GOLF CLUB HEAD

Abstract

This head 2 includes a head body h1 as a first member and a face plate p1 as a second member. A boundary k1 of the first member and the second member exists on a surface of the head. A deposition layer is formed in a region including the boundary k1 on the surface of the head. A temperature Tp in a deposition process is equal to or less than 150° C. Preferably, the deposition layer is formed by PVD. Preferably, the first member and the second member are stuck with an adhesive. Preferably, the deposition layer has a surface layer and a lower layer. Preferably, the exposed deposition layer is a TiC layer. Preferably, a total thickness Tt of the deposition layer is 0.5 μm or greater and 3.0 μm or less.

Description

The present application claims priority on Patent Application No. 2011-183128 filed in JAPAN on Aug. 24, 2011, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf club head.

2. Description of the Related Art

A golf club head may be subjected to surface processing. Typical surface processings are painting and plating.

Japanese Patent Application Laid-Open No. 2001-327636 discloses a golf club head covered with a coating layer formed by vapor phase coating. The gazette discloses an iron head having a face plate made of a titanium alloy. Examples of the vapor phase coating include PVD (physical vapor deposition method), CVD (chemical vapor deposition method), and a diffusion method.

SUMMARY OF THE INVENTION

In the head described in the literature, a boundary exists between the face plate and a head body. It was found that when a head having a boundary between members is subjected to deposition, a defect occurs near the boundary.

It is an object of the present invention to provide a golf club head capable of suppressing a deposition defect in a boundary between members.

A golf club head of the present invention includes a first member; and a second member. A boundary of the first member and the second member exists on a surface of the head. A deposition layer is formed in a region including the boundary on the surface of the head. A temperature Tp in a deposition process is equal to or less than 150° C.

Preferably, the deposition layer is formed by PVD.

Preferably, the first member and the second member are stuck with an adhesive.

Preferably, the deposition layer has a surface layer and a lower layer.

Preferably, the exposed deposition layer is a TiC layer.

Preferably, a total thickness Tt of the deposition layer is 0.5 μm or greater and 3.0 μm or less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head of a first embodiment of the present invention;

FIG. 2 is a front view of the head of FIG. 1;

FIG. 3 is a cross sectional view taken along line F3-F3 of FIG. 2;

FIG. 4 is an enlarged cross sectional view in a face surface;

FIG. 5 is an enlarged view in a circle F5 of FIG. 2;

FIG. 6 is an enlarged cross sectional view in a face surface of a head according to a second embodiment; and

FIG. 7 is an enlarged cross sectional view in a face surface of a head according to a third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate references to the accompanying drawings.

As shown in FIGS. 1 to 3, a head 2 is an iron type golf club head. The head 2 has a face 4, a hosel 6, and a sole 8. The hosel 6 has a hosel hole 10. A face groove gv is formed in the surface of the face 4. The description of the face groove gv is omitted in FIG. 3.

The central part of the face 4 is subjected to shot blast processing. All the face grooves gv are located in a region R5 subjected to the shot blast processing. A region Rn which is not subjected to the shot blast processing exists in each of the toe side and the heel side of the face 4. A symbol b1 represents a boundary line of the region R5 and the region Rn.

The head 2 has a head body h1 as a first member and a face plate p1 as a second member. The head body h1 (first member) is a metal. The material of the head body h1 is stainless steel. The face plate p1 (second member) is a metal. The material of the face plate p1 is a titanium alloy. The head 2 is a cavity back iron. The shape of the head 2 is not restricted.

The head body h1 has a face opening. The contour of the face opening is substantially equal to that of the face plate p1. The face plate p1 is fitted into the face opening (see FIG. 3). The face plate p1 constitutes most of the face 4. All the face grooves gv are formed in the face plate p1. In FIG. 2, a boundary k1 of the face plate p1 and the head body h1 is illustrated. The boundary k1 is hardly noticeable in an actual head. Therefore, the description of the boundary k1 is omitted in FIG. 1.

In the face 4, the face plate p1 and the head body h1 constitute the same plane PL1. The plane PL1 is a face surface. The boundary k1 is located on the plane PL1.

The face 4 is subjected to surface processing. The whole face 4 is subjected to the surface processing. The surface processing is deposition. In the embodiment, PVD is employed as the deposition.

In the embodiment, the shot blast processing is performed after deposition processing. The deposition processing may be performed after the shot blast processing.

