JPS62103368A - Ceramic coating metal - Google Patents

Abstract

PURPOSE:To improve adhesive property of a ceramic coating layer, by interposing a compd. layer composed of nitride, carbide or oxide of element composing a metal base material between the material and ceramic coating layer. CONSTITUTION:On the surface of the metal base material 11 such as cast iron, stainless steel, one kind or more of the compd. layer 12 composed of nitride, carbide or oxide of composing element of the metal base material is formed by about 100Angstrom -5mum thickness. Next, the ceramic coating layer 13 is formed by CVD method, etc. In this time, if main nonmetallic element composing the layer 12 is made to the same element as main nonmetallic element composing the layer 13, the layers 12 and 13 can be continuously formed in the same equipment. In this way, adhesive property of the layer 13 is improved and wear resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a ceramic coated metal with improved adhesion of a ceramic coating layer, and is particularly used for rotary compression elements such as compressors.

[Technical background of the invention and its problems]

In order to improve the wear resistance of mechanical parts, ceramic coating is applied to the surface of the metal base materials that make up the mechanical parts.
This is an attempt to extend the life of the device.

For example, the ceramic mentioned above using a compressor as an example.

The coating technology will be explained below. First, the structure of the compressor will be explained with reference to FIG. In FIG. 2, a motor (not shown) is housed in a casing 1, and a shaft 2 rotated by the motor is supported by a bearing in a frame 3 and passes through a cylinder 4, and its lower end is connected to a sub-bearing 5. Bearing 1 = Pivotally supported. The portion of the shaft 2 inside the cylinder 4 serves as a crank portion (eccentric portion), and a roller 6 is fitted between this crank portion and the cylinder 4, and the rotation of the shaft 2 causes the gyrroller 6 to move in a planetary motion. do. Further, a blade 7 is provided passing through the cylinder 4, and one end side of the blade 7 comes into contact with the outer periphery of the row 26 due to the biasing force of the sedge ring 8, dividing the inside of the cylinder 4 into a suction chamber and a discharge chamber. In response to the planetary motion of the Ail roller 6, the blade 7f'i moves forward.

Refrigerant gas is sucked in from the suction port, compressed, and discharged from the discharge port in accordance with the planetary motion of the row 26 as the shaft 2 rotates. Refrigerating machine oil 9 is stored in the container. As the shaft 2 rotates, this refrigerating machine oil 9 is sucked up along a pump fzo provided at the lower end of the shaft 2, and lubricates the sliding parts.

The wear of the compressor is mainly divided into blades 7 and 7 shafts 2. The blade 7 reciprocates as the shaft 2 rotates, but at this time, the pressure difference between the two chambers in the divided cylinder 4 causes it to rub against the inner surface of the through hole of the cylinder 4, causing both the blade 7 and the cylinder 4 to wear out. Also,
Since the end of the blade 7 is pressed against the coke 6 by the spring 8, the outer periphery of the roller 6 also wears out. On the other hand, the shaft 2 receives pressure from the spring 8 and the cylinder 4 via the row 26, and the frame 3 and sub-bearing 5
Since the shaft 2 rotates at high speed in a slightly curved shape, the outer surface of the shaft 2, the inner surface of the frame 3, and the sub-bearing 5 are similarly worn.

In order to completely prevent such wear, attempts have been made to apply a ceramic coating to the surface of the metal base material constituting each of the above-mentioned members to improve the wear resistance of the metal (for example, JP-A-57-32096, JP-A-58- 77192, Japanese Patent Publication No. 5
9-128992, Utsukai Showa 57-71785, Utsukai Showa 5
7-71786, Utility Model Publication No. 59-168591, etc.). The ceramic coating layer described in these publications is applied to the surface of a metal base material by thermal spraying or chemical vapor deposition (CVD).
It is formed by , su..., tuttering method, etc.

However, these publications do not consider the adhesion of the ceramic coating layer to the metal base material, which is a factor governing wear resistance.

In fact, when a shaft with a ceramic coating on the surface of carbon steel is assembled with a compressor using the method described above and the 7-yaft is rotated at high speed, the ceramic coating layer peels off and adhesive wear easily occurs. It had the disadvantage of causing Such problems occur not only in the rotary compression element of the compressor, but also in various mechanical parts, cutting tools, etc. provided on sliding parts when ceramic coating is applied.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and aims to provide a ceramic coated metal with good adhesion of the ceramic coating layer and improved wear resistance, thereby extending the life of the device. be.

