KR101466930B1 - Dielectric glass nanopowder of Ta2O5 based composition and manufacturing method thereof - Google Patents

Abstract

The Ta ₂ O ₅ -based dielectric nanopowder manufacturing method according to an embodiment of the present invention is characterized in that raw material powders of Ta ₂ O ₅ -B ₂ O ₃ -ZnO-SiO ₂ -Na ₂ O series are mixed and melted and then quenched Preparing a precursor of the micropowder; Supplying the precursor to a plasma processing apparatus with a powder feeding gas; Supplying a central gas and a sheath gas to the electromagnetic plasma processing apparatus; Generating a plasma by an induction coil in the electromagnetic plasma processing apparatus; And supplying quenching gas to the electromagnetic plasma processing apparatus.

RF plasma, environmentally friendly, dielectric, nano powder, tantalum oxide (Ta2O5)

Description

TECHNICAL FIELD The present invention relates to a Ta 2 O 5 based dielectric nanopowder and a method of manufacturing the same,

The invention tens containing relates to a harmful Pb component and the expensive oxidation decarburization volume containing no Bi (Ta ₂ O ₅₎ based dielectric nano powder, and a method of producing a human body, oxidation decarburization volume (Ta ₂ O ₅₎ The present invention relates to a method of manufacturing a Ta ₂ O ₅ -based dielectric nano powder having a spherical shape and a uniform particle size of 20 to 500 nm by injecting a micrometer-sized dielectric powder into an RF (radio frequency) plasma processing apparatus.

The PDP includes a top plate on which a transparent conductive film (ITO) electrode, a bus (BUS) electrode, a dielectric layer, and a magnesium oxide protective layer are formed, an address electrode, a reflective film, a barrier rib, Plasma gas is injected into the inner space between the lower surface plates.

The glass composition for a transparent dielectric used in a conventional plasma display panel has PbO, B ₂ O ₃ and SiO ₂ having a low sintering temperature, a linear expansion coefficient similar to that of the substrate, and a proper dielectric constant in accordance with the thermal characteristics of the front and rear glass substrates, .

A lead-free composition that is comparable to a PbO-based compound as a composition of this dielectric has not yet been developed.

PbO-based glass compositions, which are currently used as transparent transparent dielectrics for PDPs, contain a large amount of PbO, which is harmful to the human body and has a serious effect on environmental pollution. And causing chemical pollution by soil and water pollution. Further, in the case of a composition containing a large amount of PbO in the prior art, it can be a considerable burden on the weight when it is made into a large area in the final product. Among the B ₂ O ₃ -based glasses and alkaline earth oxides used as a substitute for lead (Pb) -free low melting point glass, BaO-based glass also contains a heavy metal component classified as a poisonous substance and is a non-environmentally compatible material. Usage is inappropriate composition.

Japanese Unexamined Patent Publication No. 2000-226231 discloses that ZnO is 20 to 45 wt%, B ₂ O ₃ is 20 to 34 wt%, SiO ₂ is 20 to 45 wt%, R ₂ O (K ₂ O, Na ₂ O and Li ₂ O) is 4 to 12 wt%, RO (a sum of BaO and CaO) is 0 to 3 wt%, and NaF is 0.5 to 8 wt%. US Patent No. 6,417,123 also discloses that ZnO is 20 to 45 wt%, BaO is 15 to 45 wt%, B ₂ O ₃ is 15 to 35 wt%, SiO ₂ is 3 to 15 wt%, and PbO 0 to 24.5% by weight. The above glass compositions all provide glass compositions that can be used for PDP transparent dielectrics and barrier formers. However, the glass composition of the Japanese Laid-Open Patent Application (Kokai) discloses that the glass composition containing R ₂ O (K ₂ O, Na ₂ O, Li ₂ O) alkaline components is highly likely to react with the electrode, However, the use of the PbO-based component still fails to meet the object of the lead-free low-melting glass.

DISCLOSURE OF THE INVENTION The present invention has been made in order to solve the problems of conventional dielectrics containing harmful components, and it relates to a dielectric nano powder of a composition of oxide decontamination (Ta ₂ O ₅ ) which does not contain lead or bismuth harmful to the human body, .

The Ta ₂ O ₅ -based dielectric nanopowder manufacturing method according to an embodiment of the present invention is characterized in that raw material powders of Ta ₂ O ₅ -B ₂ O ₃ -ZnO-SiO ₂ -Na ₂ O series are mixed and melted and then quenched Preparing a precursor of the micropowder; Supplying the precursor to a plasma processing apparatus with a powder feeding gas; Supplying a central gas and a sheath gas to the electromagnetic plasma processing apparatus; Generating a plasma by an induction coil in the electromagnetic plasma processing apparatus; And supplying quenching gas to the electromagnetic plasma processing apparatus.

In the step of generating the plasma, the power supplied to the induction coil may be 15 to 150 kW.

The central gas may include an inert gas of 5 to 50 SLPM, and the blocking gas may include an inert gas of 10 to 120 SLPM and oxygen of 10 to 120 SLPM.