The face groove gv is formed by cutting processing. Specifically, the face groove gv is processed by a cutter. The processing is NC processing. NC stands for “Numerical Control”. After the face groove gv is formed, the deposition processing is performed. Therefore, the surface of the face groove gv (including the bottom surface of the face groove gv) is also subjected to the deposition processing.

As shown in FIG. 2, the heel side end of the face plate p1 is substantially disposed along a boundary line b1. On the other hand, the toe side end of the face plate p1 is substantially disposed along the contour of the head 2. The face plate p1 has the region R5 and the region Rn. The toe side portion of the face plate p1 is the region Rn. The face plate p1 has the boundary line b1.

The surface of the face 4 is a plane. The whole plane portion is subjected to the deposition. The region subjected to the deposition includes the boundary k1.

Examples of the deposition include PVD (physical vapor deposition method) and CVD (chemical vapor deposition method). Examples of the PVD include vacuum deposition, sputtering, ion plating, ion beam deposition, and ion implantation deposition. Examples of the CVD include plasma CVD, laser excitation CVD, and light excitation CVD. In respect of a pressure in a chamber in which a chemical reaction is performed, examples of the CVD include normal pressure CVD and low-pressure CVD. The deposition can be executed in known facilities.

Examples of a substance to be deposited include TiC, TiN, TiAlN, TiCN, CrN, Zr, ZrN, SiC, Al₂O₃, BN, SiO₂, TiO₂, ZrO₂, and MgF₂. DLC (diamond like carbon) may be used. These are known as a substance to be deposited.

FIG. 4 is a cross sectional view of the vicinity of the surface of the head 2. A surface layer Ls is formed on the surface of the face 4. The surface layer Ls is a deposition layer. The surface layer Ls is formed by the PVD. The surface layer Ls is an exposed deposition layer.

In the embodiment, TiC (titanium carbide) is used. That is, the surface layer Ls is a TiC layer. The TiC exhibits a black color.

FIG. 5 is an enlarged view in a circle represented by F5 in FIG. 2. An appearance defect part fa is represented by a two-dot chain line in FIG. 5. The appearance defect part fa is observed in a head to which the present invention is not applied. The appearance defect part fa forms a color difference capable of being visually recognized as compared with the surrounding portion. The appearance defect part fa can be visually recognized. The appearance defect part fa reduces a product value. When the appearance defect part fa occurs, the deposition processing needs to be redone (modified). In the embodiment, the appearance defect part fa hardly occurs. Even when the appearance defect part fa occurs, the deposition processing can be modified (redone).

Many tests are performed in order to eliminate the appearance defect part fa. As a result, it is found that a condition in the deposition process can change the rate of occurrence of the appearance defect part fa. Particularly, it is found that a temperature Tp in the deposition process contributes to the suppression of the appearance defect part fa.

In respect of suppressing the appearance defect part fa, the temperature Tp is preferably equal to or less than 150° C., more preferably equal to or less than 140° C., still more preferably equal to or less than 130° C., and yet still more preferably equal to or less than 120° C. When the temperature Tp is too low, the deposition may become difficult or the adhesiveness may be reduced. In this respect, the temperature Tp is preferably equal to or greater than 90° C., and more preferably equal to or greater than 100° C. When a plurality of deposition layers is present, the temperature Tp preferably satisfies these preferred temperature ranges in all the deposition processes.

The processing temperature Tp is conventionally a normal temperature, i.e., about 300° C. in the PVD processing of the head. An integral-structured head including a face and a body causes no problem at the processing temperature. However, it is found that a problem of an appearance defect is caused when a boundary of a plurality of members exists. The appearance defect part fa is consequently decreased by lowering the temperature Tp.

The details of the occurrence cause of the appearance defect part fa are unclear. However, the occurrence cause can be guessed by analyzing results of examples to be described later. One of the causes capable of being guessed is that a substance (hereinafter, also referred to as an inhibitor Pt) inhibiting the deposition exists in the boundary k1. Examples of the inhibitor Pt include an adhesive, cutting oil, and putty. The adhesive is used to join the face plate p1 and the head body h1. The cutting oil is used when the face groove gv is formed by cutting processing. The putty can be used to prevent the cutting oil from entering the boundary k1. It is consider that a failure is caused in the deposition because these inhibitors Pt remain. Particularly, the adhesive is apt to flow at a high temperature. Therefore, the adhesive may flow out during high temperature processing.