[Summary of the invention]

The ceramic coating metal of the present invention includes a metal base material,
A compound layer formed on the surface of the metal base material and comprising at least one kind of nitride, carbide, or oxide as a constituent element of the metal base material, and a ceramic coating layer formed on the surface of the compound layer. It is characterized by:

That is, as shown in FIG. 1, a compound layer 12 is formed on the surface of a metal base material 1, and a ceramic coating layer 13 is further formed on the surface thereof.

In the present invention, the metal substrate 11rr1 is usually made of cast iron or stainless steel, but it facilitates the formation of nitrides, carbides, or oxides.
It is desirable that at least one kind of elements such as rSt + B*Ta is included. Also, nitride,
The thickness of the compound layer 12 made of at least one of carbides and oxides is preferably 100 to 5 μm. Further, the thickness of the ceramic coating layer 13 is 50 mm.
The depth may be wide ranging from 0λ to 30μm, but preferably 2o
ooi~10ttmT: Yes. Regarding the compound layer 12 and the ceramic coating layer 13, a composite compound layer may be formed.

In the ceramic coated metal having the structure D, since the compound layer 12 is interposed between the metal base material 11 and the ceramic coating layer 13, the adhesion of the ceramic coating layer 13 is good and the wear resistance is improved. Improve yourself.

Methods for forming the above structure can be roughly divided into the following two methods. In other words, after applying nitriding, carbonizing or oxidizing treatment to the metal base material, chemical vapor deposition equipment (CVD equipment) is used.
) and forming a ceramic coating layer by the CVD method; ■Metal substrate is charged into a t-CVD device, and a reaction gas for forming a compound layer and a reaction gas for forming a ceramic coating layer are formed. This is a method in which a compound layer and a ceramic coating layer are sequentially formed by the JCVD method by sequentially introducing a compound layer and a ceramic coating layer.

In the former method, the nitride layer is formed by ordinary gas nitriding, ion nitriding, or hot bath nitriding, the carbide layer is formed by gas carburizing, and the oxide layer is formed by using a solution or in a high-temperature oxidizing atmosphere. Examples include processing. Also,
Ion implantation may be used as a special method. However, since these treatments are not intended for surface hardening, a thickness of the compound layer of 100X to 5 μm is sufficient.

Thereafter, the metal base material on which these compound layers have been formed is placed into, for example, a CVD apparatus, a reactive gas is introduced, and a ceramic coating layer is formed by the CVD method. In addition to the CVD method, there are other methods for forming the ceramic coating layer.
Suba, Kling method, ion grating method, thermal spraying method, etc. can be used.

In the latter method, after the metal substrate is charged into the CVD apparatus, the reaction is first performed using, for example, NH3 (or N2 and H2).
) is introduced to form a nitride layer, and NH3 (or N2
and H2) and SiH4' to form a Si3N4 layer. By changing the reaction gas for forming the ceramic coating layer, in addition to 5i-Nut, Ti-
Ceramic coating layers such as NPi, Ta-N layer, B-N layer, W-N layer, Zr-N layer, etc. can be formed. Similarly, when forming a carbide layer, carbonic acid is first
When methane gas, ethane gas, etc. are introduced to form the entire oxide layer, oxygen and gold are introduced, and then a hydride, chloride, or organic compound of the element to be coated is introduced to form a ceramic coating layer.

In the latter method, the main nonmetallic element that usually constitutes the compound layer and the main nonmetallic element that constitutes the ceramic coating layer are the same element.

Since this method allows the compound layer and the ceramic coating layer to be formed continuously in the same apparatus, it has the advantage of being more time-saving than the former method.

Various types of CVD reaction methods are known for use in each of the above methods. Glazma excitation reaction, photoexcitation reaction, radar
It is preferable to use an excitation reaction or a hydrolysis reaction. especially,
The plasma CVD method can be used in a wide range of applications because it can use a variety of reactive gases.

When using the plasma C method, the reaction conditions are changed as appropriate depending on the purpose and materials. For example, the heating temperature is 300°C or higher when nitriding a base material whose main component is iron;
When forming a ceramic coating layer as a Tl'z component, the temperature is 300°C or higher, preferably 500°C or higher,
When forming a ceramic coating layer containing St as a constituent, the temperature is 300°C or less, preferably 200 to 250°C. Regarding the gas flow rate, for example, in the case of nitriding, N2, NH3, etc.
SCCM~2 SLM, when coating Si-N layer, add SiH4 to the above gas at 50~300 SC
The conditions are changed, such as mixing CM. Note that the plasma CVD apparatus may be of a capacitively coupled type or an inductively coupled type, but the capacitively coupled type is preferable in order to obtain uniform plasma in a large volume for the purpose of mass production.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on examples.

Example 1 An example in which the ceramic coated metal of the present invention is applied to the shaft of a compressor will be described.

