JPH01110249A - Analyzer for gas contained in metal material - Google Patents

Abstract

PURPOSE:To obtain an analyzer for gas in metal material having a vacuum chamber light and easy to manufacture, by forming a close oxide film in the inner surface of an aluminum vacuum chamber. CONSTITUTION:Two manipulators 2 holding a sample S and an ion gun 3 for ion beam etching are arranged in a vacuum chamber 1. In the vacuum chamber 1, for example, the inner surface thereof is washed and dried to make a dry surface purified and cleared of a hydrated oxide film and then, is heated contacting a gas containing oxygen but none of atmospheric air containing moisture to form a close oxide film in the inner surface thereof. This makes it hard to suck moisture or the like that would lower vacuum when the vacuum chamber 1 is evacuated with a vacuum exhauster 32 thereby achieving a higher analyzing accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an apparatus for analyzing minute amounts of gas in metal materials such as aluminum, copper, iron, magnesium, etc.

In this specification, the terms "aluminum,""copper,""iron," and "magnesium" include each alloy as well as a pure metal.

Prior art and its problems For example, aluminum materials contain internal gases and gases adsorbed on their surfaces, and substances such as water that react with aluminum and generate gases are adsorbed on their surfaces. These gases are mainly H2 gas, with very small amounts of CO gas, CO2 gas, H2o gas, etc. also present. Depending on the use of aluminum material,
Since the above gases are extremely harmful, it is necessary to reduce the amount of these gases to a very small amount.
The results have been achieved to some extent with respect to the surface gases (hereinafter collectively referred to as surface gases). However, the reality is that sufficient research has not yet been conducted on internal gases. If the amount of internal gas in the aluminum material, especially the amount of H2 gas, is large, the following problems may occur.

In other words, when aluminum material is used for vacuum purposes, such as particle acceleration pipes (beams) used in accelerators such as synchrotrons, a large amount of gas is released when the beam is run inside the pipe. The problem is that the pressure inside the pipe becomes very high. This is the result of the synchrotron radiation emitted from the beam entering the inner surface of the pipe and knocking out the internal gas of the aluminum material. In addition, when aluminum material is used as a deposition substrate, a phenomenon called "E blistering" occurs when Se, A-5T, etc. are deposited on the substrate surface, but this is also due to the effect of internal gas release. I know that.

Furthermore, it is known that surface defects such as cracks, blisters, and skin scratches that occur during rolling are due to the effects of internal gases in aluminum materials. therefore,
There is a demand for the development of aluminum materials with very small amounts of internal gas, but in order to develop aluminum materials with very small amounts of internal gas, it is necessary to accurately analyze the internal gas.

Analysis of internal gases in metal materials is carried out by using a device equipped with a vacuum chamber, evacuating the chamber, and then heating the material in the vacuum.

Conventionally, the analyzer described above has been equipped with a vacuum chamber made of stainless steel. however,
Vacuum chambers made of stainless steel have problems in that they are difficult to process and are heavy.

An object of the present invention is to provide an apparatus for analyzing gas in metal materials that solves the above-mentioned problems.

Means for Solving the Problems The apparatus for analyzing gas in metal materials according to the present invention is equipped with an aluminum vacuum chamber, and a honey oxide film is formed on the inner surface of the vacuum chamber.

In the above, there are, for example, the following two methods for forming a honey oxide film on the inner surface of the vacuum chamber.

