-15 minutes under the condition of 80-200 rpm.

After mixing and stirring, a mixed slurry is obtained. In the invention, the mixed slurry is sprayed on the surface of the polycrystalline quartz crucible to obtain the coating of the polycrystalline quartz crucible. The present invention has no special limitation on the spraying method, and any spraying method known to those skilled in the art will suffice. In the present invention, it is preferable to use a spraying machine to spray the silicon carbide slurry.

In the present invention, firstly, the polycrystalline quartz crucible is placed on the rotary heater, and the rotary heater is started to heat the polycrystalline quartz crucible so that the temperature of the inner wall of the polycrystalline quartz crucible is 20-120°C. The spray gun pressure is set to 20-40 par, preferably 25-35 par; the distance between the spray gun outlet of the spray coating machine and the surface of the polycrystalline quartz crucible is controlled to be 10-60 cm, preferably 20-50 cm. After the polycrystalline quartz crucible is ready, turn on the spraying machine and start spraying. During the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within the range of 20-120 degrees Celsius during the spraying process .

In the process of spraying, we should also pay attention to the uniformity, and there should be no "wet spraying" phenomenon, so as to ensure the toughness and strong adhesion of the coating, and the coating will not have problems such as peeling, powder falling, cracking, etc., which is beneficial to Demolding of the boule after final ingot casting.

In the above preparation method, the mass ratio of the silicon nitride to the binder is (400-1000):(10-200), preferably (500-900):(50-150). Wherein, the present invention has no special limitation on the specific source of the silicon nitride, which is generally commercially available. In the present invention, silicon nitride powder is preferably used to prepare the coating, and the mesh number of the silicon nitride powder is preferably 300-2500 mesh, more preferably 500-1000 mesh

The binder is an organic binder and/or an inorganic binder, wherein the organic binder is selected from one of polyvinyl butyral, polyvinyl valyl and polyvinyl butyl acetal One or more, the present invention has no special limitation on the source of the above-mentioned organic binder, generally commercially available.

The inorganic binder in the present invention is selected from one or more of nano silicon dioxide, ceramic glue and nano silicon nitride. In the present invention, there is no special limitation on the source of the above-mentioned inorganic binder, which is generally commercially available. In the present invention, the particle size of the nano silicon dioxide is preferably 1-100 nm, more preferably 15-45 nm; the particle size of the nano-silicon nitride is preferably 100-1300 nm, more preferably 400-900 nm.

The binding agent described in the present invention can be organic binding agent, also can be inorganic binding agent, also can be the composite binding agent of organic binding agent and inorganic binding agent, wherein, in the described composite binding agent The mass ratio of the organic binder to the inorganic binder is (15-40):(5-10), preferably (20-35):(6-9).

The polycrystalline quartz crucible coating of the present invention has a thickness of 80-700 μm, preferably 150-480 μm.

In the present invention, an organic binder and/or an inorganic binder is added as an additive to silicon nitride to prepare a coating, and one or more components in the organic binder and/or inorganic binder are used in combination to obtain a coating The layer of non-stick pan can enhance the bonding force of the coating, reduce the high-temperature sintering process and reduce energy consumption. The obtained coating has good compactness and mechanical strength.

The results show that the elastic modulus of the coating of the polycrystalline quartz crucible provided by the present invention is ≥63.8Gpa, the bending strength is ≥692MPa, and the coating density is ≥3.51g/cm ³ .

In order to further understand the present invention, the polycrystalline quartz crucible coating provided by the present invention and its preparation method are described below in conjunction with examples, and the scope of protection of the present invention is not limited by the following examples.

Example 1

Weigh 400g of 450 mesh silicon nitride powder with an electronic scale, measure 1200ml of deionized water with a graduated cylinder, and measure 150g of composite binder with a graduated cylinder. In the composite binder, polyvinyl butyral, size The mass ratio of nano-silica to nano-silicon nitride for 20nm purpose is 20:13:45, and then mix the above materials into a measuring cylinder containing a stirrer, stir for 15 minutes at 220rpm, and then stir at 160rpm Stirring was continued for 5 minutes to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 80-120 degrees Celsius. The distance between the spray gun of the spraying machine and the crucible wall is controlled at 30cm, and the spray pressure is adjusted to 35par , Turn on the spraying machine for spraying. During the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within the range of 80--120 degrees Celsius during the spraying process. In the process of spraying, we should also pay attention to the uniformity, and there should be no "wet spraying" phenomenon. After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 400 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5.

