JP5280675B2 - Surface modification method and coated body - Google Patents

Description

  The present invention relates to a surface modification method using a laser and a covering used therefor.

  The present inventor does not directly irradiate the surface of the workpiece with a pulsed laser having a high peak power density, but covers the surface to be processed with a laser absorption enhancing coating, and short pulse high peak from above the laser absorption enhancing coating. Proposed a laser peening method that can irradiate the output laser to form a fine concavity due to the shock wave of laser peening on the surface to be processed, or to drive particles such as solid lubricant onto the surface to be processed ( Patent Document 1).

  However, in this laser peening method, since the base sheet of the laser absorption enhancement film is made of a resin film or a metal thin film, the base sheet is plastically deformed by laser irradiation, and the impact force due to the generation of plasma is efficiently applied to the work surface. There was a case that could not be done. For example, a sufficient compressive residual stress could not be applied by a peening process such as a weld toe. In addition, for example, when a hard solid lubricant such as metal carbide or ceramic is driven into the sliding surface of a sliding member made of steel using an aluminum foil as a base sheet, the solid lubricant is stably applied to the sliding surface. It could not be buried.

Moreover, in this prior art, since a desired three-dimensional shape cannot be formed on the surface to be processed, there is a problem that the application range is restricted.
JP 2007-169753 A

  The present invention has been made in order to solve the above-mentioned problems, and it is possible to efficiently apply an impact force generated by plasma generation to a surface to be processed and to impart a desired function to the surface to be processed. It is an object of the present invention to provide a quality method and a coated body used therefor.

Surface modification method of the present invention comprises a plasma generation layer that generates plasma by absorbing laser over the surface to be processed of the workpiece, have a flat or concave-convex shape on one surface, higher than the plasma generation layer Covering with a coating body having a hard layer having hardness, irradiating the plasma generation layer of the coating body with a laser of short pulse high peak output, and forming the uneven surface of the hard layer on the work surface by a shock wave of laser peening It is characterized by being pressure-molded.

  According to the surface modification method of the present invention, the covering covering the workpiece surface is integrally provided with the plasma generation layer and the hard layer, so that the impact force associated with the plasma generation is effective through the hard layer. Can be applied to the work surface. And since the predetermined uneven | corrugated shape is formed in the workpiece opposing surface of a hard layer, the to-be-processed surface is plastically deformed and pressure-molded to this uneven shape. By this pressure molding, surface modification such as refinement of crystals and elimination of minute surface defects can be performed on the work surface. Further, high compressive residual stress can be effectively applied to the work surface.

  In the surface modification method of the present invention, before the laser is irradiated, a fixed object that adheres to the surface to be processed and imparts a desired function to the surface to be processed may be disposed between the covering and the surface to be processed. desirable. A fixed object disposed between the covering and the processing surface is embedded in the processing surface by a shock wave of laser peening. At this time, the surface to be processed is pressure-molded into the concavo-convex shape of the hard layer, so that the fixed object can be three-dimensionally arranged on the surface to be processed. By arranging the fixed object on the processing surface in a three-dimensional manner, it is possible to obtain a processing surface that effectively exhibits a desired function.

  In the surface modification method of the present invention, the covering may be made of a plate-shaped or strip-shaped steel material, and may have a hard layer formed by a hardening process on one surface side of the steel material. The covering according to the present invention includes a plasma generation layer and a hard layer. The plasma generation layer needs to absorb the laser to generate plasma, and to have strength and ductility that do not break due to shock waves. For this reason, the steel material is suitable because it has a suitable strength and ductility, and is a material that easily absorbs a laser to become plasma. In addition, a hardened layer can be easily formed by a known hardening process such as quenching, carburizing, nitriding / nitriding, hard plating, hardening vapor deposition, and work hardening. Therefore, a steel material in which a concavo-convex shape is formed on one surface by a well-known method such as embossing or laser processing, and the above-described hardening treatment is performed on the one surface side is suitable as a coating body according to the present invention.

  Further, the covering is formed by joining a plasma generation layer made of any one of plate-like or band-like metal, metal compound, resin, and synthetic rubber and a hard layer made of a material having a hardness higher than that of the plasma generation layer. It is good also as a laminated body. Depending on the thickness of the coated body, pressure molding and embedding of a fixed object may be insufficient in a cured layer obtained by curing one surface as described above. In such a case, the plasma generating layer and the hard layer may be made of different materials and bonded together to form a coating.

