JP6209479B2 - Surface modification method using ceramics - Google Patents

Description

  The present invention provides a high degree of heat resistance, strength, seizure resistance, creep resistance, etc. for various base materials and parts used under severe conditions such as in a high-temperature atmosphere with ceramics on the surface of the metal base material. The present invention relates to a surface modification method for modification.

  Conventionally, as a means for modifying the surface of a base material that requires wear resistance, etc., surface modification material made of super hard material having excellent wear resistance is applied to the surface of the base material for electric welding, gas welding or brazing. The joining method is adopted. However, in the former joining by welding, a large number of cracks are likely to occur at the time of welding or after welding due to the difference in the linear expansion coefficient between the base material and the surface modifying material, thereby reducing the durability of the modified surface. Incorporation of components on the substrate side as impurities in the surface modification material at the welded part adversely affects various physical properties such as corrosion resistance, wear resistance, strength, etc., and the desired modification performance cannot be fully exhibited. There was a problem. In addition, in the latter joining by brazing, the brazing material does not spread sufficiently between the base material surface and the surface modifying material, the joining strength is insufficient, and the surface modifying material is easily peeled off during use. However, there was a difficulty that a sufficient durability could not be obtained.

  On the other hand, the present applicant previously arranged a large number of surface modifiers on the surface of the substrate as a surface modifying means with a gap between each other and the surface of the substrate. We propose a method of joining surface modifiers and surface modifiers together with a base material by pouring and filling a melt of a filler (brazing material) consisting of a brazing composition by powder spraying with (Patent Document 1). In this surface modification means, the entire surface of the substrate to be surface-modified is three-dimensionally densely covered by a surface modification layer comprising a large number of surface modification materials and a filler material that fills the gaps between them. Therefore, excellent reforming performance and durability of the modified surface can be obtained.

Japanese Patent No. 369430

However, the surface modification means according to the proposal has been difficult to apply to various equipment and parts used particularly in a high temperature atmosphere. For example, for use at a high temperature such as 1200 ° C., a filler having a high melting point such as 1300 ° C. or more is required as the filler (brazing material). However, in the case of powder spraying using a gas burner as a heat source, etc. This is because the filler cannot be melted because the energy density is low. Further, TIG - even (tungsten inert gas) welding, energy density in the argon arc 15.0kW / cm ² before and after, since the plasma arc is about 50~100kW / cm ^2, to ensure the brazing material of the high melting point When melting, the welding speed cannot be increased, the work efficiency deteriorates, and in the arc, the penetration width of the brazing material inevitably increases. The surface modification due to the difference in linear expansion coefficient from the base material because the area ratio of the surface modification material on the surface is low and sufficient surface modification action cannot be achieved and the heat input per weld length increases. It becomes easy to produce the thermal bad influence with respect to the crack of a material and a base material. On the other hand, in surface modification that imparts high heat resistance, it is necessary to use ceramics as the surface modification material. However, if the high temperature when melting the high melting point brazing material reaches the surface modification material, the heat transfer property With low ceramics, the temperature gradient from the heated part to the non-heated part becomes very large and cracks are likely to occur.

  In view of the above-described circumstances, the present invention uses ceramics as a surface modifying material as a means for modifying a metal substrate surface used under severe conditions such as in a high temperature atmosphere, A high-quality surface-modified layer that is heat-resistant, high-strength, and excellent in durability can be formed efficiently at high speed, and a method that does not easily cause cracks in the surface-modified material and thermal adverse effects on the substrate during the formation process is provided. The purpose is to do.

  In order to achieve the above object, the surface modification method using ceramics according to the first aspect of the present invention is an area in which a large number of ceramic chips are spaced from each other by 0.5 to 5 mm and covered with ceramic chips. / Fixed so that the ratio of the surface area of the substrate surface exposed between the ceramic chips is in the range of 40/60 to 96/4, and continuously in the net-like gap formed between the arranged ceramic chips By irradiating a laser beam while supplying the filler material to the molten metal, the filler material is melted and filled to fill the gap.

  According to a second aspect of the present invention, in the surface modification method of the first aspect, the ceramic chip has a bottom width of 5 to 15 mm, a length of 5 to 30 mm, and a thickness of 3 to 30 mm. In the peripheral portion of the modified surface, a chip whose length is adjusted within the above range is used.

