JPH07113195A - Formation of metallic film - Google Patents

Abstract

PURPOSE:To provide a sliding surface constituting body which consists of a film having six-ridge Fe crystals which are made fine and uniform and having excellent sliding characteristics. CONSTITUTION:The current of a power source for plating is controlled to draw pulse waveforms in such a manner that,this current rises from the min. value, attains the max. value and falls clown to the min. value at the time of forming the sliding surface constituting body 4 having the many hexagonal pyramid- shaped six-ridge Fe crystals 71 on the sliding surface 4a by an electroplating method. The ratio TON/TC of the energization time TON and the cycle time TC is set at TON/TC <=0.45 when the energization time from the start of rising of the current before the start of the falling is defined as TON and the cycle time thereof as TC with the time from the previous start of the rising to the next start of the rising as one cycle. As a result, the sliding surface 4a is formed of the aggregate of the six-ridge Fe crystals 7, and the oil retaining property thereof is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal coating, and more particularly to a method for forming a metal coating having a large number of pyramidal metal crystals or truncated pyramidal metal crystals on the surface by a plating method.

[0002]

2. Description of the Related Art Conventionally, as a metal coating of this kind, for example, in a piston for an internal combustion engine, an Fe plating layer provided for improving wear resistance is provided on the outer peripheral surfaces of the land and the skirt of an Al alloy base material. Are known.

However, under the present circumstances where the internal combustion engine tends to have high speed and high output, the conventional Fe plating layer has a relatively smooth sliding surface, so that the oil retention, that is, the There was a problem that seizure resistance was poor due to insufficient oil retention and poor initial conformability.

Therefore, the present applicant has previously developed an Fe plating layer having a large number of pyramidal Fe crystals or truncated pyramidal Fe crystals on its sliding surface.

According to this structure, the two adjacent Fe crystals are in a state of being bitten into each other, whereby the sliding surface has a large number of fine ridges and a large number of ridges formed between the ridges. Since it has an intricate appearance of fine valleys and a large number of fine ridges due to the mutual biting of the ridges, the Fe plating layer has good oil retention. Also, the preferential wear of the tip side of the Fe crystal improves the initial conformability of the Fe plating layer.

[0006]

In order to obtain excellent sliding characteristics as described above, it is necessary to make pyramidal Fe crystals and the like finer and uniform in particle size.

It is an object of the present invention to provide a method for forming the metal film which can meet the above requirements.

[0008]

According to the present invention, a metal film having at least one of a large number of pyramidal metal crystals or truncated pyramidal metal crystals on a surface is formed by a plating method.
The output of the plating energy source is controlled so as to draw a pulse waveform as the output rises from the minimum value to the maximum value and then falls to the minimum value, from the start of rising of the output to the start of falling. When the output time of T _ON is T _ON and the cycle time from the start of the previous rise to the start of the next rise is 1 cycle and the cycle time is T _c , the output time T _ON
And the cycle time T _c , the ratio T _ON / T _c is T _ON / T _c ≦
It is characterized in that it is set to 0.45.

[0009]

When the output of the plating energy source is controlled as described above and the ratio T _ON / T _c of both times is set as described above, the surface is made finer and its grain size is made uniform. It is possible to form a metal film having a large number of pyramidal metal crystals or the like, and the existence rate S of the pyramidal metal crystals or the like on the surface can be S ≧ 40%.

As a result, for example, in the piston having the metal coating, the metal coating exhibits excellent sliding characteristics under lubrication. Further, when the existence ratio S is set to S ≧ 90%, the sliding property of the metal film without lubrication can be improved.

However, the ratio T _ON / T _{c of} both times is T _ON / T
_{When c} > 0.45, the existence rate S of the pyramidal metal crystal or the like becomes S <40%, and the significance of providing the metal crystal or the like is lost.

[0012]

1 and 2, a piston 1 for an internal combustion engine is shown.
Has a base material 2 made of Al alloy, and the land portion 3 _{1 of the} base material 2
_{On the} outer peripheral surface of the skirt portion 32, a layered sliding surface structure 4 as a metal film is formed by plating.

As shown in FIG. 3, the sliding surface structure 4 is composed of an aggregate of metal crystals having a body-centered cubic structure (bcc structure). The aggregate grows in a columnar shape from the base material 2 and has a large number of (hhh) oriented metal crystals whose mirror index (hhh) surface is directed to the sliding surface (surface) 4a side with the inner wall 5 of the cylinder bore. Have.

An electroplating method is applied to the formation of the sliding surface structure 4. At that time, as shown in FIG. 4, the current density CD of the plating power source rises from the minimum current density CDmin to the maximum current density CDmax, and then decreases to the minimum current density CDmin. It is controlled to draw a pulse waveform as time T elapses.