The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast. After demoulding, it is observed that the coating of the polycrystalline quartz crucible does not peel, powder or crack. The polycrystalline quartz crucible coating was microscopically observed under 600 times magnification using a usb portable electron microscope. The results are shown in Fig. 1 and Fig. 2, Fig. 1 is an electron micrograph of the polycrystalline quartz crucible coating prepared in Example 1, and Fig. 2 is an electron microscopic image of the polycrystalline quartz crucible coating prepared in Example 1. It can be seen from Figure 1 and Figure 2 that the coating after ingot casting has no sticking phenomenon and less silicon infiltration.

The performance measurement result of the polycrystalline quartz crucible coating that table 1 embodiment 1～5 provides

Example 2

Take by weighing 450g of 500 purpose silicon nitride powders with an electronic scale, measure the deionized water of 1250ml with a graduated cylinder, measure the composite binder of 175g with a graduated cylinder, in the composite binder, polyvinyl amyl ester, ceramic glue, The mass ratio of nano silicon nitride is 25:15:43. Then the above materials were mixed and introduced into a measuring cylinder containing a stirrer, stirred for 15 minutes under the condition of 220 rpm, and then continued to stir for 5 minutes under the condition of 160 rpm to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 100 degrees Celsius. The distance between the spray gun of the spraying machine and the crucible wall is controlled at 25cm, adjust the spray pressure to 20par, and turn on The spraying machine is used for spraying. During the spraying process, the infrared temperature measuring gun is used to measure the temperature to ensure that the spraying temperature is maintained within the range of 100 degrees Celsius during the spraying process. In the process of spraying, we should also pay attention to the uniformity, and there should be no "wet spraying" phenomenon. After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 389 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5. The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast. After demoulding, it is observed that the coating of the polycrystalline quartz crucible does not peel, powder or crack.

Example 3

Take by weighing 450g of 450 mesh silicon nitride powders with an electronic scale, measure the deionized water of 1250ml with a graduated cylinder, measure the composite binder of 200g with a graduated cylinder, in the composite binder, polyvinyl amyl ester, polyvinyl butadiene The mass ratio of ester acetal, nano-silicon dioxide with a size of 30nm and nano-silicon nitride is 30:26:47. Then the above materials were mixed and introduced into a measuring cylinder containing a stirrer, stirred for 15 minutes under the condition of 220 rpm, and then continued to stir for 5 minutes under the condition of 160 rpm to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 120 degrees Celsius. The distance between the spray gun and the crucible wall is controlled at 25cm, and the spray pressure is adjusted to 30par. Spraying, during the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within 100 degrees Celsius during the spraying process, and pay attention to the uniformity during the spraying process , there can be no "wet spray" phenomenon. After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 427 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5.

The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast. After demoulding, it is observed that the coating of the polycrystalline quartz crucible does not peel, powder or crack.

Example 4

Weigh 400g of 470-mesh silicon nitride powder with an electronic scale, measure 1200ml of deionized water with a graduated cylinder, and measure 150g of polyvinyl butyral binder with a graduated cylinder, and then mix the above materials into a graduated cylinder containing a stirrer Inside, stir under the condition of 220rpm for 15 minutes, and then continue stirring for 5 minutes under the condition of 120rpm to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 100 degrees Celsius. The distance between the spray gun and the crucible wall is controlled at 25cm, and the spray pressure is adjusted to 30par. During the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within the range of 120 degrees Celsius during the spraying process. The phenomenon of "wet spray". After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 416 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5.

The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast. After demoulding, it is observed that the coating of the polycrystalline quartz crucible does not peel, powder or crack.

Example 5

Weigh 450g of 600-mesh silicon nitride powder with an electronic scale, measure 1400ml of deionized water with a graduated cylinder, and measure 180ml of inorganic binder with a graduated cylinder. The size of the inorganic binder is 20nm nano-silica: nanometer The mass ratio of silicon nitride was 15:47, stirred at 220 rpm for 15 minutes, and then continued to stir at 150 rpm for 5 minutes to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 100 degrees Celsius. The distance between the spray gun of the spraying machine and the crucible wall is controlled at 25cm, and the spray pressure is adjusted to 30par. The spraying machine is used for spraying. During the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within the range of 110 degrees Celsius during the spraying process. During the spraying process, attention should also be paid to uniformity. The phenomenon of "wet spray". After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 385 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5.