The Ta ₂ O ₅ -based dielectric nanopowder according to an embodiment of the present invention is manufactured by any one of the above-mentioned manufacturing methods, and the Ta ₂ O ₅ -based dielectric nanopowder is spherical in shape and has a diameter of 50 to 200 nm to be.

The Ta ₂ O ₅ -based dielectric nanopowder prepared according to the present invention can solve the environmental pollution problem, produce a glass composition having a low firing temperature, and satisfying the basic characteristics of a dielectric glass layer for a plasma display panel. Therefore, it can be used as a raw material for a paste or an ink for forming a PDP top plate or a bottom plate dielectric thick film, or can be used as an additive in a conductive paste or a conductive ink.

It will be described in detail for the decarburization of cerium oxide with an electromagnetic wave plasma apparatus according to the present invention, the drawings and the embodiments hereinafter with reference to the accompanying (Ta ₂ O ₅₎ based dielectric nano powders and their preparation.

delete

In order to explain a method of manufacturing a dielectric nano powder of oxide type taustite (Ta ₂ O ₅ ) according to an embodiment of the present invention, an electromagnetic wave (RF) plasma processing apparatus, which is one of the combustion gas- do. 1 is a schematic diagram of a torch generating portion of an electromagnetic (RF) plasma processing apparatus. The precursor powder is injected into the upper portion of the torch generating portion, and an auxiliary gas for enhancing the processing efficiency of plasma is injected together. The auxiliary gas supplied with the precursor powder includes a sheath gas, a central gas, a powder feeding gas, etc., and an inert gas such as argon, oxygen, and a gas mixture thereof are mainly used do.

The blocking gas is injected to prevent vaporized powder from adhering to the inner surface of the wall provided with the induction coil of the plasma torch generating portion to which the precursor is supplied. The central gas is injected into the inner wall of the torch-generating portion in order to uniformly flush the precursor. The powder injection gas is injected to ensure smooth supply of the precursor powder.

The precursor powder injected into the torch generator is vaporized or melted in an electromagnetic wave plasma, condensed or quenched by a quenching gas injected from a lower end thereof, and a series of reactions are performed in the form of nano powder.

(Ta ₂ O ₅ ), zinc oxide (ZnO), boron oxide (B ₂ O ₃ ), silicon oxide (SiO ₂ ), and sodium oxide (Na ₂ O) powders for supply to the electromagnetic plasma apparatus as raw materials After mixing well, it is melted, quenched and mechanically pulverized using a ball mill to produce a micro-sized precursor. The content of the ingredients are respectively Ta ₂ O _{5 5} ~ 35 weight%, zinc (ZnO) 5 ~ 30 wt%, boron oxide _{(B 2 O 3) 15 ~} 50 % by weight, silicon oxide (SiO ₂₎ 3 ~ 10% by weight, and 5 to 30% by weight of sodium oxide (Na ₂ O).

The precursor in the form of a micropowder is injected into the induction plasma torch through a powder injector. The induction coil of the electromagnetic plasma processing apparatus is preferably controlled to 15 to 150 kW. If the electric power supplied to the induction coil is higher than 150 kW, the precursor becomes excessively large, so that the production amount of the fine powder itself becomes small, and the economical efficiency decreases. On the other hand, when the supplied power is less than 15 kW, the plasma is not generated and the coarse powder is produced in a large amount, so that the productivity of the nano powder is greatly deteriorated.

Powder feeding gas, central gas and sheath gas are supplied to the induction plasma torch, and quenching gas is supplied at the lower end of the induction plasma. Controlling the type and ratio of these gases can control particle size and chemical composition. Therefore, it is necessary to establish optimal conditions for these auxiliary gases.

It is most preferable that the inert gas and the oxygen are mixedly injected at 10 to 120 SLPM and 10 to 120 SLPM, respectively, and the center gas is injected at 5 to 50 SLPM as the inert gas. Here, Standard Liters Per Minute (SLPM) means a flow rate of gas supplied at 20 ° C and atmospheric pressure as a unit representing the flow rate of gas supplied under a certain condition.

Since the final product, amorphous nano powder, has a very high surface area and is highly reactive with gases, an inert gas must be used. Oxygen gas improves the condensability of the amorphous nano powder. Is suitably used for stabilizing the plasma.

The central gas also serves to stabilize the plasma along with the blocking gas, and has the most excellent effect in the flow rate range.

