WO2015052761A1

WO2015052761A1 - Piston ring and seal ring for turbocharger

Info

Publication number: WO2015052761A1
Application number: PCT/JP2013/077293
Authority: WO
Inventors: 清行川合; 田中　昭二; 昌幸大平
Original assignee: Ｔｐｒ株式会社
Priority date: 2013-10-08
Filing date: 2013-10-08
Publication date: 2015-04-16
Also published as: JPWO2015052761A1

Abstract

Provided are a piston ring and a seal ring for a turbocharger that are provided with a hard covering film having superior cracking and peeling resistance. In the piston ring and the seal ring for a turbo charger, which are such that at least one surface selected from the outer peripheral surface, a first lateral surface, and a second lateral surface of a substrate is covered by a hard covering film, the hard covering film has an NaCl-type crystal structure, contains at least Ti, Al, and N, has a composition in which the atom ratio (Al/(Ti+Al)) of Al to Ti and Al is in the range of 0.10-0.63, has a void area ratio in a cross section of the hard covering film that is no greater than 2.2%, and has a ratio (I₂₀₀/I₁₁₁) of the diffraction peak strength in the (200) plane with respect to the diffraction peak strength in the (111) plane in an X-ray diffraction measurement of the hard covering film that is greater than 1 and no greater than 15.

Description

Piston ring and turbocharger seal ring

The present invention relates to a piston ring and a turbocharger seal ring used in an internal combustion engine. Snippet

As a hard coating provided on the outer peripheral surface of the piston ring, a TiN coating is proposed in addition to a CrN coating or a coating Cr (N, O) in which oxygen is dissolved in CrN (Patent Documents 1 and 2). . Furthermore, a TiAlN coating having wear resistance superior to conventional hard chromium plating and TiN coating has also been proposed (Patent Document 3). The TiN film and TiAlN film are also used in other fields, for example, a sealing ring of a mechanical seal, a cutting tool, a gear machining tool for dry machining, and the like (Patent Documents 4 to 6).

JP 2013-29190 A (Claim 1, paragraph 0001, etc.) JP 2013-29191 A (Claim 1, paragraph 0001, etc.) JP-A-5-141534 (Claim 1, paragraph 0024, etc.) JP-A-11-124665 (Claim 1, paragraph 0001, etc.) JP 2000-233320 A (Claim 1 etc.) JP 2006-281363 A (Claim 1, paragraph 0009, etc.)

On the other hand, for the purpose of adapting to recent exhaust gas regulations and improving fuel efficiency, automobile engines are being promoted to have higher compression ratios and direct fuel injection. In some cases, alcohol is contained in the fuel, and in some areas, vehicles that are 100% alcohol fuel are also popular. As a result, as illustrated in FIG. 1, the back pressure to the piston ring 3 mounted in the groove 2G formed in the outer peripheral surface 2S of the piston 2 in the cylinder 1 is increased, or the engine lubricating oil is diluted. In this case, changes such as an increase in sliding resistance between the outer peripheral surface 3S of the piston ring 3 and the cylinder bore 1S made of an iron-based material constituting the inner wall of the cylinder 1 occur. For this reason, a slight crack or peeling may occur in the CrN-based hard coating 3F that has been widely used in the past, which constitutes the outer peripheral surface 3S of the piston ring 3 during actual operation, and a hard coating 3F that is excellent in crack resistance and peeling properties is provided. A piston ring 3 is required. However, the conventional piston rings having hard coatings described in Patent Documents 1 to 3 and the like cannot sufficiently satisfy the above-described characteristics.

Also, a turbocharger seal ring used for an internal combustion engine is used in a more severe environment than a piston ring for an internal combustion engine in terms of operating temperature and oxidizing atmosphere. In the turbocharger, as shown in FIG. 2, the turbine wheel 4 rotates by the energy of the engine exhaust gas, and the rotational speed of the turbine shaft 5 formed integrally with the turbine wheel 4 reaches 100,000 revolutions per minute. . On the other hand, the turbocharger seal ring 6 is mounted in a groove 5G formed on the outer peripheral surface 5S of the turbine shaft 5 made of iron-based material, and is held in a bearing housing 8 that supports the turbine shaft 5 via a bearing 7. Has been. Since the groove 5G of the turbine shaft 5 and the side surface of the turbocharger seal ring 6 are in contact with each other, as shown in FIG. 2, both side surfaces (first side surface 6BS1) of the seal ring base 6B are used. Further, the hard coating 6F is formed on the second side surface 6BS2) to improve the wear resistance of both side surfaces (first side surface 6S1 and second side surface 6S2) of the seal ring. For this reason, the hard coating mainly used on both side surfaces of the turbocharger seal ring needs to be excellent in crack resistance and peelability similarly to the hard coating mainly used on the outer peripheral surface of the piston ring.

