WO1994027930A1 - Corps fritte en ceramique et procede de traitement de la surface d'un tel corps - Google Patents
Corps fritte en ceramique et procede de traitement de la surface d'un tel corps Download PDFInfo
- Publication number
- WO1994027930A1 WO1994027930A1 PCT/JP1994/000856 JP9400856W WO9427930A1 WO 1994027930 A1 WO1994027930 A1 WO 1994027930A1 JP 9400856 W JP9400856 W JP 9400856W WO 9427930 A1 WO9427930 A1 WO 9427930A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sintered body
- processing
- wavelength
- ceramic
- laser
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/91—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics involving the removal of part of the materials of the treated articles, e.g. etching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28D—WORKING STONE OR STONE-LIKE MATERIALS
- B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/0036—Laser treatment
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/53—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete
- C04B41/5338—Etching
- C04B41/5346—Dry etching
Definitions
- the present invention relates to a ceramics sintered body and a surface processing method thereof.
- Fine ceramics which have high hardness and high strength properties, are being used for wear-resistant parts and sliding parts. Roughness and fine cracks are present on the surface of the ceramic after sintering, that is, on the sintered skin. If these defects are left untouched, the ceramics sintered body will be broken starting from these defects and behave very fragile. Therefore, in order to use the ceramics sintered body for actual mechanical parts, etc., it is necessary to remove latent defects contained in the surface layer of the ceramics sintered body and improve the surface strength .
- Damaged or defective parts on the surface of the ceramic sintered body after processing can be recovered by heat treatment.
- defects are recovered at a minute level, macro defects that affect the reliability of components are not sufficiently recovered, and the excellent strength and strength inherent in ceramics It was insufficient to obtain a member fully utilizing the characteristics.
- An object of the present invention is to provide a method for processing the surface of a ceramics sintered compact that can minimize the occurrence of a surface damaged portion.
- Another object of the present invention is to provide a ceramic sintered body which has few surface damages after processing and has practically high reliability as a mechanical part.
- the surface of the predetermined area of the ceramic sintered body is irradiated with a laser beam having a wavelength in the ultraviolet region to irradiate the surface of the predetermined area. Remove the layer.
- excimer molecules such as ArF, KrF, and XeCI are preferably used as a laser medium. Used laser is used.
- the thickness of the surface layer to be removed is greater than 2; zm.
- the laser light or the ceramic sintered body is moved continuously or intermittently so that the irradiation of the laser light reaches the entire surface of the predetermined region.
- the objective lens of the oscillator which oscillates laser light having a wavelength in the ultraviolet region, and the objective lens during processing so that the distance between the surface of the ceramics sintered body to be processed is kept constant. It is preferable to adjust the distance from the ceramic sintered body.
- a rough processing is performed on a predetermined area of the ceramic sintered body, and thereafter, the rough processing is performed as a finish processing.
- the surface layer of the predetermined area is removed by irradiating the surface of the predetermined area with laser light having a wavelength in the ultraviolet region.
- the processing efficiency is improved.
- a mechanical grinding process or a process using a laser beam having a wavelength in an infrared region is employed.
- the thickness of the surface layer removed by a laser beam having a wavelength in the ultraviolet region is 2 / m or more.
- the surface layer in a predetermined region is removed by irradiation with a laser beam having a wavelength in an ultraviolet region.
- the surface of the predetermined area after the removal of the surface layer does not contain the molten and coagulated material of ceramics. Also preferably, after removal of the surface layer
- the surface roughness of the surface of the constant region is a center line average roughness Ra of JISB 0601 and is as follows.
- the ceramics sintered body having this surface has a three-point bending strength of 1 OOOMPa or more in accordance with JISR1661.
- the material in the predetermined region is, for example, a silicon nitride sintered body.
- a feature of the present invention in one aspect is that a surface layer in a predetermined region is removed by irradiating a laser beam having a wavelength in an ultraviolet region to the surface of the predetermined region of the ceramic sintered body.
- the feature of the present invention in another aspect is that, in order to improve the processing efficiency, first, a predetermined region of the ceramic sintered body is subjected to rough processing, and thereafter, rough processing is performed as finishing processing. The purpose is to remove a surface layer in a predetermined region by irradiating a laser beam having a wavelength in an ultraviolet region to the surface of the predetermined region.