First, gray cast iron was cut into a predetermined shape and degreased with Shirtoratriclean, and then placed in a capacitively coupled plasma CVD apparatus consisting of a stainless steel container and set on a substrate. Next, the inside of the apparatus was evacuated to about 10 Torr using a mechanical booster pump and a rotary pump. Thereafter, in order to remove the gas adsorbed on the inner wall and shaft of the apparatus, the furnace was evacuated to 10-6 to 10-'' Torr using an oil diffusion pump or a cryopump, and the substrate heating temperature was set at 300°C.

Next, is the exhaust system a mechanical booster? Switch to pump and rotary pump, and increase NH3 to 1000 SC.
While introducing CMO through the flow, the internal pressure was increased to approximately 1 Torr.
was maintained.

Next, 1 kW of high frequency power of 13.56 MHz was applied to generate plasma, and the shaft was nitrided for 1 hour. Next, SiH4 gas! :NH, gas was introduced so that the flow rate ratio with the gas was 1, and high frequency power of 400 W was applied to generate plasma.
A 2 μm silicon nitride layer was coated in minutes. The surface of the shaft taken out at the nitriding stage was blackened, indicating that iron nitride had been produced.

On the other hand, for comparison, a shaft surface was not nitrided and only a 2 μm thick silicon nitride layer was formed by plasma CVD (comparative example).

Regarding the above two types of shafts, chemical analysis revealed that the composition of the silicon nitride layer was gold, Ifremo St, N
, ~58 was obtained, which deviated from the stoichiometric ratio, but there was no particular problem.

A part of the two types of shafts obtained was cut out,
The results of identifying surface components using X-ray diffraction are shown in Figure 3 (
Example 1) and FIG. 4 (comparative example) respectively. Third
As shown in the figure, in the Nyaft of Example 1, ε-Fe2-
The existence of a 3N layer was confirmed. On the other hand, as shown in FIG. 4, in the shaft of the comparative example, only the peak caused by Fe in the base material appeared, and the presence of the ε-Fe2-3N layer was not observed. In any case, no peak due to the nitride layer is observed, but this is because the silicon nitride layer is amorphous or microcrystalline.

Also, Ohnoe electron spectroscopy analysis of the surface layer of the two-product shaft? The results of examining the V depth distribution of each element are shown in FIG. 5 (Example 1) and FIG. 6 (Comparative Example). Fifth
As can be seen from the figure, ε− in the shaft of Example 1
The thickness of the Fe2-3N layer is about 6000mm! It is. On the other hand, as can be seen from the sixth factor, in the shaft of the comparative example, ε-Fl! 12-5 Presence of N layer is not recognized. This corresponds to the X-ray diffraction results shown in FIG.

Next, various tests were conducted on the two types of shafts to examine the adhesion of the silicon nitride layer. First, when a scratch test was conducted, Example 1
For the shaft of 8-1ON1 for the shaft of the comparative example 3N
The following results were obtained, and it was confirmed that the shaft of Example 1 had better adhesion of the silicon nitride layer.

Further, the adhesion of the silicon nitride layer was evaluated using a wear resistance evaluation apparatus as shown in FIG.

In this device, the shaft 2 is sandwiched between the sub-bearings 5.5, and while the shaft 2 is rotated, the sub-bearings 5.
The total load due to tightening in step 5 is changed, and the torque change Ek at that time is investigated. The rotation speed of the shaft was 290 rpm, and the load was 22. The volume was increased to 155 ul at a rate of 7/3 mIn. Figure 8 shows the relationship between load and torque obtained in this test. As can be seen from FIG. 8, the torque increase curve of the shaft of the comparative example is very unstable. This is considered to be because the adhesion of the silicon nitride layer in the shaft of the comparative example was poor, and the silicon nitride layer peeled off during the test. On the contrary,
It is presumed that the shaft of Example 1 had a very smooth and smooth torque increase curve, and that the adhesion of the silicon nitride layer was good.

Furthermore, when attempting to scratch the surfaces of the two types of shafts with a cutter knife, the shaft of Example 1 showed a tendency to be less likely to be scratched than the shaft of Comparative Example.

As described above, it was confirmed that the adhesion of the silicon nitride layer was significantly improved by forming the ε-Fe2-3N layer on the surface of the cast iron.

Furthermore, as components other than the shaft of Example 1, the frame and cylinder were made of gray cast iron, the rollers were made of eutectic graphite cast iron, and the blades were made of sintered material, and the compressor shown in Fig. 2 was assembled and tested on an actual machine. As a result, the shaft was able to withstand 7000 r without peeling of the 5t-N layer.
It showed good rotation up to pm.

Example 2 An example in which the ceramic coated metal of the present invention is applied to a compressor blade will be described.

