KR101409171B1 - Manufacturing method of ceramic ware using the amorphous coating of base material - Google Patents

Abstract

The present invention relates to a method for manufacturing ceramics by using amorphous coating to the base material of the ceramics wherein the method comprises: a step of inserting silicon and feldspar with a solvent into a stirrer; a step of stirring after inserting into the stirrer 0.1-15 parts by weight of a calcium source material and a silicon source material with respect to 100 parts by weight of the silicon and the feldspar in a mole ratio of 1:5-5:1; a step of inserting a basic material into slurry manufactured by stirring so as to control the pH range of the same at 7-12; a step of drying the pH controlled outcome and calcining at a temperature lower than the temperature where the calcium source material and the silicon source material are crystallized for acquiring the silicon and feldspar on which amorphous phase is coated; a step of mixing kaolin, clay, the silicon and feldspar where the amorphous phase is coated with water; and a step of firing the molded mixture. The present invention can lower a firing temperature by using the amorphous coating of the basic ceramics material and improve fracture toughness and bending strength.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing ceramics using amorphous coating of ceramics raw materials,

The present invention relates to a method for manufacturing ceramics, and more particularly, to a method for manufacturing ceramics capable of lowering a firing temperature and improving fracture toughness and bending strength by using an amorphous coating of a ceramics raw material.

Pottery is a term that includes pottery and porcelain. Ceramics are mainly made of materials such as clay, feldspar, quartz and stoneware, and ceramics are products obtained by mixing and molding these materials at a certain ratio, followed by firing and curing. Pottery has a high absorption rate, so it produces a dull sound when tapped and has a relatively low durability. It has a low absorption rate and gives a clear sound when touched and has excellent durability.

When ceramics are manufactured, they are sintered at a relatively high temperature after molding. When the sintering temperature is high, energy consumption is high and the sintering temperature is not easily controlled. In addition, since the mechanical characteristics of the sintering body It may not be good. Therefore, many studies have been made to lower the firing temperature.

In addition, many attempts have been made to improve the fracture toughness and bending strength of ceramics.

The present invention provides a method for manufacturing ceramics which can reduce the firing temperature and improve fracture toughness and bending strength by using an amorphous coating of a ceramic material.

The present invention relates to a method for producing a silicon carbide powder, comprising the steps of charging silica and feldspar with a solvent into a stirrer, mixing the calcium source material and the silicon source material in a molar ratio of 1: 5 to 5: 1 to 100 parts by weight of the total content of the silica and feldspar Adding a basic substance to the slurry to adjust the pH to a range of 7 to 12, drying the pH-adjusted resultant and adding the calcium source material and the silicon source material Calcining at a temperature lower than the crystallization temperature to obtain amorphous phase coated quartz and feldspar; mixing kaolin and clay and amorphous phase coated quartz and feldspar with water; molding the mixed result; And then calcining the resultant. The present invention also provides a method for manufacturing ceramics using the amorphous coating of a raw material for ceramics.

According to the present invention, there is provided a method for manufacturing a semiconductor device, comprising the steps of charging silica with a solvent into a stirrer, mixing the calcium source material and the silicon source material in a molar ratio of 1: 5 to 5: Adding a basic substance to the slurry so as to adjust pH to a range of 7 to 12, drying the pH-adjusted product, and drying the calcium source material and the silicon source material to crystallize A step of calcining the feldspar with a solvent at a temperature lower than the temperature to charge the feldspar with a solvent, mixing the calcium source material and the silicon source material in the molar ratio of 1: 5 to 5: 0.1 to 15 parts by weight based on 100 parts by weight of the total amount of the slurry, stirring the mixture, adding a basic substance to the slurry to adjust pH to 7 to 12, And calcining the calcined product at a temperature lower than the temperature at which the calcium source material and the silicon source material are crystallized to obtain an amorphous phase coated feldspar; mixing kaolin, clay, and amorphous phase coated silica and feldspar with water A step of mixing, a step of molding the mixed product, and a step of baking the resultant product. The present invention also provides a method of manufacturing a ceramic using the amorphous coating of a ceramic raw material.

The calcium source material, calcium acetate monohydrate (calcium acetate monohydrate) (Ca ( CH 3 COO) 2 · H 2 O), calcium bromide dihydrate _{(calcium bromide dihydrate) (CaBr 2} · 2H 2 O), calcium carbonate ( calcium carbonate (CaCO ₃ ), calcium chloride (CaCl ₂ ), calcium chloride dihydrate (CaCl ₂ .2H ₂ O), calcium citrate tetrahydrate (Ca ₃ (C ₆ H ₅ O ₇ ) ₂ .4H ₂ O), calcium fluoride (CaF ₂ ), calcium hydride (H ₂ Ca), calcium hydroxide (Ca (OH) ₂ ) Calcium hypochlorite (Ca (OCl) ₂ ), calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂ .4H ₂ O), calcium oxalate monohydrate (calcium oxalate monohydrate) (COO) ₂ Ca.H ₂ O), calcium oxide (CaO), calcium propionate e) ((CH ₃ CH ₂ COO) ₂ Ca), calcium stearate (Ca [CH ₃ (CH ₂ ) ₁₆ COO] ₂ ), calcium sulfate (CaSO ₄ ), calcium sulfate dihydrate ) CaSO ₄ .2H ₂ O and calciumsulfate hemihydrate (CaSO ₄ .1 / 2H ₂ O).