First, after cleaning and drying the inner surface of the granular material for a vacuum chamber made of an aluminum plate to create a clean and dry surface from which the hydrated oxide film has been removed, the inner surface of the box-like material is exposed to moisture-containing air. In this method, an oxide film is formed on the inner surface of a box-shaped body by heating it in a state in which it is in contact with an oxygen-containing gas without contacting it. Specific methods for cleaning and drying the inner surface of the box-shaped body include, for example, alkaline cleaning using caustic soda or acid cleaning using sulfuric acid to wash away processing oil and remove the residue formed on the inner surface of the box-shaped body. There is a method of removing the hydrated oxide film and then drying it at low temperature in an inert gas atmosphere or vacuum atmosphere. In the above,
Drying after alkaline cleaning or acid cleaning is preferably performed in a vacuum atmosphere. This is because, after the above-mentioned cleaning, it can be placed in a vacuum oven and dried while being evacuated. This drying is preferably carried out at a temperature ranging from room temperature to 120°C, particularly from 70 to 90°C. This is because if the drying temperature exceeds 120°C, a hydrated oxide film may be formed during this drying process. Furthermore, it is preferable to perform a hydrated oxide film formation inhibiting treatment by immersing the box-shaped body in a treatment liquid for inhibiting hydrated oxide film formation before drying after alkaline or acid cleaning. As the treatment liquid for suppressing the formation of a hydrated oxide film, one of chromic acid, silicic acid, vanadic acid, zirconic acid, phosphoric acid (polyphosphoric acid), permanganic acid, tungstic acid, molybdic acid, and salts thereof is used. An aqueous solution containing -4 is used. The solute concentration in the processing solution is 0°000
0001-5vt%, preferably 0°000001-0
．． The content is preferably within the range of 0.0005 wt%.

Do not allow the chamber box-like body to come into contact with moisture-containing atmosphere.
In order to heat the box in contact with an oxygen-containing gas, place the box-shaped body in an oxygen-mixed inert gas atmosphere, a commercially available inert gas atmosphere, or an industrially obtained inert gas atmosphere, or Alternatively, the inert gas may be filled into a box-shaped body and the box-shaped body may be sealed. Alternatively, the box-shaped body may be placed in a vacuum atmosphere, or the inside of the box-shaped body may be evacuated. Furthermore, the box-shaped body may be placed in an atmosphere of 100% pure oxygen or dry air, or these may be filled in the box-shaped body and the box-shaped body may be sealed. As the oxygen mixed inert gas, oxygen 0.5 to 30
It is preferable to use one containing volX, particularly 1 to 10 volX, with the remainder being an inert gas. Furthermore, commercially available inert gases and industrially obtained inert gases contain a trace amount of oxygen as an impurity. Furthermore, the vacuum atmosphere and the evacuated box-like body contain enough oxygen to form an oxide film on the inner surface of the box-like body. Also,
The heating temperature is preferably 120-500°C, especially 200-300°C, and the heating time is preferably 0.1-24 hours, especially 0°5-6 hours. If the heating temperature and heating time are below the above lower limit values, the formation of the oxide film will not be successful, and if the upper limit values are exceeded, part of the amorphous film will crystallize and become mixed, resulting in the formation of a honey film. This is because there is a risk that it will disappear.

Part 2: After applying dry etching to create a clean and dry surface from which the hydrated oxide film has been removed, the inner surface of the box-shaped body is
This method forms an oxide film on the inner surface of a box-shaped body by heating it in contact with an oxygen-containing gas without contacting the atmosphere containing moisture.

Specific examples of dry etching include discharge cleaning, reactive gas etching, plasma ψ etching, reactive ion etching, reactive ion beam etching,
Ion beam etching, reactive laser beam etching
You can also do things like etching. If the inner surface of the aluminum box-shaped body is made clean and dry with the hydrated oxide film removed by dry machining, the processing oil is washed away and the hydrated oxide film is removed by acid cleaning or alkaline cleaning. There is no need for a drying process after washing, unlike in the case of washing. The method of heating the inner surface of the box-shaped body while not contacting the moisture-containing atmosphere but contacting the oxygen-containing gas is the same as in the first method described above.

Function: The gas analyzer in metal materials of the present invention is equipped with a vacuum chamber made of aluminum, so it is lighter and easier to process than conventional ones equipped with a vacuum chamber made of stainless steel. .

In addition, the gas analyzer in metal materials of the present invention has a honey oxide film formed on the inner surface of the vacuum chamber, so
When the inside of the vacuum chamber is evacuated, substances such as moisture that reduce the degree of vacuum become difficult to adsorb. Furthermore, even if these substances are adsorbed, they can be easily removed before gas analysis work.