The temperature of the plasma generated from the induction plasma torch is 5,000 to 10,000K, and the inside of the reaction chamber is formed into a high-temperature environment to thermally decompose the precursor into nanoparticles. The resulting nanoparticles are chemically and rearranged in the reaction chamber for several seconds, cooled by quench gas, and made into final nano-sized powders.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Example 1]

Oxidation decarburization volume (Ta ₂ O _5), zinc (ZnO), silicon oxide (SiO _2), boron oxide (B ₂ O _3), respectively 15, 15, 10, 45 of sodium oxide (Na ₂ O) oxide powder, 15% by weight. The mixed powders were mechanically pulverized and mixed by a ball milling method using a zirconia ball. The pulverized mixture was subjected to heat treatment in a platinum crucible at 1000 ° C for 1 hour to completely melt and chemically react, and then the melt was poured onto a stainless steel plate having a thickness of 5 mm and cooled. The produced plate glass is subjected to a mechanical ball milling process to obtain a micro powder having a size of 0.5 to 50 μm. The precursor of the micropowder was put into a powder feeder and an argon gas was poured into the reaction chamber. The plasma was injected with argon gas to generate RF plasma at the toothed portion, and the plasma power was adjusted to 30 kW.

[Test Example 1] Analysis of particle shape and size

(SEM) was used to compare the particle size and shape of the Ta ₂ O ₅ dielectric nanopowder prepared using the dielectric micropowder precursor and the RF plasma processing apparatus. A photograph of the surface taken with an electron microscope is shown in Fig. As shown in FIG. 2, the micro powder as a precursor has a rough and irregular surface and a size of 5 to 50 μm. On the other hand, a Ta ₂ O ₅ -based dielectric nanopowder prepared by using an RF (radio frequency) plasma processing apparatus has a smooth surface, a perfect spherical shape, and a size of 80 to 120 nm.

[Test Example 2] Analysis of crystal structure

The X-ray diffractometer (XRD) was used to confirm the crystal structure of the Ta ₂ O ₅ -based dielectric nanopowder prepared by using the dielectric micropowder precursor and the electromagnetic wave (RF) plasma processing apparatus. Respectively. As shown in FIG. 3, it was confirmed that both of the above materials have a perfect amorphous structure.

[Test Example 3] Measurement of vitrification temperature

In order to measure the vitrification temperature of the Ta ₂ O ₅ -based dielectric nanopowders prepared by using the dielectric micropowder precursor and the RF plasma processing apparatus, the temperature was raised at a rate of 5 ° C./min and a temperature of 20 ° C./min using a differential scanning calorimeter (DSC) Thermal analysis was performed in the temperature range of 800 ℃. The results of the experiment are shown in Fig. The measured vitrification temperature was 492.4 캜 for a micropowder precursor, and 445.4 캜 for a Ta ₂ O ₅ -based dielectric nanopowder prepared by using an electromagnetic wave (RF) plasma treatment apparatus

[Test Example 4] Measurement of dielectric constant

In order to measure the dielectric constant of the Ta ₂ O ₅ -based dielectric nanopowder according to the present invention, the prepared nano-dielectric powder was made into pellets and then sintered at 450 ° C for 1 hour. Then, silver paste And then fired at 250 ° C for 30 minutes to form an electrode. The diameter of the sintered dielectric pellets was 100 mm and the thickness was 4 mm. The measured relative dielectric constant was 11.3, which was found to be suitable for PDP top plate dielectric.

1 is a schematic view of a torch portion of an electromagnetic (RF) plasma processing apparatus,

2 is a scanning electron micrograph (SEM) photograph of a dielectric micropowder (precursor powder) and a Ta ₂ O ₅ -based dielectric nanopowder prepared according to one embodiment of the present invention,

3 is an X-ray diffraction diagram of a dielectric micropowder (precursor powder) and a Ta ₂ O ₅ -based dielectric nanopowder produced by an embodiment of the present invention,

FIG. 4 is a thermal analysis graph of a differential scanning calorimeter (DSC) showing the transition temperature of the dielectric micropowder (precursor powder) and the Ta ₂ O ₅ dielectric nanocomposite prepared according to one embodiment of the present invention.

Claims (4)

Mixing the raw material powders of Ta ₂ O ₅ -B ₂ O ₃ -ZnO-SiO ₂ -Na ₂ O series, melting them, and quenching them to prepare a precursor of the micropowder; Supplying the precursor to a plasma processing apparatus with a powder feeding gas; Supplying a central gas and a sheath gas to the electromagnetic plasma processing apparatus; Generating a plasma by an induction coil in the electromagnetic plasma processing apparatus; And Ta ₂ O ₅ based dielectric nano powder production method including a step of supplying a quench gas (quenching gas) to the electromagnetic wave plasma processing apparatus. The method according to claim 1, In the step of generating the plasma, Of the power supplied to the induction coil 15 ~ 150kW, Ta ₂ O ₅ based dielectric nano powder production method. The method according to claim 1, The central gas may include, An inert gas of 5 to 50 SLPM, The blocking gas may include, A process for producing a Ta ₂ O ₅ based dielectric nanopowder comprising an inert gas of 10 to 120 SLPM and oxygen of 10 to 120 SLPM. A Ta ₂ O ₅ -based dielectric nano powder produced by the method according to any one of claims 1 to 3, The Ta ₂ O ₅ based shape of the dielectric nano-powder is spherical, the diameter of 50 ~ 200nm, Ta ₂ O ₅ based dielectric nano-powder.

Images