JPS60116762A - Surface treatment of metallic material - Google Patents

Abstract

PURPOSE:To obtain a nonoxidizing coating layer controlling the reactivity of rare earth elements and having excellent adhesion with good mass productivity, by coating the rare earth elements with Ni or the like in case of forming a coating layer contg. the rare earth elements with a diffusion penetrating process, on the surface of a metallic material to be treated. CONSTITUTION:Rare earth elements are subjected to a physical vapor deposition on a surface of heat-resistant metallic material such as an iron steel and Ni-base alloy to be treated and one or more kinds of Ni, Al, Cr and Co are subjected to a physical vapor deposition thereon. The material to be treated is subjected to a Cr or Al diffusion penetrating treatment due to chemical vapor deposition. Namely, said material is buried in a penetrate contg. Cr and thereafter is heated while introducing gaseous H2 into a vessel. In this case, since the rare earth elements are coated with Ni or the like and those reactivities are controlled, neither oxides nor halides are formed and an excellent nonoxidizing coating layer contg. the rare earth elements having excellent adhesion can be mass-produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of metal materials, and more particularly to a method for forming a surface coating layer containing a rare earth element on the surface of a metal material.

Adding chromium, aluminum, silicon, etc. to steel, nickel-based, cobalt-based alloys, etc. improves oxidation resistance, so these elements are not necessarily present in materials called heat-resistant metals. Being looked at. However, chrome,
Adding large amounts of elements such as aluminum laminate and silicon will reduce the high temperature strength of the material. The reality is that the amount has to be limited. Therefore, in order to improve the insufficient high-temperature oxidation resistance, a method of applying an oxidation-resistant coating to the surface of the material has been used.

This oxidation-resistant coating often has chromium, aluminum, silicon, etc. as its main components. Conventional methods for coating with these elements include the following treatments.

(a) Thermal spraying method: Spraying a coating agent using a gas flame, electric arc, or plasma as a heat source.

(b) Vapor deposition method 2: Deposit the coating agent in a vacuum container.

(c) Diffusion infiltration method: The material to be treated is buried in a penetrant containing a coating component and heated.

Thermal spraying has the advantage of being able to process all kinds of coating materials (metals, alloys, ceramics, etc.), but has the disadvantage that the coating layer is porous and has poor adhesion to the material being treated. Therefore, it cannot be used with confidence in applications that require high reliability.

In addition, although vapor deposition is extremely useful as a coating for metals and alloys, it is not suitable for mass production because it must be treated under reduced pressure such as 1'0-2 to 10-4 torr, and it inevitably increases costs. There is a drawback.

This point diffusion infiltration method has excellent adhesion and is suitable for mass production because the treated metals are metallurgically bonded, and is often used as a heat-resistant coating method for gas turbine blades.

The main metals currently used as heat-resistant coatings for this type of blade are chromium, aluminum, chromium-aluminum alloy, and silicon. For other elements, a composite coating method is also known in which the metal to be treated is coated with platinum or rhodium in advance by electroplating, and then aluminum is diffused and penetrated, but these methods are expensive because they use precious metals. There is a drawback.

For the past few years, it has been known that adding small amounts of rare earth elements (yttrium, cerium, tellurium) to metals or oxidation-resistant coatings significantly improves oxidation resistance. Although it has been coated with a metal-containing earth element alloy, it has not yet been put to practical use because it is difficult to form a coating layer containing a rare earth element by a diffusion infiltration method. The reason for this is thought to be as follows.

In general, in the diffusion infiltration method, the metal element to be treated is contained in a penetrant, and the material to be treated is buried in it and maintained at a high temperature. However, even if rare earth elements are included in the penetrant, ,
Due to its strong chemical reactivity, rare earth elements are not formed on the surface of the material to be treated without forming oxides or other chemical compounds. Even when treated, rare earth elements quickly react with the halogen elements (chlorine, fluorine, bromine, etc.) contained in the penetrant, forming halogen compounds with high vapor pressure and volatilizing from the surface being treated. Therefore, if only a small amount remains in the coating layer, the intended purpose cannot be achieved.