If a hydrated oxide film, which is produced when an aluminum material is processed in a moist atmosphere, exists instead of a honeyed oxide film, the following problems will occur. That is, as is well known, aluminum is a metal that is very easily oxidized, and an oxide film is formed on the surface even if it comes into contact with a trace amount of oxygen. Furthermore, when placed in an environment containing moisture such as water or humidity, a hydrated oxide film is formed on the surface. The higher the temperature of the hydrated oxide production reaction, the more remarkable the growth of the permanent oxide film, and in a high temperature environment, a hydrated oxide film such as boehmite or vialite is formed on the aluminum surface. The quality of such a hydrated oxide film is much rougher and more porous than that of an aluminum oxide film formed in an environment where no moisture is present, and the pore morphology is also complicated. In addition, the film thickness is also thick. By the way, when a box-shaped body for a vacuum chamber is molded, a hydrated oxide film is generated on the inner surface of the box-shaped body due to contact with the atmosphere containing moisture.

Furthermore, since this hydrated oxide film is exposed to high temperatures during molding, the formation reaction of the hydrated oxide film is promoted, resulting in a thick film. The film quality of this hydrated oxide film is as described above, and since it is a thick film, a large amount of water is adsorbed to the film. Moreover, since the film is rough and porous, substances that reduce the purity of high-purity gases such as moisture, 11-hydrocarbon, carbon dioxide, and carbon monoxide present in the atmosphere are adsorbed to the film even after molding. Moreover, since the hydrated oxide film is as described above, it is in the form of being occluded within the film. As a result, it becomes difficult to desorb, and it is difficult to remove it. When the inside of the chamber is evacuated during gas analysis, gases such as H2 are released from the film, resulting in a decrease in the degree of vacuum and a decrease in analysis accuracy.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2 showing the principle of the apparatus of this invention, the apparatus for analyzing extremely small amounts of gas is constructed using a vacuum chamber (1
), two manipulators (2) that hold a sample (S) made of a metal material at the upper part of the vacuum chamber (1), and a manipulator whose tip is located inside the chamber (1) at the back side of the vacuum chamber (1). (2) and an ion gun (3) for ion beam etching, which is attached so as to face the sample (S) held by the sample (S).

Inside the vacuum chamber (1), there are an alumina crucible (5) for melting a sample placed on a mounting table (4), and a crucible (
5) and a heater (6) wound around the periphery of the heater (6). Both ends of the heater (6) are connected to a vacuum chamber (1
) is connected to the terminal (7) provided on the bottom wall. Further, an analyzer (8) for analyzing the surface condition of the sample after ion beam etching by Auger analysis is provided on the top wall of the vacuum chamber (1). Vacuum chamber (1
), there are four vacuum exhaust devices (10) (11)
(12) (13), Bayart-Albert Vacuum Gauge (
14), a quadrupole mass filter (15) for analyzing the gas extracted from the sample (S) and an external conductor (16) connected to the terminal (7) are provided. The first evacuation device (10) includes an aluminum evacuation pipe (18) connected to the vacuum chamber (1) via an orifice (17), and an evacuation pipe (18) connected to the vacuum chamber in the following order. It consists of a valve (19), a turbomolecular pump (20), and a low-pressure pump (21) that are arranged in series from the (1) side. Then, the valve (1) in the exhaust pipe (18)
A Beyert-Alpert vacuum gauge (22) is also provided in a portion closer to the vacuum chamber (1) than the vacuum chamber (1). The second evacuation device (11) is connected to an aluminum evacuation pipe (23) connected to the vacuum chamber (1), and is connected in series from the vacuum chamber (1) side to the evacuation pipe (23) in the following order. The valve (24) provided in the turbo molecular pump (2
5) and a rotary pump (26). The third and fourth evacuation devices (12) and (13) evacuate the aluminum evacuation pipe (27) connected to the vacuum chamber (1) and the evacuation pipe (27) in the following order, respectively. Valves (
28) and a getter pump (29). The getter pump (29) contains a hydrogen storage alloy and is capable of adsorbing hydrogen gas in the vacuum chamber (1).