The present invention has been made in view of the above problems, and a piston ring and a turbocharger provided with a hard coating excellent in crack resistance and peelability when a counterpart material that slides or contacts is an iron-based material. An object of the present invention is to provide a seal ring for use.

The piston ring for an internal combustion engine according to the present invention is a piston ring in which a hard coating is coated on at least one surface selected from the outer peripheral surface, the first side surface, and the second side surface of the piston ring base material. A crystal structure of at least one, including at least Ti, Al and N and having an atomic ratio of Al to Ti and Al (Al / (Ti + Al)) in the range of 0.10 to 0.63 The void area ratio in the cross section of the hard coating is 2.2% or less, and the ratio of the diffraction peak intensity of the (200) plane to the diffraction peak intensity of the (111) plane in the X-ray diffraction measurement of the hard coating (I ₂₀₀ / I ₁₁₁ ) is more than 1 and 15 or less.

In one embodiment of the piston ring of the present invention, the atomic ratio (Al / (Ti + Al)) is preferably in the range of 0.18 to 0.56.

The turbocharger seal ring used in the internal combustion engine of the present invention is a turbo in which a hard coating is coated on at least one surface selected from the outer peripheral surface, the first side surface, and the second side surface of the turbocharger seal ring base material. In the seal ring for charger, the hard coating has a NaCl-type crystal structure, contains at least Ti, Al and N, and has an atomic ratio of Al to Ti and Al (Al / (Ti + Al)) of 0.10 to 0 The composition has a composition in the range of .63, the void area ratio in the cross section of the hard coating is 2.2% or less, and (200) with respect to the diffraction peak intensity of the (111) plane in the X-ray diffraction measurement of the hard coating. The ratio of the diffraction peak intensity of the surface (I ₂₀₀ / I ₁₁₁ ) is more than 1 and 15 or less.

In one embodiment of the seal ring for turbocharger of the present invention, the atomic ratio (Al / (Ti + Al)) is preferably in the range of 0.18 to 0.56.

According to the present invention, it is possible to provide a piston ring and a turbocharger seal ring excellent in crack resistance and peelability.

It is a model end view which shows an example of the use condition of the piston ring for internal combustion engines. It is a model end view which shows an example of the use condition of the seal ring for turbochargers used for an internal combustion engine. Here, FIG. 2 (A) is an overall view showing the structure in the vicinity of the turbine shaft, and FIG. 2 (B) shows the structure in the vicinity of the seal ring for turbocharger shown in the dotted line in FIG. 2 (A). It is an enlarged view. It is a schematic diagram of a ring-on-rotor friction tester used for evaluation of crack resistance / peelability. It is a schematic diagram of a pin-on-plate reciprocating friction tester used for evaluation of wear resistance and opponent attack.

The piston ring and the turbocharger seal ring of the present embodiment (hereinafter, when both the piston ring and the turbocharger seal ring are referred to may be simply referred to as “seal member”), the outer peripheral surface of the base material, It is a sealing member in which a hard coating is coated on at least one surface selected from a first side surface and a second side surface (a surface opposite to the first side surface). Here, the hard coating has a NaCl-type crystal structure, contains at least Ti, Al and N, and has an atomic ratio of Al to Ti and Al (Al / (Ti + Al)) of 0.10 to 0.63. Having a composition within the range. The void area ratio in the cross section of the hard coating is 2.2% or less, and the ratio of the diffraction peak intensity of the (200) plane to the diffraction peak intensity of the (111) plane in the X-ray diffraction measurement of the hard coating (I ₂₀₀ / I ₁₁₁ ) is more than 1 and 15 or less.