The putty is a padding material, and is used to fill up recesses, cracks and holes or the like. Examples of the putty include an epoxy putty, a polyester putty, a plaster putty, and a calcium carbonate putty.

The adhesive is not restricted. Examples of the adhesive include an acrylic adhesive, an epoxy adhesive, and an urethane adhesive. In respect of joining strength, the epoxy adhesive is preferable. In respect of heat resistance, the urethane adhesive is preferable. When the temperature Tp in the deposition process is lowered as described later, the deterioration of the adhesive caused by heat is suppressed. Therefore, when the temperature Tp is low, even an adhesive having comparatively low heat resistance can be used. In this respect, an epoxy adhesive having low heat resistance and an excellent adhesive force can be preferably used. When the temperature Tp is low, the degree of freedom of selection of the adhesive is improved. When the temperature Tp is low, the adhesive is hardly deteriorated, thereby maintaining the adhesiveness. Therefore, the face plate p1 is surely fixed.

In the head 2, the number of the deposition layers is 1. The number of the deposition layers may be 1, 2, or equal to or greater than 3. Hereinafter, an example in which the number of the deposition layers is 2 will be described.

FIG. 6 is an enlarged cross sectional view of a face 22 in a head 20 according to a second embodiment. The head 20 is the same as the head 2 of the first embodiment except that the number of the deposition layers is 2.

In the head 20, the number of the deposition layers is plural. In the head 20, the number of the deposition layers is 2. A surface layer Ls and a second layer Lg are deposition layers. The surface layer Ls and the second layer Lg are formed by PVD. The surface layer Ls is a TiC layer. The second layer Lg is a CrN (chromium nitride) layer.

The second layer Lg is an example of a lower layer. The lower layer is a layer inside the surface layer Ls. The number of the lower layers may be 1, or, may be equal to or greater than 2. The lower layer (second layer Lg) is brought into contact with a material (metal material). The material is the face plate p1 or the head body h1.

As described above, the TiC layer exhibits a black color. Therefore, the face 22 of the head 20 exhibits a black color as in the head 2. When the TiC layer is removed by abrasion, the CrN layer is exposed. The CrN layer exhibits a glossy metal color.

It is found that the CrN layer is effective in maintaining appearance. When the TiC layer is removed in the case of the head 2, the metal material of the head body h1 or the face plate p1 is exposed. It is found that the appearance is apt to be reduced when the metal material is exposed. When the TiC layer is removed by the use of the head 2 in a bunker or the like, the removing trace looks like many flaws. The trace looking like the flaws impairs the appearance. The trace gives a negative impression that the surface processing is removed to a user. The TiC layer is black, and a portion in which the black is lost is conspicuous.

It is found that the removing trace is inconspicious when the CrN layer exists. The details of the reason are unclear. The reason to be guessed is that the degree of smoothness of the surface of an exposed part when the CrN layer exists is increased as compared with the case where the metal material is exposed. It is considered that the appearance of the surface is improved when the degree of smoothness is high, and the removing trace is inconspicious. When the degree of smoothness is high, a negative impression that the surface processing is removed hardly arises.

FIG. 7 is an enlarged cross sectional view of a face 32 in a head 30 according to a third embodiment. The head 30 is the same as the head 2 of the first embodiment except that the number of the deposition layers is 2.

In the head 30, the number of the deposition layers is plural. In the head 30, the number of the deposition layers is 2. A surface layer Ls and a second layer Lg are deposition layers. The surface layer Ls and the second layer Lg is formed by PVD. The surface layer Ls is a TiC layer. A second layer Lg is a Zr (zirconium) layer.

As described above, the TiC layer exhibits a black color. Therefore, the face 32 of the head 30 exhibits a black color as in the head 2. When the TiC layer is removed by abrasion, the Zr layer is exposed. The Zr layer exhibits a glossy metal color.

It is found that the Zr layer is effective in maintaining appearance. When the TiC layer is removed in the case of the head 2, the metal material of the head body h1 or the face plate p1 is exposed. It is found that the appearance is apt to be reduced when the metal material is exposed. When the TiC layer is removed by the use of the head 2 in a bunker or the like, the removing trace looks like many flaws. The removing trace impairs the appearance. The trace gives a negative impression that the surface processing layer is removed to a user. The TiC layer is black, and a portion in which the black is lost is conspicuous.

It is found that the removing trace is inconspicious when the Zr layer exists. The details of the reason are unclear. The reason to be guessed is that the degree of smoothness of the surface of an exposed part when the Zr layer exists is increased as compared with the case where the metal material is exposed. It is considered that the appearance of the surface is improved when the degree of smoothness is high, and the removing trace is inconspicious.