In view of the above, the present inventors conducted intensive research with the aim of obtaining a diffusion layer containing rare earth elements. After treating the surface of the metal to be treated with a highly reactive rare earth element by vapor deposition, etc., By coating metals such as aluminum, chromium, or nickel by vapor deposition, etc., the reactivity of the rare earth elements mentioned above can be suppressed, and then by applying diffusion infiltration treatment with aluminum, chromium, etc., high-temperature rare earth elements can be contained. Having experimentally confirmed that a diffusion permeation layer can be obtained, the method of the present invention has been developed to achieve the above object.

That is, the gist of the present invention is as follows: (1) A rare earth element is vapor-deposited on the surface of a metal material that is a workpiece, and one or more elements of nickel, aluminum, chromium, or cobalt are vapor-deposited thereon. rear,
A surface treatment method for metal materials characterized by subjecting this to a conventional chromium or aluminum diffusion and penetration treatment (2) A layer consisting of rare earth elements, nickel, aluminum, chromium, etc. Or the surface of a metal material, characterized in that layers consisting of one or more elements of cobalt are alternately deposited and laminated by a vapor deposition method, and then subjected to a conventional chromium or aluminum diffusion and infiltration treatment. It lies in providing a processing method.

The idea of the present invention is that as a first step, rare earth elements are coated on the surface of the object to be treated using a vapor deposition method, and as a second step, nickel, aluminum, chromium, etc. are coated using the same vapor deposition method. A diffusion permeation layer containing a rare earth element can be obtained by performing a chrono- or aluminum diffusion permeation treatment according to a conventional method. Its characteristics are listed as follows. -1 (1) The vapor deposition method can be processed in a container where the atmosphere can be reduced in pressure or controlled to be non-oxidizing, so even highly reactive rare earth elements can be coated on the surface of the object to be processed without changing them. be able to. Moreover, the thickness of the coating layer can be freely controlled3, and this phenomenon ultimately helps to change the amount of rare earth elements in the diffusion layer.

(2) By coating the rare earth element coating layer with nickel, chromium, and aluminum Ramura in the same atmosphere as above, the rare earth element coating layer does not come into contact with the outside air and retains its reactivity. Therefore, it can be freely placed in the atmosphere or in the atmosphere for subsequent diffusion and infiltration treatment, and is easy to handle.

(3) The metal to be coated on the rare earth element coating layer can be freely selected depending on the type of subsequent diffusion/penetration treatment. In other words, if aluminum is coated and then subjected to aluminum diffusion infiltration treatment, an aluminum diffusion infiltration layer containing rare earth elements will be obtained.If chromium is coated and then aluminum diffusion infiltration treatment is applied, a chromium-aluminum layer containing rare earth elements will be obtained. A diffusion-infiltrated layer of the alloy is obtained.

(4) A diffusion permeation layer containing a large amount of highly reactive rare earth elements can be easily obtained, and oxidation resistance can be significantly improved.

(5) Since the steps (1) and (2) above are carried out in the same apparatus, operation is easy.

The method of the invention can be advantageously applied to gas turbine blades, heat-resistant parts of boilers (burner phasers, spacing pieces, etc.).

The present invention will be specifically described below.