By setting Al / (Ti + Al) to 0.63 or less, wurtzite AlN can be prevented from crystallizing in the hard coating, and as a result, the hardness and strength of the hard coating are surely lowered. Can be suppressed. Moreover, it can suppress that the crack resistance and peelability of a hard film fall by making Al / (Ti + Al) 0.1 or more. Al / (Ti + Al) is more preferably within the range of 0.18 to 0.56.

Further, by setting in excess of 1.0 I _{200 /} I _111, it is possible to suppress the occurrence of cracks or peeling of the hard coating at a high load slide. Moreover, by setting I ₂₀₀ / I ₁₁₁ to 15 or less, it is possible to suppress the residual stress in the hard coating from being increased, and as a result, it is possible to suppress the occurrence of peeling. I ₂₀₀ / I ₁₁₁ is more preferably within a range of 3.0 to 13.

The hard coating used in the seal member of the present embodiment includes a metal element and a non-metal element in an atomic ratio of approximately 1: 1, where the metal element includes Ti and Al as main elements, The metal element contains N as a main element, and may be a TiAlN film substantially containing only Ti, Al, and N. However, the hard coating may contain other elements other than Ti, Al, and N as necessary. For example, a part of Ti and Al can be replaced with another metal element, or a part of N can be replaced with another nonmetallic element. Other metal elements X1 other than Ti and Al and other non-metal elements X2 other than N are included in appropriate amounts as long as they do not adversely affect the mechanical properties of the hard coating, particularly crack resistance and peelability. For example, in terms of atomic ratio, X1 / (Ti + Al + X1) may be 0.1 or less, more preferably 0.05 or less, and even more preferably less than 0.02. X2 / (N + X2) may be less than 0.02.

Further, the hard coating used in the seal member of the present embodiment may contain non-metallic elements B, C, O, etc. if necessary, or these elements are not contained at all. May be. When C is added, it is possible to suppress a decrease in the coefficient of friction due to an improvement in slipperiness and an aggressiveness to the mating material that comes into contact with the seal member of the present embodiment. Moreover, when C is contained in a hard film, the atomic ratio (C / (C + N)) of C with respect to N and C may be included more than 0 and less than 0.02. The film composition of the hard coating can be measured by various analysis methods, but the sealing member of this embodiment is measured by fluorescent X-ray analysis (XRF). At this time, since there is a possibility that the Ti Ll line acts as an interference line with respect to the N Kα line, pure Ti or the like is analyzed in advance to obtain the ratio of the Ti Ll line to the Ti Kα line. . In addition, since the analytical value of C tends to fluctuate depending on the amount of organic matter adsorbed on the sample surface, sputter cleaning is performed immediately before the analysis.

Further, the micro Vickers hardness (Hv) of the hard coating is preferably 1700 or more, and more preferably 1800 or more. By setting the micro Vickers hardness to 1700 or more, it becomes easy to ensure the strength required as a hard coating for a piston ring or a turbocharger seal ring. On the other hand, if the upper limit value of the micro Vickers hardness is too high, crack resistance and peelability deteriorate, and therefore, practically, it is preferably 2500 or less.

The indentation elastic modulus of the hard coating (to be precise, it means “indentation elastic modulus including Poisson's ratio”), which means a value represented by EIT / (1-νs ² ), where EIT is the indentation elastic modulus, νs Is the Poisson's ratio of the hard coating.) Is preferably 320 GPa or more, and more preferably 350 GPa or more. By setting the indentation elastic modulus to be 320 GPa or more, it is possible to suppress a decrease in the rigidity of the hard coating, thereby easily ensuring crack resistance and peelability. On the other hand, the upper limit value of the indentation elastic modulus is not particularly limited, but it is preferable that the upper limit is substantially about 390 GPa. For the samples for micro Vickers hardness and indentation elastic modulus measurement, the surface of the film formed to have a film thickness of 15 μm or more is polished flat with emery paper of about # 1000 to # 1500, and further converted into a diamond slurry. And buffed. In either measurement, the same diamond indenter as in the Vickers hardness measurement was used as the indenter, and a nanoindentation tester HM-2000 manufactured by Fisher Instruments was used. In both cases, the measurement load was 100 gf. If the sample is too thin, it is affected by the hardness of the base material, and accurate measurement cannot be performed.

The method of forming the hard coating is not particularly limited, and examples thereof include physical vapor deposition methods (PVD methods) such as ion plating methods and sputtering methods, chemical vapor deposition methods (CVD methods), and plasma CVD methods. Although a known film forming method can be used, an arc ion plating method is preferable.