The manipulator (2) is axially movable. □
Also, the vacuum chamber (1) on the peripheral surface of the manipulator (2)
) is sealed with a sealing member.

The casing (31) of the ion gun (3) is provided with a vacuum evacuation device (32) and an inert gas supply device (33). The vacuum evacuation device (32) is connected to the casing (3
Aluminum vacuum exhaust pipe (3) connected to
4) and the casing (3■) on the exhaust pipe (34) in the following order.
It consists of a valve (35), a turbomolecular pump (36), and a rotary pump (37) that are arranged in series from ) side. The inert gas supply device (33) is provided between an inert gas cylinder (39) connected to the casing (31) via an aluminum supply pipe (38) and a supply pipe (38). In addition, a trap (40) in which liquid nitrogen is introduced to remove impurities contained in the inert gas, and a variable type trap (40) provided between the casing (31) and the trap (40) in the supply pipe (38) It consists of a leak valve (41).

Further, a throttle nozzle (42) is interposed between the casing (31) of the ion gun (3) and the vacuum chamber (1). The inert gas introduced into the ion gun (3), ionized and accelerated passes through the throttle nozzle (42). enters the vacuum chamber (1) and collides with the sample (S).

A specific example of the gas analyzer is shown in FIGS. 3 and 4.

The vacuum chamber (1) is a rectangular parallelepiped chamber box (5
0), a manipulator insertion port (51) provided at the upper left side and an upper right side of the peripheral wall of the box-shaped body (50), and a manipulator insertion port (51) provided at the upper rear surface of the box-shaped body (51). The ion gun mounting port (52) and four exhaust ports (53) to (5B) provided at the lower part of the peripheral wall of the box-shaped body (50)
), a Bayart-Albert vacuum gauge mounting port (57), and a quadrupole mass filter mounting port (58).

The box-like body (50) is formed of an aluminum plate in which the peripheral wall, top wall, and bottom wall all serve as a heating fluid passage and a cooling fluid passage, and are provided with a tubular bulge (59) having an inlet and an outlet. It is something that

The tubular bulge (59) has a semicircular cross section as shown in FIG. 4, and bulges only inward of the chamber (1). The cross-sectional shape of the tubular bulge (59) is 6 mm as shown in FIG.
It may also be angular. The tubular ampullae has a hexagonal cross section (
70). Further, the cross-sectional shape of the tubular bulge is not limited to these shapes. Also, Figures 3 and 4
Although not shown in the figure, heating and cooling fluid supply pipes are connected to the inlet of the tubular bulge (59), and a discharge pipe of the same is connected to the outlet.

Each day (51) to (58) consists of a short cylindrical protrusion provided on the box-shaped body (50) and a flange provided at the tip of the protrusion. Each exhaust port (53) using a flange
~ (56) aluminum exhaust pipe (18) (23)
(27) is connected, and a Beyert-Alpert vacuum gauge (14) and a quadrupole mass filter (15) are attached to the respective attachment ports (, 57) and (58).

A partition plate (60) is interposed between the flange (53a) at the tip of the exhaust port (53) and the flange (18a) at the tip of the exhaust pipe (18). 17) is formed. Also, exhaust pipe (18)
A Bayart-Alpert vacuum gauge attachment port (61) is provided near the end of the valve, and a Bayart-Alpert vacuum gauge (22) is attached thereto. This attachment port (61) also consists of a short cylindrical protrusion and a flange at the tip of the protrusion.

Then, the inner surface of the vacuum chamber (1), that is, the inner surface of the box-shaped body (50) and all the mounting ports (51) to (58)
) and (61), a honey oxide film is formed on the inner surface of the protrusion. In addition, each exhaust pipe (18) (23) (27
) has a sticky oxide film formed on its inner surface.

The casing (31) of the ion gun (3) is made of aluminum and is attached to the attachment port (52). Further, the casing (31) is provided with an exhaust port (63) and an inert gas supply port (64).

On both days (83) and (64), the casing (31
) a short cylindrical aluminum protrusion;
It consists of a flange provided at the tip of the protrusion.

