KR20110033393A - Synthetic method of 100nm-scale cerium oxide from needle-like cerium carbonate - Google Patents

Abstract

PURPOSE: A method for manufacturing 100nm scale cerium oxide based on needle-shaped cerium carbonate is provided to improve the yield of the cerium oxide by controlling a reaction condition for forming the cerium carbonate. CONSTITUTION: A method for manufacturing a cerium oxide includes the following: 0.4 to 1M cerium chloride aqueous solution is stirred at temperature between 40 and 60 degrees Celsius, and ammonium bicarbonate is added(S110). Needle-shaped cerium carbonate is obtained by separating solid and liquid from the resultant of the cerium chloride aqueous solution and the ammonium bicarbonate(S120). The needle-shaped cerium carbonate is plasticized at temperature between 600 and 700 degrees Celsius to obtain needle-shaped cerium oxide(S130). Polyacrylic acid and 0.5 to 1M ammonia water are added to the needle-shaped cerium oxide to obtain cerium oxide grains, the average grain size of which is between 80 and 100nm.

Description

 Synthetic method of 100 nm-scale cerium oxide from needle-like cerium carbonate}

The present invention relates to a method for producing cerium oxide having an average particle size of 80 to 100 nm.

Cerium carbonate is widely used as a starting material for preparing nano-sized cerium oxide powder. From the product obtained by calcining and pulverizing a conventional plate-like cerium carbonate [Ce ₂ (CO ₃ ) ₃ XH ₂ O], the classification is performed to obtain a cerium oxide powder having a size of 100 nm. Because it is composed of nano-sized cerium oxide manufacturing efficiency is low. In general, since the shape of cerium carbonate has a characteristic of maintaining the original shape as it is even after being converted to cerium oxide after firing, a manufacturing technique capable of controlling the shape of cerium carbonate is required to maximize the grinding effect.

As described above, when a cerium oxide particle having a size of 100 nm is prepared from a conventional plate-like cerium carbonate [Ce ₂ (CO ₃ ) ₃ .XH ₂ O], the average particle size of the particle is less than 100 nm. Accordingly, an object of the present invention is to provide a method for effectively producing cerium oxide particles having an average particle size of 80 to 100 nm.

More specifically, in the present invention, when acryl bicarbonate is added to an aqueous solution of cerium chloride to prepare cerium carbonate, reaction conditions are controlled to prepare acicular cerium carbonate [Ce (OH) (CO ₃ )], and the firing and pulverization process is performed. After the preparation of cerium oxide particles having an average particle size of 80 ~ 100nm, the purpose is to increase the production yield.

The present invention relates to a method for producing cerium oxide particles of 80 to 100nm after the addition of ammonium bicarbonate to an aqueous solution of cerium chloride to produce acicular cerium carbonate, followed by firing and grinding. The production method according to the present invention can produce fine cerium oxide particles having an average particle diameter of 80 to 100 nm than the cerium oxide particles produced by calcining a conventional plate-like cerium carbonate, and has an advantage of high manufacturing efficiency.

The present invention will be described in more detail with reference to FIG. 1.

The present invention a) 0.4 ~ 1M cerium chloride aqueous solution while stirring at 40 ~ 60 ℃, the reaction by adding ammonium bicarbonate (110) solid-liquid separation to prepare a needle-like cerium carbonate (120);

b) calcining the acicular cerium carbonate at 600 to 700 ° C. to produce acicular cerium oxide (130); And

c) adding polyacrylic acid and 0.5-1M ammonia water to the acicular cerium oxide and pulverizing 140 to prepare cerium oxide particles having an average particle size of 80 to 100 nm;

It relates to a cerium oxide particle production method comprising a.

In the step a), ammonium bicarbonate is gradually added to the aqueous solution of cerium chloride while stirring at 40 to 60 ° C. to prepare cerium carbonate. When stirring at ℃, it is possible to produce a needle-like cerium carbonate, and when firing the needle-like cerium carbonate can be prepared nano-sized cerium oxide particles of the present invention.