As shown in the head 20 and the head 30, it is found that the existence of a second deposition layer under the surface layer improves the appearance when the surface layer is removed. The color of the metal material (stainless steel and a titanium alloy or the like) resembles that of the second layer. Therefore, it seems that the appearance when the surface layer is removed is not changed depending on the existence or non-existence of the second layer. However, in fact, it is found that the existence of the second layer improves the appearance during the abrasion of the surface layer. This was unexpected for those skilled in the art.

As shown in examples to be described later, the deposition process is modified in the head 2, the head 20, and the head 30. As a result, in the head 2 and the head 20, it is found that a success rate Sr of the modification of the deposition process is low. On the other hand, it is found that the success rate Sr is high in the head 30.

In the modification of the deposition process, a removing process is first performed. A remover is used in the removing process. Preferred examples of the remover include H₂O₂ (hydrogen peroxide). Next, a redeposition process is performed. The redeposition process is the same as the original deposition process. As described later, it is estimated to difficult to completely remove CrN using H₂O₂.

The reason why the success rate Sr is high in the head 30 is discussed. When the deposition layer tends to be removed by the remover, it is considered that the success rate Sr is high. When the deposition layer is hardly removed by the remover, it is considered that the success rate Sr is low. When the deposition layer remains in the removing process, it is guessed that the remaining deposition layer causes the defect of the redeposition.

In respect of improving the success rate Sr, the deposition layer below the surface layer Ls preferably has higher removability caused by the remover than that of the surface layer. Examples of the remover include hydrogen peroxide and sodium hydroxide. Preferred examples of the remover include the hydrogen peroxide. Although the sodium hydroxide (NaOH) is also tried, the corrosion of the face material is caused.

In respect of durability, the total thickness Tt of the deposition layer is preferably equal to or greater than 0.5 μm, and more preferably equal to or greater than 1.0 μm. When the thickness Tt is excessive, the removal is apt to be caused. In respect of suppression of the removal and ease of the modification, the total thickness Tt of the deposition layer is preferably equal to or less than 3.0 and more preferably equal to or less than 2.5 μm.

In respect of durability, the thickness of the TiC layer is preferably equal to or greater than 0.3 μm, and more preferably equal to or greater than 0.8 μm. In respect of suppression of the removal and ease of the modification, the thickness of the TiC layer is preferably equal to or less than 2.6 μm, and more preferably equal to or less than 2.1 μm.

In respect of making the removal of the surface layer inconspicuous, the thickness T2 of the lower layer is preferably equal to or greater than 0.1 μm, and more preferably equal to or greater than 0.2 μm. In respect of suppression of the removal and ease of the modification, the thickness T2 of the lower layer is preferably equal to or less than 0.5 μm, and more preferably equal to or less than 0.4 μm. The lower layer means a portion except the surface layer in the deposition layer.

A time Tm required for the deposition process can be set so that the thickness of the deposition layer is suitable.

EXAMPLES

Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be interpreted in a limited way based on the description of the examples.

Tests A, B, and C were executed. In the test A, only TiC was used for a deposition layer. In the test B, TiC (first layer) and CrN (second layer) were used for the deposition layer. In the test C, TiC (first layer) and Zr (second layer) were used for the deposition layer. The results of the test A are shown in following Tables 1 and 2. The results of the test B are shown in the following Table 3. The results of the test C are shown in the following Table 4.

[Test A]

Example 1a

The same head as the head 2 was produced. A face groove gv of a face plate p1 was formed by cutting processing (NC processing). Cutting oil was used during the NC processing. The face plate p1 was press-fitted into an opening of a head body h1. Fitting caused by press-fitting was used in combination with an adhesive to fix the face plate p1. The face plate p1 was joined to the head body h1 by the adhesive. “EW2010” (trade name) manufactured by Sumitomo 3M Limited was used as the adhesive. A face surface was washed before a deposition process. An organic solvent was used for the washing. Specifically, the washing was a wiping process. In the wiping process, the face surface was wiped by a cloth including the organic solvent. The deposition process was performed after the washing. The kind of the deposition was PVD. PVD processing was executed under known conditions such as a vacuum condition. The deposition layer was TiC. In the deposition process, a processing temperature Tp was 150° C. A time Tm required for the deposition was 80 minutes. Specifications and evaluation results of example 1a are shown in the following Table 1.