  According to a third aspect of the present invention, in the surface modification method according to the first or second aspect, the ceramic chip has a trapezoidal cross section in the width direction and / or the longitudinal direction.

The invention according to claim 4, in any of the surface modification method of the claim 1 to 3, wherein the ceramic _{chip, TiB 2, Cr 3 C 2} , W 2 C, WC, SiC, Si 3 N 4, sialon , Cordierite, and alumina-graphite.

  According to a fifth aspect of the present invention, in the surface modification method according to any one of the first to fourth aspects, the filler material is made of an alloy material having a melting point of 1150 ° C. or higher.

  According to a sixth aspect of the present invention, in the surface modification method according to any one of the first to fifth aspects, a convex portion having a height of 0.1 to 0.5 mm is formed on the lower surface of the ceramic chip having electrical conductivity. By placing a ceramic chip on the surface to be modified of the substrate and energizing it, the ceramic chip is fused and fixed to the substrate with the convex portions.

  According to a seventh aspect of the present invention, in the surface modification method according to any one of the first to fifth aspects, a conductive metal layer is formed on a peripheral surface of the ceramic chip having no electrical conductivity, and the ceramic chip is coated with a substrate. The ceramic chip is fused and fixed to the base material with the conductive metal layer by placing it on the modified surface and energizing it.

  According to an eighth aspect of the present invention, in the surface modification method according to any one of the first to fifth aspects, a recess is formed in the surface to be modified of the substrate, and the ceramic chip is fitted into the recess and mechanically fixed. I am going to do it.

  According to the surface modification method according to the first aspect of the present invention, the surface to be modified of the metal substrate is made of a large number of ceramic chips arranged at a specific interval (0.5 to 5 mm) between each other. Then, it is densely covered with a surface modification layer composed of a melted and solidified material of a filler material in which gaps continuous in a net shape between the arrays are filled. The surface modification layer is formed by separating the surface modification material ceramics into small chips that are independent of each other, providing good stress dispersion in each chip, and the stress deformation and thermal deformation present in the surrounding area. Since it is absorbed by the toughness of the molten and solidified material, cracks due to changes in load and temperature changes are less likely to occur. In addition, since the melted and solidified material of the filler material filling the gaps is continuous in a network with a specific width, a large number of ceramic chips are constrained together by the molten and solidified material, so that the entire surface-modified layer is strengthened. In addition to being integrated, a high bonding strength between the surface modified layer and the base material is obtained, and in addition, the area ratio of the ceramic chip covering the surface to be modified of the base material is in a specific range. Insulation, seizure resistance, creep resistance, etc. are fully exhibited. Therefore, the surface-modified base material has high heat resistance and high durability capable of maintaining sufficient strength even in a severe use environment that receives a compressive load or friction in a high temperature atmosphere.

  In this surface modification method, when the gap between the ceramic chips is filled with the melted solidified material of the filler metal, a laser is applied while continuously supplying the filler material to the gap by a laser overlay welding technique. By irradiating the beam, the filler material is melted to fill the gap. By using a laser beam as a heat source in this way, although the gap is as narrow as 0.5 to 5 mm, the irradiation spot diameter can be heated at a high energy density in accordance with the width of the gap. Because even if it has a very high melting point, it is possible to join efficiently at high speed, the penetration width of the filler metal is small, and the heat input per length is significantly less than gas welding and arc welding, It is difficult to cause cracks in the ceramic chip and thermal adverse effects on the substrate, and a high quality surface modified layer can be formed.

  According to the invention of claim 2, since the ceramic chip has a specific size, the stress dispersibility is high, and cracking due to load change or temperature change is less likely to occur.

  According to the invention of claim 3, since the cross section in the width direction or / and the longitudinal direction of the ceramic chip forms a trapezoid, the cross section in the width direction of the melt-solidified filler material filling the gap between the chips becomes a wedge shape, As a result, the binding force of the ceramic chip due to the molten solidified product is remarkably increased. Therefore, even if the ceramic chip is a material having poor wettability to the filler material, sufficient fixing strength due to the melted and solidified product of the filler material can be obtained.

  According to the invention of claim 4, since the ceramic chip is made of a specific material, the compressive load strength and the wear resistance in a high temperature atmosphere are further improved.

  According to invention of Claim 5, since the said filler material consists of alloy materials with melting | fusing point 1150 degreeC or more, high suitability can be exhibited as an object for the modified layer of the base-material surface exposed to high temperature.

