JPS60174866A - Method and apparatus for oxidizing metal consisting essentially of iron - Google Patents

Abstract

PURPOSE:To form oxide films having good quality on the surface of metals consisting essentially of iron with good productivity by constituting both ends of an oxidizing apparatus of low temp. zones of a nonoxidative atmosphere and the center of a high temp. zone of an oxidative atmosphere. CONSTITUTION:Dry gaseous N2 in blown through blow ports 38, 43 to an oxidizing apparatus 10 and is discharged through force evacuating ports 40, 41. The apparatus is delineated and formed with low-temp. zones A, C and a high-temp. zone B by air curtains. Dry N2 is blown respectively through blow ports 18, 36 into the zones A, C to maintain a nonoxidative atmosphere therein. The gaseous mixture contg. satd. steam obtd. by feeding the gaseous N2 and gaseous O2 from a gaseous N2 source 22 and a gaseous O2 source 24 at a specific ratio to a hermetic water tank 28 is blown through a blow port 20 into the zone B to maintain an oxidative atmosphere therein. Metals consisting essentially of iron are fed successively into such apparatus 10 by a wire net-like endless conveyor 16 so that oxide films are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for oxidizing metals containing iron (Fe) as a main component, which can efficiently obtain a high-quality oxide film.

In manufacturing matched sealed hermetic terminals, the metal outer ring and lead wire are oxidized to obtain excellent airtightness, and the surface has excellent adhesion to the metal base and good wettability with glass. Generally, a manufacturing method is adopted in which a good spinel-type Fe104 oxide film is formed and then combined with glass and sealed. The quality of the oxide film produced in this case controls the final quality of the product, such as airtightness, so
There is a need for a method and apparatus that can stably and efficiently generate a high-quality oxide film.

Conventionally, this type of oxidation method uses a conveyor-type continuous oxidation treatment furnace to oxidize parts in an atmosphere of 600 to 1000
A method of forming a film on the surface by heating to ℃ is known. Although this method has excellent processing ability, the oxide film obtained in the atmosphere has poor adhesion to the metal substrate, so vibrations during assembly of the metal outer ring and glass often cause the oxide film to deteriorate. It has the disadvantage that cracks and peeling occur, impeding airtightness and lowering reliability.

Another method is to use a batch type oxidation treatment furnace. When using this method, for example, when oxidizing an iron-nickel-cobal (Fe-Ni-Co) alloy,
A predetermined amount of parts is placed in a batch-type oxidation treatment furnace, and the temperature is first raised in a non-oxidizing atmosphere in a dry nitrogen (NQ) gas atmosphere until the temperature reaches the transition point or higher, and then the inside of the furnace is heated with wet nitrogen. The atmosphere is switched to an oxidizing atmosphere of (N2) gas or a mixed gas of wet N2 gas and wet oxygen (08) gas to oxidize each predetermined amount of shingles. In this batch method, it is possible to reliably obtain a non-oxidizing atmosphere and a high-temperature oxidizing atmosphere that produces a spinel-type oxide film with excellent adhesion, so it is possible to produce a high-quality oxide film. There are advantages that can be achieved. However, since it is necessary to alternately switch one processing furnace between a non-oxidizing atmosphere and an oxidizing atmosphere, there is a drawback that work efficiency is extremely poor and productivity is extremely low.

The present invention has been made in view of the above-mentioned difficulties, and its purpose is to provide a method and apparatus for oxidizing metals containing iron as a main component, which can produce a high-quality oxide film with high productivity. It is characterized by a low-temperature zone with a non-oxidizing atmosphere of dry nitrogen gas on the inlet side, and a wet zone in the middle where metals mainly composed of iron, such as iron, iron-Nisokel alloy, and iron-nickel-cobalt alloy, are heated. A high-temperature zone with an oxidizing atmosphere made of nitrogen gas or a mixture of wet nitrogen gas and wet oxygen gas is continuously passed through a furnace, which has a low-temperature zone with a non-oxidizing atmosphere made of dry nitrogen gas on the outlet side. Then, the metals are successively oxidized one after another.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The figure schematically shows an oxidation device 10 according to the invention.