Examples 2a to 14a

Heads of examples 2a to 14a were obtained in the same manner as in the example 1a except for specifications shown in Table 1. These specifications and evaluation results are shown in the following Table 1. In the example 8a, water was used in place of the solvent in the washing. In the example 9a, the adhesive was not used.

Comparative Examples 1a to 5a

Heads of comparative examples 1a to 5a were obtained in the same manner as in the example 1a except for specifications shown in Table 2. These specifications and evaluation results are shown in the following Table 2.

TABLE 1
Specifications and evaluation results of test A (Examples)
		Example	Example	Example	Example	Example	Example	Example
		1a	2a	3a	4a	5a	6a	7a
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	—	—	—	—	—	—	—
Surface	Temperature Tp	150	140	130	120	110	100	90
layer	(° C.)
	Time Tm	80	80	80	80	80	80	80
	(minute)
	Thickness T1	1.2	1.2	1.2	1.2	1.2	1.2	1.2
	(μm)
Lower	Temperature Tp	—	—	—	—	—	—	—
layer	(° C.)
	Time Tm	—	—	—	—	—	—	—
	(minute)
	Thickness T2	—	—	—	—	—	—	—
	(μm)
Total thickness Tt of	1.2	1.2	1.2	1.2	1.2	1.2	1.2
deposition layer (μm)
Adhesive	Use	Use	Use	Use	Use	Use	Use
Washing process	Solvent	Solvent	Solvent	Solvent	Solvent	Solvent	Solvent
Appearance defect ratio	B	B	B	A	A	A	B
Modification evaluation	B	B	B	B	B	B	B
Bunker endurance test	B	B	B	B	B	B	B
		Example	Example	Example	Example	Example	Example	Example
		8a	9a	10a	11a	12a	13a	14a
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	—	—	—	—	—	—	—
Surface	Temperature Tp	110	110	110	110	110	110	110
layer	(° C.)
	Time Tm	80	80	110	50	200	140	210
	(minute)
	Thickness T1	1.2	1.2	1.9	0.7	3.0	2.6	3.2
	(μm)
Lower	Temperature Tp	—	—	—	—	—	—	—
layer	(° C.)
	Time Tm	—	—	—	—	—	—	—
	(minute)
	Thickness T2	—	—	—	—	—	—	—
	(μm)
Total thickness Tt of	1.2	1.2	1.9	0.7	3.0	2.6	3.2
deposition layer (μm)
Adhesive	Use	Nonuse	Use	Use	Use	Use	Use
Washing process	Water	Solvent	Solvent	Solvent	Solvent	Solvent	Solvent
Appearance defect ratio	B	A	A	A	A	A	A
Modification evaluation	B	B	B	B	B	B	C
Bunker endurance test	B	B	B	B	B	B	C

TABLE 2
Specifications and evaluation results of test A (Comparative Examples)
	Comparative	Comparative	Comparative	Comparative	Comparative
	Example	Example	Example	Example	Example
	1a	2a	3a	4a	5a
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	—	—	—	—	—
Surface	Temperature Tp	300	200	170	300	300
layer	(° C.)
	Time Tm	80	80	80	80	80
	(minute)
	Thickness T1	1.2	1.2	1.2	1.2	1.2
	(μm)
Lower layer	Temperature Tp	—	—	—	—	—
	(° C.)
	Time Tm	—	—	—	—	—
	(minute)
	Thickness T2	—	—	—	—	—
	(μm)
Total thickness Tt of	1.2	1.2	1.2	1.2	1.2
deposition layer (μm)
Adhesive	Use	Use	Use	Nonuse	Use
Washing process	Solvent	Solvent	Solvent	Water	Water
Appearance defect ratio	D	D	D	B	E
Modification evaluation	C	C	C	C	C
Bunker endurance test	B	B	B	B	B

[Test B]

Example 1b

The same head as the head 20 was produced. A head of example 1b was obtained in the same manner as in the example 1a except that CrN was formed as a lower layer (second layer) and specifications of each layer were shown in Table 3. Specifications and evaluation results of the example 1b are shown in the following Table 3.

Examples 2b to 10b and Comparative Examples 1b to 4b

Heads of examples 2b to 10b and comparative examples 1b to 4b were obtained in the same manner as in the example 1b except for specifications shown in Table 3. These specifications and evaluation results are shown in the following Table 3.

