JP3311151B2 - High strength inorganic coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength inorganic film, and more particularly, to an inorganic film having a large number of columnar inorganic crystals grown from a base material and having a high strength.

[0002]

2. Description of the Related Art Heretofore, as this kind of inorganic coating, for example, in a piston pin for an internal combustion engine, an Fe plating layer provided on an outer peripheral surface of a steel base material for the purpose of improving abrasion resistance has been known.

[0003] However, under the current situation in which the internal combustion engine tends to operate at high speed and high output, the conventional inorganic coating has an oil retaining property, that is, an oil retaining property, due to its relatively smooth sliding surface. There was a problem that the oiliness was insufficient and the seizure resistance was poor.

Accordingly, the present applicant has previously provided a large number of columnar inorganic crystals grown from a base material as an inorganic film,
Those having the tip portions made of pyramidal metal crystals have been developed (see, for example, Japanese Patent Application Laid-Open No. 4-351333 and the drawings).

[0005] With this configuration, the sliding surface has an intricate appearance composed of a number of fine peaks and a number of fine valleys formed between the peaks. Good oil retention. Thereby, the seizure resistance of the inorganic film is improved.

[0006]

However, various studies have been made on the above-mentioned inorganic coating. However, in the inorganic coating, the bonding strength between the columnar inorganic crystal and the adjacent columnar or granular inorganic crystal is relatively low. In order to cope with a harsher sliding environment, it is necessary to increase the bonding force, improve the strength of the inorganic film against a sliding load in a direction crossing the growth direction of the columnar inorganic crystal, and improve its crack resistance. It turned out to be necessary.

An object of the present invention is to provide the high-strength inorganic film capable of satisfying the above demand.

[0008]

The high-strength inorganic film according to the present invention comprises a large number of columnar inorganic crystals grown from a base material, and at least some of the columnar inorganic crystals have side surfaces along the growth direction. high binding columnar inorganic crystals der constructed from most atomic dense crystal plane is, all
In the columnar inorganic crystal, the high binding columnar inorganic crystal
Existence ratio A is wherein A ≧ 40% der Rukoto.

[0009]

SUMMARY OF The sides of high integrity columnar inorganic crystals is composed of the most atomic dense crystal planes, thus the close-packed plane
Runode, its a close-packed plane, bond density is high between the crystal planes of the columnar or granular mineral crystals adjacent thereto, coupling strength between these crystals Ru enhanced. Therefore, high-binding columns
Setting the abundance ratio A of the crystalline inorganic crystal as described above
Thus, the strength of the inorganic film against a load in a direction intersecting with the growth direction of the columnar inorganic crystal can be improved, and the crack resistance can be improved.

[0010]

In FIG. 1, a piston pin 1 for an internal combustion engine has a pipe-shaped base material 2 made of steel. 4 are formed. As shown in FIG. 2, the sliding surface constituting member 4 is composed of an aggregate of metal crystals (inorganic crystals) having a body-centered cubic structure (bcc structure) in the embodiment, and the aggregate is shown in FIG. as such, a number of columnar metal crystals grown from the base material 2 (columnar mineral crystals) 5 _1, 5 _2, 5 _3, 5 ₄
Is provided. The sliding surface structure 4 includes a large number of granular metal crystals 6.
It may also have.

[0011] columnar metal crystals 5 ₁ to 5 _4, for example, in Miller indices of (hhh) plane, towards the sliding surface 4a side (hh
h) Oriented metal crystals, in this case columnar metal crystals 5
The tip of _{1-5 4,} can be formed into a triangular pyramid-shaped metal crystals 8 as shown in hexagonal pyramid-shaped metal crystals 7 in the sliding surface 4a, as shown in FIG. 4, or FIG. The hexagonal pyramid-shaped metal crystal 7 has a smaller average particle size and a substantially uniform particle size as compared with the triangular pyramid-shaped metal crystal 8. (Hhh) In the oriented metal crystal, there is a correlation between the particle size and the height,
Therefore, the fact that the particle size is substantially uniform means that the height is also substantially equal.

[0012] At least a portion of those in the columnar metal crystals 5 ₁ to 5 _4, as shown in FIG. 6, the most atomic density is high crystal plane on all sides 10 along its growth direction a, thus in close-packed plane A certain (hh0) plane with Miller index (FIG. 2)
Constructed from the reference) is a high integrity columnar metal crystals 5 _1. High binding in this case, all the columnar metal crystals 5 ₁ to 5 ₄
Prevalence A is is set to A ≧ 40% of the polymerizable columnar metal crystals 5 ₁
It is. The abundance A of the columnar metal crystals having a high binding
The total number of columnar metal crystals including crystalline columnar metal crystals
D _1, the number of all high binding columnar metal crystals was D ₂
In this case, A = (D ₂ / D ₁ ) × 100 (%)
It is.