FIG. 1 shows an example of a vapor deposition apparatus for carrying out this process. This device is composed of a vacuum container 1, a vacuum hole 2, a gas inlet 5, an anode/processing metal 4, a cathode/processing object 5, an electron beam gun 6, a processing material heater 7, and an IK current heater 8. This is an ion brating device. When coating a rare earth element and other gold (4) on it, the operation is as follows. First, the air in the vacuum container 1 is operated by an empty pump (not shown), and the vacuum hole 2 is to the outside of the system, and reduce the internal vacuum to 10-s to 10'''6torr.
r Set to 5 degrees. After that, from the gas inlet 5,
, 99%) of argon gas is introduced into the vacuum container 1,
10-" torr. Put the rare earth element into the anode 4, attach the object to be treated to the cathode 5, and then turn on DC +4L +fJj 8 to O while operating the object heater 7.
When N 2 , a glow discharge phenomenon occurs between the cathode 5 and the 1◆ electrode 4 in the vacuum chamber 1, and the ionized argon ions collide with the surface of the object to be treated on the cathode 5 to clean that surface. ,
After this phenomenon continues for about 15 to 20 minutes, when the electron beam can 6 is activated, the rare earth element on the anode 4 is heated and becomes vapor, which collides with and adheres to the object to be treated on the cathode 5. After the vapor deposition of the rare earth element is completed, if the metal of the anode 4 is changed and the same operation is performed, the rare earth element will be further coated. The thickness of each metal coating can be varied by controlling the deposition time.

Next, FIG. 2 shows a diffusion and infiltration treatment apparatus that is carried out after vapor deposition. This device consists of a carbon steel container 1 in which aluminum is diffused and permeated, a penetrant 2, a gas inlet 6, and a gas outlet 4. A material to be treated 5 is buried in the penetrant 2 and heated from the outside. It is processed by

For example, when performing chromium diffusion and infiltration treatment, a mixture of 55% chromium powder, 63% alumina, and 2% anthene chloride (wt%) is used as the penetrant, and after burying the material 5 to be treated, hydrogen 1000 ~ while introducing gas into container 1
It can be treated by heating to 1100°C.

Further, when aluminum is to be diffused and permeated, aluminum powder can be used instead of the chromium powder described above.

The effects of the method of the present invention are as follows: 1. When coating rare earth elements and elements such as aluminum, nickel, and chromium thereon using the S deposition method, all of the coating is done in a controlled container; Chemical changes are difficult to occur in the coating layer, and even if taken out of the container, the top layer of aluminum, nickel, chromium, etc. will only be slightly oxidized, while the rare earth elements in the inner layer will oxidize because they are shielded from the outside air. Never.

Therefore, even in the diffusion infiltration treatment carried out as a post-treatment, there is no exposure to the atmosphere, and various chemical reactions occur on the topmost metal coating layer, and through this, metals diffuse and infiltrate from the outside. Come and go.

Here, we will explain the chemical reactions that occur in the diffusion penetrant when only rare earth elements are evaporated (referred to as case Q) and when nickel is evaporated after rare earth elements are evaporated (referred to as case ■). , the case where chromium diffusion and penetration treatment is applied will be explained.

Yttrium was deposited as the rare earth element.

First, when the penetrant is heated, the halogen compound contained therein is decomposed. When the halogen compound is, for example, ammonium chloride, hydrogen chloride is generated as shown in the following formula (1).

NU40tNH3+ 13C1... (1) This hydrogen chloride reacts with the chromium powder in the penetrant to produce chromium chloride as shown in equation (2).

Or + 2HO/=-→crct2+ ) (2---
--(2) This chromium chloride is mixed with hydrogen gas in the atmosphere (
6) A reaction occurs as shown in the formula, fine and highly active metallic chromium is produced, and the metallic chromium adheres to the surface of the object to be treated,
Thereafter, diffusion and infiltration treatment is performed by diffusing and infiltrating the inside.

0rOt2 + H2-→Cr + 2HO4...”・
(31(4) The types and conditions of the diffusion treatment performed after vapor deposition are as follows.