TABLE 3
Specifications and evaluation results of test B
		Example	Example	Example	Example	Example	Example	Example	Example
		1b	2b	3b	4b	5b	6b	7b	8b
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	CrN	CrN	CrN	CrN	CrN	CrN	CrN	CrN
Surface	Temperature Tp	110	110	110	110	110	110	110	110
layer	(° C.)
	Time Tm	80	80	80	80	80	110	20	150
	(minute)
	Thickness T1	1.2	1.2	1.2	1.2	1.2	1.9	0.25	2.7
	(μm)
Lower	Temperature Tp	110	110	110	110	110	110	110	110
layer	(° C.)
	Time Tm	3	6	15	60	6	6	3	6
	(minute)
	Thickness T2	0.15	0.3	0.4	1.2	0.3	0.3	0.15	0.3
	(μm)
Total thickness Tt of	1.35	1.5	1.5	1.6	1.5	2.2	0.4	3.0
deposition layer (μm)
Adhesive	Use	Use	Use	Use	Use	Use	Use	Use
Washing process	Solvent	Solvent	Solvent	Solvent	Water	Solvent	Solvent	Solvent
Appearance defect ratio	A	A	A	A	C	A	A	A
Modification evaluation	C	C	C	C	C	C	C	C
Bunker endurance test	A	A	A	A	A	A	C	A
					Comparative	Comparative	Comparative	Comparative
			Example	Example	Example	Example	Example	Example
			9b	10b	1b	2b	3b	4b
	Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC
	substance	Lower layer	CrN	CrN	CrN	CrN	CrN	CrN
	Surface	Temperature Tp	110	110	300	200	170	110
	layer	(° C.)
		Time Tm	160	130	80	80	80	80
		(minute)
		Thickness T1	2.9	2.3	1.2	1.2	1.2	1.2
		(μm)
	Lower	Temperature Tp	110	110	110	110	110	170
	layer	(° C.)
		Time Tm	6	6	6	6	6	6
		(minute)
		Thickness T2	0.3	0.3	0.3	0.3	0.3	0.3
		(μm)
	Total thickness Tt of	3.2	2.6	1.5	1.5	1.5	1.5
	deposition layer (μm)
	Adhesive	Use	Use	Use	Use	Use	Use
	Washing process	Solvent	Solvent	Solvent	Solvent	Solvent	Solvent
	Appearance defect ratio	A	A	D	D	D	D
	Modification evaluation	C	C	C	C	C	C
	Bunker endurance test	C	A	A	A	A	A

[Test C]

Example 1c

The same head as the head 30 was produced. A head of example 1c was obtained in the same manner as in the example 1a except that Zr was formed as a lower layer (second layer) and specifications of each layer were shown in Table 4. Specifications and evaluation results of the example 1c are shown in the following Table 4.

Examples 2c to 9c and Comparative Examples 1c to 4c

Heads of examples 2c to 9c and comparative examples 1c to 4c were obtained in the same manner as in the example 1c except for specifications shown in Table 4. These specifications and evaluation results are shown in the following Table 4.

TABLE 4
Specifications and evaluation results of test C
		Example	Example	Example	Example	Example	Example	Example
		1c	2c	3c	4c	5c	6c	7c
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	Zr	Zr	Zr	Zr	Zr	Zr	Zr
Surface	Temperature Tp	110	110	110	110	110	110	110
layer	(° C.)
	Time Tm	80	80	80	80	80	110	180
	(minute)
	Thickness T1	1.2	1.2	1.2	1.2	1.2	1.9	2.8
	(μm)
Lower	Temperature Tp	110	110	110	110	110	110	110
layer	(° C.)
	Time Tm	6	8	10	15	6	6	6
	(minute)
	Thickness T2	0.2	0.3	0.4	0.6	0.2	0.2	0.2
	(μm)
Total thickness Tt of	1.4	1.5	1.6	1.8	1.4	2.1	3.0
deposition layer (μm)
Adhesive	Use	Use	Use	Use	Use	Use	Use
Washing process	Solvent	Solvent	Solvent	Solvent	Water	Solvent	Solvent
Appearance defect ratio	A	A	A	A	C	A	A
Modification evaluation	A	A	A	A	A	A	A
Bunker endurance test	A	A	A	C	A	A	A
				Comparative	Comparative	Comparative	Comparative
		Example		Example	Example	Example	Example
		8c	Example 9c	1c	2c	3c	4c
Deposition	Surface layer	TiC	TiC	TiC	TiC	TiC	TiC
substance	Lower layer	Zr	Zr	Zr	Zr	Zr	Zr
Surface	Temperature Tp	110	110	300	200	170	110
layer	(° C.)
	Time Tm	190	135	80	80	80	80
	(minute)
	Thickness T1	3.0	2.4	1.2	1.2	1.2	1.2
	(μm)
Lower	Temperature Tp	110	110	110	110	110	170
layer	(° C.)
	Time Tm	6	6	6	6	6	6
	(minute)
	Thickness T2	0.2	0.2	0.2	0.2	0.2	0.2
	(μm)
Total thickness Tt of	3.2	2.6	1.4	1.4	1.4	1.4
deposition layer (μm)
Adhesive	Use	Use	Use	Use	Use	Use
Washing process	Solvent	Solvent	Solvent	Solvent	Solvent	Solvent
Appearance defect ratio	A	A	D	D	D	D
Modification evaluation	C	A	A	A	A	A
Bunker endurance test	C	A	A	A	A	A

