JP2018092918A - Pipe material and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered pipe material having high bonding reliability.SOLUTION: The pipe material includes: an outer layer made of a Ni-based alloy; an inner layer provided inside the outer layer and made of a Pt-based alloy; and an intermediate layer between the outer layer and the inner layer. The manufacturing method of the same is also provided.SELECTED DRAWING: None

Description

  The present invention relates to, for example, a tube material used as a discharge electrode of a spark plug for an internal combustion engine and a method for manufacturing the same.

  A spark plug is disclosed in which an annular ground electrode is provided and a discharge gap is formed between the inner peripheral surface of the ground electrode and the outer peripheral surface of the center electrode (Patent Document 1).

JP, 2006-51636, A

  In Patent Document 1, an annular ground electrode formed by joining a ring-shaped electrode base material made of a Ni-based alloy and a simple substance such as Pt or Ir provided on the inner peripheral surface thereof or a noble metal layer made of these alloys is disclosed. Have been described.

  High performance and high reliability are desired for the pipe material as the ground electrode together with the center electrode. In particular, it is necessary to improve the bonding reliability. Spark plug electrodes with severe cooling cycles due to engine start / stop are subject to repeated thermal stress between the layers, and are prone to problems such as cracks and delamination (low bonding reliability).

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multilayer pipe material with high bonding reliability.

An outer layer made of a Ni-based alloy;
An inner layer provided on the inner side of the outer layer and made of a Pt-based alloy;
It is the pipe material provided with the intermediate | middle layer between the said outer layer and the said inner layer, and its manufacturing method.

  According to the configuration of the present invention, bonding is improved by promoting diffusion between layers, and a multilayered pipe material with high bonding reliability can be provided. For example, when this pipe material is used as an electrode of a spark plug, the intermediate layer can relieve the thermal stress between the outer layer and the inner layer, and it is possible to suppress problems such as cracking due to repeated thermal stress accompanying engine start / stop and interlayer peeling. In addition, since the heat treatment temperature necessary for diffusion can be lowered, grain growth of the outer layer and the inner layer does not proceed, and occurrence of problems such as grain boundary cracking can be suppressed.

It is a cross-sectional schematic diagram of the pipe material shown in 1st Embodiment. It is a cross-sectional enlarged image of the pipe material shown in 1st Embodiment. It is a cross-sectional enlarged image of the pipe material which is not based on this invention. It is a cross-sectional schematic diagram of the pipe material shown in 2nd or 3rd embodiment. It is a cross-sectional enlarged image of the pipe material shown in 2nd Embodiment.

[First Embodiment]
The first embodiment of the present invention is a tube material comprising an outer layer made of a Ni-based alloy, an inner layer made of a Pt-based alloy provided inside the outer layer, and an intermediate layer between the outer layer and the inner layer. (FIG. 1), the intermediate layer is a tube material having a composition containing any one of Au, Ni, Ag, Pd, and Pt in addition to the outer layer and the components of the outer layer. Alternatively, the intermediate layer is a tube material having a composition including any combination of Ag and Pd, Pd and Ni, and Pt and Ni in addition to the outer layer and the components of the outer layer.

  As the Ni-based alloy, for example, alloys such as Inconel 600 and Inconel 601 manufactured by Special Metal can be used. As the Pt-based alloy, for example, 90Pt10Ni (mass%), 74.4Pt20Ir5.6Ni (mass%), or the like can be used.