(1) Composition of penetrant for chromium diffusion and penetration treatment Chromium powder 35thialumina 〃 63ammonium chloride 2 tons Treatment conditions Temperature 1050°C Time 10 hours (11) Composition of penetration agent for aluminum diffusion and penetration treatment Aluminum powder 20% Alumina 〃 78ammonium chloride 2nd treatment conditions Temperature: 1050°C Time: 10h The effect of the present invention is that the cross section after each diffusion and penetration treatment is polished,
The content of yttrium was analyzed using a line microanalyzer, and the highest content value was shown by comparing it with the case of ①.

Table 1 shows the results of chromium diffusion and penetration after vapor deposition.
In contrast, in the case of the present invention, the content was 10 to 30 times that amount, making it possible to obtain a very good diffusion-infiltration treated layer.

Table 2 shows the results of aluminum diffusion and penetration treatment after vapor deposition, and it was confirmed that even in this case, a large amount of specific baytrium content was contained.

Table 1 ■ The concentration in the case of only yttrium vapor deposition is assumed to be 1, and the ratio is shown.

Table 2 It was shown in

In the first case of (2), if the reactions in (1) to (6) above proceed and the desired treated layer is not obtained, the rare earth element is exposed to the atmosphere, so it is similar to (2). The following reaction (4) occurs, and all of the deposited rare earth elements turn into chloride vapor and volatilize from the surface of the object to be treated, so that only a chromium diffusion permeation layer is formed.

Re+2HC1-+RqCj14+H2...
(4) Here, Re represents a rare earth element.

In order to confirm the effects of the present invention, processing was carried out under the following conditions.

Example 1 Yttrium (Y) was used as a rare earth element and was deposited to a thickness of 10 μm using the apparatus shown in FIG.

As materials to be treated: (1) 5US304 stainless steel (2) 80% nickel-20% chromium (3) 40% nickel-20 chromium 40 cobalt
Each was finished with dimensions of 10 mm in diameter and 50 mm in length using carbon steel containing 12% carbon.

The following metals were deposited to a thickness of 10 μm on the yttrium deposited layer.

■ Nickel ■ Chromium ■ Aluminum Example 2 Rare earth elements include yttrium (Y) and cerium (Cθ
), Teryllium (Te), on which a vapor-deposited layer of nickel, cobalt, or aluminum is applied in a layered manner, and after repeating the above operations until an appropriate layer thickness is obtained (of course, the top layer is (as nickel, cobalt, or aluminum), chromium diffusion infiltration treatment. The object to be processed was made of 80% Ni-20% Car.

The vapor deposited layer in this case is schematically shown in FIG.

