KR101230241B1

KR101230241B1 - Method of Aerosol Deposition for Ceramic Powder

Info

Publication number: KR101230241B1
Application number: KR1020100116095A
Authority: KR
Inventors: 지영호; 정세진; 이희진; 허승헌
Original assignee: 거림테크 주식회사; 한국세라믹기술원
Priority date: 2010-11-22
Filing date: 2010-11-22
Publication date: 2013-02-06
Also published as: KR20120054793A

Abstract

The present invention relates to a method of uniformly forming a ceramic vapor deposition film through a method in which a ceramic powder is accelerated by a vacuum expansion principle (aerosol deposition method: AD method hereinafter) and impinges on a substrate.
The present invention includes an aerosol chamber having a rotary gas injector for injecting a transport gas into the chamber; A low vacuum deposition chamber having a substrate disposed therein; And a transport tube having one end communicating with the aerosol chamber and the other end inserted into the deposition chamber and open toward the substrate. (A) introducing ceramic powder into the aerosol chamber by an aerosol deposition apparatus configured to include; (b) injecting a transport gas through the rotary gas injector to form a rotary air stream of the transport gas in the aerosol chamber, thereby aerosolizing the ceramic powder and preventing the ceramic powder from being laminated to the bottom of the aerosol chamber; and (c) depositing the aerosol on the substrate by accelerating the aerosol with a vacuum expansion principle and discharging the aerosol through the transport tube into the deposition chamber; It provides a ceramic powder aerosol deposition method to be carried out.

Description

Ceramic powder aerosol deposition method {Method of Aerosol Deposition for Ceramic Powder}

The present invention relates to a method of forming a uniform deposited film through a method in which a ceramic horse is accelerated by a vacuum expansion principle (aerosol deposition method: AD method hereinafter) and impinges on a substrate.

The thermal spraying method is a method of obtaining a coating by activating a base powder by using plasma or thermal energy at high temperature and directly injecting high temperature and high pressure compressed air through the nozzle. It has been widely used in ceramic coatings for aircraft or large structures. However, work must be done in fireproof clothing in an enclosed space, and there are disadvantages such as noise pollution, sparks, air pollution and energy waste.

Recently, a solid powder coating method using a cold spray method that has developed a thermal spraying method has attracted much attention. This is related to the direct wiring of solid state powder. Similar to the thermal spraying method, the compressed gas is injected through the nozzle, and the solid powder is bumped into the base metal at high speed at room temperature to form a coating. At this time, the compressed gas container is heated to several hundred degrees to obtain a high pressure compressed gas. It does not just go through a powder activation process like plasma in thermal spraying. This cold spraying method requires very high acceleration due to the resistive gas pressure of the deposition part, which requires a unique nozzle design, high temperature and high pressure compressed gas holding technology, and generates noise during coating.

The aerosol deposition (AD) technique used in the present invention is based on the principle of vacuum expansion and its roots are based on cluster beam sources that are widely used in the basic sciences. Supersonic cluster sources achieve accelerations of 10 ³ to 10 ⁴ m / s by spraying gases into the chamber in a vacuum or pulsed state. Aerosol deposition, on the other hand, uses heavier powders, so it does not gain tremendous acceleration like a cluster source, but it can produce a good deposition film even at subsonic speeds. An example is a 4 nm powder aerosol deposition method (Huh et. Al. Appl. Phys. Lett. 91, 093118, 2007). This paper introduces the fact that 4nm particles are accelerated to about 200m / s by the vacuum expansion principle and collide on the silicon substrate, so that the direct bonding between particle-substrate and particle-particle is achieved. The aerosol deposition method is much quieter than the thermal spraying method or the cold spray method and is an environmentally friendly energy saving process technology compared to the CVD, PVD, thermal spraying method and the cold spray method. Unlike the cluster source, it can be implemented with low vacuum technology.

The present invention aims to produce a uniform deposited film through a method of accelerating a ceramic powder aerosol with a vacuum expansion principle (AD method applied) and then impinging on an electrode. Although the AD method is a very general and simple method for forming a thin film (see FIG. 1), serious process problems occur when forming a thin film by depositing ceramic powder. That is, the chamber for aerosolizing the ceramic powder must be provided separately, typically the following problems occur.

When ceramic powder aerosol is continuously sent from the aerosol chamber to the deposition chamber, a problem arises in which powders are deposited in the bottom corner of the aerosol chamber (see FIG. 2). In other words, due to the combination of gravity and friction force, the powder is settled or stagnated and accumulated in the lower side of the aerosol chamber (the corner of the aerosol chamber). In this case, the ceramic powder accumulated in the corners is intermittently discharged into the deposition chamber as agglomerates, which causes a great obstacle in obtaining a uniform ceramic deposition film. This phenomenon creates a uniform aerosol and makes it difficult to deliver a certain concentration of aerosol to the deposition chamber.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of forming a uniform ceramic deposition film in large areas by solving the above problems.

In the present invention, the following means is applied to solve the above-mentioned problem.

That is, a rotary gas ejector is installed at the gas injection unit provided in the aerosol chamber to prevent the transport gas from colliding with all walls when the transport gas is injected into the aerosol chamber, thereby preventing the ceramic powder from being deposited at the lower end of the aerosol chamber (FIG. 3).

By providing the aerosol in a uniform state from the aerosol chamber to the deposition chamber by the method provided by the present invention, it is possible to manufacture a variety of ceramic thin film, thick film at room temperature and to provide a variety of products on the market, the commercial ripple effect is very It is expected to be large. One TiO ₂ film exemplified in the present invention can be used directly as a dye-sensitized solar cell when coated on a transparent conductive film (eg, FTO film).