  The manufacturing method corresponding to the first embodiment includes an inner side surface (inner peripheral surface) of a tube material made of a Ni-based alloy corresponding to the outer layer or an outer side surface (outer peripheral surface) of a round bar made of a Pt-based alloy corresponding to the inner layer. A plating step of providing any one of Au, Ni, Ag, Pd, Pt, or two layers of Ag and Pd, two layers of Pd and Ni, and two layers of Pt and Ni A combination step of combining a pipe and a round bar, each of which has a plating layer, so that the round bar is positioned in the hole of the pipe, and the combined pipe and round bar. By heating at a predetermined temperature (for example, 900 ° C. to 1265 ° C.) and a predetermined time (for example, 0.5 to 6 hours) in a vacuum or an inert gas atmosphere, A predetermined temperature (for example, 80%) in an active gas atmosphere Heat treatment step of joining the tightly attached tube material and the round bar by pressurizing at a constant pressure (for example, 30 to 180 MPa) and a predetermined time (for example, 0.5 to 6 hours) with a hot isostatic pressure. And a drilling step for forming a pipe by providing a hole in the round bar portion of the joined pipe with a round bar by a mechanical means, and a cutting step for cutting the pipe provided with the hole.

  In the plating step, a known method can be applied as the plating means, and electrolytic plating, electroless plating, vapor deposition, sputtering, and the like are suitable.

  Next, in the combining step, the pipe material and the round bar provided with the plating layer on either side are combined so that the round bar is positioned in the hole of the pipe material. For example, the round bar is inserted into the hole of the pipe material.

  In the processing step, the combined pipe and the round bar are brought into close contact with each other. For example, a swaging machine can be used for the processing. In a swaging machine, the combined pipe and round bar are inserted between a pair of dies that reciprocate while rotating. The tube material is pressurized in the diametrical direction, and the outer diameter is reduced, so that the tube material and the round bar are in close contact with each other. In addition, it is good also as a drawing process which shrinks the outer diameter of a pipe material with a wire drawing die.

Next, in the heat treatment step, for example, the tube material and the round bar which are brought into close contact with each other by heating at a predetermined temperature in a vacuum or in an inert gas atmosphere are joined. The heating temperature is preferably 1150 ° C to 1265 ° C.
Alternatively, in the heat treatment step, the substrate is hot at a predetermined temperature (for example, 800 ° C. to 1200 ° C.), a predetermined pressure (for example, 30 to 180 MPa), and a predetermined processing time (for example, 0.5 to 6 hours) in an inert gas atmosphere such as Ar. The pipe and the round bar which are brought into close contact with each other by applying isotropic pressure are joined.

  In the heat treatment step, the plating layer diffuses to both adjacent surfaces to form an intermediate layer. In the intermediate layer, the components of the outer layer, the inner layer, and the plating layer are diffused to have a composition containing each component. Even if the plating is two layers of Ag and Pd, two layers of Pd and Ni, and two layers of Pt and Ni, the components of the outer layer, the inner layer and the plating layer are diffused in the intermediate layer. It becomes the composition containing. The component elements of the plating layer have good diffusibility with the Ni-based alloy and the Pt-based alloy, and can be a tube material with high bonding reliability with little or no non-diffusible portion compared to a tube material without a plating layer.

  In particular, when Au or Pd is included in the plating layer, these components and Ni as the outer layer component form a low melting point phase and diffusion is further promoted, so that a pipe material with higher bonding reliability can be obtained. .

  Next, in the drilling step, holes are provided by a mechanical means in the round bar portion of the diffusion-bonded pipe with a round bar to obtain a multilayer pipe. Next, in the cutting step, the multilayer pipe material is cut with a wire saw or the like.

  In the pipe of the first embodiment of the present invention, the plating layer is provided in the plating process, so that the diffusion of the inner layer (Pt-based alloy) and the outer layer (Ni-based alloy) is promoted in the heat treatment process, and good bonding is achieved. Is obtained (FIG. 2). On the other hand, when the plating layer is not provided, a partial bonding failure (peeling or non-diffusion) may be observed (FIG. 3).

[Second Embodiment]
A second embodiment of the present invention is a tube comprising an outer layer made of a Ni-based alloy, an inner layer made of a Pt-based alloy provided inside the outer layer, and an intermediate layer between the outer layer and the inner layer. The intermediate layer is a layer made of any of Pd, PtNi alloy, and PdNi alloy, and is a tube material in which the outer layer and the intermediate layer are diffusion bonded, and the intermediate layer and the inner layer are diffusion bonded. That is, the outer layer and the intermediate layer are integrated via the diffusion layer, and the intermediate layer and the inner layer are integrated via the diffusion layer.