More specifically, the molar ratio of cerium chloride and ammonium bicarbonate in a) is 1: 1 to 3, and when the reaction temperature is maintained in the above range, acicular cerium carbonate may be produced, and if it is largely out of the range, The generation efficiency of acicular cerium carbonate may be reduced. In addition, the vigorous stirring during the stirring in step a) is good in reactivity, the needle-like cerium carbonate can be effectively produced. More specifically, in the above a), the stirring speed may reduce by-products due to the reaction when the stirring speed is 700 to 900 rpm. In addition, it is preferable that ammonium bicarbonate is added in an aqueous solution. When the ammonium bicarbonate aqueous solution is added, the concentration is preferably added at a concentration of 0.5 to 0.8M.

The needle-like cerium carbonate prepared after the reaction is preferably solid-liquid separated, followed by step c).

In the present invention, the needle-like cerium carbonate may be calcined at 600 to 700 ° C. in step b), and when calcined at the temperature range, cerium oxide particles generated after the grinding process may be manufactured in nano size. When calcined in the above temperature range, there is an advantage in that a cerium oxide having a porous structure split into smaller particles may be produced while carbonate gas and water vapor are released from cerium carbonate.

In the present invention, it is preferable to grind by adding polyacrylic acid and 0.5 ~ 1M ammonia water to the needle-like cerium oxide in c), and to produce finer cerium oxide particles by acting as a dispersant when the polyacrylic acid and ammonia water is pulverized. In this case, the content ranges from 0.001 to 0.004 parts by weight of the polyacrylic acid and 0.01 to 0.04 parts by weight of the ammonia water, based on 100 parts by weight of acicular cerium oxide. After the polyacrylic acid and the ammonia water is added, water may be further added and pulverized, and the range of water may be 750 to 850 parts by weight based on 100 parts by weight of acicular cerium oxide.

By adding and grinding the ammonia water, pH of the cerium oxide particles prepared after grinding may be maintained at 7 to 9. At this time, when the pH is more than neutral, the zeta-potential value of the cerium oxide particles is maintained at -30 to -40 so that the dispersibility is good. In addition, if the pH range is maintained, it can be effectively used as a CMP slurry of a semiconductor wafer. Polyacrylic acid may serve to prevent aggregation of the pulverized product.

In addition, the cerium oxide particles according to the present invention are characterized in that the semiconductor CMP slurry.

In the present invention, the grinding in c) is made of a planetary mill, and the grinding medium uses a zirconia ball having an average particle diameter of 2 to 5 mm, and the weight ratio of the acicular cerium oxide and zirconia ball is 1: 20 to Characterized in that 25, the cerium oxide particles having an average particle diameter of 80 ~ 100nm when pulverized under the above conditions can be obtained with a narrow particle size distribution with high efficiency. When grinding with the planetary mill, it is effective to grind for 4 to 5 hours at a rotational speed of 400 to 600 rpm, and the grinding time may vary depending on the amount of cerium oxide to be crushed.

The production method according to the present invention can produce fine cerium oxide particles having an average particle diameter of 80 to 100 nm than the cerium oxide particles produced by calcining a conventional plate-like cerium carbonate, and has an advantage of high manufacturing efficiency.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to the following examples.

Example 1

Needle-shaped Cerium carbonate  Produce

While maintaining 50 ° C, 200 ml of a 200 ml cerium chloride aqueous solution at 0.5 M concentration was prepared by adding 200 ml of an aqueous ammonium bicarbonate solution having a concentration of 0.75 M with vigorous stirring at 700 rpm. The cerium carbonate prepared above was observed with an electron microscope and shown in FIG. 2. The cerium carbonate prepared above is shown in FIG. 3 by x-ray diffraction analysis. The cerium carbonate prepared through FIGS. 2 and 3 was acicular cerium carbonate having a structure of Ce (OH) (CO ₃ ). The needle-like cerium carbonate prepared above was dried.