When forming a hard film by the arc ion plating method, for example, the hard film is formed by the following procedure. First, the degreased and cleaned substrate is placed in a vacuum chamber, and the inside of the vacuum chamber is depressurized until the pressure reaches about 1.3 × 10 ⁻³ Pa. Next, the substrate is heated to about 573K to 673K. Then, ion bombardment is performed by applying a bias voltage of about −600 to −800 V to the substrate. Thereafter, the bias voltage is lowered to about −5 to −50 V, and the process gas is introduced into the vacuum chamber. As a result, arc discharge is performed, and at least one selected from the outer peripheral surface, the first side surface, and the second side surface of the base material is a metal component derived from a metal target as a deposition source and a non-metal component derived from a process gas. A nitride-based film is formed by depositing on one surface.

Here, a Ti—Al alloy target is used as the metal target, and the ratio of Ti and Al constituting the target is appropriately selected according to the target composition of the hard coating. When only a single composition metal target is used, Al / (Ti + Al) in the hard coating is almost uniquely determined by the metal target composition used. For example, the atomic ratio of Ti and Al in the metal target is 3: 1, and when this is used alone, Al / (Ti + Al) = 1 / (3 + 1) = 0.25 in the hard coating. Further, Al / (Ti + Al) in the hard coating can be adjusted by a combination of metal targets having different compositions and respective arc current values when forming a film using them. For example, when a metal target having an atomic ratio of Ti and Al of 3: 1 and 1: 1 is used to form a film with the same arc current, Al / (Ti + Al) = (1 / (3 + 1) in the hard coating ) + 1 / (1 + 1)) / 2 = 0.375. Furthermore, since the evaporation amount of the metal target changes by raising and lowering the arc current value of each metal target, the composition of the hard coating is controlled by increasing the arc current value of the metal target that contains a large amount of the component to be increased. can do. In general, when the metal target material is consumed, the film formation efficiency is lowered. Therefore, in order to manage the composition of the hard coating with high accuracy, it is preferable to use a metal target having the same amount of consumption.

As the process gas, only N ₂ gas is usually used. However, depending on the composition of the hard coating, N ₂ gas and CH ₄ gas (mixed with C), O ₂ gas (mixed with O), TMS, A mixed gas in which various gases such as tetramethylsilane, C and Si are mixed at a predetermined ratio can be used. Thus, the hard film which has a desired composition can be obtained by selecting a composition of a metal target and process gas.

I ₂₀₀ / I ₁₁₁ can be changed by a bias voltage, an internal pressure during film formation, or the like. For example, the diffraction peak of the (200) plane can be controlled to be relatively higher than the diffraction peak of the (111) plane by increasing the bias voltage or decreasing the internal pressure. In addition, by adding C to the hard coating, the diffraction peak of the (111) plane can be controlled to be relatively higher than the diffraction peak of the (200) plane.

In addition, when forming a hard film by the arc ion plating method, unreacted particles called droplets are mixed in the hard film. The unreacted particles are formed in the form of particles taken into the hard film without sufficiently reacting with a gas component such as N ₂ gas by releasing a large amount of film forming raw material at once from an arc spot on the metal target. It means a substance. In the arc ion plating method, it is difficult to make the droplets completely zero. In addition, voids are formed in the periphery of the unreacted particles and in the traces of the unreacted particles dropping out in the hard coating. And the unreacted particle which exists in such a hard film, and the space | gap formed resulting from this unreacted particle reduce the mechanical characteristic of a hard film. For this reason, when forming a hard coating, it is necessary to suppress the number and size of generated unreacted particles and to reduce the proportion of voids formed due to unreacted particles.