Wherein the silicon source material is selected from the group consisting of calcium silicate (CaSiO ₃ ), calcium silicate hydrate (CaSiO ₃ .nH ₂ O, n being a positive real number), potassium silicate (K ₂ SiO ₃ ), sodium hexafluorosilicate (Na ₂ SiF ₆ ), sodium metasilicate (Na ₂ SiO ₃ ), sodium metasilicate nonahydrate (Na ₂ SiO ₃ .9H ₂ O), sodium metasilicate pentahydrate (Na ₂ SiO ₃ .5H ₂ O), sodium orthosilicate hydrate (2Na ₂ O SiO ₂ .nH ₂ O, , Sodium silicate fluoride (Na ₂ SiF ₆ ), tetraallyl orthosilicate (C ₁₂ H ₂₀ O ₄ Si), tetraethyl orthosilicate (Si ( OC ₂ H _{5) 4),} tetramethyl ammonium Silicate _{(tetramethylammonium silicate) ((CH 3} ) 4 N (OH) · 2SiO 2), tetramethyl ortho silicate (tetramethyl orthosilicate) (Si (OCH 3) 4), tetrapropyl orthosilicate (tetrapropyl orthosilicate) and tetrabutyl And tetrabutyl orthosilicate. The term " tetrabutyl orthosilicate "

The basic substance may be at least one selected from the group consisting of ammonium hydroxide, lithium hydroxide monohydrate (HLiO.H ₂ O), potassium hydroxide, sodium amide and sodium hydroxide ). ≪ / RTI >

Wherein the calcium source material is calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂ .4H ₂ O), the silicon source material is tetraethylorthosilicate (Si (OC ₂ H ₅ ) ₄ ) It may be ammonium hydroxide.

The firing is preferably performed at a temperature of 1125 to 1300 캜.

The calcination is preferably carried out in an oxidizing atmosphere at a temperature of 500 to 1000 캜.

The feldspar may consist of nephelin cyanite.

In the step of mixing the kaolin, the clay, and the amorphous phase coated silica and feldspar with the water, the kaolin, the clay, the clay, the amorphous phase coated silica, and the amorphous phase The water is mixed so that the solid content of the feldspar coated with the kaolin, the clay and the amorphous phase coated with the amorphous phase is 50 to 70% by weight.

In order to improve dispersibility, 100 parts by weight of the solid content of feldspar coated with kaolin, clay, amorphous phase and silica coated with amorphous phase was mixed with benzyl Benzyltrimethylammonium hydroxide (C ₁₀ H ₁₇ NO), diethylamine (C ₄ H ₁₁ N), ethylamine, propylamine, butylamine, pentyl But are not limited to, pentyl amine, methylamine (CH ₅ N), tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium and 0.001 to 3 parts by weight of at least one material selected from tetrabutyl ammonium hydroxide and tetrabutyl ammonium hydroxide.

According to the present invention, by using the amorphous coating of the ceramic material, the firing temperature can be lowered and the fracture toughness and bending strength can be improved.

In addition, the method for manufacturing ceramics of the present invention can obtain a ceramics which is relatively simple, has high reproducibility, is densified while being fired at a relatively low temperature.

1 is a graph showing fracture toughness with respect to sintering temperature.
Fig. 2 is a graph showing the flexural strength of the specimen produced according to Example 3 and Comparative Example 1. Fig.
3 is a graph showing a density change according to sintering temperature.
4A to 4E are scanning electron microscope (SEM) photographs showing a case where firing was performed at 1,230 ° C. as a test piece manufactured according to Comparative Example 1. FIG.
5A to 5E are scanning electron microscope (SEM) photographs showing the case where firing was performed at 1175 DEG C as a specimen manufactured according to Example 1. Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not.

Pottery is a term that includes pottery and porcelain. Ceramics are mainly made of materials such as clay, feldspar, quartz and stoneware, and ceramics are products obtained by mixing and molding these materials at a certain ratio, followed by firing and curing. Pottery has a high absorption rate, so it produces a dull sound when tapped and has a relatively low durability. It has a low absorption rate and gives a clear sound when touched and has excellent durability. In the following, the term porcelain is used to mean both porcelain and porcelain.

The present invention provides a method of manufacturing ceramics capable of lowering the firing temperature and improving fracture toughness and bending strength by using an amorphous coating of a ceramic material.