An exhaust pipe (34) and an inert gas supply pipe (38) are connected using this flange. And both mouths (8
3) A honey oxide film is formed on the inner surface of the casing (31) including the protrusion (84). Additionally, a flange (42a) formed at the outer end of the throttle nozzle (42) is located between the flange (52a) at the tip of the casing attachment port (52) and the flange (31a) of the casing (31).
a) is sandwiched.

Next, a method for analyzing trace gases in aluminum materials using the apparatus according to the present invention will be described.

First, a heated fluid such as Freon is passed through the tubular bulging portion (59) to perform a baking process on the vacuum chamber (1), and then the vacuum chamber is cooled to room temperature. Then, a cooling fluid such as liquid nitrogen is caused to flow inside the tubular bulge (59), and the evacuation devices (10) to (13), (3
2), the vacuum chamber (1) and the ion gun (3) are evacuated to a high vacuum state. Next, after setting the sample (S) on the manipulator (2), the sample (S) is placed in the vacuum chamber (
1) Insert the tip of the manipulator (2) inside. In this state, an inert gas such as Ne or Ar is introduced into the ion gun (3) and ionized. The ionized inert gas is accelerated by an extraction electrode and an accelerating electrode, passed through a throttle nozzle (42), and elastically collided with the sample (S). In this way, the sample (S) is subjected to ion beam etching. At this time, the pressure inside the ion gun (3) increases by introducing an inert gas, but the throttle nozzle (
42), the degree of pressure increase in the vacuum chamber (1) becomes smaller than the degree of pressure increase in the ion gun (3), and naturally the amount of impurities in the vacuum chamber (1) decreases. , approximately 17,300. Therefore, the amount of impurities adsorbed on the surface of the sample (S) after ion beam etching can be reduced. Thereafter, the sample (S) is removed from the manipulator (2) and dropped into the crucible (5), and the crucible (5) is heated by the heater (6) to melt the sample (S) and extract the internal gas. , the amount of gas is quantified using a quadrupole mass filter (15).

Examples of experiments conducted using the apparatus according to the present invention will be described below.

That is, gas analysis was performed under the following conditions.

Sample: High purity aluminum with a purity of 99.99%, pressure in the vacuum chamber and ion gun before ion beam etching: 1 x 10-10 Inert gas used for ion beam etching and its pressure =... N es 3
Acceleration voltage during X 10-' Torrs ion beam etching...2 kV.

Emission current during ion beam etching...3
0mA.

Dose amount during ion beam etching -1, Ox 1018 tons/Cl112 When ion beam etching was performed under the above conditions, the pressure inside the vacuum chamber during ion beam etching was I x 10-6
It was Torr.

Thereafter, the inside of the vacuum chamber (1) was further evacuated to bring the pressure to I x 10 Torr, and subsequent gas analysis revealed that the internal H2 gas was 0°0005c.
c/100gAl.

Effects of the Invention The device for analyzing gas in metal materials of the present invention is equipped with an aluminum vacuum chamber, so it is lighter and easier to process than conventional devices equipped with a stainless steel vacuum chamber. be.

In addition, the gas analyzer in metal materials of the present invention has a honey oxide film formed on the inner surface of the vacuum chamber, so
When the inside of the vacuum chamber is evacuated, substances such as moisture that reduce the degree of vacuum become difficult to adsorb. Furthermore, even if these substances are adsorbed, they can be easily removed before gas analysis work. Therefore, it is possible to maintain a high degree of vacuum inside the vacuum chamber, and the accuracy of gas analysis in metal materials can be improved.

[Brief explanation of the drawing]

Figure 1 is a front view explaining the principle of the device of this invention, Figure 2 is a front view explaining the principle of the device of this invention.
3 is a perspective view specifically showing the device of the present invention, FIG. 4 is a partially enlarged horizontal sectional view of FIG. 3, and FIG. 5 is a sectional view showing a modification of the tubular bulge. It is a diagram. (1)...Vacuum chamber. that's all

Claims (1)

[Claims] A gas analysis device for metal materials that is equipped with an aluminum vacuum chamber and has a honey oxide film formed on the inner surface of the vacuum chamber.