1 is a schematic diagram of a general aerosol deposition apparatus.
FIG. 2 is a schematic diagram of a problem occurring in the aerosol chamber over time when the ceramic powder aerosol is continuously sent from the aerosol chamber to the deposition chamber.
3 is a schematic view of a rotary gas injector mounted in an aerosol chamber.
4 is an electron micrograph of a TiO ₂ deposited film prepared according to the present invention.

The present invention includes an aerosol chamber having a rotary gas injector for injecting a transport gas into the chamber; A low vacuum deposition chamber having a substrate disposed therein; And a transport tube having one end communicating with the aerosol chamber and the other end inserted into the deposition chamber and open toward the substrate. (A) introducing ceramic powder into the aerosol chamber by an aerosol deposition apparatus configured to include; (b) spraying a transport gas through the rotary gas injector to form a rotary air stream of the transport gas in the aerosol chamber, thereby aerosolizing the ceramic powder and preventing the ceramic powder from being laminated to the bottom of the aerosol chamber. And (c) depositing the aerosol on the substrate by accelerating the aerosol with a vacuum expansion principle and discharging the aerosol through the transport tube into the deposition chamber. It provides a ceramic powder aerosol deposition method to be carried out.

TiO ₂ may be used as the ceramic. In this case, the substrate may have a structure in which a TiO ₂ film is deposited on the transparent conductive film as a part of a dye-sensitized solar cell by applying a transparent conductive film.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail with reference to the embodiment in which the TiO ₂ powder of the ceramic material is applied.

The aerosol deposition apparatus used in the present invention is configured to include an aerosol chamber 10, the deposition chamber 20 and the transport pipe 30 as shown in FIG.

The ceramic powder 1 is introduced into the aerosol chamber 10 (step (a)). The transport gas 2 is injected into the aerosol chamber 10 through the gas inlet 11. The gas inlet 11 may be equipped with a flow rate control unit 12 to supply a certain amount of transport gas. When the transport gas is injected into the ceramic powder located on the bottom of the aerosol chamber 10, the ceramic powder particles are blown to the gas phase, thereby forming an aerosol 3 (step (b)). The ceramic powder aerosol 3 formed as above is accelerated and injected into the deposition chamber 20 through the transport pipe 30 by the pressure difference between the aerosol chamber 10 and the deposition chamber 20 in a low vacuum state. Thus, an aerosol is deposited on the substrate to form a ceramic deposition film on the substrate (step (c)). An injection end of the aerosol may be controlled by combining various injection nozzles 31 having different cross-sectional areas and shapes at the end of the transport pipe 30 introduced into the deposition chamber 20. The aerosol accelerated at high speed is deposited upon the substrate 21. The substrate 21 may be fixed to the holder 22, and the holder 15 may be coupled to the height adjusting unit 16 to adjust the distance between the substrate 21 and the injection nozzle 31. The critical velocity for the aerosol 3 to be injected and deposited on the substrate is 150 m / sce or more. The gas in the deposition chamber 20 remaining after the aerosol 3 is deposited on the substrate may be discharged through the exhaust 24 as shown in FIG. 1.

However, as the aerosol is formed and the aerosol is deposited on the substrate, the ceramic powder begins to accumulate in the corners of the aerosol chamber 10 as illustrated in FIG. In this case, intermittent discharge of powder lumps may occur intermittently, which causes serious problems in forming a uniform thin film.

In order to solve this problem, in the present invention, by installing a rotary gas injector at the end of the gas inlet 11, in step (b) it is induced to the gas injection to rotate in various directions instead of one-way gas injection inside the aerosol chamber At the same time, a rotary airflow is formed so that aerosol is formed and ceramic powders are not laminated to the bottom of the aerosol chamber. 3 is a schematic diagram of a rotary gas injector used in the present invention.

Meanwhile, TiO ₂ may be used as the ceramic, and FIG. 4 shows a TiO ₂ deposited film manufactured by the method provided by the present invention. In this case, by applying a transparent conductive film (FTO, etc.) as the substrate, the structure in which the TiO ₂ deposition film is formed on the transparent conductive film can be used as part of the dye-sensitized solar cell.

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 embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Therefore, the claims of the present invention include modifications and variations that fall within the true scope of the invention.

1: Ceramic Powder 2: Transport Gas
3: aerosol 4: exhaust gas
10: aerosol chamber
11 gas inlet 12 flow control unit
13: rotary gas injector
20: deposition chamber
21: substrate 22: holder
23: height adjustment 24: exhaust
30: pipeline
31: injection nozzle
100: aerosol deposition apparatus

Claims

An aerosol chamber having a rotary gas injector for injecting a transport gas into the chamber; A low vacuum deposition chamber having a substrate disposed therein; And a transport tube having one end communicating with the aerosol chamber and the other end inserted into the deposition chamber and open toward the substrate. Ceramic powder aerosol deposition method performed in each of the following steps by an aerosol deposition apparatus configured to include a.
(a) introducing a ceramic powder into the aerosol chamber;
(b) spraying a transport gas through the rotary gas injector to form a rotary air stream of the transport gas in the aerosol chamber, thereby aerosolizing the ceramic powder and preventing the ceramic powder from being laminated to the bottom of the aerosol chamber. ; And
(c) depositing the aerosol on the substrate by accelerating the aerosol with a vacuum expansion principle and discharging the aerosol through the transport tube into the deposition chamber;

In claim 1,
Ceramic ceramic aerosol deposition method, characterized in that the TiO ₂ .

In claim 2,
The substrate is a ceramic powder aerosol deposition method, characterized in that the transparent conductive film.