As the intermediate layer, a second tubular material having a hollow circular cross section made of any one of Pd, PtNi alloy, and PdNi alloy is used. The inner layer (Pt-based alloy) has a linear expansion coefficient of about 9 × 10 ⁻⁶ K ⁻¹ and the outer layer (Ni-based alloy) has a linear expansion coefficient of about 16 × 10 ⁻⁶ K ⁻¹ , while the intermediate layer ( (Pd, PtNi alloy, PdNi alloy) has a linear expansion coefficient of 12 × 10 ⁻⁶ K ⁻¹ , and is set between the values of the two linear expansion coefficients.

  The manufacturing method corresponding to the second embodiment includes a hollow first cross-section tube made of a Ni-based alloy corresponding to the outer layer, and a hollow cross-section made of any of Pd, PtNi alloy, and PdNi alloy corresponding to the intermediate layer. A circular second tube material and a round bar having a circular cross section made of a Pt-based alloy corresponding to the inner layer, the second tube material is located in the hole of the first tube material, and the second tube material A combination step in which the round bars are positioned in the holes of the first, a processing step for bringing the combined first pipe member, the second pipe member and the round bar into close contact, and a predetermined temperature in a vacuum or an inert gas atmosphere. (For example, 900 ° C. to 1265 ° C.), heating at a predetermined time (for example, 0.5 to 6 hours), or a predetermined temperature (for example, 800 ° C. to 1200 ° C.) at a predetermined pressure in an inert gas atmosphere such as Ar (For example, 30-180M a) a heat treatment step for joining the first tube member, the second tube member and the round bar which are in close contact with each other by applying hot isostatic pressing for a predetermined time (for example, 0.5 to 6 hours); A drilling step for forming a pipe by providing a hole in a round bar portion of the pipe with a round bar by a mechanical means, and a cutting step for cutting the pipe provided with the hole. The heating temperature in the heat treatment step is preferably 1050 ° C to 1265 ° C.

In the tube material of the second embodiment, a gap assumed during heating in the heat treatment step can be reduced by inserting a second tube material made of any of Pd, PtNi alloy, and PdNi alloy as an intermediate layer (FIG. 4). FIG. 5). That is, as described above, since the linear expansion coefficient of the intermediate layer is set in the middle of the values of the linear expansion coefficient of the inner layer and the outer layer, the expansion difference between the outer layer and the intermediate layer and the expansion difference between the intermediate layer and the inner layer are In comparison with the case where the intermediate layer is not provided, the gap is further reduced, and diffusion bonding is promoted.

[Third Embodiment]
In the third embodiment of the present invention, the intermediate layer is composed of two layers, the first intermediate layer is provided inside the outer layer, and the second intermediate layer is between the first intermediate layer and the inner layer. The first intermediate layer has a composition containing any of Au, Cu and Ni in addition to the components of the outer layer and the second intermediate layer, and the second intermediate layer is made of Pd, PtNi alloy, PdNi alloy. And a tube material in which the second intermediate layer and the inner layer are diffusion-bonded. The outer layer and the second intermediate layer are integrated via the first intermediate layer, and the second intermediate layer and the inner layer are integrated via the diffusion layer.

  In addition to the manufacturing method of the second embodiment, the manufacturing method corresponding to the third embodiment includes an inner surface of the first tube material made of a Ni-based alloy corresponding to the outer layer or Pd corresponding to the second intermediate layer. And a plating step of providing a plating layer of any one of Au, Cu, and Ni on the outer surface of the second tubular member having a hollow circular cross section made of any one of PtNi alloy and PdNi alloy.