By processing such a multi-layer vapor deposition layer, a diffusion-infiltration treated layer containing different kinds of rare earth elements was obtained, and it was also possible to contain the rare earth element throughout the thick diffusion layer. In both Examples 1 and 2, surface treatments with excellent oxidation resistance were obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an example of a vapor deposition apparatus used in the method of the present invention, FIG. 2 is a diagram illustrating an example of a diffusion infiltration treatment apparatus used in the method of the present invention, and FIG. 5 is a diagram illustrating one or more types of each. FIG. 2 is an explanatory diagram of a method of alternately stacking layers of a rare earth element and layers of one or more metals by a vapor deposition method. 1st figure 2nd figure U-embedded material continuation amendment: 1981, 814, 2-2019 Commissioner of the Patent Office Manabu Shiga, 1st year, 1'1, 1988, 1st, 1st application No. 224275 - No. 2, Name of the invention 7, Surface treatment method for metal interpolation 3, t1 old
Osamu Fushiki, 2-5-1-4 Marunouchi, Chiyoda-ku, Tokyo
Person 1 (°C Toranomon, Minato-ku, Tokyo) - 111, No. 6 No. 2, None Z Subject of amendment (1) "Claims" column (2) of the specification 4
Column 8 of "Detailed Description of the Invention", Contents of Amendment (1) [Claim A on page 1 of the specification is revised in the appendix. (2) On page 5, line 14, "Rare earth elements are applied by vapor deposition, etc." [Rare earth elements are applied by physical vapor deposition, etc.]
I am corrected. (3) On page 5, line 16, "by vapor deposition, etc." is corrected to "by physical vapor deposition, etc." (4) "High temperature" on page 5, line 20 is corrected to "high concentration El." (5) "After the element is vapor deposited" on page 6, line 7 of the same is corrected as "
After physical vapor deposition of the elements,” is corrected. (6) "Chromium by conventional method" in lines 7 and 8 of page 6 is corrected as "chrome j by chemical vapor deposition method." (7) 1 vapor deposition method in line 15 of page 6 of the same document. ``1 physical vapor deposition method'' is corrected. (8) On page 6, line 14 of the same document, "chromium by conventional method" is corrected to "chromium by chemical vapor deposition". (9) On page 6, line 19, “Elements are deposited by vapor deposition,”
'' should be corrected to ``The elements were deposited by physical vapor deposition.'' (11, page 7, line 2, "to coat." is replaced with "to coat to prevent the rare earth elements from being exposed.")
I am corrected. (11+ Correct "according to the usual method" in lines 2 to 6 of page 7 of the same document to "by chemical vapor deposition". ``(1
) The physical vapor deposition method is corrected as ". On page 9, line 1, "J for vapor deposition" is corrected to "For physical vapor deposition." (141, page 10, line 9, after 1st vapor deposition” is corrected to ``after physical vapor deposition.” ]. σe Correct "vapor deposition method," in line 6 of page 11 of the same year, to "physical vapor deposition method."0'I)"..." in lines 5 to 4 from the bottom of page 12 of the same year.・・・
・By doing so, ``diffusion treatment'' is corrected to ``coating by chemical vapor deposition'' by doing 1. Qa Same page 12, 2nd line from the bottom [(4) After vapor deposition...
"..." is corrected to "(4) After physical vapor deposition...". u9 On the second line from the bottom of page 12, "Diffusion treatment performed" is corrected to "Diffusion treatment performed by chemical vapor deposition." (b) On page 14, line 6, “Table 2 shows that after vapor deposition...
” is corrected to 1 Table 2 is after physical vapor deposition...]. Q. Table 1 on page 14 of the same is corrected as follows. "Table 1■ The concentration in the case of yttrium physical vapor deposition only is 1,
It is shown as a ratio. (a) Table 2 on page 15 of the same is amended as follows. "Table 2 - Setting the concentration in the case of only yttrium physical vapor deposition as 1,
It is shown as a ratio. 2) On page 17, line 4, "Chromium..." is corrected to "Chromium..." by chemical vapor deposition. Claims (1) After physically depositing a rare earth element on the surface of the metal material that is the object to be treated, and physical vapor depositing one or more elements of nickel, aluminum, chromium, or cobalt thereon, A method for surface treatment of metal materials, characterized by subjecting the material to chromium or aluminum diffusion and penetration treatment by chemical vapor deposition. (2) A layer made of rare earth elements, nickel, and aluminum on the surface of the metal material that is the object to be treated. A metal characterized in that layers consisting of one or more elements of chromium or cobalt are alternately deposited and laminated by a physical vapor deposition method, and then subjected to a chromium or aluminum diffusion and infiltration treatment by a chemical vapor deposition method. Competitive surface treatment method.

Claims (2)

[Claims] (1) After depositing a rare earth element on the surface of the metal material that is the object to be treated, and depositing one or more elements of nickel, aluminum, chromium, or cobalt thereon,
A surface treatment method for metal materials characterized by subjecting the material to a conventional chromium or aluminum diffusion and penetration treatment. (2) A layer consisting of a rare earth element and a layer consisting of one or more elements of nickel, aluminum, chromium, or cobalt on the surface of the metal material that is the object to be treated,
1. A method for surface treatment of metal materials, which comprises performing a deposition layering process alternately using a vapor deposition method, and then subjecting the layer to a conventional chromium or aluminum diffusion and penetration treatment.