A method of manufacturing a ceramic using amorphous coating of a ceramic material according to a first preferred embodiment of the present invention comprises the steps of charging silica and feldspar together with a solvent into a stirrer, mixing the calcium source material and the silicon source material at a ratio of 1: To 5: 1 by weight based on 100 parts by weight of the total amount of the feldspar and the feldspar, and adding a basic substance to the slurry to adjust the pH to 7 to 12 A step of drying the pH controlled product and calcining at a temperature lower than the temperature at which the calcium source material and the silicon source material are crystallized to obtain an amorphous phase coated silica and feldspar; a step of calcining kaolin, clay and amorphous phase coated silica And feldspar with water, molding the mixed product, and calcining the molded product.

A method of manufacturing a ceramic using amorphous coating of a ceramic material according to a second preferred embodiment of the present invention comprises the steps of charging silica into a stirrer together with a solvent, mixing the calcium source material and the silicon source material at a ratio of 1: : 1 to 0.1 part by weight based on 100 parts by weight of the total amount of the silica, stirring the mixture, adding a basic substance to the slurry to adjust the pH to 7 to 12, Drying the resultant product and calcining the resultant product at a temperature lower than the temperature at which the calcium source material and the silicon source material are crystallized to obtain an amorphous phase coated silica; charging the feldspar with a solvent into an agitator; And silicon source material at a molar ratio of 1: 5 to 5: 1, based on 100 parts by weight of the total feldspathic content, Adding a basic substance to the resulting slurry to adjust the pH to a range of 7 to 12, drying the pH-adjusted product and calcining the calcium source material at a temperature lower than the temperature at which the silicon source material is crystallized, Obtaining calcined feldspar, mixing kaolin and clay, and amorphous phase coated silica and feldspar with water, molding the mixed product, and calcining the molded product.

Hereinafter, a method for producing ceramics using amorphous coating of ceramics raw material will be described in more detail.

The raw materials of ceramics, silica and feldspar, are charged into the agitator together with the solvent. The stirrer may be a ball milling machine. It is preferable to mix the solvent so that the solid content of the silica and the feldspar is 50 to 70 wt%. The solvent may be isopropyl alcohol (IPA), ethanol, distilled water, or the like. The feldspar may consist of a nepheline syenite.

0.1 to 15 parts by weight of a calcium source material and a silicon source material are added to the agitator in a molar ratio of 1: 5 to 5: 1 based on 100 parts by weight of the total content of the silica and the feldspar.

The calcium source material, calcium acetate monohydrate (calcium acetate monohydrate) (Ca ( CH 3 COO) 2 · H 2 O), calcium bromide dihydrate _{(calcium bromide dihydrate) (CaBr 2} · 2H 2 O), calcium carbonate ( calcium carbonate (CaCO ₃ ), calcium chloride (CaCl ₂ ), calcium chloride dihydrate (CaCl ₂ .2H ₂ O), calcium citrate tetrahydrate (Ca ₃ (C ₆ H ₅ O ₇ ) ₂ .4H ₂ O), calcium fluoride (CaF ₂ ), calcium hydride (H ₂ Ca), calcium hydroxide (Ca (OH) ₂ ) Calcium hypochlorite (Ca (OCl) ₂ ), calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂ .4H ₂ O), calcium oxalate monohydrate (calcium oxalate monohydrate) (COO) ₂ Ca.H ₂ O), calcium oxide (CaO), calcium propionate e) ((CH ₃ CH ₂ COO) ₂ Ca), calcium stearate (Ca [CH ₃ (CH ₂ ) ₁₆ COO] ₂ ), calcium sulfate (CaSO ₄ ), calcium sulfate dihydrate ) CaSO ₄ .2H ₂ O and calciumsulfate hemihydrate (CaSO ₄ .1 / 2H ₂ O).

Wherein the silicon source material is selected from the group consisting of calcium silicate (CaSiO ₃ ), calcium silicate hydrate (CaSiO ₃ .nH ₂ O, n being a positive real number), potassium silicate (K ₂ SiO ₃ ), sodium hexafluorosilicate (Na ₂ SiF ₆ ), sodium metasilicate (Na ₂ SiO ₃ ), sodium metasilicate nonahydrate (Na ₂ SiO ₃ .9H ₂ O), sodium metasilicate pentahydrate (Na ₂ SiO ₃ .5H ₂ O), sodium orthosilicate hydrate (2Na ₂ O SiO ₂ .nH ₂ O, , Sodium silicate fluoride (Na ₂ SiF ₆ ), tetraallyl orthosilicate (C ₁₂ H ₂₀ O ₄ Si), tetraethyl orthosilicate (Si ( OC ₂ H _{5) 4),} tetramethyl ammonium Silicate _{(tetramethylammonium silicate) ((CH 3} ) 4 N (OH) · 2SiO 2), tetramethyl ortho silicate (tetramethyl orthosilicate) (Si (OCH 3) 4), tetrapropyl orthosilicate (tetrapropyl orthosilicate) and tetrabutyl And tetrabutyl orthosilicate. The term " tetrabutyl orthosilicate "

The stirring may use a ball milling process. The ball milling process will be described with reference to a ball milling machine containing silica, feldspar, a calcium source material, a silicon source material, and a solvent. The ball used for the ball milling is preferably a ceramic ball such as alumina or zirconia, and the balls may be all the same size or may be used together with balls having two or more sizes. The size of the ball, the milling time, and the rotation speed per minute of the ball miller. For example, in consideration of the size of the particles, the size of the balls may be set in the range of about 1 mm to 50 mm, and the rotational speed of the ball miller may be set in the range of about 50 to 500 rpm. The ball milling is preferably performed for 1 to 48 hours. By ball milling, silica and feldspar are pulverized into fine sized particles and have a uniform particle size distribution. By stirring as described above, the silica and the feldspar are pulverized to form a slurry state.