Nanoscale  Cerium Oxide Particles Manufacturing

The prepared cerium carbonate was calcined at 700 ° C., and then ground using a planetary mill. The grinding port was YSZ (yttria stabilized zirconia) and had a volume of 80 ml. The ball used for grinding was 2 mm in size. 5 g of cerium oxide calcined with cerium carbonate at 700 ° C. was charged into a grinding port, followed by 120 g of a grinding ball. 0.1 g of polyacrylic acid, 1 g of 1 M ammonia water and 40 g of water were added as a dispersant. The loaded grinding port was installed in a planetary mill and ground at a rotational speed of 500 rpm for 5 hours. The pulverized product was recovered and analyzed in the particle size of the cerium oxide particles prepared by using a microparticle size analyzer, as shown in Table 1 and FIG. 6. As can be seen in Table 1 and Figure 6 it can be seen that the average particle size of the prepared cerium oxide particles is 92nm.

An electron micrograph of the cerium oxide prepared in Example 1 is shown in FIG. 7.

[Comparative Example 1]

Plate Cerium carbonate  Produce

The same procedure as in Example 1 was performed except that the reaction temperature was brought to room temperature, and the rest was performed in the same manner as in Example 1. An electron micrograph of the prepared cerium carbonate is shown in FIG. 4 and the result of the x-ray diffraction analysis is shown in FIG. 5. 4 and 5, the cerium carbonate prepared was found to be a plate-like cerium carbonate having a structure of Ce ₂ (CO ₃ ) ₃ · H ₂ O.

Cerium Oxide Particles Manufacturing

The same procedure as in Example 1 was carried out, and cerium carbonate was used as the plate-like cerium carbonate prepared above. The particle size distribution of the prepared cerium oxide particles was analyzed in the same manner as in Example 1 and shown in FIG. 8 and Table 2 below. 8 and Table 2 confirmed that the average particle size of the cerium oxide particles prepared was 165 nm.

Comparative Example 2

The same procedure as in Example 1 was performed except that no ammonia water was added, and the rest was performed in the same manner as in Example 1. As a result of analyzing the particle size distribution of the prepared cerium oxide particles in the same manner as in Example 1, it was confirmed that the average particle size was 173 nm.

Table 1

Table 2

Figure 1 is a schematic diagram showing the step of producing cerium oxide particles according to the present invention.

FIG. 2 is a schematic diagram showing an electron micrograph of the acicular cerium carbonate of Example 1. FIG.

Figure 3 shows the x-ray diffraction analysis of the acicular cerium carbonate of Example 1.

Figure 4 is a schematic diagram showing an electron micrograph of the plate-like cerium carbonate prepared in Comparative Example 1.

5 is a schematic view showing the results of x-ray diffraction analysis of the plate-like cerium carbonate prepared in Comparative Example 1. FIG.

6 is a view showing a particle size distribution of the cerium oxide particles prepared in Example 1.

7 is a schematic view showing an electron micrograph of the cerium oxide prepared in Example 1.

8 is a diagram showing a particle size distribution of cerium oxide particles prepared in Comparative Example 1. FIG.

Claims (6)

a) preparing a needle-like cerium carbonate by reacting with 0.4 to 1 M aqueous solution of cerium chloride at 40 to 60 ° C. while adding ammonium bicarbonate and reacting the solution; b) calcining the acicular cerium carbonate at 600 to 700 ° C. to produce acicular cerium oxide; And c) preparing cerium oxide particles having an average particle size of 80 to 100 nm by pulverizing polyacrylic acid and 0.5 to 1 M ammonia water in the acicular cerium oxide; Cerium oxide particles production method comprising a. The method of claim 1, C) 0.001 to 0.004 parts by weight of the polyacrylic acid, and 0.01 to 0.04 parts by weight of the 0.5-1M ammonia water, based on 100 parts by weight of the acicular cerium oxide. 3. The method of claim 2, In the c) further water is added to the cerium oxide particles production method, characterized in that the 750 ~ 850 parts by weight based on 100 parts by weight of the acicular cerium oxide. The method of claim 1, The molar ratio of cerium chloride and ammonium bicarbonate in a) is 1: 1 to 3, characterized in that the cerium oxide particles. The method of claim 1, In c), the grinding is performed by a planetary mill, and the grinding media uses zirconia balls having an average particle diameter of 2 to 5 mm, and the weight ratio of the acicular cerium oxide and zirconia balls is 1: 20 to 25. A cerium oxide particle manufacturing method. The method of claim 1, Cerium oxide particles production method, characterized in that the stirring speed in the a) is 700 ~ 900rpm.

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