  The plating layer thus formed is diffused to both adjacent surfaces in the heat treatment step to form a first intermediate layer. In the first intermediate layer, the components of the outer layer, the second intermediate layer, and the plating layer are diffused to have a composition including each component. In the heat treatment step, for example, the heat treatment can be performed at a predetermined temperature (for example, 900 ° C. to 1265 ° C.) in vacuum. Alternatively, in the heat treatment step, it is hot at a predetermined temperature (for example, 800 ° C. to 1200 ° C.), a predetermined pressure (for example, 30 to 180 MPa), a predetermined time (for example, 0.5 to 6 hours) in an inert gas atmosphere such as Ar The pressure can be increased. The heating temperature in the heat treatment step is preferably 1050 ° C to 1265 ° C.

  In the pipe material of the third embodiment of the present invention, by providing the second intermediate layer (Pd, PtNi alloy, PdNi alloy), the difference in linear expansion coefficient can be buffered, and by providing the plating layer The diffusion of the second intermediate layer (Pd, PtNi alloy, PdNi alloy) and the outer layer (Ni-based alloy) is promoted, and as a result, bonding is promoted.

Example 1
A tube having a hollow circular cross section made of Inconel 601 corresponding to the outer layer and a round bar having a circular cross section made of 90 PtNi (mass%) corresponding to the inner layer were prepared. The dimensions of the tube material were an outer diameter of 6.4 mm and an inner diameter of 4.0 mm, and the diameter of the round bar was 3.8 mm.

On the outer surface of the round bar, a plating layer having the following elements and thickness was formed by electrolytic plating (plating step).
Example 1-1 Au 5 μm
Example 1-2 Pd 5 μm
Example 1-3 Ni 5 μm

  Next, the pipe and the round bar were combined by inserting the round bar on which the plating layer was formed in the hole of the pipe (combining step).

  Next, the tube material combined with the round bar was swaged. The diameter of the tube material was reduced by swaging, and the tube material and the round bar were brought into close contact (processing step). Thereafter, the tube was cut to a length of 20 mm.

The cut tube material was heat-treated in vacuum, and the tube material and the round bar were diffusion-bonded (heat treatment step). The heat treatment temperature and time were as follows.
Example 1-1 1250 ° C., 1 hour Example 1-2 1250 ° C., 1 hour Example 1-3 1265 ° C., 1 hour

  Next, a hole having a circular cross section was drilled along the axis with a drill and a reamer in the center of the round bar joined to the pipe (drilling step).

  A multilayer pipe material having a hole in the center of a round bar was cut into a predetermined size with a wire saw (cutting step).

  In Example 1-4 and Example 1-5, the material of the outer layer is Inconel 600, which is a Ni-based alloy, and two outer peripheral plating layers of a round bar having a circular cross section made of 90 PtNi (mass%) are used. did. In Example 1-4, a round bar was plated with 2 μm of Pd and further plated with 1 μm of Ni. In Example 1-5, Pt was plated on a round bar by 4 μm, and Ni was further plated by 1 μm. The heat treatment temperature and time in the heat treatment step were 1150 ° C. and 1 hour in both Example 1-4 and Example 1-5. Other processes and conditions were the same as those in Example 1-1 to Example 1-3.

In Examples 1-6 to 1-9, the material of the outer layer is Inconel 601 that is a Ni-based alloy, and the plating layer on the outer peripheral surface of a round bar having a circular cross section made of 90 PtNi (mass%) is Ni 10 μm. . In the processing step, the combined first tube material, the second tube material, and the round bar were brought into close contact with each other in the cold. In the heat treatment step, hot isostatic pressing was performed in an Ar atmosphere. The heat treatment temperature, pressure, and time were as follows. Other processes and conditions were the same as those in Example 1-1 to Example 1-3.
Example 1-6 900 ° C., 150 MPa, 5 hours Example 1-7 1000 ° C., 150 MPa, 5 hours Example 1-8 1100 ° C., 150 MPa, 5 hours Example 1-9 1200 ° C., 150 MPa, 5 hours