A basic substance is added to the slurry obtained by stirring to adjust the pH to 7 to 12. The basic substance is preferably slowly added until the pH is 7 to 12 and stirred for a predetermined time (for example, 10 minutes to 48 hours).

The basic substance may be at least one selected from the group consisting of ammonium hydroxide, lithium hydroxide monohydrate (HLiO.H ₂ O), potassium hydroxide, sodium amide and sodium hydroxide ). ≪ / RTI >

The pH controlled product is dried and calcined at a temperature below the temperature at which the calcium source material and the silicon source material are crystallized to obtain amorphous phase coated silica and feldspar. The drying is preferably performed at a temperature of 60 to 180 DEG C for 10 minutes to 24 hours. The calcination is preferably performed in an oxidizing atmosphere (for example, oxygen or air atmosphere) at a temperature of 500 to 1000 DEG C lower than a temperature at which the calcium source material and the silicon source material are crystallized. The calcination is preferably performed for 10 minutes to 24 hours. By the calcination, the calcium source material, the silicon source material, and the organic component contained in the basic substance are burned away.

Although the method of coating the amorphous phase by mixing the calcium source material and the silicon source material together has been described in the foregoing embodiments, the amorphous phase may be separately coated on the calcium source material and the silicon source material. In this case, It is needless to say that the same method as the description of FIG. More specifically, the silica is charged into a stirrer together with a solvent, and the calcium source material and the silicon source material are mixed in a molar ratio of 1: 5 to 5: 1 in the agitator in an amount of 0.1 to 15 Adding a basic component to the slurry to adjust the pH to a range of 7 to 12, drying the pH-adjusted product, and drying the calcium source material and the silicon source material at a temperature lower than the crystallization temperature Calcined at temperatures to obtain amorphous coated silicates. The feldspar is charged into a stirrer together with a solvent and 0.1 to 15 parts by weight of a calcium source material and a silicon source material are added to the stirrer in a molar ratio of 1: 5 to 5: 1, based on 100 parts by weight of the total feldspar, A basic substance is added to the slurry to adjust the pH to a range of 7 to 12, and the pH-adjusted product is dried and calcined at a temperature lower than the temperature at which the calcium source material and the silicon source material are crystallized, Coated feldspar can be obtained.

Through the above process, CaO-SiO ₂ amorphous phase is coated on the surface of the silica and feldspar. By using the amorphous coating of silica and feldspar, the firing temperature can be lowered and fracture toughness and bending strength can be improved.

Kaolin, clay, and amorphous coated silica and feldspar are mixed with water. The kaolin, the clay, the clay, the amorphous phase-coated silica and the amorphous phase-coated feldspar are mixed preferably in an amount of 25 to 34 wt%, 5 to 10 wt% of the clay, 29 to 39 wt% It is preferable that the water is mixed so that the solid content of the feldspar coated with the clay and the amorphous phase coated with the silica and amorphous phase is 50 to 70 wt%. In order to improve the dispersibility, benzyltrimethylammonium hydroxide (C ₁₀ H ₁₇ NO), diethylamine (C ₄ H ₁₁ N), and ethylamine (100 parts by weight) were added to 100 parts by weight of the solid content ethylamine, propylamine, butylamine, pentylamine, methylamine (CH ₅ N), tetramethyl ammonium hydroxide, tetraethylammonium hydroxide 0.001 to 3 parts by weight of at least one material selected from the group consisting of tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide and tetrabutyl ammonium hydroxide can be added.

The mixing may utilize a ball milling process. The ball milling process is performed by rotating the ball milling machine at a constant speed using a ball milling machine containing amorphous phase coated silica, amorphous phase coated feldspar, kaolin, clay and distilled water. The ball used for the ball milling is preferably a ceramic ball such as alumina or zirconia, and the balls may be all the same size or may be used together with balls having two or more sizes. The size of the ball, the milling time, and the rotation speed per minute of the ball miller. For example, in consideration of the size of the particles, the size of the balls may be set in the range of about 1 mm to 50 mm, and the rotational speed of the ball miller may be set in the range of about 50 to 500 rpm. The ball milling is preferably performed for 1 to 48 hours. By ball milling, the silica, feldspar, kaolin and clay are pulverized into fine sized particles and have a uniform particle size distribution. The slurry is formed by mixing as described above, and the slurry is dried. The drying is preferably performed at a temperature of 60 to 180 DEG C for 10 minutes to 24 hours. Sieve classification may be performed to use only particles of a desired size or smaller with respect to the dried product.