  In the surface modification method of the present invention, the fixed matter can be a metal, an alloy, a metal compound, a resin, or a ceramic powder. By embedding these granular materials having various functions in the processing surface, the respective functions can be imparted to the processing surface.

Further, the fixed object may be a micro component such as an IC chip, a semiconductor, a microchip, an optical element, and a micromachine. Conventionally, these micro components have been mounted on a substrate such as an electronic circuit by a method such as brazing or bonding. However, by applying the surface modification method of the present invention using a covering, the microcomponent can be easily mounted on a desired mounting surface in the same manner as the powder and granular material.

  The hardness of the hard layer is desirably HV150 or more in order to firmly fix the above powdery particles and micro parts.

  In the surface modification method of the present invention, before irradiating the laser, one or more of heat treatment, plating treatment, metal spraying treatment, build-up treatment, and vapor deposition treatment is performed on the work surface of the work piece in advance. It is desirable to apply. By subjecting the work piece to these treatments and forming a soft layer in advance on the work surface, the work surface can be pressure-formed more reliably and the fixed object can be embedded more reliably. be able to.

  In addition, it is desirable to form a periodic fine structure or a fine groove in advance on the work surface of the work piece before irradiating the laser. It is preferable to apply a polyamide or acrylic adhesive and / or a mixture of the adhesive and a fixed substance.

  By having such a fine structure or groove on the surface to be processed, it is possible to accurately embed fine powder particles. Further, by applying an adhesive and / or a mixture of these adhesives and a fixed substance, a solid lubricant such as molybdenum disulfide can be firmly held on the sliding surface.

The covering of the present invention is a covering of a work piece that indirectly irradiates a work piece by irradiating a laser, and a plasma generation layer that absorbs the laser to generate plasma, and the work piece of irregularities possess the opposing surface, characterized by comprising integrally the hard layer is a higher hardness than the plasma generation layer.

  According to the present invention, various functions can be imparted to the surface to be processed by appropriately selecting the uneven shape and the fixed object on the surface of the covering. In addition, a micro component such as an IC chip can be easily mounted on a predetermined substrate.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an explanatory diagram showing an outline of the first embodiment, in which 10 is a workpiece, 20 is a covering that covers the surface to be processed, 30 is a laser emitting portion, and 31 is a condensing lens.

  First, the covering 20 according to the present embodiment will be described. The covering 20 includes a plasma generation layer 21 that generates a plasma by absorbing a laser, and a hard layer 22. Therefore, the coating body 20 can be configured by forming a hard layer 22 by performing an appropriate curing process on one side of a plate-like or strip-like metal that is easily converted to plasma by laser irradiation. For example, when the covering is a steel sheet, the hard layer 22 is formed by performing hardening treatment such as quenching, carburizing, or carburizing / nitriding on one surface. That is, the hardened layer, the carburized layer, or the nitriding / nitriding layer of the steel sheet is the hard layer 22, and the untreated portion of the steel sheet is the plasma generation layer 21. Further, when the cover 20 is an aluminum sheet, the hard layer 22 may be formed by applying an aging treatment or a hard anodizing treatment to one surface thereof.

  The covering 20 is not limited to a single material having the two-layer structure as described above, but is a laminate in which the material of the plasma generation layer 21 and the material of the hard layer 22 are separated and joined together. You may comprise as a body. In this case, a material that is easily converted to plasma by laser irradiation is the plasma generation layer 21, and another material harder than the plasma generation layer 21 is the hard layer 22. For example, a low carbon steel sheet is used as the plasma generation layer 21, and a sheet-like carburized and hardened sheet formed by carburizing treatment is laminated as the hard layer 22 on the low carbon steel sheet and bonded with an adhesive or the like. It may be 20.

  A concave / convex shape 22 a composed of a concave portion 221 and a convex portion 222 is formed on the side of the covering 20 that faces the processed surface 10 a of the hard layer 22. An example of the uneven shape is shown in FIG. 2A and 2B are a perspective view and a schematic cross-sectional view of the cover 20 as viewed from the back surface (surface facing the surface to be processed). The irregular shape 22a may be a regular lattice shape as shown in (a) or an irregular shape as shown in (b). However, the depth d of the recess 221 is preferably 1 to 30 μm. If the depth d of the recess 221 is less than 1 μm, sufficient compressive residual stress cannot be applied to the surface to be processed, and formation of a deep concavo-convex shape exceeding 30 μm requires more than usual laser output, so Absent. More preferably, it is 3-10 micrometers. Such a concavo-convex shape can be formed by a known method such as embossing, laser processing, or rolling. The uneven shape may be formed before or after the curing process.