Therefore, in the hard film (hard film containing unreacted particles and having voids) formed by the arc ion plating method, the area ratio (void area ratio) due to the voids in the hard film in the cross section of the hard film Is 2.2% or less. The cross-sectional area ratio of unreacted particles contained in the hard coating is preferably about 1.5% or less. By setting the void area ratio to 2.2% or less, local strength reduction of the hard coating can be suppressed, and as a result, cracking and peeling of the hard coating can be suppressed when a high load is applied to the hard coating. Is extremely easy. In addition, by making the cross-sectional area ratio of the unreacted particles about 1.5% or less, it is possible to suppress the occurrence of microscuffing in the portion where the unreacted particles are formed in the hard coating. Damage to the coating can be suppressed. The void area ratio is more preferably 1.8% or less, and the closer to 0%, the better. Further, the cross-sectional area ratio of unreacted particles is preferably as close to 0%. In addition, since the coarser the unreacted particles, the more easily microscuffing occurs. Therefore, the particle size of the unreacted particles is preferably 7 μm or less, more preferably 5 μm or less, and the smaller the particle size, the better. . When the void area ratio and the cross-sectional area ratio of the hard coating used for the seal member of this embodiment are substantially 0%, the hard coating is formed using a film forming method other than the arc ion plating method. It is preferred to be membraned.

The method for reducing the number and size of the voids is not particularly limited. For example, the gap may be decreased by increasing the distance between the metal target and the substrate to be deposited and setting the bias voltage higher. It is valid. In order to reduce the number and size of the unreacted particles, for example, it is effective to arrange an adhesion preventing plate or the like in the vicinity of the metal target. In addition, since the number and size of voids and unreacted particles increase as the metal target wears out due to film formation, increasing the frequency of replacement of the metal target is also effective in reducing the number and size of voids and unreacted particles. It is valid. In addition to this, recently, a technique for reducing the number of unreacted particles by strengthening the magnetic field of the evaporation source has been developed.

Further, the void area ratio in the cross section of the hard coating and the cross sectional area ratio of the unreacted particles were obtained by the following procedure. First, the piston ring or turbocharger seal ring is cut to a length of about 1 cm in the circumferential direction, and the hard coating is processed by the ion milling method or the focused ion beam method (FIB method), so that the cross section of the hard coating is obtained. To expose. Then, the cross section of the hard film was image | photographed with the scanning electron microscope. The cross-sectional image (about 45 μm × 60 μm) of the hard coating thus obtained was subjected to binarization analysis using commercially available image analysis software. In the binarization analysis, the void area ratio was binarized for the void portion and the other portions, and the cross-sectional area ratio was binarized for the unreacted particle portion and the other portions. And about the same measurement sample, the average value of 5 visual fields was calculated | required as a void | hole area ratio or a cross-sectional area ratio.

The base material used for forming the hard coating can be used without particular limitation as long as it is a known base material used for piston rings or turbocharger seal rings. For example, stainless steel, spring steel, and high-speed tools can be used. A base material made of steel or heat-resistant steel can be used. In addition, when using the base material which consists of stainless steel, you may use the base material which gave the nitriding process previously and removed the compound layer.

When the seal member of this embodiment is a piston ring, the hard coating is formed so as to cover the outer peripheral surface of the piston ring base material. Moreover, the hard film may be formed into the other surface as needed. If a specific example is given, in the sealing member of this embodiment, in addition to providing the hard coating 3F so as to cover the outer peripheral surface 3BS of the piston ring base 3B as illustrated in FIG. That is, you may provide a hard film so that 1st side surface 3B1 and / or 2nd side surface 3B2 may be covered. When the seal member of the present embodiment is a turbocharger seal ring, the hard coating is formed to cover the first side surface and / or the second side surface of the turbocharger seal ring base material. Moreover, the hard film may be formed into the other surface as needed. If a specific example is given, in the sealing member of this embodiment, as illustrated in FIG. 2, a hard coating 6F is provided so as to cover the first side surface 6BS1 and the second side surface 6BS2 of the turboring seal ring base material 6B. In addition, a hard coating may be provided so as to cover the outer peripheral surface 6BE, which is the surface facing the bearing housing 8. In the example shown in FIG. 2, the hard coating 6F provided on one of the first side surface 6BS1 and the second side surface 6BS2 may be omitted.

Note that an undercoat layer may be provided between the seal member substrate and the hard coating as necessary in order to improve the adhesion between the seal member substrate and the hard coating. As this undercoat layer, for example, a thin film mainly composed of Ti, Cr, Ti—Al alloy or the like can be used.

The film thickness of the hard coating is not particularly limited, but is preferably 10 μm or more in the case of a piston ring from the viewpoint of ensuring durability. The upper limit value of the film thickness is not particularly limited, but is preferably 30 μm or less from the practical viewpoint such as productivity. On the other hand, in the case of a turbocharger seal ring, about 3 μm is preferable from the viewpoint of durability and practicality.