The mixed result is molded. The above-mentioned molding can be variously adopted, such as injection molding, extrusion molding, etc.

The molded product is calcined. Hereinafter, the firing step will be described in detail.

The molded product is charged into a furnace such as an electric furnace, and a sintering process is performed. The firing step is preferably performed at a temperature of about 1125 to 1300 DEG C for about 10 minutes to 48 hours. It is desirable to keep the pressure inside the furnace constant during firing.

The firing is preferably performed at a temperature in the range of 1125 to 1300 ° C. If the sintering temperature is less than 1125 ° C, the thermal or mechanical properties of the ceramics may not be good due to incomplete sintering. If the sintering temperature is higher than 1300 ° C, energy consumption is high and not only economical but also excessive grain growth, This may not be good.

The firing temperature is preferably raised at a heating rate of 1 to 50 ° C / min. If the heating rate is too slow, the time is long and productivity is deteriorated. If the heating rate is too high, thermal stress is applied due to a rapid temperature rise It is preferable to raise the temperature at the temperature raising rate in the above range.

The firing is preferably carried out at a firing temperature for 10 minutes to 48 hours. If the firing time is too long, it is not economical since the energy consumption is high. Further, it is difficult to expect further firing effect. If the firing time is small, the physical properties of the ceramic material may not be good due to incomplete firing.

The firing is preferably carried out in an oxidizing atmosphere (for example, oxygen (O ₂ ) or air atmosphere) or a reducing atmosphere.

After the firing process is performed, the furnace temperature is lowered to unload the ceramics. The furnace cooling may be effected by shutting down the furnace power source to cool it in a natural state, or optionally by setting a temperature decreasing rate (for example, 10 DEG C / min). It is preferable to keep the pressure inside the furnace constant even while the furnace temperature is being lowered.

Hereinafter, embodiments according to the present invention will be specifically shown, and the present invention is not limited to the following embodiments.

≪ Example 1 >

Silicate and nepheline synite were coated with amorphous phase. The amorphous coating process was as follows.

Silicate and nephelin cyanite were added to isopropyl alcohol (IPA) to a solids content of 60% by weight. The silica and the nephelin cyanite were added in a weight ratio of 29.5: 34. The silica used had a specific surface area of 1 m < 2 > / g and the nephelin cyanite had a specific surface area of 1 m < 2 > / g.

1 part by weight of calcium nitrate (Ca (NO ₃ ) ₂ .4H ₂ O) as a calcium source and tetraethly orthosilicate (TEOS) as a silicon source at a molar ratio of 1: 1 And ball milling was performed for 2 hours. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

To the slurry obtained through the ball milling process as described above, 0.1 mol of ammonium hydroxide was slowly added until the pH reached 9, and the mixture was stirred for 1 hour and then dried in an oven at 100 ° C.

The dried product was heated to a temperature of 700 캜 and calcined for 30 minutes. And the temperature was raised to 700 ° C at a heating rate of 5 ° C / min. The calcination was performed in an air atmosphere.

The calcined product was pulverized and passed through a sieve having a pore size of 150 mu m to obtain amorphous phase coated silica and nephelin cyanite powder.

Kaolin and clay were mixed with amorphous coated silicate and nepheline synite powder and used as a starting material.

Silica coated with amorphous phase, nephelin cyanite, and kaolin and ball clay were added to distilled water so that the solid content was 60% by weight. Amorphous coated quartz and nephelin cyanite, and kaolin and ball clay at a weight ratio of 63.5: 29.2: 7.3 (total content of amorphous coated quartz and nepelin cyanite: kaolin content: ball clay content) . Cerasperse 5468CF (SAN NOPCO KOREA Ltd.) as a dispersant was added at a concentration of 0.2 mg / m < ² > relative to the solid content to form a slurry state.

A ball mill was performed for 24 hours to obtain a uniform slurry. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

The slurry was dried at 100 DEG C for 24 hours and then passed through a sieve having a pore size of 75 mu m to obtain a powder.

4 g of the powder was uniaxially pressed for 1 minute at a pressure of 0.5 ton / cm 2 using a bar-shaped metal mold (10 mm x 40 mm x 50 mm) to compress the powder into a bar shape , And cold isotatic pressing (CIP) at 2000 bar for 1 minute.

The thus obtained molded body was 5ℓ / in N ₂ gas atmosphere in which the flow rate supplied to the min was raised to 2 ℃ / min rate to 850 ℃, 5ℓ / air flow rate supplied to the min (air) from the gas atmosphere, the sintering temperature (1125 ℃ To 1300 占 폚) at a rate of 5 占 폚 / min, followed by firing at a firing temperature for 1 hour, followed by cooling to room temperature.

≪ Example 2 >

Silicate and nephelin cyanite were added to isopropyl alcohol (IPA) to a solids content of 60% by weight. The silica and the nephelin cyanite were added in a weight ratio of 29.5: 34. The silica used had a specific surface area of 1 m < 2 > / g and the nephelin cyanite had a specific surface area of 1 m < 2 > / g.