- the surface layer which is a factor that reduces the strength of the sintered body, is reduced on the surface of the sintered body.
- the occurrence of heat damage and fine cracks is observed.
- Such defects are particularly likely to occur in melt-bonded ceramics such as gay nitride.
- the surface of the ceramic sintered body is processed by irradiating laser light that can be processed in a non-contact manner, the above-mentioned defects are not generated, and as a result, It is thought that the original strength of the material can be exhibited.
- laser oscillators as processing beam sources used industrially are roughly divided into those that emit beams in the infrared region, Some of them oscillate in the ultraviolet region. Since the laser beam can concentrate high energy on a very small area, irradiating the workpiece with the laser beam causes the irradiated part to melt or evaporate. It is known that by using this phenomenon to control the laser beam, it can be applied to material removal processing. For metal materials, cutting, welding, alloying, cladding, surface melt solidification, and uniform solution treatment are performed using laser light.
- the material processed by the YAG laser is applied as it is to machine parts, especially parts that require sliding parts, the possibility of damaging the mating material increases.
- the surface roughness may give a notch effect to the member in some cases, it is necessary to reduce the surface roughness of the processed surface in order to ensure the reliability of the member.
- irradiation energy of the laser beam having a wavelength in the ultraviolet region is large c Therefore, when irradiated with laser light having a wavelength in the ultraviolet region to the surface of the workpiece, a large irradiation It is thought that the energy directly acts on the bound species of the substance, and sublimates the substance to remove it. For this reason, since the melt is not formed by the irradiation of the laser light having a wavelength in the ultraviolet region, it is considered that the surface roughness caused by the melt is not formed.
- the ceramics to which the present invention is applied is not limited to gay nitride, but is applicable to all ceramics such as alumina, gay carbide, boron carbide, zirconium, and aluminum nitride. Can be done. Processing conditions can be changed as appropriate depending on the applied material.
- the laser beam focused on a line or a rectangle is used.
- the laser light or the ceramics sintered body is moved continuously or intermittently while irradiating the laser light so that the irradiation of the laser beam reaches the entire surface of the predetermined region of the ceramics sintered body. Eventually, only the surface layer in a predetermined region irradiated with the laser beam is removed.
- a curved or inclined surface can be formed by rotating the workpiece continuously or intermittently about the rotation axis and moving the workpiece or beam perpendicular to the rotation axis. Becomes Since beam irradiation can be performed in three dimensions, for example, it is possible to machine the inside of a cylinder, and unlike the conventional machine grinding, it is possible to machine the outer surface and inner surface with a single device, which is cost-effective. The lit also increases.
- the objective lens and the ceramic are processed during processing so that the distance between the objective lens of the laser oscillator that oscillates laser light and the surface to be processed of the ceramic sintered body is kept constant. It is preferable to adjust the distance from the sintered body. The reason for this is that, with respect to the removal processing in the depth direction, as the processing progresses, the focal length set at the initial irradiation surface changes, and as a result, the energy density at the irradiation part changes, so the material removal rate This is because the shape may change and the desired shape may not be obtained.
- the surface of the ceramic sintered body after the removal becomes smooth with little unevenness.
- the thickness of the surface layer to be removed is preferably 2 m or more. If this thickness is less than 2 m, the ceramic It is not possible to completely remove defects before surface processing such as open pores, impurities, and micro cracks introduced during the manufacturing process of the box sintered body.
- the upper limit of the thickness of the removed surface layer, C 0 2 laser Ya as a laser beam is limited from the practical point of view having a wavelength in the infrared region
- Nd-YAG laser There is an Nd-YAG laser. Wavelength of C_ ⁇ 2 laser is 1 0.1, wavelength of N d-YAG laser is 1. a 0 6 m. Compared to these laser light wavelengths, the wavelength of a KrF excimer laser, which is an example of laser light having a wavelength in the ultraviolet region, is 248 nm, which is considerably shorter. Usually, the critical focal diameter is said to be about the wavelength. Since laser processing involves inputting processing energy to the workpiece using a beam, the beam diameter is considered to have a significant effect on processing accuracy. From this point as well, it can be understood that high-precision and extremely smooth processed surfaces can be easily obtained by performing surface processing using laser light having a wavelength in the ultraviolet region.