In Examples 1-10 to 1-13, the outer layer material is Inconel 601 which is a Ni-based alloy, and the outer peripheral plating layer of a round bar made of 90 PtNi (mass%) is 10 μm in Au. . In the processing step, the combined first tube material, the second tube material, and the round bar were brought into close contact with each other in the cold. In the heat treatment step, hot isostatic pressing was performed in an Ar gas atmosphere. The heat treatment temperature, pressure, and time were as follows. Other processes and conditions were the same as those in Example 1-1 to Example 1-3.
Example 1-10 900 ° C., 150 MPa, 5 hours Example 1-11 1000 ° C., 150 MPa, 5 hours Example 1-12 1100 ° C., 150 MPa, 5 hours Example 1-13 1200 ° C., 150 MPa, 5 hours

(Example 2)
In Example 2, a first tubular member having a hollow circular cross section made of Inconel 601 which is an Ni-based alloy as an outer layer, a second tubular member made of Pd having a thickness of 0.5 mm as an intermediate layer, and 74.4Pt20IrNi (inner layer). Each was a round bar with a circular cross section consisting of mass%).

  In the combination step, the second tube material was inserted into the hole portion of the first tube material, and a round bar was inserted into the hole portion of the second tube material.

  The heat treatment temperature and time in the heat treatment step were 1100 ° C. and 1 hour. Other than that, it was set as the process and conditions similar to Example 1-1-Example 1-3.

(Example 3)
In Example 3, 1 μm of Au was plated on the outer peripheral surface of the second pipe member made of Pd having a thickness of 0.5 mm as an intermediate layer. The other processes and conditions were the same as in Example 2.

(Comparative example)
In Comparative Example 1 and Comparative Example 2, the plating step in Example 1-1 to Example 1-3 was omitted, and the heat treatment temperature and time in the heat treatment step were 1270 ° C., 1 hour, 1250 ° C., and 1 hour, respectively. . Other than that, it was set as the process and conditions similar to Example 1-1-Example 1-3.

  Table 1 shows configurations, heat treatment conditions, and determination results of Examples and Comparative Examples.

(Evaluation)
Bondability was evaluated by polishing the cut surface of the tube with water-resistant abrasive paper and buff, observing with an electron microscope and an attached energy dispersive X-ray analyzer (hereinafter referred to as SEM / EDS), or by line analysis. . Since the average atomic weight of the inner layer containing Pt is larger than that of the Ni-based alloy of the outer layer, it is observed brightly. If there is a diffusion layer, that is, a composition gradient between the outer layer and the inner layer, the contrast appears as a light gradation, and the thickness can also be measured. The thickness of the diffusion layer can also be measured by SEM / EDS line analysis.
The determination shown in Table 1 was based on the following. “○” indicates that there is no non-diffuse part or less than 10% of the circumference between each layer, “△” indicates that the non-diffuse part exceeds 10% of the circumference and less than 50%, and “×”.

(result)
The pipe materials of Example 1 all exhibited the cross-sectional image of FIG. In Example 1-1 to Example 1-5, an intermediate layer (diffusion layer) having a thickness of 70 μm or more was present between the outer layer and the inner layer. In the pipe materials of Examples 1-6 to 1-13 subjected to hot isostatic pressing, an intermediate layer (diffusion layer) having a thickness of at least 100 μm was present. In any case, when the inside of the intermediate layer was qualitatively analyzed by EDS, components of the plating layer were detected.
The pipe material of Example 2 exhibits the cross-sectional image of FIG. 5, and has a thickness between the outer layer (first pipe material) and the intermediate layer (second pipe material), and between the intermediate layer (second pipe material) and the inner layer. A diffusion layer having a thickness of 30 μm or more was present. The thickness of the diffusion layer was measured by EDS line analysis.
In the pipe material of Example 3, an intermediate layer (diffusion layer) having a thickness of 70 μm or more was present between the outer layer (first pipe material) and the intermediate layer (second pipe material). When the inside of this intermediate layer was qualitatively analyzed by EDS, the component Au of the plating layer was detected. Further, a diffusion layer having a thickness of 30 μm or more was present between the intermediate layer (second tube material) and the inner layer. The thickness of the diffusion layer was measured by EDS line analysis.
On the other hand, the tube material of Comparative Example 1 has insufficient diffusion despite the heat treatment temperature as high as 1270 ° C., and an interface with a clear contrast (non-diffusion portion) between the outer layer and the inner layer is 2 in the entire circumference. About 30% remained. Moreover, the pipe material of the comparative example 2 exhibited the cross-sectional image of FIG. 3, and the diffusion layer was not observed over the perimeter. The diffusion layer was not confirmed by EDS line analysis.