(Ca (NO ₃ ) ₂ .4H ₂ O) as a calcium source and tetraethly orthosilicate (TEOS) as a silicon source at a molar ratio of 1: 1 to 2 parts by weight per 100 parts by weight of the solid content And ball milling was performed for 2 hours. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

The subsequent steps were carried out in the same manner as in Example 1 above.

≪ Example 3 >

Silicate and nephelin cyanite were added to isopropyl alcohol (IPA) to a solids content of 60% by weight. The silica and the nephelin cyanite were added in a weight ratio of 29.5: 34. The silica used had a specific surface area of 1 m < 2 > / g and the nephelin cyanite had a specific surface area of 1 m < 2 > / g.

(Ca (NO ₃ ) ₂ .4H ₂ O) as a calcium source and tetraethly orthosilicate (TEOS) as a silicon source at a molar ratio of 1: 1 to 5 parts by weight with respect to 100 parts by weight of the solid content And ball milling was performed for 2 hours. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

The subsequent steps were carried out in the same manner as in Example 1 above.

<Example 4>

Silicate and nephelin cyanite were added to isopropyl alcohol (IPA) to a solids content of 60% by weight. The silica and the nephelin cyanite were added in a weight ratio of 29.5: 34. The silica used had a specific surface area of 1 m &lt; 2 &gt; / g and the nephelin cyanite had a specific surface area of 1 m &lt; 2 &gt; / g.

(Ca (NO ₃ ) ₂ .4H ₂ O) as a calcium source and tetraethly orthosilicate (TEOS) as a silicon source at a molar ratio of 1: 1 to 10 parts by weight with respect to 100 parts by weight of the solid content And ball milling was performed for 2 hours. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

The subsequent steps were carried out in the same manner as in Example 1 above.

A comparative example that can be compared with the embodiments of the present invention is shown in order to more easily grasp the characteristics of the first to fourth embodiments. It is to be noted that Comparative Example 1 described below is provided merely for comparison with the characteristics of the embodiments, and is not a prior art of the present invention.

&Lt; Comparative Example 1 &

Zeolite and nepheline synite were mixed with kaolin and ball clay and used as a starting material. The silica used had a specific surface area of 1 m &lt; 2 &gt; / g and the nephelin cyanite had a specific surface area of 1 m &lt; 2 &gt; / g.

Silicate and nephelin cyanite were added to distilled water, and kaolin and ball clay were added to a solid content of 60% by weight. Silicate, nephelin cyanite, kaolin and ball clay were added in a weight ratio of 29.5: 34: 29.2: 7.3 (content of silicate: content of nephelin cyanite: content of kaolin: content of ball clay). Cerasperse 5468CF (SAN NOPCO KOREA Ltd.) as a dispersant was added at a concentration of 0.2 mg / m &lt; ² &gt; relative to the solid content to form a slurry state.

A ball mill was performed for 24 hours to obtain a uniform slurry. The ball milling was performed at a rotating speed of about 200 rpm, and a ball used for ball milling was a 10 mm ball made of alumina.

The slurry was dried at 100 DEG C for 24 hours and then passed through a sieve having a pore size of 75 mu m to obtain a powder.

4 g of the powder was uniaxially pressed for 1 minute at a pressure of 0.5 ton / cm 2 using a bar-shaped metal mold (10 mm x 40 mm x 50 mm) to compress the powder into a bar shape , And cold isotatic pressing (CIP) at 2000 bar for 1 minute.

The thus obtained molded body was 5ℓ / in N ₂ gas atmosphere in which the flow rate supplied to the min was raised to 2 ℃ / min rate to 850 ℃, 5ℓ / air flow rate supplied to the min (air) from the gas atmosphere, the sintering temperature (1125 ℃ To 1300 占 폚) at a rate of 5 占 폚 / min, followed by firing at a firing temperature for 1 hour, followed by cooling to room temperature.

Fracture toughness, bending strength and density were measured to evaluate the characteristics of the specimens prepared according to Examples 1 to 4 and Comparative Examples, and the experimental results are shown below.

Specimens were prepared to measure fracture toughness. The specimen was fabricated by machining a sintered body into a parallelepiped shape with a size of 4 mm (W) x 3 mm (B) x 30 mm (L). Using a cemented blade, a V- I got it. Using a universal testing machine (Inspect table 250KN, Hegewald & Peschke, UTM), the fracture load of the specimen was measured at a crosshead speed of 0.5 mm / min at a distance of 16 mm between the supports. Was calculated using Equations (1) to (3).

[Equation 1]

&Quot; (2) &quot;

&Quot; (3) &quot;

Where K is the fracture toughness (MPa · m ^0.5 ), P is the fracture load (MN), B is the thickness of specimen (m) S is the support span m and W is the width of specimen m and a is the depth of the notch m).