First, a blade cut from SUS 303 stainless steel into a predetermined shape was annealed to increase and remove residual stress, degreased with trichlorene, and charged into a gas carburizing furnace. Next, Co + CO2 (Co concentration 60%) was introduced as a carburizing gas, and carburization was carried out at 500°C.

The thickness of the carburized layer was adjusted by time and was set to 0.5 μm. Thereafter, the blade was taken out, the soot adhering to the surface was removed by pickling, and the blade was further cleaned with trichlene. The component of this carburized layer was mainly Fe5C.

Then, the blade was placed in a plasma CVD apparatus similar to that used in Example 1, the substrate heating temperature was set to 550°C, and TiCl4 and CH4 were flowed at a gas flow rate ratio of 1:5 to form Fe5. A TI-N layer was formed on the surface of the C layer.

As members other than the blade of this Example 2, /YAFT,
The frame and cylinder were all made of gray cast iron, and the rollers were made of eutectic graphite cast iron.The compressor shown in Figure 2 was assembled and tested on an actual machine.
Layer C exhibited stable rotation at high speed without peeling.

Example 3 An example in which the ceramic coated metal of the present invention is applied to a roller of a compressor will be described.

First, eutectic graphite cast iron was cut into a predetermined shape, degreased using a roller cleaning machine, and heated at 300°C in a water atmosphere of 20 atm.
10001 (') Fe 3 on the surface
04 f The iron oxide layer, which is the main component, was completely formed. Next, the roller was flowed at a ratio of 1:4 to that used in Example 1 to
A B-C layer mixed with oxygen was formed on the surface of the 304 layer.

As members other than the rollers in this Example 3, the shaft 7), frame and cylinder are made of gray cast iron, and the plate 1"1sU
Each roller was made of s301X stainless steel, the compressor shown in FIG. 2 was assembled, and an actual machine test was conducted. As a result, the B-C layer on the roller surface did not peel off, and stable rotation at high speed was achieved.

It goes without saying that the present invention is not limited to members constituting a compressor, but can be similarly applied to mechanical parts or cutting tools used in sliding parts of other loads. Moreover, as the ceramic coating layer, in addition to those used in Examples 1 to 3 above, Zr t Ta, Nb + At+
It may also contain V, Ca, etc. as constituent elements. Since these ceramic coating layers have different hardnesses, one having appropriate characteristics may be selected depending on the purpose of use.

〔Effect of the invention〕

As detailed above, according to the ceramic coated metal of the present invention, it is possible to improve the adhesion of the ceramic coating layer and significantly improve the wear resistance, thereby extending the life of equipment such as compressors and high-speed rotation characteristics. This method has remarkable effects, such as the ability to improve

[Brief explanation of drawings]

Fig. 1 is a sectional view of the ceramic coated metal according to the present invention, Fig. 2 is a partially cutaway front view of the compressor, and Fig. 3
Figures 4 and 4 are X-ray diffraction/turn diagrams of the shafts of Example 1 and Comparative Example, respectively, and Figures 5 and 6 are the depths of component elements obtained by Ohnoe spectroscopy of the shafts of Example 1 and Comparative Example, respectively. A diagram showing the directional distribution, Figure 7 is a cross-sectional view of the wear resistance tester, and Figure 8 shows the relationship between the load and torque of the shaft of Example 1 and Comparative Example obtained by the same wear resistance tester. It is a characteristic diagram. 1... Casing, 2... Shaft, 3... Frame, 4... Cylinder, 5... Sub-bearing, 6
...Roller, 7.Blade, 8.Spring, 9.Refrigerating machine oil, 10.Pump, 1..Metal base material, 12..Compound layer, 13.. Ceramic coating layer. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 j I3 Figure 4 f! ;! , @ (am) rice seal (type comparison)

Claims (4)

[Claims] (1) A metal base material, a compound layer formed on the surface of the metal base material and consisting of at least one of nitrides, carbides, or oxides as constituent elements of the metal base material, and a compound layer formed on the surface of the compound layer. A ceramic coated metal characterized by comprising a ceramic coating layer. (2) The ceramic coating metal according to claim 1, wherein the main nonmetallic element constituting the compound layer and the main nonmetallic element constituting the ceramic coating layer are the same element. (3) The compound layer has at least one of iron nitride or chromium nitride as a main component, and the ceramic coating layer has at least one of silicon nitride, titanium nitride, or boron nitride as a main component. A ceramic coated metal according to claim 2. (4) The ceramic coated metal according to claim 1, which is applied to at least one of a blade, a shaft, a roller, a cylinder, a frame, and a sub-bearing that constitute a rotating compression element of a compressor. .