The output time from the start of the rise of the current density CD to the start of the fall thereof is T _ON, and one cycle from the start of the previous rise to the start of the next rise is defined as
When the cycle time is T _c , the ratio of the output time T _ON and the cycle time T _c , that is, the time ratio T _ON / T _c is T _ON
/ T _c ≦ 0.45 is set.

In this case, the minimum current density C of the plating power source is
Dmin to CDmin = 0 and average current density CDm to
For example, by setting CDm ≧ 2.5 A / dm ² , the abundance S of (hhh) oriented metal crystals can be S ≧ 40%.

On the other hand, the minimum current density CDmin is given by CDmin =
0, and the time ratio T _ON / T _{c is set} to T _ON / T _c ≦ 0.35.
In addition, the average current density CDm is CDm ≧ 3.5 A / dm
^When each is set to ² , the existence rate S of (hhh) oriented metal crystals can be S ≧ 90%.

Under the above-mentioned forming conditions, if the abundance S of (hhh) oriented metal crystals is set to S ≧ 90%, substantially the entire sliding surface 4a is hexagonal pyramid-shaped (or hexagonal pyramid) as shown in FIG. It can be formed from a trapezoidal metal crystal, that is, an aggregate of hexagonal metal crystals 7 ₁ having 6 ridgelines 6. The hexagonal metal crystal 7 ₁ is more than the triangular pyramid-shaped (or triangular truncated pyramid) (hhh) oriented metal crystal shown in FIG. 6, that is, the tri-ridged metal crystal 7 ₂ having three ridge lines 6. Small average particle size,
Moreover, the particle size is also substantially uniform. In the (hhh) oriented metal crystal, there is a correlation between the grain size and the height, so that the grain size being substantially uniform means that the heights are also substantially equal.

Moreover, in these hexagonal metal crystals 7 ₁ , adjacent ones are in a state of being bitten into each other. As a result, the sliding surface 4a has a larger surface area as compared with the case where it is formed of the tri-ridged metal crystal 7 _2. Also, a large number of extremely fine ridges 8 and a large number of ridges formed between the ridges 8 are formed. Since it has a very intricate appearance composed of extremely fine valleys 9 and a large number of extremely fine ridges 10 (see FIG. 7) due to the mutual biting of the ridges 8, the sliding surface structure 4 has Very good oil retention.
In addition, the initial conformability of the sliding surface structure 4 is also good due to preferential wear of the hexagonal metal crystal 7 _{1 on} the tip side.

Furthermore with the uniform finer Rokuryo metal crystals _71, while avoiding the high local surface pressurization can achieve fine differentiation sliding load, thereby slide surface construction 4
Exhibits excellent wear resistance not only under lubrication but also under non-lubrication.

As shown in FIG. 8, the inclination of the (hhh) plane with respect to the virtual surface 11 along the sliding surface 4a is hexagonal metal crystal 7 ₁
Of the sliding surface structure 4 affects the oil retaining property, the initial running-in property, and the wear resistance of the sliding surface structure 4. Therefore, the inclination angle θ formed by the (hhh) plane with respect to the virtual surface 11 is set to 0 ° ≦ θ ≦ 15 °. In this case, (hhh)
The direction of inclination of the surface is not limited. Tilt angle θ is θ>
When it becomes 15 °, the oil retaining property, the initial conformability and the wear resistance of the sliding surface structure 4 are deteriorated.

(Hhh) The abundance S of oriented metal crystals is
For example, when 40% ≦ S <90%, the sliding surface 4a is formed of an assembly of hexagonal metal crystals 7 ₁ and trihedral metal crystals 7 ₂ . The sliding characteristics of this sliding surface structure 4 are
It becomes lower than that in the case where almost all of a is formed of hexagonal metal crystals 7 ₁ .

In the above forming method, the minimum current density CDmin of the plating power source is set to CDmin ≥0.2 A / dm ² , the time ratio T _ON / T _{c is set} to T _ON / T _c ≤0.35, and the average current is further set. When the densities CDm are set to CDm ≧ 3.5 A / dm ² , hexagonal metal crystals 7 ₁ whose slopes 12 are substantially flat can be deposited as shown in FIG.

Since this hexagonal metal crystal 7 ₁ has a high hardness,
This is effective in improving the wear resistance of the sliding surface structure 4.

Also, the minimum current density CDmi of the power supply for plating is
n to CDmin ≦ −0.2 A / dm ² , and the time ratio T _ON /
T _c to T _ON / T _c ≦ 0.35, and further average current density C
When Dm is set to CDm ≧ 3.5 A / dm ² ,
As shown in FIG. 10, a relatively deep valley 1 between adjacent ridgelines 6
Hexahedral metal crystals 7 ₁ having 3 can be deposited.