- a laser beam with an ultraviolet region wavelength of 0.3 or less in surface roughness JISB 0601. It is desirable that the surface be processed so that the center line average roughness R a) is obtained.
- processing using ultraviolet light is regarded as finishing processing, and processing using laser light having a wavelength in the infrared region or mechanical grinding processing is used as rough processing.
- unevenness of a processing surface caused by irradiation with an infrared laser is removed by irradiation with an ultraviolet laser which is a finishing process. Since rough processing is performed with high removal efficiency, and the ultraviolet laser is used only for finishing processing with low removal efficiency, high efficiency and high reliability processing can be achieved as a whole process.
- the three-point bending test strength of this machined surface in accordance with JISR 1601 is 100 It is preferable that the pressure be 0 MPa or more. With such strength, it can be sufficiently used as a mechanical part. If grinding is performed as the surface processing of ceramics sintered bodies as in the past, it is necessary to perform lapping to remove defects such as cracks and particles falling off during grinding. Becomes On the other hand, in the surface processing method of the present invention using a laser beam having a wavelength in the ultraviolet region for at least finishing, defects such as cracks and dropout of particles can be suppressed during processing, so that lapping must be performed. Absent. Furthermore, the method of the present invention can be easily carried out even in a place where it is difficult to grind by grinding using a grindstone, and its industrial value is extremely high.
- the ceramic sintered body obtained according to the present invention is extremely It does not break even when a large stress is applied, and can be advantageously applied to mechanical parts that require high reliability.
- mechanical components include, for example, valves for internal combustion engines, piston rings, and piston pins.
- valves for internal combustion engines for example, when grinding the stem part of a valve for an internal combustion engine, many breaks occur, but according to the surface processing method of the present invention, no breakage is observed, and a ceramic valve having high strength and high reliability is provided. Can be obtained.
- FIG. 1 is a perspective view showing an example of a surface processing method according to the present invention. '
- FIG. 2 is a perspective view showing another example of the surface processing method according to the present invention.
- FIG. 3 is an illustrative cross-sectional view showing, in an enlarged manner, a processed portion in FIG.
- an excimer laser having a wavelength of 248 nm using KrF gas was used as a laser medium.
- a test piece 2 was placed on a worktable 1, and a work surface 2 a of the test piece 2 was irradiated with a linearly focused beam.
- the worktable 1 was moved in the direction indicated by the arrow A so that the entire surface of the processed surface 2a of the test piece 2 was irradiated with the beam 3.
- the surface layer of the processed surface 2a of the test piece 2 was removed.
- the thickness of the removed surface layer was l O ⁇ m.
- the surface of the test piece was ground with a # 200 diamond grindstone.
- the surface layer of the test piece was removed with a thickness of 10 m using an Nd-YAG laser (wavelength 1.06 // m).
- the strength and the Weibull coefficient decrease.
- defects in the surface layer are sufficiently removed, so that the strength can be kept high and the variation can be reduced.
- Rough processing was performed on the same silicon nitride sintered body as in Example 1 using an Nd-YAG laser as an infrared light and a diamond grindstone, and finishing was performed using a KrF excimer laser as an ultraviolet light. .
- the surface where the maximum stress was generated in the three-point bending test was left unprocessed and the other surface was Preliminary processing was performed to dimensions of 4 mm x 3.1 mm x 40 mm by grinding.
- the pre-processed test piece was subjected to a 0.1 mm removal process, and was rough-processed until the remaining allowance was 10 m, and then a finishing process was performed.
- a # 200 resin-bonded grindstone was used as a diamond grindstone for rough machining.
- the worktable in the vertical direction is maintained so that the distance between the outermost surface of the beam irradiation and the objective lens of the laser oscillator optical system is kept constant as the processing proceeds in the depth direction.
- the distance between the outermost surface of the beam irradiation and the objective lens of the laser oscillator optical system is kept constant as the processing proceeds in the depth direction.