12 is an inlet opening, and 14 is an outlet opening. 16 is an endless conveyor that moves continuously from the inlet opening 12 towards the outlet opening 14. *The other device 10 is formed in a low temperature zone A with a non-oxidizing atmosphere on the inlet opening 12 side, a high temperature zone B with an oxidizing atmosphere in the center, and a low temperature zone C with a non-oxidizing atmosphere on the outlet opening 14 side. .

18 is a dry N2 gas inlet for introducing dry N2 gas into the low temperature zone A, and is connected to the inlet opening 12 of the oxidizer 10.
It is located near the top. 20 is wet N2 gas or wet Nx gas and wet 0.20 in high temperature zone B.
This is an inlet for blowing mixed gas with gas, and is located in high temperature zone B.
is located at the top center of the 22 is N, gas source, 24
is an OJP gas source, which is connected to a pipe 26 so that both gases from the gas source are mixed, and the tip of the pipe 26 is opened into the water of a sealed water tank 28 to bubble in the water and add moisture to the mixed gas. is given. The sealed water tank 28 is equipped with a temperature control device (not shown), so that various temperature settings can be made. A mixed gas of wet N2 gas containing water vapor and wet N2 gas is obtained.The mixed gas is guided to the air inlet 2o by an introduction pipe 3o connecting the airtight water tank 28 and the air inlet 2o, and from the air inlet 20 at a high temperature. Zone B
blown inside. Numerals 32 and 34 are pulps provided in the N2 gas source 22 and the 02 gas source 24, respectively. The valve 3
By operating 2°34, N2 gas or 0
Single gases of two gases can also be obtained, and arbitrary mixed gases with different mixing ratios of both gases can be obtained.

36 is a dry N2 gas inlet for introducing dry N2 gas into the low temperature zone C, and is connected to the outlet opening 14 of the oxidizer 1o.
It is located near the top.

38 is a dry N2 gas blowing port provided at the upper part of the boundary between the low temperature zone A and the high temperature zone B of the oxidizer 1o, which blows dry N2 gas downward to separate the low temperature zone A and the high temperature zone B. Form a N2 gas curtain.

Reference numeral 40 denotes a gas forced exhaust port provided at the boundary, opposite to the dry N2 gas inlet 38, which draws in the dry N2 gas from the dry N2 gas inlet 38 and discharges the dry N2 gas from the dry N2 gas inlet 38. At the same time as forming a gas curtain, the gas in the low temperature zone A and the high temperature zone B is drawn in and exhausted.

42 is a dry N2 gas inlet provided at the boundary between the high temperature zone B and the low temperature zone C, and 44 is a forced gas exhaust port provided opposite to the dry N2 gas inlet 42; A dry N2 gas curtain is formed.

Note that the endless conveyor 16 is formed, for example, in a mesh shape, and is configured to prevent the material to be oxidized from falling, but to allow gas to pass therethrough.

In addition, appropriate heating sources (not shown) are provided in each of the low temperature zones A, C and high temperature zone B of the oxidizer IO so that they can be heated.

To explain the oxidation treatment step, for example, Fe-Ni
- To oxidize the Co alloy, first, set the temperature in high temperature zone B to 430°C or higher, the transition temperature at which a spinel type oxide film of good quality is obtained during each of the above gas flows, and then set the maximum temperature in high temperature zone B to Set the temperature profile of the oxidizer as follows. The temperature profile in this case is, for example, as shown in FIG. If the object to be oxidized is placed on the endless conveyor 16 and passed through the oxidizer 10 continuously, a high-quality oxide film can be formed on the surface of the object to be oxidized. In other words, the material to be oxidized is gradually heated as it passes through the low temperature zone A, and the temperature rises to 430°C or higher when it enters the high temperature zone B. is formed.