  From the above results, it has been clarified that the pipe material of the present invention promotes diffusion between layers as compared with a pipe material not provided with an intermediate layer. In addition, the pipe of the present invention was able to obtain sufficient diffusion even at a lower heat treatment temperature than that of a pipe without an intermediate layer.

Claims (7)

An outer layer made of a Ni-based alloy;
An inner layer provided on the inner side of the outer layer and made of a Pt-based alloy;
A tube comprising an intermediate layer between the outer layer and the inner layer.   The intermediate layer has a composition containing any of Au, Ni, Ag, Pd, Pt, Ag and Pd, Pd and Ni, and Pt and Ni in addition to the components of the outer layer and the inner layer. Item 1. The pipe material according to Item 1.   The intermediate layer is a layer made of any of Pd, PtNi alloy, and PdNi alloy, the outer layer and the intermediate layer are diffusion bonded, and the intermediate layer and the inner layer are diffusion bonded. The tube material according to claim 1. The intermediate layer consists of two layers,
A first intermediate layer is provided inside the outer layer, and a second intermediate layer is provided between the first intermediate layer and the inner layer;
The first intermediate layer has a composition containing any of Au, Cu, and Ni in addition to the components of the outer layer and the second intermediate layer,
The pipe material according to claim 1, wherein the second intermediate layer is a layer made of any one of Pd, PtNi alloy, and PdNi alloy, and the second intermediate layer and the inner layer are diffusion-bonded. It is a manufacturing method of the pipe material according to claim 2,
Au, Ni, Ag, Pd, Pt, or any one of the inner surface of the tube made of Ni-based alloy corresponding to the outer layer or the outer surface of the round bar made of Pt-based alloy corresponding to the inner layer, or A plating step of providing any one of two layers of Ag and Pd, two layers of Pd and Ni, and two layers of Pt and Ni;
A combination step of combining the pipe and the round bar provided with a plating layer on any of the surfaces so that the round bar is positioned in the hole of the pipe, and
A processing step of bringing the combined pipe material and the round bar into close contact with each other;
A heat treatment step of joining the tightly attached tube and the round bar by heating in a vacuum or an inert gas atmosphere or by applying a hot isostatic pressure in an inert gas atmosphere;
A drilling step of providing a hole by mechanical means in the round bar portion of the joined round bar-attached pipe material,
A cutting step of cutting the pipe provided with the hole;
A method for manufacturing a pipe material. It is a manufacturing method of the pipe material according to claim 3,
A first tubular member having a hollow circular section made of a Ni-based alloy corresponding to the outer layer, a second tubular member having a hollow circular section made of any one of Pd, PtNi alloy and PdNi alloy corresponding to the intermediate layer, and the inner layer A round bar having a circular cross-section made of a Pt-based alloy corresponding to the second pipe material is located in the hole of the first tube material, and the round bar is located in the hole portion of the second tube material. Combining processes to be combined,
A processing step of bringing the combined first tube material, the second tube material, and the round bar into close contact;
The first tube member, the second tube member, and the round bar that are in close contact are joined by heating in a vacuum or an inert gas atmosphere, or by hot isostatic pressing in an inert gas atmosphere. A heat treatment process,
A drilling step of providing a hole by mechanical means in the round bar portion of the joined round bar-attached pipe material,
A cutting step of cutting the pipe provided with the hole;
A method for manufacturing a pipe material. It is a manufacturing method of the pipe material according to claim 4,
In addition to the process of manufacturing a pipe material according to claim 6,
The method further includes a plating step of providing a plating layer of any one of Au, Cu, and Ni on the inner surface of the first tube material or the outer surface of the second tube material before the combination step of claim 6. A method for manufacturing a pipe material.