The hexagonal metal crystal 7 ₁ has a good oil retaining property due to the valley 13 thereof, and therefore is effective in improving the seizure resistance of the sliding surface constituting body 4.

As a metal crystal having a bcc structure, F is
Examples thereof include crystals of e, Cr, Mo, W, Ta, Zr, Nb, V, etc., or alloys thereof.

As the plating method, in addition to the electroplating method,
For example, a PVD method which is a vapor phase plating method, a CVD method, a sputtering method, an ion plating and the like can be mentioned.
When performing W and Mo plating by the sputtering method, for example, Ar pressure is 0.2 to 1 Pa, base material temperature is 150 to 300 ° C., and average Ar acceleration power (energy source) is 1 to 1.5 kW.
To control. When performing W plating by the CVD method, for example, the flow rate of WF ₆ (raw material) is 2 to 15 cc / min, the chamber internal pressure is 50 to 300 Pa, the base material temperature is 100 to 400 ° C., and the average output of the ArF maximer laser (energy source) is used. Is controlled to 5 to 40 W.

[Example 1] A 15 µm-thick layer formed of an aggregate of Fe crystals by applying an electric Fe plating method to the outer peripheral surface of the land portion 3 ₁ and the skirt portion 3 _{2 of the} Al alloy base material 2 A plurality of internal combustion engine pistons 1 were manufactured by forming the sliding surface constructing body 4, and the following various considerations were performed on the sliding surface constructing body 4.

A. Regarding time ratio T _ON / T _c Table 1 shows the plating bath conditions in Examples 1 to 24 and 50 to 54 of the sliding surface structure 4.

[0031]

[Table 1] Table 2 shows the plating treatment conditions of Examples 1-14. In this case, in Examples 1 to 6, CDm = 7 A / dm ² , and in Examples 7-1.
In 4, the CDm is set to 4 A / dm ² for each CD.
T _ON / T _c was changed at constant m.

[0032]

[Table 2] Table 3 shows the plating treatment conditions of Examples 15-24. In this case, in Examples 15 to 19, CDm = 3.5 A / dm ² , and in Examples 20 to 24, CDm = 3 A / dm ² , respectively, and T _ON / T _c was changed at each constant CDm.

[0033]

[Table 3] Table 4 shows the plating treatment conditions of Examples 50 to 54. In this case, T _ON / T _c was changed at a constant CDm = 2.5 A / dm ² .

[0034]

[Table 4] Tables 5 to 9 show sliding surfaces 4 in Examples 1 to 24 and 50 to 54.
The crystal morphology of a, the area ratio A and the average grain size d of the hexagonal Fe crystals, the abundance S of each oriented Fe crystal, and the hardness are shown.

[0035]

[Table 5]

[0036]

[Table 6]

[0037]

[Table 7]

[0038]

[Table 8]

[0039]

[Table 9] The area ratio A of the hexahedral Fe crystal is A = (C / B) × 100 (where B is the area of the sliding surface 4a and C is the area occupied by all the hexahedral Fe crystals on the sliding surface 4a. %) Was calculated as. Further, the grain size of the hexagonal Fe crystal is the distance between both corners facing each other with the apex interposed, that is, the average value of the three distances.

The existence ratio S is X in Examples 1 to 24 and 50 to 54.
It is obtained by the following method based on the line diffraction diagram (the X-ray irradiation direction is the direction perpendicular to the sliding surface 4a). Explaining Example 8 as an example, FIG. 11 is an X-ray diffraction diagram of Example 8, and the abundance S of each oriented Fe crystal was obtained from the following equation. Note that, for example, {110} orientation F
The e crystal means an oriented Fe crystal in which the {110} plane faces the sliding surface 4a side. {110} oriented Fe crystal: S ₁₁₀ = {(I ₁₁₀ / IA
₁₁₀ ) / T} × 100, {200} oriented Fe crystal: S ₂₀₀ = {(I ₂₀₀ / IA
₂₀₀ ) / T} × 100, {211} oriented Fe crystal: S ₂₁₁ = {(I ₂₁₁ / IA)
₂₁₁ ) / T} × 100, {310} oriented Fe crystal: S ₃₁₀ = {(I ₃₁₀ / IA
₃₁₀ ) / T} × 100, {222} oriented Fe crystal: S ₂₂₂ = {(I ₂₂₂ / IA)
₂₂₂ ) / T} × 100 where I ₁₁₀ , I ₂₀₀ , I ₂₁₁ , I ₃₁₀ , and I ₂₂₂ are measured values (cps) of the X-ray reflection intensity of each crystal plane, and I ₁₁₀ =
0.8K, I ₂₀₀ = 0.4K, I ₂₁₁ = 1.7K, I
₃₁₀ = 0.15K, a I ₂₂₂ = 9.8K. Also IA
₁₁₀ , IA ₂₀₀ , IA ₂₁₁ , IA ₃₁₀ , IA ₂₂₂ are AS
X-ray reflection intensity ratio of each crystal plane in TM card, IA
₁₁₀ = 100, IA ₂₀₀ = 20, IA ₂₁₁ = 30, IA
₃₁₀ = 12, a IA ₂₂₂ = 6. Furthermore, T is T =
(I ₁₁₀ / IA ₁₁₀ ) + (I ₂₀₀ / IA ₂₀₀ ) + (I
₂₁₁ / IA ₂₁₁ ) + (I ₃₁₀ / IA ₃₁₀ ) + (I ₂₂₂ /
IA ₂₂₂ ) = 1.73K.