1 is a graph showing fracture toughness with respect to sintering temperature. Fig. 1 (a) shows the fracture toughness of the specimen prepared according to Comparative Example 1, Fig. 2 (b) shows the fracture toughness of the specimen prepared according to Example 1, (D) shows the fracture toughness of the specimen prepared according to Example 3, and (e) shows the fracture toughness of the specimen prepared according to Example 4. Fig.

Referring to FIG. 1, calcium nitrate (Ca (NO ₃ ) ₂ .4H ₂ O) as a calcium source and tetraethly orthosilicate (TEOS) as a silicon source are mixed with silica and nephelin cyanite (Ca (NO ₃ ) ₂ .4H ₂ O) and tetraethyl orthosilicate (TEOS) were added in an amount of 1 part by weight based on 100 parts by weight of the total amount of calcium silicate The maximum fracture toughness was found to be 2 parts by weight based on 100 parts by weight of the total amount of the knit.

It was found that the sintering temperature was 1150 to 1175 ° C in Examples 1 to 4 and lower than 50 ° C in the case where the amorphous phase was not coated on the silica and nepaline cyanite (Comparative Example 1). When the amorphous phase is not coated on the silica and nephelin cyanite (in the case of Comparative Example 1), the sintering does not proceed sufficiently and the pores are present when the temperature is lower than 1225 ° C.

The fracture toughness of Example 1 and Example 2 was 1.5 MPam ^{0 .5} , which was found to increase by up to 50% compared to the case where the amorphous phase was not coated on the silica and nephelin cyanite (in the case of Comparative Example 1) lost.

The specimens were fabricated by machining the sintered body to a size of 4 mm × 3 mm × 30 mm. Using UTM (universal testing machine, Inspekt table 250KN, Hegewald & Peschke) min at a crosshead speed of 3 m / min.

Fig. 2 is a graph showing the flexural strength of the specimen produced according to Example 3 and Comparative Example 1. Fig. FIG. 2 (a) shows a specimen prepared according to Comparative Example 1, and FIG. 2 (b) shows a specimen prepared according to Example 3.

2, calcium nitrate (Ca (NO ₃ ) ₂ .4H ₂ O) and tetraethylorthosilicate (TEOS) were added to 100 parts by weight of the total amount of silica and nephelin cyanite in accordance with Example 3 The bending strength was increased by 173% when the amorphous phase was not coated on the silica and nephelin cyanite (in the case of Comparative Example 1).

The density of the specimens prepared according to Comparative Example 1 and Examples 1 to 4 was measured using the Archimedes method. 3 is a graph showing a density change according to sintering temperature. Fig. 3 (a) shows the density of the sample prepared according to Comparative Example 1, (b) shows the density of the sample prepared according to Example 1, and (c) (D) shows the density of the specimen prepared in accordance with Example 3, and (e) shows the density of the specimen prepared according to Example 4. Fig.

Referring to FIG. 3, the sintering temperature for obtaining the maximum density was found to be 1150 to 1175 ° C.

The microstructures of the specimens prepared according to Comparative Example 1 and Example 1 were analyzed. 4A to 4E are SEM photographs showing the case where the sample was produced at 1,230 DEG C as a sample prepared according to Comparative Example 1, and the magnifications were varied. 5A to 5E are SEM photographs showing the case where firing was performed at 1175 DEG C as a specimen manufactured according to Example 1, and the magnifications are shown in different magnifications.

4A to 5E, when the amorphous phase was coated on the silica and nephelin cyanite in comparison with the case where the amorphous phase was not coated on the silica and nephelin cyanite (Comparative Example 1) 1) has a microstructure with few pores and few defects even though the sintering temperature is low. This suggests that the bending strength and fracture toughness are increased.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, This is possible.

Claims (11)