Valuation methods are as follows.

[Appearance Defect Ratio]

Ten heads were produced for each of the examples and the comparative examples. An appearance defect part fa near a boundary k1 was visually confirmed. The head in which the appearance defect part fa was visually recognized was determined to be defective. The appearance defect ratio was evaluated at five stages in accordance with the following standard:

A: a defect ratio equal to or less than 20%;

B: a defect ratio greater than 20% and equal to or less than 40%;

C: a defect ratio greater than 40% and equal to or less than 60%;

D: a defect ratio greater than 60% and equal to or less than 80%;

E: a defect ratio greater than 80%.

[Modification Evaluation]

The deposition process was modified (redone) for all the heads. A removing process and a redeposition process were executed. In the removing process, a hydrogen peroxide solution was used as a remover. Next, the redeposition process was performed in the same manner as in the original deposition process to which the head was subjected. Then, an appearance defect was visually confirmed. The appearance defect was evaluated at three stages in accordance with the following standard:

A: a defect ratio equal to or less than 10%;

B: a defect ratio greater than 10% and equal to or less than 50%;

C: a defect ratio greater than 50%.

[Bunker Endurance Test]

A shaft and a grip were attached to each of the heads of each of the examples and the comparative examples to produce a golf club. A bunkershot was performed 40 times, and a state of a sole was quantitatively evaluated by image processing (binarization). The golf club was evaluated at three stages in accordance with the following standard:

A: removal of TiC (black) and flaws of the sole are not so conspicuous;

B: removal of TiC (black) and flaws of the sole are slightly conspicuous; and

C: removal of TiC (black) and flaws of the sole are conspicuous.

The evaluation results of Tables 1 to 4 are analyzed as follows.

[Test A]

In the examples 1a to 14a, the appearance defect ratio is low. This is considered to be because the temperature Tp in the deposition process is low. In the examples 4a to 6a having a lower temperature Tp, the appearance defect ratio is lower. These results suggest that the adhesive acts as an inhibitor Pt.

In the example 8a, not a solvent but water is used in the washing process. The appearance defect ratio of the example 8a is slightly lower than that of the example 5a. For this reason, the remaining of the inhibitor Pt is estimated to contribute to the occurrence of the appearance defect part fa.

In the example 9a, the adhesive is not used, and the appearance defect ratio is low. In the example 10a, the time Tm (T1) is lengthened and a thickness Tt is thickened.

In the examples 1a to 13a, the modification evaluation was good. It is considered to be because TiC is almost perfectly eliminated by the remover. Since the thickness Tt was thick in the example 14a, the modification evaluation was inferior.

In the comparative examples 1a to 3a and 5a the appearance defect ratio is deteriorated. This is considered to be because the temperature Tp is high. This result suggests that the adhesive acts as the inhibitor Pt.

The comparative example 4a has a comparatively good appearance defect ratio. In the comparative example 4a, the adhesive is not used. This result suggests that the adhesive acts as the inhibitor Pt.

In the examples 1a to 13a, the result of the bunker endurance test is not good. This is considered to be because the exposure of the metal material (head body h1) reduces the appearance. Since the thickness Tt was too thick in the example 14a, the bunker endurance test was deteriorated.

[Test B]

In the examples 1b to 10b (except for the example 5b), the appearance defect ratio is good. This is considered to be because the temperature Tp is low. This result suggests that the adhesive acts as the inhibitor Pt.