FIG. 12 is an electron micrograph showing the crystal structure of the sliding surface 4a in Example 8, in which a large number of hexagonal pyramidal hexagonal Fe crystals are observed. As shown in Table 6, the area ratio A of the hexagonal Fe crystal is A = 96%, and the average particle diameter d is d = 3.
μm. The hexagonal Fe crystal is a {222} oriented Fe crystal in which the (hhh) plane, and thus the {222} plane, faces the sliding surface 4a side. In this case, {222} oriented Fe
As shown in Table 6 and FIG. 11, the crystal abundance S is S = 9.
It is 4.3%.

FIG. 13 is an X-ray diffraction pattern of Example 14. Figure 1
4 is an electron micrograph showing the crystal structure of the sliding surface 4a in Example 14, in which many granular Fe crystals are observed.

FIG. 15 shows the relationship between the time ratio T _ON / T _c and the abundance S of {222} oriented Fe crystals in Examples 1 to 24 and 50 to 54, and points (1) to (( 24), (5
0) to (54) correspond to Examples 1 to 24 and 50 to 54, respectively. As is clear from FIG. 15, the time ratio T _ON / T
_By setting _c to T _ON / T _c ≦ 0.45, the abundance ratio S of {222} oriented Fe crystals can be S ≧ 40% at each average current density CDm.

In this case, the average current density Dm is Dm ≧ 3.
5 A / dm ² , and the time rate T _ON / T _c is T _ON / T _c ≤
If set to 0.35, respectively, {222} oriented Fe
The abundance S of crystals is S ≧ 90%, and in FIG.
90% ≦ S ≦ 100% and 0 <T _ON / T _c ≦ 0.3
In the region of No. 5, most of the {222} oriented Fe crystals take the form of hexagonal Fe crystals.

On the other hand, in FIG. 15, the region excluding the hexagonal Fe crystal single region from the region of S ≧ 40% and T _ON / T _c ≦ 0.45 is a hexagonal Fe crystal and a trihedral Fe. It becomes a mixed region of crystals.

B. Regarding Fe Ion Concentration Fe ^{2+ in} Plating Bath Table 10 shows the plating bath conditions in Examples 25 to 36 of the sliding surface structure 4.

[0047]

[Table 10] Table 11 shows the plating treatment conditions of Examples 25 to 36. In this case, in Examples 25 to 27, CDm = 7 A / dm ² and Example 28
CDm = 4 A / dm ² for ~ 31, and C for Examples 32-34.
Dm = 3.5 A / dm ² , and in Examples 35 and 36, CDm
= 3 A / dm ² , and the Fe ion concentration Fe ²⁺ was changed as shown in Table 10 at a constant CDm.

[0048]

[Table 11] Tables 12 and 13 show the crystal morphology of the sliding surface 4a, the area ratio A of the hexagonal Fe crystals and the average grain size d, the abundance S of each oriented Fe crystal and the hardness in Examples 25 to 36, respectively.

[0049]

[Table 12]

[0050]

[Table 13] FIG. 16 shows Examples 25 to 36 and Examples 2, 8, 16, 2 above.
Fe ion concentration of the plating bath in No. 1 Fe ²⁺ and {22
2} shows the relationship with the abundance S of oriented Fe crystals,
Points (2), (8), (16), (21), (25) ~
(36) corresponds to Examples 2, 8, 16, 21, 25-36, respectively. As is clear from FIG. 16, for example, when the average current density CDm ≧ 3 A / dm ² , the Fe ion concentration Fe
By setting ²⁺ to Fe ²⁺ ≧ 0.6, the abundance ratio S of {222} oriented Fe crystals can be S ≧ 40%. The abundance ratio S of {222} oriented Fe crystals is S ≧ 9.
To achieve 0%, the average current density CDm ≧ 3.5 A /
It is necessary to set the Fe ion concentration Fe ²⁺ in dm ² to Fe ²⁺ ≧ 1.