  The thickness of the covering 20 configured as described above is preferably 5 to 120 μm. If the thickness of the covering body 20 is less than 5 μm, the covering body 20 may be damaged due to the generation of plasma. On the other hand, if it exceeds 120 μm, the stress due to the shock wave may not be effectively transmitted to the work surface. So it is not appropriate. More preferably, it is 15-50 micrometers. Further, in order to effectively perform desired pressure molding on the surface 10a to be processed, 10 to 30% of the covering 20 thickness t may be the hard layer 22. If the hard layer 22 is less than 10% of the coating thickness t, the hard layer may break due to high plasma pressure, and effective pressure molding may not be possible. A thickness exceeding 30% is not preferable because the rigidity of the covering 20 is too high and the covering 20 cannot be deformed following the laser irradiation. Therefore, the thickness of the hard layer 20 is more preferably 10 to 20% of the covering 40.

  In order to absorb laser energy more effectively, a laser absorption enhancement layer in which graphite, black pigment, or the like is applied to the upper surface of the covering 20 (the surface of the plasma generation layer 21) may be formed.

Will now be described processing method for performing a desired pressing the treated surface 10a of the workpiece 10 with the covering body 20 configured as described above.

  First, the facility 20 is installed so that the surface 20a of the workpiece 10 is opposed to the concavo-convex surface 22a and the covering 20 is in close contact therewith.

Next, a laser having a short pulse high peak output with a pulse width of 1 to 50 ns and an output density of 1 [GW / cm ² ] to 50 [GW / cm ² ] is irradiated toward the covering 20. Specifically, a Qd Nd: YAG laser device is used, the pulse energy is 1.0 [mJ / pulse] to 2000 [mJ / pulse], the wavelength is 532 [nm] to 1080 [nm], and the laser power density 5 [GW / cm < ² >] to 15 [GW / cm < ² >] and a frequency laser set to several 1 [Hz] to several 1000 [Hz] are emitted toward the cover 20. At this time, a condensing lens 31 is provided in a laser condensing unit (not shown) or a laser emitting unit 30 in the laser device, and the laser irradiation diameter on the surface of the plasma generation layer 21 of the covering 20 is 0.1 mm or more. The laser is focused so as to be 6.0 mm.

  When the laser is emitted as described above, the laser L reaches the plasma generation layer 21 of the covering 20, and the plasma generation layer 21 is rapidly heated to a high temperature of 5000 [° C.] or more and explosively generates plasma. Occur. That is, part or all of the plasma generation layer 21 is turned into plasma, and particles such as atoms, molecules, ions, and electrons that are constituents of the plasma generation layer 21 are explosively emitted. Then, reaction force due to explosive release of these particle groups is applied as a shock wave from the hard layer 22 to the work surface 10a of the work piece 10. That is, for example, a reaction force of 1 [GPa] to 10 [GPa] (10,000 atm to 100,000 atm) acts on the work surface 10a. Since the hard layer 22 of the covering 20 facing the processing surface 10a has a concavo-convex shape 22a, the surface layer portion of the processing surface 10a is plastically deformed by the pressure generated by the plasma generation and is added to the concavo-convex shape 22a. It is pressure formed. Next, the covering 20 is scraped off from the workpiece 10 to obtain the workpiece 10 in which a desired uneven shape 22a is press-formed on the processing surface 10a.

  By applying the work surface that has been pressure-molded in this way to the sliding surface of the sliding member, the sliding contact portion (convex portion) and the oil sump (concave portion) are uniformly and easily spread over the entire sliding surface. Can be formed. In addition, by applying such pressure forming, crystal subdivision, disappearance of existing cracks, work hardening, and the like occur on the work surface 10a, and high pressure resistance and fatigue strength are imparted to the pressure formed surface. Can do.

  Further, since a high pressing force of, for example, several GPa is applied to the work surface 10a, it is possible to apply a high compressive residual stress to the deep part of the pressure forming surface. For example, by applying such pressure forming to the weld toe, the fatigue strength of the welded portion can be increased, and the life of the welded structure can be extended.