Also, after forming the hard film, it is preferable to perform lapping or polishing to make the surface of the hard film have a roughness Ra of 0.2 or less. By reducing the roughness, it becomes easier to suppress the damage of the hard coating by suppressing the wear of the counterpart material and reducing the frictional resistance.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to only the following examples.

(Preparation of sample for evaluation)
After setting the piston ring base material in the arc ion plating apparatus, the inside of the apparatus was evacuated and decompressed, and the base material was heated. Thereafter, ion bombardment was performed by applying a predetermined bias voltage to the substrate. Next, after setting the bias voltage to a predetermined value, a process gas is introduced into the apparatus to form a hard coating having a thickness of 20 μm on the outer peripheral surface of the base material, and an evaluation piston ring sample is obtained. It was. In addition, a sample having a hard film formed on the tip of the pin was also prepared for the evaluation of the wear resistance and the opponent attack property under the same conditions as the piston ring sample.

When forming the hard film, a metal target composed of a metal composition corresponding to the composition of the hard film formed in each of the examples and comparative examples shown in Table 1 and Table 2 is used, and as a process gas, N ₂ gas or a mixed gas in which N ₂ gas and CH ₄ gas were mixed at a predetermined ratio was used according to the composition of the hard coating film formed in each example and comparative example. The hard coating Cr (N, O) of Comparative Example 1 is a coating in which O is dissolved in CrN having a NaCl-type crystal structure, and a metallic element and a nonmetallic element are approximately 1: 1 in atomic ratio. The metallic element contains Cr, the nonmetallic element contains N as a main element, and O contains atomic ratio O / (N + O) = 0.3. Therefore, when forming a Cr (N, O) film, a metal Cr target was used, and a mixed gas in which N ₂ gas and O ₂ gas were mixed at a predetermined ratio was used as the process gas. The purpose of adding O to CrN is to strengthen the coating by dissolving O in the hard coating and suppress the occurrence of cracks and peeling. Further, in each of the examples and comparative examples, the internal pressure during film formation was appropriately set within a range of 2 Pa to 5 Pa and the bias voltage within a range of −10 V to −50 V so that a desired value of I ₂₀₀ / I ₁₁₁ was obtained. Selected. In addition, as for the values of the cross-sectional area ratio of the voids and unreacted particles, the distance between the metal target and the substrate, the bias voltage, the presence or absence of the deposition plate, the amount of target material used, the magnetic field distribution near the target surface, etc. It was made to fluctuate by changing suitably.

(Evaluation)
For the obtained samples of Examples and Comparative Examples, I ₂₀₀ / I ₁₁₁ , composition of hard coating, void area ratio and cross-sectional area ratio of unreacted particles, micro Vickers hardness, and indentation elastic modulus were measured. . In addition, crack resistance / peeling resistance, wear resistance, and opponent attack were also evaluated. These results are shown in Tables 1 and 2 below.

The evaluation methods for crack resistance / peelability, wear resistance and opponent attack properties shown in Tables 1 and 2 are as follows.

<Crack resistance / peelability>
The crack resistance / peelability of the hard coating was evaluated by the following procedure using a ring-on-rotor friction tester shown in FIG. First, the outer peripheral surface of the test piece 10 obtained by cutting a piston ring sample in the circumferential direction of the piston ring from about 1 cm to 2 cm is pressed against a steel rotor 12 rotating at a constant speed by applying a load P with a weight. Seizure was generated. In this state, after rotating the rotor 12 for a certain period of time, it was confirmed whether or not the hard coating was cracked or peeled. If no damage was observed, the load P was further increased and retested. By repeating this, the load P at which cracks and peeling began to occur was confirmed. The lubricating oil was supplied using a tubing pump or an air dispenser. The test conditions are as follows. Further, the results shown in Table 1 and Table 2 show the relative value of the load P at which cracks and peeling began to occur in the test piece 10 of Comparative Example 1 as a reference value 1. A larger value means that the hard coating is more excellent in crack resistance and peelability. The evaluation result of crack resistance / peelability is preferably 1.0 or more.
・ Initial load P: 40N
・ Rotation speed of the rotor 12: 1000 rpm
・ Rotation time of the rotor 12 per test: 1 min