Charging silica and feldspar together with a solvent into an agitator;
Adding a calcium source material and a silicon source material in a molar ratio of 1: 5 to 5: 1 to the agitator in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the total content of the silica and the feldspar;
Adding a basic substance to the slurry to adjust the pH to a range of 7 to 12;
drying the pH controlled product and calcining at a temperature below the temperature at which the calcium source material and the silicon source material are crystallized to obtain amorphous phase coated silica and feldspar;
Mixing kaolin, clay, and amorphous coated silica and feldspar with water;
Molding the mixed result; And
And calcining the resultant product. The method of claim 1, wherein the amorphous coating of the ceramics is performed using the amorphous coating.
Charging the silica with the solvent into an agitator;
Adding a calcium source material and a silicon source material to the agitator in a molar ratio of 1: 5 to 5: 1 in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the total amount of the silica;
Adding a basic substance to the slurry to adjust the pH to a range of 7 to 12;
drying the pH controlled product and calcining at a temperature below the temperature at which the calcium source material and the silicon source material are crystallized to obtain an amorphous phase coated silica;
Charging feldspar with a solvent into an agitator;
Adding a calcium source material and a silicon source material to the agitator in a molar ratio of 1: 5 to 5: 1 in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the total feldspar;
Adding a basic substance to the slurry to adjust the pH to a range of 7 to 12;
drying the pH controlled product and calcining the calcium source material and the silicon source material at a temperature below the crystallization temperature to obtain an amorphous phase coated feldspar;
Mixing kaolin, clay, and amorphous coated silica and feldspar with water;
Molding the mixed result; And
And calcining the resultant product. The method of claim 1, wherein the amorphous coating of the ceramics is performed using the amorphous coating.
3. The method of claim 1 or 2,
Calcium carbonate monohydrate (Ca (CH ₃ COO) ₂ .H ₂ O), calcium bromide dihydrate (CaBr ₂ .2H ₂ O), calcium carbonate (CaCO ₃ ), calcium chloride (CaCl ₂ ), calcium chloride dihydrate ₂ · 2H ₂ O), calcium citrate tetrahydrate (Ca ₃ (C ₆ H ₅ O ₇ ) ₂ · 4H ₂ O), calcium fluoride (CaF ₂ ), calcium hydride (CaH ₂ ), calcium hydroxide (Ca (OH) _2), calcium hypochlorite (Ca (OCl) _2), calcium nitrate tetrahydrate _{(Ca (NO 3) 2 ·} 4H 2 O), calcium-oxa rate monohydrate ((COO) ₂ Ca · H ₂ O), calcium oxide (CaO), calcium propionate _{((CH 3 CH 2 COO)} 2 Ca), calcium stearate _{(Ca [CH 3 (CH 2} ) 16 COO] 2), calcium sulfate (CaSO ₄ ), calcium sulfate dihydrate (CaSO ₄ · 2H ₂ O) and calcium sulfate hemihydrate _{(CaSO 4 · 1 / 2H 2} O) , characterized in that ceramic source consisting of one or more materials that are selected from The method of pottery with the amorphous coating.
3. The method of claim 1 or 2,
Calcium silicate (CaSiO ₃ ), calcium silicate hydrate (CaSiO ₃ .nH ₂ O, where n is a positive real number), potassium silicate (K ₂ SiO ₃ ), sodium hexafluorosilicate (Na ₂ SiF ₆ ), sodium metasilicate Na ₂ SiO ₃ ), sodium metasilicate nonahydrate (Na ₂ SiO ₃ .9H ₂ O), sodium metasilicate pentahydrate (Na ₂ SiO ₃ .5H ₂ O), sodium orthosilicate hydrate (2Na ₂ O SiO ₂ · nH ₂ O, n is a positive real number), sodium silico fluoride (Na ₂ SiF _6), tetra-aryl ortho silicate _{(C 12 H 20 O 4 Si} ), tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ), tetramethylammonium silicate ((CH ₃ ) ₄ N (OH) 2SiO ₂ ), tetramethyl orthosilicate (Si (OCH ₃ ) ₄ ), tetrapropyl orthosilicate and tetrabutyl orthosilicate Characterized in that the amorphous coating of the ceramic material is made of at least one material. Yonghan method of pottery.
3. The method according to claim 1 or 2,
Characterized in that it is made of at least one material selected from the group consisting of ammonium hydroxide, lithium hydroxide monohydrate (HLiO.H ₂ O), potassium hydroxide, sodium amide and sodium hydroxide.
The method of claim 1 or 2, wherein the calcium source material is calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂ .4H ₂ O)
The silicon source material is tetraethyl silicate _{(Si (OC 2 H 5)} 4),
Wherein the basic material is ammonium hydroxide. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
The method according to claim 1 or 2, wherein the calcination is performed at a temperature of 1125 to 1300 ° C.
The method according to claim 1 or 2, wherein the calcination is performed in an oxidizing atmosphere at a temperature of 500 to 1000 캜.
The method of claim 1 or 2, wherein the feldspar comprises nephelin sialonite.
3. The method of claim 1 or 2, wherein in mixing the kaolin, clay, and amorphous coated silica and feldspar with water,
25 to 34% by weight of the kaolin, 5 to 10% by weight of the clay, 29 to 39% by weight of an amorphous phase coated silica, and 25 to 34% by weight of an amorphous phase coated feldspar,
Wherein the water is mixed so that the solid content of the feldspar coated with the kaolin, the clay, the amorphous phase-coated quartz and the amorphous phase is 50 to 70% by weight, and the amorphous phase-coated amorphous phase is mixed with the water.
3. The method of claim 1 or 2, wherein in mixing the kaolin, clay, and amorphous coated silica and feldspar with water,
In order to improve the dispersibility, benzyltrimethylammonium hydroxide (C ₁₀ H ₁₇ NO 3), diethylamine (C ₁₀ H ₁₇ NO 3) were added to 100 parts by weight of solids of feldspar coated with kaolin, clay and amorphous phase, diethylamine (C ₄ H ₁₁ N), ethylamine, propylamine, butylamine, pentylamine, methylamine (CH ₅ N), tetramethylammonium hydroxide One or more substances selected from tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide and tetrabutyl ammonium hydroxide 0.001 To 3 parts by weight of an amorphous coating of a ceramics raw material.

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