  In the present embodiment, the laser irradiation to the covering 20 may be performed through water. For example, it is a method of irradiating a laser while placing the covering 20 on the workpiece 10 or placing the covering 20 in the water or flowing water through the irradiation unit. In this method, since the expansion of the plasma is suppressed by the inertial force of water covering the covering 20, the intensity of the shock wave applied to the work surface of the work piece is higher than when the cover is directly irradiated with laser. Therefore, it is possible to efficiently press-mold the surface to be processed. In this case, using a second harmonic of a YAG laser having a wavelength of 532 [nm] allows water to pass through more easily than using a normal YAG laser having a wavelength of 1064 [nm]. The wavelength of the laser is preferably 532 [nm].

[Second Embodiment]
In the second embodiment, in addition to the first embodiment, before irradiating the laser, the desired surface is given a desired function by being fixed to the surface to be processed between the covering and the surface to be processed. This is a mode in which the fixed object is fixed to or embedded in the processed surface together with the pressure forming of the processed surface by arranging the fixed object.
Here, the case where the fixed substance is a granular material having a desired function will be described. Examples of the powder having a desired function include solid lubricant particles that improve sliding characteristics, self-cleaning and hydrophilic photocatalyst particles, and antibacterial particles having antibacterial properties. it can. The present embodiment can be carried out in the same manner as in the first embodiment, except that these granular materials are arranged between the work surface and the cover before laser irradiation.

  For example, as shown in FIG. 3, the granular material 40 which should be embedded in the recessed part 221 of the uneven | corrugated shape 22a of the film body 20 is filled and made to adhere. In the same manner as in the first embodiment, the film body 20 is disposed in close contact with the surface to be processed 10a and irradiated with the laser L. The uneven shape 22a is pressure-molded on the processing surface 10a by laser irradiation, and at the same time, the granular material 40 is driven and embedded in the processing surface 10a. As shown in FIG. 3, when the granular material 40 is disposed only in the concave portion 221 on the surface of the covering 20, the granular material 40 is pressed against the work surface 10a as shown in FIG. It can be embedded only in the top surface of the convex portion 221 ′ of the formed uneven surface 22a ′. In addition, when the powder body 40 is disposed only on the convex portion 222 on the surface of the covering body 20, the powder body 40 is projected on the uneven surface transferred to the processing surface 10a as shown in FIG. It can be embedded only in the bottom surface of the portion 222 ′. Needless to say, the granular material 40 may be embedded in both the top surface of the convex portion 221 ′ and the bottom surface of the concave portion 221 ′.

  For example, if a solid lubricant is embedded in the sliding surface of the sliding member as the granular material 40 as shown in FIG. 4A, the concave portion 222 ′ becomes an oil reservoir, and the solid embedded in the top surface of the convex portion 221 ′. The lubricant particles are in sliding contact with the mating member. Therefore, the frictional resistance of the sliding surface can be further reduced by reducing the sliding contact area and improving the lubricity. In addition, the pressure-molded surface 22a 'has improved wear resistance due to crystal refinement, work hardening, and the like, so that it can be a sliding surface excellent in lubricity and durability.

  In addition, if silver particles having antibacterial properties are embedded in the bottom surface of the recess 221 ′ formed on the surface of a stainless steel plate or the like as shown in FIG. 4B, the silver particles easily fall off from the surface of the stainless steel plate. Never do. Therefore, the antibacterial property of the stainless steel plate can be maintained for a long time.

  The powder body 40 is not limited to the above metal particles, and for example, a powder body made of a metal compound, ceramics, resin, or the like can be appropriately used depending on the purpose.

In the present embodiment, it is desirable that the hardness of the hard layer 22 of the covering 20 is HV300 or more in order to effectively fix or embed the granular material 40 on the work surface 10a. In particular, when the granular material 40 has a high hardness such as CuO or SiO ₂ , HV 800 to 1000 is preferable. The thickness of the hard layer 22, the hardness of the material structure and granular material 40 of the plasma generation layer 21 and the hard layer 22, varies depending on the size or material, 10-30 approximate thickness of the covering body 20 %. If it is less than 10%, for example, it is not possible to effectively embed high hardness materials such as metal compounds and ceramics. Further, the thickness is more than 30% is not suitable because it is broken can not ductility of the covering body is deformed to follow the plasma pressure decreases.

  As described above, in order to firmly fix or embed the granular material on the surface to be processed, it is desirable that the surface to be processed is preliminarily treated so that the embedded granular material is easily fixed.