C. Regarding pH of Plating Bath Table 14 shows the plating bath conditions in Examples 37 to 47 of the sliding surface structure 4.

[0052]

[Table 14] Table 15 shows the plating treatment conditions of Examples 37 to 47. In this case, in Examples 37 to 39, CDm = 7 A / dm ² , and in Example 40.
CDm = 4 A / dm ² for ~ 42, and C for Examples 43-45.
Dm = 3.5 A / dm ² , and in Examples 46 and 47, CDm = 3
It is set to A / dm ² respectively, and at each CDm constant,
The pH was changed as shown in Table 14.

[0053]

[Table 15] Tables 16 and 17 show the crystal morphology of the sliding surface 4a, the area ratio A of the hexagonal Fe crystals and the average grain size d, the abundance ratio S of each oriented Fe crystal, and the hardness in Examples 37 to 47, respectively.

[0054]

[Table 16]

[0055]

[Table 17] FIG. 17 shows Examples 37 to 47 and Examples 2, 8, 16, 2 above.
The relationship between the pH of the plating bath and the abundance ratio S of {222} oriented Fe crystals in FIG. 1 is shown by points (2), (8),
(16), (21), (37) to (47) are examples 2, 8 and
16, 21, 37-47 respectively. As is clear from FIG. 17, for example, the average current density CDm ≧ 3 A /
By setting the pH to ≧ 4.5 in dm ² , the abundance ratio S of {222} oriented Fe crystals can be S ≧ 40%. Further, in order to set the existence ratio S of the {222} oriented Fe crystal to S ≧ 90%, the average current density CDm
It is necessary to set the pH to pH ≧ 5.5 at ≧ 3.5 A / dm ² .

D. About seizure resistance and wear resistance Examples of sliding surface structure 4 1, 7, 8, 11 to 14, 17, 2
2-22 and 31 were subjected to a seizure test by a chip-on-disk method under lubrication, and {222} orientation F
The relationship between the abundance S of the crystals and the seizure load was determined.
The test conditions are as follows. Disc material Al-1
0wt% Si alloy, disk rotation speed 15m / sec,
Lubrication amount 0.3 ml / min, sliding surface area of chip made of sliding surface structure 1 cm ² .

Further, each example 1, 7, 8, 11-14, 1
7, 22 to 24, 31 were subjected to a wear test by a chip-on-disk method without lubrication, and the relationship between the abundance S of {222} oriented Fe crystals and the wear amount of the chips was obtained. The test conditions are as follows. Disk material Al-10 wt% Si alloy, disk rotation speed
0.5m / sec, load 100N, sliding distance 1km, sliding surface area of chip made from sliding surface structure 1cm
² . The amount of wear is the amount of loss (mg) per 1 cm ² of chip area.

Table 18 shows the seizure test and abrasion test results. 18 and 19 are graphs of Table 18, showing points (1), (7), (8), and (11) -in both figures.
(14), (17), (22) to (24) and (31) correspond to Examples 1, 7, 8, 11 to 14, 17, 22 to 24 and 31, respectively.

[0059]

[Table 18] As is clear from Table 18 and FIG. 18, when the abundance S of the {222} -oriented Fe crystals S ≧ 40%, the oil retaining property and the initial running-in property of the sliding surface 4a are improved, and the seizure resistance is significantly improved. improves. In particular, it is clear that the seizure resistance is remarkably improved due to the high density of the hexagonal Fe crystals in the presence ratio S ≧ 90% of the {222} oriented Fe crystals.

As is clear from Table 18 and FIG.
When the abundance rate S of the {222} oriented Fe crystals is S ≧ 40%, the wear amount is small, and therefore, good wear resistance can be obtained even without lubrication. In particular, {222} oriented Fe
When the crystal abundance ratio S ≧ 90%, the wear resistance becomes extremely good due to the high density of the hexagonal Fe crystals.

[Second Embodiment] In the first embodiment, the minimum current density CDmin is set to CDmin = 0A / dm ² , but in the present embodiment, CDmin ≧ 0.2A / dm ² or CDmin ≦ −. It is set to 0.2 A / dm ² .

Table 19 shows the plating bath conditions in Examples 1 to 7 of the sliding surface structure 4. In addition, Example 4 is Example 8 of Example 1.
Is the same as.

[0063]

[Table 19] Table 20 shows the plating treatment conditions of Examples 1 to 7.

[0064]

[Table 20] Table 21 shows the crystal morphology of the sliding surface 4a in Examples 1 to 7, the area ratio A of the hexagonal Fe crystals and the average grain size d, and the respective oriented Fe.
The crystal abundance S and hardness are shown respectively.