[0013] When composed of high binding all aspects 9 of the columnar metal crystals 5 ₁ (hh0) plane, bond density between the crystal plane of the (hh0) plane and a columnar metal crystals adjacent (or granular metal crystals) since increases the bonding force between these crystals Ru enhanced. Therefore, the presence of high binding columnar metal crystals 5 ₁
It used to set the rate A as described above, the direction b (Figure 3 thereby intersecting the growing direction a of the columnar metal crystals 5 ₁ to 5 ₄
(See FIG. 2), the strength of the sliding surface structure 4 against the sliding load can be improved, and the crack resistance thereof can be improved.

[0014] High binding columnar metal crystals 5 _1, as shown in FIG. 3 and 6, when viewed ultrafine portions of the base material 2 the outer peripheral surface of the proximal end of the crystal 5 ₁ binds with microscopically flat And grown substantially perpendicularly with a substantially uniform grain size from the plane. Such particle size control is achieved in the electroplating process by reducing the cathode current density with the passage of plating time. In this case, by changing the degree of reduction of the cathode current density, the columnar metal
The presence ratio A of ₁ changes at a high level. Incidentally, setting the cathode current density constant, the presence of the high binding columnar metal crystals 5 ₁ whose value is changed at a low level.

As shown in FIGS. 3 and 7, the columnar metal crystal is
In the case of the growth 5 ₂ or 5 ₃ in a tapered or tapered shape, or in the case of the growth 5 ₄ having an inclination angle θ with respect to the growth direction a, all the side surfaces 9 are atoms. It is composed of a crystal plane with a low density, that is, a high index plane, for example, a (h3h5h) plane with a Miller index. According to such a crystal plane, the effect of improving the bonding strength between the two crystals is low.

As the metal crystal having the bcc structure, F
e, Cr, Mo, W, Ta, Zr, Nb, V, etc., or a crystal of a simple substance or alloy.

In the plating process for forming the sliding surface structure 4, the plating bath and the cathode current density conditions when the electric Fe plating process is performed are as shown in Table 1.

[0018]

[Table 1] As the plating process, in addition to the electroplating process, for example, a PVD method, a CVD method, a sputtering method, an ion plating method or the like, which is a vapor phase plating method, can be used. Conditions for performing W and Mo plating by sputtering are, for example, A
r pressure 0.2-1Pa, average Ar acceleration power DC1
The power of the base material is 1.5 kW and the temperature of the base material is 150 to 300 ° C. In this case, the particle size control is performed by reducing the average Ar acceleration power as the sputtering time elapses. CVD
The conditions for performing W plating by the method include, for example,
WF ₆ , gas flow rate 2-15 cc / min, chamber pressure 50-300 Pa, base material temperature 400-600 ° C., ArF
The average output of the excimer laser is 5 to 40 W. In this case, the particle size control is performed by decreasing the average output of the ArF excimer laser as the film formation time elapses.

Hereinafter, specific examples will be described.

The outer peripheral surface 3 of the pipe-shaped base material 2 made of steel (JIS SCM420) is subjected to an electric Fe plating process to form a 15 μm thick formed of an aggregate of Fe crystals.
To form a plurality of piston pins 1 for an internal combustion engine.

In each example of the sliding surface structure, Table 2 shows Example 1.
, Table 3 of Examples 8 to 14, Table 4 of Examples 15 to 21,
Table 5 shows the electro-Fe plating conditions of Examples 22 to 28, respectively.

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5] Table 6 is Examples 1 to 7, Table 7 is Examples 8 to 14, Table 8 is Examples 15 to 2.
1, Table 9 shows the area ratio B of the columnar Fe crystal and the abundance A of the columnar Fe crystal having a high binding property for Examples 22 to 28, respectively.

[0026]

[Table 6]

[0027]

[Table 7]

[0028]

[Table 8]

[0029]

[Table 9] Area ratio B of the columnar Fe crystals, C ₁ the area of the longitudinal section of each example, when the area occupied by the whole of the columnar Fe crystals in its longitudinal section and _{C 2, B = (C 2} / C 1) × 100
(%). The portions other than the columnar Fe crystals are composed of granular Fe crystals. Further, the abundance A of the high-coupling columnar Fe crystals is represented by A, where D _{1 is} the total number of columnar Fe crystals including the high-coupling columnar Fe crystals, and D ₂ is the number of all the high-coupling columnar Fe crystals. = (D ₂ / D ₁ )
× 100 (%).

FIG. 8 is an X-ray diffraction diagram of Example 5 (the X-ray irradiation direction is perpendicular to the sliding surface). In the figure, for example, $ 2
22} means a {222} oriented Fe crystal, and the {222} oriented Fe crystal means that the {222} plane is
It is an oriented Fe crystal directed to the a side. The numerical value means the abundance (%) of each oriented Fe crystal, and the abundance S was obtained from the following equation. {211} oriented Fe crystal: S ₂₁₁ = {(I ₂₁₁ / IA)
₂₁₁ ) / T} × 100, {222} oriented Fe crystal: S ₂₂₂ = {(I ₂₂₂ / IA)
₂₂₂ ) / T｝ × 100 where I ₂₁₁ and I ₂₂₂ are the measured values (cps) of the X-ray reflection intensity of each crystal plane, and IA ₂₁₁ and IA ₂₂₂ are AS
The ratio of the X-ray reflection intensity of each crystal plane in the TM card, IA
₂₁₁ = 30, IA ₂₂₂ = 6. Further, T is T =
(I ₂₁₁ / IA ₂₁₁ ) + (I ₂₂₂ / IA ₂₂₂ ).