  For example, when the granular material is silver and the workpiece is martensitic stainless steel (for example, a knife) having a hardness higher than that of the granular material, the surface to be processed is heat-treated, plated, or sprayed. A soft layer 12 having a lower hardness than the granular material embedded in the surface to be processed is formed by performing an appropriate base treatment such as a treatment, a build-up treatment, or a vapor deposition treatment. The thickness of the soft layer 12 is approximately 2 to 10 μm, although it varies depending on the type of powder and the ground treatment method.

Moreover, it is also preferable to form a periodic fine structure by laser processing on the processing surface as a base treatment. For example, a groove having a width of 0.2 to 3 μm and a depth of 1 to 2 μm is formed in a lattice shape at intervals of 0.5 to 5 μm on a sliding surface of a gear or the like with a femtosecond laser or an excimer laser. By applying a mixture of molybdenum disulfide and resin, covering with the above-described covering 20, and irradiating with a laser, the molybdenum disulfide particles can be reliably embedded in the groove. Examples of the resin mixed with molybdenum disulfide include an epoxy-based, acrylic-based, or polyamide-based adhesive or adhesive material.
[Third Embodiment]
In the present embodiment, instead of the powder particles in the second embodiment, a micro component such as an IC chip or a semiconductor is embedded (attached) on a predetermined surface of the workpiece as a fixed object, and the fixed object is different. Except for this, it can be carried out in the same manner as in the second embodiment.

Figure 5 is a schematic cross-sectional view conceptually showing the object to be covered body 20 and the micro component 50 according to the present embodiment. The hard layer 22 of the covering body 20 has a recess 221 to the workpiece facing surface, a portion of the micro component 50 is embedded is held fitted. The micro component 50 is held by being bonded to the recess 221 with an adhesive 60. The micro component 50 to which the covering body 20 holding a is placed on the processing surface 10a, irradiating the laser as in the embodiment. By laser irradiation, the micro component 50 is embedded in the workpiece 10 as shown in FIG. When the workpiece 10 has a higher hardness than the micro component 50, the soft layer 12 may be formed in advance on the surface into which the micro component 50 is driven in the same manner as in the second embodiment.

This aspect is suitable, for example, when embedding (mounting) a micro component such as an IC chip or a micro resistor on a circuit board. Here, the volume of the micro component 50 is preferably 0.01 to 10 mm ³ .

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, embodiments described below are also included in the technical scope of the present invention, and the scope of the present invention other than the following does not depart from the gist of the present invention. It can be implemented with various changes.
(1) In the second embodiment, the metal or resin powder has been described. However, the powder may be a granulate obtained by granulating a composition having a desired function. For example, titanium oxide powder having a photocatalytic function is mixed with an adhesive material together with zeolite or silica gel to form a composition, and granulated into pellets of several μm to several hundred μm. And this pellet is embed | buried in the workpiece surface like 2nd Embodiment. In this way, hydrophilicity and antifouling properties can be imparted to the surface to be processed.
(2) In the second embodiment, the case where the workpiece is an inorganic material such as a metal, an alloy, or a metal compound has been described. However, the workpiece may be an organic material such as resin, rubber, wood, paper, or cloth. Good. For example, if a microchip is embedded in clothes, functions for identifying and recognizing individuals can be provided.
(3) In the above embodiment, a desired function is imparted to the surface to be processed by a single surface modification. However, the surface to be processed such as using a covering with different concavo-convex shapes or embedding different fixed objects. A plurality of times of pressure forming may be performed. Thereby, a workpiece having a plurality of different surface functions can be obtained. For example, it is possible to obtain an electrical component having both a conductive function and a nonconductive function by first embedding Ni powder and then fixing the resin.
(4) In the above embodiment, the case where the fixed object is a granular material or a micro component has been described. However, the fixed object may be a metal foil. For example, a metal foil having a thickness of 5 to 50 μm is disposed on the surface of the workpiece, and pressure molding is performed as in the first embodiment. Since the surface of the workpiece and the metal foil are pressed into a concavo-convex shape while producing a new surface, the metal foil can be firmly bonded to the surface of the workpiece by micro bonding (cladding). For example, if an iridium or platinum foil is joined to the microelectrode, an inexpensive electrode can be formed.
(5) In the third embodiment, the case of one type of micro component has been described. However, a plurality of types of micro components may be embedded at the same time. For example, the workpiece facing surface of the hard layer 22 to form an uneven shape as shown in FIG. 6 (a), micro-unit product 5 2, 53, holds a 54 to each predetermined recess, appropriately covering body 20 if the working surface by coating the laser irradiation, to form a recess 222 'as in FIG. 6 (b), each micro-unit product 5 2, 53, may be embedded in the workpiece surface 54 at the same time . Reference numeral 61 denotes a composition such as an insulating material. In addition, an electronic circuit can be formed on the surface to be processed by fixing the conductors connecting the micro components together.