Since the inside of the low temperature zone A is maintained in a non-oxidizing atmosphere by dry N2 gas, an oxide film with poor adhesion at low temperatures is not formed.

In addition, low temperature zone A, high temperature zone B, and low temperature zone C are effectively partitioned by a dry N2 gas curtain, so that the gases between each zone do not mix, and the non-oxidizing atmosphere and oxidizing atmosphere of each zone are dissolved. It is maintained as follows.

In addition, depending on the non-oxide material, the temperature profile described above can be set optimally according to the material, and the high temperature zone B
The oxidizing gas that is blown into the interior is optimally set in terms of mixing ratio, moisture, etc., depending on the material.

The present invention can be applied to a wide variety of metals including iron and iron-based metals. For example, a high-quality oxide film can be formed even in steam blackening treatment of sintered metal.

As described above, according to the method of the present invention, a high-quality oxide film can be formed on the surface of the object to be oxidized, and the oxidation treatment can be performed continuously, thereby improving productivity. Furthermore, according to the device of the present invention, a non-oxidizing atmosphere and an oxidizing atmosphere are separated by a gas curtain that transmits temperature but blocks gas flow, thereby forming a high-quality oxide film. We were able to provide the equipment.

Although the present invention has been variously explained above using preferred embodiments, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. I mean Ron.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the outline of the device of the present invention, and FIG.
- Figure 2 is a temperature curve showing an example of a temperature profile in an oxidizer during oxidation treatment of a -Ni-Co alloy. 10...Oxidizer, 12...Inlet opening sound 14...
・Outlet opening, 16... Endless conveyor, 18... Dry N2 gas inlet, 20... Inlet, 22... N
x gas source, 24...Oz gas source, 26...pipe,
28... Sealed water tank, 30... Introduction pipe, 32.
34...Valve, 36.38...Dry N2 gas inlet, 40...Gas forced exhaust port, 42...Dry N2 gas inlet, 44...Gas forced exhaust port. Patent Applicant Shinko Electric Industry Co., Ltd. Representative Takekio Mitsunobu Figure 2 8 Procedural Amendments March 16, 1980 Kazuo Wakasugi, Commissioner of the Japan Patent Office 1, Indication of Case 1982 Patent Application No. 30907 3, Amendment Patent applicant 4, agent 8, content of amendment 1) Amend "non-oxidized material" in line 7 of page 9 of the specification to "oxidized material". 2) For drawings, please correct Figure 2 as shown in the attached sheet.

Claims (1)

[Claims] 1. Metals mainly composed of iron, such as iron, iron-nickel alloys, iron-nickel-cobalt alloys, etc., are placed in a low temperature zone with a non-oxidizing atmosphere using dry nitrogen gas on the inlet side, and A high-temperature zone with an oxidizing atmosphere made of wet nitrogen gas or a mixture of wet nitrogen gas and wet oxygen gas passes continuously through a furnace, each of which has a low-temperature zone with a non-oxidizing atmosphere made of dry nitrogen gas on the outlet side. A method for oxidizing a metal containing iron as a main component, characterized in that the metal is oxidized one after another. 2, a, e - In an oxidizing device that continuously oxidizes metals whose main component is iron such as nickel alloys and iron-nickel-cobalt alloys, the inlet side is equipped with a dry nitrogen gas inlet at a low temperature in a non-oxidizing atmosphere. The high temperature zone has an oxidizing atmosphere with an inlet in the middle for blowing wet nitrogen gas or a mixture of wet nitrogen gas and wet oxygen gas into the zone, and a non-oxidizing atmosphere with a dry nitrogen gas inlet at the outlet side. and to form a dry nitrogen gas curtain at the boundary between the zones,
An apparatus for oxidizing metals containing iron as a main component, characterized in that a dry nitrogen gas inlet is provided at the boundary between the zones, and a forced gas exhaust port is provided opposite the dry nitrogen gas inlet.