[0065]

[Table 21] 20 is an X-ray diffraction diagram of Example 1, and FIG. 21 is an electron micrograph showing the crystal structure of the sliding surface 4a in Example 1. As is clear from FIG. 21, the minimum current density CDmin
Is set to CDmin ≤ -0.2 A / dm ² , {22
The 2} oriented Fe crystal becomes a hexagonal Fe crystal having a relatively deep valley between adjacent ridgelines.

FIG. 22 is an X-ray diffraction pattern of Example 7, and FIG. 23 is an electron micrograph showing the crystal structure of the sliding surface 4a in Example 7. As is clear from FIG. 23, when the minimum current density CDmin is set to CDmin ≧ 0.2 A / dm ² , the {222} oriented Fe crystal becomes a hexagonal Fe crystal in which each slope is substantially flat.

Regarding Examples 1 to 7, under the same conditions as described above,
When a seizure test under lubrication and a wear test under non-lubrication were conducted, the results shown in Table 22 were obtained. 24 and 25 are graphs of Table 22, showing points (1) to
(7) corresponds to Examples 1 to 7, respectively.

[0068]

[Table 22] As is clear from Table 22 and FIG. 24, the minimum current density CD
When min is set to CDmin ≦ −0.2 A / dm ² , oil retention becomes good due to each valley of each hexagonal Fe crystal, and seizure resistance is improved as in Examples 1 to 3.

As is clear from Table 22 and FIG.
When the minimum current density CDmin is set to CDmin ≧ 0.2 A / dm ² , the hardness of each hexagonal Fe crystal becomes high, so
The wear resistance becomes good as shown by ~ 7.

As shown in FIG. 26, the sliding surface structure 4 may be composed of an aggregate of metal crystals having a face-centered cubic structure (fcc structure). The aggregate grows in a columnar shape from the base material 2 and includes (3hhh) oriented metal crystals with the (3hhh) plane facing the sliding surface 4a side by the Miller index.
hh) The abundance S of oriented metal crystals is set to S ≧ 40%. As shown in FIG. 27, the (3hhh) oriented metal crystal 6 is a four-sided pyramidal metal crystal 7 ₃ having a quadrangular pyramid shape on the sliding surface 4a.

As shown in FIG. 28, since the inclination of the (3hhh) surface with respect to the virtual surface 11 along the sliding surface 4a appears as the inclination of a quadrangular pyramid, the oil retaining property and the initial conformability of the sliding surface constituting body 4 are shown. Affect. Therefore, the inclination angle θ formed by the (3hhh) plane with respect to the virtual surface 11 is set to 0 ° ≦ θ ≦ 15 ° for the same reason as above. in this case,
The inclination direction of the (3hhh) plane is not limited.

A metal crystal having an fcc structure is P
Examples thereof include crystals of b, Ni, Cu, Pt, Al, Ag, Au and the like, which are simple substances or alloys.

A specific example will be described below.

A camshaft for an internal combustion engine was manufactured by forming a sliding surface structure composed of an aggregate of Ni crystals by performing an electric Ni plating treatment on the outer peripheral surface of the journal of a cast iron base material.

The plating bath conditions were nickel sulfate concentration 3
00 g / liter, Ni ion concentration Ni ²⁺ = 1 mol / liter, pH = 5.5, and temperature 55 ° C. The plating conditions are: minimum current density CDmin = 0A / dm ² , maximum current density CDmax = 20A / dm ² , average current density CD
m = 4 A / dm ² , time ratio T _ON / T _c = 0.2, output time T _ON = 2 msec.

The crystal morphology of the sliding surface is a mixture of quadrangular pyramids and particles,
Area ratio of four-sided Ni crystal A = 60%, average grain size d = 4
μm, the abundance S of each oriented Ni crystal is {111} oriented Ni crystal S = 29%, {200} oriented Ni crystal
S = 15.2%, {220} oriented Ni crystal S = 4.
7%, {311} oriented Ni crystal S = 51.1%, hardness Hv = 250.