  In the present invention, the surface of the metal member, the inorganic member, and the organic member can be slidable, lubricated, heat-resistant, corrosion-resistant, creep-resistant, and wear-resistant by selecting the uneven shape of the covering and an appropriate fixed object. It is useful in a wide range of fields since it can be provided with various functions such as properties, anti-slip properties, water repellency, hydrophilicity, antibacterial properties, sterilization properties, and gloss. Moreover, it can use suitably for manufacture of the electrical component etc. which mount a micro component.

It is explanatory drawing explaining 1st Embodiment. It is the perspective view and cross-sectional schematic diagram which show an example of uneven | corrugated shape. (A) is an example of a regular shape, and (b) is an example of an irregular shape. It is explanatory drawing explaining 2nd Embodiment. It is sectional drawing which shows typically the relationship between the press-molding surface and granular material in 2nd Embodiment. (A) is a case where a granular material is embed | buried under a convex part top surface, (b) shows the case where a granular material is embed | buried under a recessed part bottom face. It is explanatory drawing explaining 3rd Embodiment. (A) Before laser irradiation, (b) shows after embedding micro parts. It is a figure explaining the modification of 3rd Embodiment. (A) is a cross-sectional schematic diagram of the covering body holding a micro component, and (b) shows a surface layer cross section after embedding the micro component.

Explanation of symbols

10: Workpiece 10a: Workpiece surface 20: Cover 21: Plasma generation layer 22: Hard layer 22a: Concave and convex shape 22a ': Press-molding surface 30: Laser emitting part 40: Powder 50: Micropart L: laser

Claims (14)

Over the surface to be processed of the workpiece, and a plasma generation layer that generates plasma by absorbing laser, have a flat or concave-convex shape on one surface, and a hard layer Ru higher hardness der than the plasma generation layer Cover with a covering body provided, irradiate the plasma generation layer of the covering body with a laser with a short pulse and high peak output, and press-mold the work surface into a flat or uneven shape of the hard layer by a laser peening shock wave A surface modification method characterized by the above.   The fixed object which adheres to the to-be-processed surface between the said covering and the to-be-processed surface, and provides a desired function to the to-be-processed surface is arrange | positioned before irradiating the said laser. Surface modification method.   The surface modification method according to claim 1, wherein the covering is made of a plate-like or belt-like steel material, and has the hard layer formed by a hardening process on one surface side of the steel material.   The surface modification method according to claim 3, wherein the curing process is any one of a quenching process, a carburizing process, a nitriding / nitriding process, a hard plating process, a curing vapor deposition process, and a work curing process.   The covering is formed by joining a plasma generation layer made of any one of a plate-like or belt-like metal, a metal compound, a resin, and a synthetic rubber, and a hard layer made of a material harder than the plasma generation layer. The surface modification method according to claim 1, which is a laminate. The surface modification method according to claim 2, wherein the fixed matter is a granular material.   The surface modification method according to claim 6, wherein the granular material is any one of a metal, an alloy, a metal compound, a resin, a ceramic, and a fragrance. The surface modification method according to claim 2 , wherein the fixed matter is a micro component. The micro components, IC chip, semiconductor, micro-chip, a surface modification method as recited in claim 8 is one of the optical elements and micro-machining down.   The surface modification method according to claim 1, wherein the hard layer has a hardness of HV150 or more.   The laser beam is irradiated with at least one of a heat treatment, a plating treatment, a metal spraying treatment, a build-up treatment, and a vapor deposition treatment on the work surface of the work piece in advance. The surface modification method according to any one of the above. The surface modification according to any one of claims 2 and 6 to 9 , wherein a periodic fine structure or a fine groove is formed in advance on the workpiece surface of the workpiece before the laser irradiation. Quality method. The periodic microstructure or fine grooves, et epoxy-based, surface modification method according to claim 12 for applying a mixture of polyamide, or acrylic adhesive and / or adhesive and the attached material . A workpiece covering that irradiates a workpiece with laser peening indirectly and irradiates the workpiece with a plasma generating layer that absorbs the laser to generate plasma, and a flat surface on the opposite surface of the workpiece. possess an irregular shape, the coating material, characterized in that integrally provided with the hard layer is a higher hardness than the plasma generation layer.

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