- Table 5 shows the average strength, Weibull coefficient, surface roughness, and time required for each test piece.
- machining with only an excimer laser takes much longer than ordinary grinding.
- high-efficiency YAG laser or rough grinding with diamond wheel the same characteristics as those obtained by excimer laser alone processing can be obtained, and the processing time can be significantly reduced. It is possible to do this.
- Tables 6 and 7 show the results of machining by changing the remaining allowance (finishing allowance) in rough machining.
- * indicates that the thickness removed by the excimer laser is less than 2 in the comparative example.
- the effect of the pre-processing was not completely removed, and the strength and the Weibull coefficient were low.
- the removal amount is 2 m or more, the processing influence layer and the processing defect due to the pre-processing can be sufficiently removed, so that high reliability can be obtained.
- FIG. 2 is an illustrative view showing a magnified processing portion.
- the feed in the B direction is intermittent, so that machining in the depth direction becomes possible, and the removal amount can be changed by changing the intermittent time.
- a desired tapered shape is formed.
- the distance between the outermost surface of the processing and the objective lens of the optical system was kept constant in order to keep the removal amount per pulse constant.
- the outermost surface of the processed product has been removed by excimer laser at least 2 m or more.
- the ceramic sintered body obtained by the present invention can be advantageously used as an abrasion-resistant component / sliding component having few surface damages.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mechanical Engineering (AREA)
- Laser Beam Processing (AREA)
- Ceramic Products (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1019950700341A KR950702511A (ko) | 1993-06-01 | 1994-05-30 | 세라믹 소결체 및 이의 표면 가공방법(Ceramic sintered body and method of processing surface of body) |
EP94916412A EP0653395A1 (en) | 1993-06-01 | 1994-05-30 | Ceramic sintered body and method of processing surface of body |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13082093 | 1993-06-01 | ||
JP5/130820 | 1993-06-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1994027930A1 true WO1994027930A1 (fr) | 1994-12-08 |
Family
ID=15043482
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1994/000856 WO1994027930A1 (fr) | 1993-06-01 | 1994-05-30 | Corps fritte en ceramique et procede de traitement de la surface d'un tel corps |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0653395A1 (ja) |
KR (1) | KR950702511A (ja) |
WO (1) | WO1994027930A1 (ja) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10167859A (ja) * | 1996-12-05 | 1998-06-23 | Ngk Insulators Ltd | セラミックス部品およびその製造方法 |
KR101455845B1 (ko) * | 2013-04-09 | 2014-11-03 | 재성정밀주식회사 | 무광택 세라믹 진공흡착 노즐팁의 제조방법 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6195770A (ja) * | 1984-10-17 | 1986-05-14 | Sumitomo Electric Ind Ltd | セラミツク焼結体の加工法 |
JPH01241389A (ja) * | 1988-03-24 | 1989-09-26 | Toshiba Corp | レーザ加工方法 |
JPH02225374A (ja) * | 1989-02-28 | 1990-09-07 | Toshiba Corp | 窒化アルミニウム部品の製造方法 |
JPH04317483A (ja) * | 1991-04-15 | 1992-11-09 | Nec Corp | セラミックの研磨方法 |
-
1994
- 1994-05-30 KR KR1019950700341A patent/KR950702511A/ko not_active Application Discontinuation
- 1994-05-30 EP EP94916412A patent/EP0653395A1/en not_active Withdrawn
- 1994-05-30 WO PCT/JP1994/000856 patent/WO1994027930A1/ja not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6195770A (ja) * | 1984-10-17 | 1986-05-14 | Sumitomo Electric Ind Ltd | セラミツク焼結体の加工法 |
JPH01241389A (ja) * | 1988-03-24 | 1989-09-26 | Toshiba Corp | レーザ加工方法 |
JPH02225374A (ja) * | 1989-02-28 | 1990-09-07 | Toshiba Corp | 窒化アルミニウム部品の製造方法 |
JPH04317483A (ja) * | 1991-04-15 | 1992-11-09 | Nec Corp | セラミックの研磨方法 |
Also Published As
Publication number | Publication date |
---|---|
EP0653395A1 (en) | 1995-05-17 |
KR950702511A (ko) | 1995-07-29 |
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