The existence ratio S is an X-ray diffraction diagram of the sliding surface structure shown in FIG. 29 (X-ray irradiation direction is a direction perpendicular to the sliding surface).
It is obtained from the following equation based on Note that, for example, the {111} oriented Ni crystal means an oriented Ni crystal with the {111} plane facing the sliding surface side. {111} oriented Ni crystal: S ₁₁₁ = {(I ₁₁₁ / IA
₁₁₁ ) / T} × 100, {200} oriented Ni crystal: S ₂₀₀ = {(I ₂₀₀ / IA
₂₀₀ ) / T} × 100, {220} oriented Ni crystal: S ₂₂₀ = {(I ₂₂₀ / IA)
₂₂₀ ) / T} × 100, {311} oriented Ni crystal: S ₃₁₁ = {(I ₃₁₁ / IA
₃₁₁ ) / T} × 100 where I ₁₁₁ , I ₂₀₀ , I ₂₂₀ , and I ₃₁₁ are measured values (cps) of the X-ray reflection intensity of each crystal plane, and I ₁₁₁ = 78.6.
K, I ₂₀₀ = 17.4K, I ₂₂₀ = 2.7K, I ₃₁₁ =
It is 27.7. In addition, IA ₁₁₀ , IA ₂₀₀ , IA ₂₂₀ ,
IA ₃₁₁ is the X-ray reflection intensity ratio of each crystal plane in the ASTM card, IA ₁₁₁ = 100, IA ₂₀₀ = 42, IA
₂₂₀ = 21, IA ₃₁₁ = 20. Furthermore, T is T =
(I ₁₁₁ / IA ₁₁₁ ) + (I ₂₀₀ / IA ₂₀₀ ) + (I
₂₂₀ / IA ₂₂₀ ) + (I ₃₁₁ / IA ₃₁₁ ) = 2.71K
Is.

FIG. 30 is a micrograph showing the crystal structure of the sliding surface. In FIG. 30, a large number of quadrilateral pyramidal Ni crystals are observed. This four-sided Ni crystal is (3hh
h) plane, and hence {311} plane is a {311} oriented Ni crystal with the sliding surface side, and the abundance ratio S is S =
It is 51.1%.

The sliding surface structure was subjected to a seizure test under lubrication and a wear test under non-lubrication under the same conditions as described above. The seizure load was 650 N and the abrasion amount was 1.6 mg. Met.

The sliding surface structure is applied to a sliding portion such as the following internal combustion engine parts. Piston (ring groove), piston ring, piston pin, connecting rod, crankshaft, bearing metal, oil pump rotor, oil pump rotor housing, camshaft, spring (end surface), spring seat, spring retainer,
Cotta, rocker arm, roller bearing outer case, roller bearing inner case, valve stem, valve face, hydraulic tappet, water pump rotor shaft, pulley, gear, transmission shaft part, clutch plate, washer, bolt (seat surface, screw part).

The present invention is not limited to the formation of the sliding surface structure, but is also applicable to the formation of a light absorber utilizing the high absorptivity of the film having the metal crystals, and the magnetic shield material utilizing the high magnetic permeability of the film. It is applied to formation etc.

[0082]

According to the present invention, the output of the plating energy source is controlled so as to draw a pulse waveform as described above, and the ratio T _ON / T _c of the output time T _ON and the cycle time T _c is set to the above. It has a large number of pyramidal metal crystals and / or truncated pyramidal metal crystals that have been made finer and uniform in particle size by being specified as follows, and are applied to various applications such as sliding surface structures. A metal film can be easily formed.

[Brief description of drawings]

FIG. 1 is a side view of a piston.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a perspective view showing a body-centered cubic structure and its (hhh) plane.

FIG. 4 is an output waveform diagram of a power supply for electroplating.

FIG. 5 is a plan view of an essential part showing an example of a sliding surface structure.

FIG. 6 is a plan view of a trihedral metal crystal.

7 is a sectional view taken along line 7-7 of FIG.

FIG. 8 is an explanatory diagram showing an inclination of a (hhh) plane in a body-centered cubic structure.

FIG. 9 is a perspective view showing an example of a hexagonal metal crystal.

FIG. 10 is a perspective view showing another example of hexagonal metal crystals.

FIG. 11 is an X-ray diffraction diagram of a first example of a sliding surface structure.

FIG. 12 is a micrograph showing a crystal structure of a sliding surface in a first example of the sliding surface structure.

FIG. 13 is an X-ray diffraction diagram of a second example of the sliding surface structure.

FIG. 14 is a micrograph showing a crystal structure of a sliding surface in a second example of the sliding surface structure.

FIG. 15 is a graph showing the relationship between the time ratio T _ON / T _c and the abundance ratio S of {222} oriented Fe crystals.

FIG. 16: Fe ion concentration of the plating bath Fe ²⁺ and {22
2 is a graph showing the relationship with the abundance ratio S of 2} oriented Fe crystals.

FIG. 17 is a graph showing the relationship between the pH of the plating bath and the abundance S of {222} oriented Fe crystals.

FIG. 18 is a graph showing the relationship between the abundance ratio S of {222} oriented Fe crystals and the seizure generation load.

FIG. 19 is a graph showing the relationship between the abundance S of {222} oriented Fe crystals and the amount of wear.

FIG. 20 is an X-ray diffraction diagram of a third example of the sliding surface structure.

FIG. 21 is a micrograph showing a crystal structure of a sliding surface in a third example of the sliding surface structure.

FIG. 22 is an X-ray diffraction diagram of a fourth example of the sliding surface structure.

FIG. 23 is a micrograph showing a crystal structure of a sliding surface in a fourth example of the sliding surface structure.