<Abrasion resistance and opponent attack>
The wear resistance and opponent attack were evaluated using a pin-on-plate reciprocating friction tester shown in FIG. In this reciprocating friction tester, an upper test piece 20 having a hard film formed on the tip of a pin is pressed against a plate-like lower test piece 22 by applying a load P by a spring load, and the lower test piece 22 reciprocates. By doing so, both are configured to slide. The upper test piece 20 is like a piston ring. Further, the lower test piece 22 is like a cylinder bore made of cast iron, and is composed of a cast iron plate. Lubricating oil was supplied using a tubing pump or an air dispenser. After operating for a fixed time at a predetermined load and speed, the wear amount of the upper test piece 20 and the lower test piece 22 was measured with a surface roughness meter. The wear amount of the upper test piece 20 means the wear amount of the hard coating provided on the tip of the pin, and the wear amount of the lower test piece 22 means the wear amount (wear depth) of the counterpart material. The test conditions are as follows. Further, the results shown in Tables 1 and 2 show the wear amount of Comparative Example 1 as a reference value 1 and show the relative value. As for the “wear resistance”, the smaller the value, the harder the wear of the hard coating. The smaller the “partner aggression” is, the more the wear of the counterpart material is suppressed. In addition, it is suitable that the abrasion resistance evaluation result is 1.0 or less, and if the opponent aggression evaluation result is 1.2 or less, there will be no great trouble in practical use.
・ Load P: 100N
Speed: 600 cpm (cpm: cycle per minute)
・ Test time: 60 min

1 Cylinder 1S Cylinder bore 2 Piston 2G Groove (piston groove)
2S outer peripheral surface (piston outer peripheral surface)
3 Piston Ring 3B Piston Ring Base 3B1 First Side (Piston Ring First Side)
3B2 Second side (piston ring second side)
3F Hard coating 3S outer peripheral surface (piston ring outer peripheral surface)
4 Turbine wheel 5 Turbine shaft 5G groove (seal ring groove for turbocharger)
5S Turbine shaft outer peripheral surface 6 Turbocharger seal ring 6S1 First side surface (seal ring first side surface)
6S2 Second side (second side of seal ring)
6B Seal ring base material (Turbocharger seal ring base material)
6BS1 first side (seal ring base material first side)
6BS2 Second side (second side of seal ring substrate)
6BE outer peripheral surface (seal ring base material outer peripheral surface)
6F Hard coating 7 Bearing 8 Bearing housing 10 Test piece 12 Rotor 20 Upper test piece 22 Lower test piece

Claims

In the piston ring in which the hard coating is coated on at least one surface selected from the outer peripheral surface, the first side surface, and the second side surface of the piston ring base material for the internal combustion engine,
The hard coating has a NaCl-type crystal structure, contains at least Ti, Al, and N, and has an atomic ratio of Al to Ti and Al (Al / (Ti + Al)) within a range of 0.10 to 0.63. Having a composition
The void area ratio in the cross section of the hard coating is 2.2% or less,
The ratio of the diffraction peak intensity of the (200) plane to the diffraction peak intensity of the (111) plane in the X-ray diffraction measurement of the hard coating (I 200 / I 111 ) is more than 1 and 15 or less. ring.
The piston ring according to claim 1, wherein
The piston ring, wherein the atomic ratio (Al / (Ti + Al)) is in a range of 0.18 to 0.56.
In a turbocharger seal ring in which a hard coating is coated on at least one surface selected from an outer peripheral surface, a first side surface, and a second side surface of a turbocharger seal ring base material used for an internal combustion engine,
The hard coating has a NaCl-type crystal structure, contains at least Ti, Al, and N, and has an atomic ratio of Al to Ti and Al (Al / (Ti + Al)) within a range of 0.10 to 0.63. Having a composition
The void area ratio in the cross section of the hard coating is 2.2% or less,
The ratio of the diffraction peak intensity of the (200) plane to the diffraction peak intensity of the (111) plane in the X-ray diffraction measurement of the hard coating (I 200 / I 111 ) is more than 1 and 15 or less. Charger seal ring.
The seal ring for a turbocharger according to claim 3,
A turbocharger seal ring, wherein the atomic ratio (Al / (Ti + Al)) is in a range of 0.18 to 0.56.