In the example 5b, water is used in the washing process. The appearance defect ratio of the example 5b is lower than that of the example 2b. For this reason, the remaining of the inhibitor Pt is estimated to contribute to the occurrence of the appearance defect part fa.

In the examples 1b to 10b, the modification evaluation is not good. This is considered to be because CrN is not completely removed by the remover and the redeposition is nonuniformed by the remaining CrN.

In the comparative examples 1b to 4b, the appearance defect ratio is deteriorated. This is considered to be because either temperature Tp is high. This result suggests that the adhesive acts as the inhibitor Pt.

In the examples 1b to 6b, the result of the bunker endurance test is good. This is considered to be because CrN as a base improves the appearance.

In the example 7b, the total thickness Tt of the deposition layer is thin. Therefore, in the bunker endurance test, TiC and CrN were removed, and the metal material (head body h1) was exposed.

[Test C]

In the examples 1c and 9c (except for the example 5c), the appearance defect ratio is good. This is considered to be because the temperature Tp is low. This result suggests that the adhesive acts as the inhibitor Pt.

In the example 5c, water is used in the washing process. The appearance defect ratio of the example 5c is lower than that of the example 1c. For this reason, the remaining of the inhibitor Pt is estimated to contribute to the occurrence of the appearance defect part fa.

In the examples 1c to 9c (except for the example 8c), the modification evaluation is good. This is considered to be because Zr tends to be removed by the remover. Since the thickness Tt was too thick in the example 8c, the modification evaluation was deteriorated.

In the example 4c, the result of the bunker endurance test is not good. When the thickness T2 of a Zr layer is large, a difference between hardness of a surface layer Ls (TiC layer) and hardness of the second layer Lg (Zr layer) is large. A difference between hardness of a head material and hardness of the second layer Lg is large. It is considered that distortion is apt to be caused in the second layer Lg (Zr layer). It is considered that the crack is apt to be caused based on the hardness difference and the distortion. In this respect, the thickness of the Zr layer is preferably equal to or less than 0.4 μm.

In the comparative examples 1c to 4c, the appearance defect ratio is deteriorated. This is considered to be because either temperature Tp is high. This result suggests that the adhesive acts as the inhibitor Pt. When a plurality of deposition layers is present, the temperature Tp is preferably low in all the deposition processes.

In the examples 1c to 9c (except for the examples 4c and 8c), the result of the bunker endurance test is good. This is considered to be because Zr as a base improves the appearance.

Because the total thickness Tt is thick in the examples 14a, 9b, and 8c, the result of the bunker endurance test is not good. It is considered that the removal is apt to be caused even when the total thickness Tt is too thick.

As described above, the examples are highly evaluated as compared with the comparative examples. From the results, the advantages of the present invention are apparent.

The present invention can be applied to all golf club heads such as a wood type head, a utility type head, a hybrid type head, an iron type head, and a putter head.

The description hereinabove is merely for an illustrative example, and various modifications can be made in the scope not to depart from the principles of the present invention.

Claims

1. A golf club head comprising:

a first member; and

a second member,

wherein a boundary of the first member and the second member exists on a surface of the head;

a deposition layer is formed in a region including the boundary on the surface of the head; and

a temperature Tp in a deposition process is equal to or less than 150° C.

2. The golf club head according to claim 1, wherein the deposition layer is formed by PVD.

3. The golf club head according to claim 1, wherein the first member and the second member are stuck with an adhesive.

4. The golf club head according to claim 1, wherein the deposition layer has a surface layer and a lower layer.

5. The golf club head according to claim 1, wherein the exposed deposition layer is a TiC layer.

6. The golf club head according to claim 1, wherein a total thickness Tt of the deposition layer is 0.5 μm or greater and 3.0 μm or less.

7. The golf club head according to claim 5, wherein a thickness of the TiC layer is 0.3 μm or greater and 2.6 μm or less.

8. The golf club head according to claim 4, wherein a thickness of the lower layer is 0.1 μm or greater and 0.5 μm or less.

9. The golf club head according to claim 1, wherein the deposition layer has a surface layer and a second layer;

the surface layer is a TiC layer; and

the second layer is a CrN layer.

10. The golf club head according to claim 1, wherein the deposition layer has a surface layer and a second layer;

the surface layer is a TiC layer; and

the second layer is a Zr layer.

11. The golf club head according to claim 1, wherein the deposition layer has a surface layer and a lower layer; and

the lower layer has higher removability than that of the surface layer, the removability caused by hydrogen peroxide.