The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast. After demoulding, it is observed that the coating of the polycrystalline quartz crucible does not peel, powder or crack.

Comparative example 1

Weigh 450g of 450-mesh silicon nitride powder with an electronic scale, measure 1400ml of deionized water with a graduated cylinder, and measure 180ml of binder with a graduated cylinder. The normal coating preparation is that the binder is ion-free silica sol, and the ratio is nitrogen Silica: ion-free silica sol: pure water = 450g: 500g: 1300ml. Stir at 220 rpm for 15 minutes, then continue to stir at 120 rpm for 5 minutes to obtain a mixed slurry.

Lift the quartz crucible on the rotary heater, start the rotary heater, and heat it so that the temperature of the inner wall of the quartz crucible can reach 110 degrees Celsius. The distance between the spray gun of the spraying machine and the crucible wall is controlled at 25cm, adjust the spray pressure to 30par, and turn on The spraying machine is spraying. During the spraying process, use an infrared temperature measuring gun to measure the temperature to ensure that the spraying temperature is maintained within the range of 120 degrees Celsius during the spraying process. During the spraying process, attention should also be paid to uniformity and no The phenomenon of "wet spray". After spraying, a polycrystalline quartz crucible coating is obtained. The coating thickness was measured to be 376 μm.

The elastic modulus, flexural strength and density of the polycrystalline quartz crucible coating were measured, and the results are shown in Table 1. Table 1 shows the performance measurement results of the polycrystalline quartz crucible coating provided in Examples 1-5.

The solar polysilicon ingot is cast under the condition of 1500° C. by using the above-mentioned polycrystalline quartz crucible, and demoulding is performed after the ingot is cast.

A usb portable electron microscope was used for microscopic observation of the polycrystalline quartz crucible coating under 600 times magnification. The results are shown in Fig. 3 and Fig. 4, Fig. 3 is an electron micrograph of the polycrystalline quartz crucible coating prepared in Comparative Example 1, and Fig. 4 is an electron microscopic image of the polycrystalline quartz crucible coating prepared in Comparative Example 1. It can be seen from Figure 3 and Figure 4 that the coating after ingot casting is seriously siliconized, and there is a phenomenon of sticking to the pot.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A polycrystalline quartz crucible coating is characterized in that, it is prepared from silicon nitride and binding agent, and described binding agent is selected from organic binding agent and/or inorganic binding agent, and described organic binding agent The binding agent is selected from one or more of polyvinyl butyral, polyvinyl valerate and polyvinyl butyl acetal, and the inorganic binder is selected from nano-silica, ceramic glue and nano-nitrided One or more of silicon. 2. The polycrystalline quartz crucible coating according to claim 1, characterized in that the mass ratio of the silicon nitride to the binder is (400-1000): (10-200). 3. The polycrystalline quartz crucible coating according to claim 1, wherein the binder is a composite binder of an organic binder and an inorganic binder. 4. polycrystalline quartz crucible coating according to claim 3, is characterized in that, the mass ratio of organic binder and inorganic binder in described composite binder is (15～40): (5～10 ). 5. A preparation method for polycrystalline quartz crucible coating, is characterized in that, comprises the following steps: A) mixing and stirring silicon nitride, binder and water to obtain a mixed slurry; B) Spraying the mixed slurry on the surface of the polycrystalline quartz crucible to obtain a polycrystalline quartz crucible coating. 6. The preparation method according to claim 1, characterized in that the mass-volume ratio of the silicon nitride, binder and water is (400-1000) g: (10-200) g: (800-2000 ) ml. 7. preparation method according to claim 5, is characterized in that, the method for described mixing and stirring is: Stir for 5-30 minutes under the condition of 180-600, and stir for 5-15 minutes under the condition of 80-200. 8. The preparation method according to claim 5, characterized in that, in step B), a sprayer is selected to spray the mixed slurry on the surface of the polycrystalline quartz crucible. 9. The preparation method according to claim 8, characterized in that, the distance between the spray gun outlet of the spray coating machine and the surface of the polycrystalline quartz crucible is 10-60 cm; the pressure of the spray gun is 20-40 par. 10. The preparation method according to claim 5, characterized in that, the spraying temperature is 20-120 degrees Celsius.