FIG. 24 is a graph showing the relationship between the minimum current density CDmin and the seizure generation load.

FIG. 25 is a graph showing the relationship between the minimum current density CDmin and the wear amount.

FIG. 26 is a perspective view showing a face-centered cubic structure and its (3hhh) face.

FIG. 27 is a plan view of a tetrahedral metal crystal.

FIG. 28 is an explanatory diagram showing the inclination of the (3hhh) plane in the face-centered cubic structure.

FIG. 29 is an X-ray diffraction diagram of a fifth example of the sliding surface structure.

FIG. 30 is a micrograph showing a crystal structure of a sliding surface in a fifth example of the sliding surface structure.

[Explanation of reference symbols] 4 Sliding surface structure (metal film) 4a Sliding surface (surface) 7 ₁ Hexahedral metal crystal (pyramidal metal crystal)

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 14, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

An electroplating method is applied to the formation of the sliding surface structure 4. At this time, as shown in FIG. 4, the current (output) I plating power source (energy source), the current I
Rises from the minimum current Imin to the maximum current Imax ,
Then, the pulse current is controlled so as to draw a pulse waveform as the time T elapses as the current decreases to the minimum current Imin .

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Then, the energization time (output time) from the start of the rise of the current I to the start of the fall is set to T _ON, and the cycle time is defined as one cycle from the start of the previous rise to the start of the next rise. When T _c , energizing time T
Ratio of _ON to cycle time T _c , that is, time ratio T _ON / T _c
Is set to T _ON / T _c ≦ 0.45.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016] CDmi In this case, the minimum current density CDmin
n = 0 and the average current density CDm, for example, CDm
By setting ≧ 2.5 A / dm ² , the existence rate S of (hhh) oriented metal crystals can be S ≧ 40%.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

[0023] In the forming method, the minimum current density CD
min to CDmin ≧ 0.2 A / dm ² , and the time ratio T _ON /
T _c to T _ON / T _c ≦ 0.35, and further average current density C
When Dm is set to CDm ≧ 3.5 A / dm ² ,
As shown in FIG. 9, hexagonal metal crystals 7 ₁ each having a substantially flat slope 12 can be deposited.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025], UpSmall current density CDmin ≤ CDmin ≤
-0.2 A / dm²And the time ratio T _ON/ T_cTo T_ON/ T
_c≦ 0.35, and the average current density CDm is CDm ≧
3.5 A / dm²If you set each to
Sea urchin, which has a relatively deep valley 13 between adjacent ridge lines 6
Metal crystal 7₁Can be deposited.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0070

[Correction method] Change

[Correction content]

As shown in FIG. 26, the sliding surface structure 4 may be composed of an aggregate of metal crystals having a face-centered cubic structure (fcc structure). The aggregate grows in a columnar shape from the base material 2, and includes (3hhh) oriented metal crystals with the (3hhh) plane facing the sliding surface 4a side by the Miller index.
hh) The abundance S of oriented metal crystals is set to S ≧ 40%. As shown in FIG. 27, (3hhh) oriented metal bond
Crystals have a quadrangular pyramid shape (or a truncated pyramid shape) on the sliding surface 4a.
Is a metal crystal that forms a ridge, that is, a tetrahedral metal crystal 7 ₃ having four ridge lines 6 .

[Procedure Amendment 8]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Dozaka 1-4-1 Chuo, Wako City, Saitama Stock Company Honda Technical Research Institute

Claims (5)

[Claims] 1. When forming a metal film having at least one of a large number of pyramidal metal crystals or truncated pyramidal metal crystals on the surface by a plating method, the output of an energy source for plating is raised from a minimum value. It is controlled so as to draw a pulse waveform as it goes up to the maximum value and then goes down to the minimum value, and the output time from the start of rising of the output to the start of falling is set to T _ON, and from the start of the previous rising. The cycle time is T until the start of the next rising, which is one cycle.
when is _c, the method of forming the metal coating, which comprises setting the ratio T _ON / T _c of the output time T _ON and the cycle time T _c to T _ON / T _c ≦ 0.45. 2. The ratio T _ON / T _c is T _ON / T _c ≦ 0.3
The method for forming a metal film according to claim 1, wherein the method is set to 5. 3. The plating method is an electroplating method, and the average current density CDm of the plating power source is CDm ≧ 3.5.
The method for forming a metal film according to claim 1, wherein the metal film is set to A / dm ² . 4. The minimum current density CDmi of the plating power source
The method for forming a metal film according to claim 3, wherein n is set to CDmin ≧ 0.2 A / dm ² . 5. The minimum current density CDmi of the plating power source
setting n to CDmin ≦ -0.2A / dm ^2, claim 3
The method for forming a metal film as described above.