FIG. 9 is a photomicrograph showing the crystal structure of the longitudinal section in Example 5, where a large number of columnar Fe crystals are observed. In this case, as shown in Table 6, the area ratio B of the columnar Fe crystal is B = 100%. This columnar Fe crystal is (hh
h), that is, a {222} oriented Fe crystal with the {222} plane facing the sliding surface, and the abundance S of the {222} oriented Fe crystal is, as shown in FIG. 91
%.

Next, a slice along the side surface of the high-coupling columnar Fe crystal in Example 5 was prepared, and the slice was irradiated with an electron beam in the depth direction. The electron diffraction pattern shown in FIG. Obtained. As shown in FIG.
It can be seen that the side face of the e crystal is composed of the (hh0) plane.

FIG. 11 is a photomicrograph showing the crystal structure of the longitudinal section in Example 1, where a large number of columnar Fe crystals are observed. However, since all of the columnar Fe crystals are grown with a tapered or tapered shape, or with an inclination angle θ, the columnar Fe crystals do not include high-coupling columnar Fe crystals.

Further, each example was peeled off from the base material, and a tensile test was performed on each example. The results shown in Table 10 were obtained.
The tensile test was performed by pulling both ends of each example in a direction intersecting the growth direction of the columnar Fe crystal at a tensile speed of 0.05 mm / min.

[0035]

[Table 10] FIG. 12 is a graph of the relationship between the abundance A of the high-binding columnar Fe crystals and the tensile strength in each example based on Tables 6 to 10. In the figure, points (1) to (28) are Examples 1 to
28 respectively. As shown in FIG.
The tensile strength is improved when the e crystal abundance A is A ≧ 15%, the tensile strength is substantially constant when 15% ≦ A ≦ 35%, and the tensile strength sharply increases when A ≧ 40%. It turns out that it improves.

On the other hand, as the area ratio B of the columnar Fe crystal becomes lower, the tensile strength becomes higher. This is due to the fact that the abundance of the randomly grown granular Fe crystal having high adhesion strength increases.

The columnar inorganic crystal is not limited to a columnar metal crystal but includes a columnar ceramic crystal and the like. Further, the present invention is applied to various uses, and is not limited to only the sliding surface structure.

[0038]

According to the present invention, by providing the crystal structure specified as described above, it is possible to provide an inorganic film having high strength.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of a main part of a piston pin.

FIG. 2 shows the body-centered cubic structure and its (hhh) plane, (hh
It is a perspective view which shows a 0) surface.

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a plan view of a hexagonal pyramid-shaped metal crystal.

FIG. 5 is a plan view of a triangular pyramid-shaped metal crystal.

FIG. 6 is a perspective view of a main part of a high-coupling columnar metal crystal.

FIG. 7 is a perspective view of a main part of a thick columnar metal crystal.

FIG. 8 is an X-ray diffraction diagram of a sliding surface structure.

FIG. 9 is a micrograph showing a crystal structure of a longitudinal section of an example of a sliding surface structure.

FIG. 10 is an electron diffraction photograph of a side surface of a high-coupling columnar Fe crystal.

FIG. 11 is a micrograph showing a crystal structure of a longitudinal section of another example of the sliding surface structure.

FIG. 12 is a graph showing the relationship between the abundance ratio of columnar Fe crystals having high binding properties and tensile strength.

[Explanation of symbols]

4 slide surface construction (inorganic film) 5 ₁ high integrity columnar metal crystals (high integrity columnar inorganic crystals) 5 _{2-5 4} columnar metal crystals (columnar mineral crystals) 9 side a growth direction

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasushi Kawato 1-4-1 Chuo, Wako-shi, Saitama Prefecture Honda R & D Co., Ltd. (56) References JP-A-6-174089 (JP, A) JP-A JP-A-6-173070 (JP, A) JP-A-5-26242 (JP, A) JP-A-5-25687 (JP, A) JP-A-5-25690 (JP, A) JP-A-4-357322 (JP , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C25D 7/00 C25D 7/10 F16C 33/12 F16J 1/16

Claims (1)

(57) [Claims] [Claim 1] with a number of columnar inorganic crystals grown from the base material (2) to (5 ₁ to 5 _4), those of at least some of their columnar inorganic crystals (5 ₁ to 5 _4), the growth direction Highly binding columnar inorganic crystal (5 ₁ ) having a side surface (9) along (a) composed of a crystal plane having the highest atomic density
Der is, the in all columnar inorganic crystals (5 ₁ to 5 ₄₎
The abundance A of the highly binding columnar inorganic crystal (5 ₁ ) is A ≧ 40.
High strength inorganic film, wherein% der Rukoto.