  According to the sixth aspect of the present invention, when a ceramic chip having electrical conductivity is used, a convex portion having a specific height is provided on the lower surface, and the ceramic chip is placed on the surface to be modified of the substrate. By energizing the ceramic chip, the ceramic chip can be fixed very easily to the base material.

  According to the invention of claim 7, when a ceramic chip having no electrical conductivity is used, the conductive metal layer is provided on the peripheral surface, and the ceramic chip is placed on the surface to be modified of the substrate. By energizing, the ceramic chip can be fixed to the substrate very easily.

  According to the eighth aspect of the present invention, the concave portion is formed on the surface of the base material to be modified, and the ceramic chip is securely fixed to the base material by mechanically fixing the ceramic chip by fitting the concave portion into the concave portion. Can be fixed.

BRIEF DESCRIPTION OF THE DRAWINGS The surface modification method which concerns on one Embodiment of this invention is shown in steps, (a) is a vertical side view of the state which arranged the ceramic chip | tip on the to-be-modified surface of a base material, (b) is a ceramic chip | tip. FIG. 4 is a longitudinal side view in the middle of joining the gap between the melted filler materials, (c) is a longitudinal side view at the end of joining, and (d) is a longitudinal side view after surface polishing. The ceramic chip used for the surface modification method is illustrated, (a) is a perspective view of a ceramic chip having a trapezoidal cross section in the width direction, and (b) is a perspective view of a rectangular parallelepiped ceramic chip. The structural example of the surface modification layer modified | reformed by the surface modification method is shown, (a) is a plan view of the surface modification layer that receives only the compressive load, and (b) is the surface modification that receives the compressive load and friction. It is a top view of a layer. The 1st fixing system of the ceramic chip | tip with respect to the to-be-modified surface of a base material is shown, (a) is a vertical side view, (b) is a vertical front view. The 2nd fixation system is shown, (a) is a vertical side view, (b) is a vertical front view. The 3rd fixation system is shown, (a) is a vertical side view, (b) is a vertical front view.

  Hereinafter, embodiments of a surface modification method using ceramics according to the present invention will be specifically described with reference to the drawings.

  In this surface modification method, first, as shown in FIG. 1A, a large number of ceramic chips 2 are arranged on a surface 1a to be modified of a metal substrate 1 with a fixed gap 4 between them. Fix it. Next, as shown in FIG. 1 (b), the powder 30 of the filler material is continuously supplied from the filler material supply pipe 5 into the net-like gap 4 formed between the arranged ceramic chips 2 and 2. By irradiating the laser beam 6a emitted from the laser processing head 6, the gap 4 is filled with the melt 3a of the filler material and solidified. As a result, as shown in FIG. 2 (c), the solidification of the filler material in which a large number of ceramic chips 2 and the net-like gaps 4 between the arrays are filled on the surface 1 a to be modified of the substrate 1. A surface modification layer 7 composed of the product 3 is formed. In this surface modified layer 7, the extra portion 3b of the molten solidified product 3 usually protrudes from the surface along the gap 4 in a bowl-like shape. By polishing the entire surface and removing the excess portion 3b of the melt-solidified product 3, the surface of the surface modification layer 7 is flattened as shown in FIG.

  Here, when the ceramic chips 2 are arranged on the surface 1a to be modified of the substrate 1, the gap G [see FIG. 1 (a)] between the ceramic chips 2 is set to 0.5 to 5 mm. . Further, the ratio of the area covered by the ceramic chip of the surface to be modified 1a / the area of the substrate surface exposed between the ceramic chips is set in the range of 40/60 to 96/4. The gap G of the gap 4 and the above-described area ratio are very important factors for obtaining the effects of the present invention described later.

  The ceramic chip 2 is not limited to the trapezoidal cross section in the width direction illustrated in FIG. 1, the trapezoidal cross section in the longitudinal direction, the trapezoidal cross section in the width direction and the longitudinal direction, and further shown in FIG. Such a rectangular parallelepiped shape can also be preferably used. The size of the ceramic chip 2 is not particularly limited, but as shown in FIGS. 2A and 2B, the bottom width W is in the range of 5 to 15 mm, the length L is in the range of 5 to 30 mm, and the thickness T is It is preferable to set it as the range of 3-30 mm. Such ceramic chips 2 are basically of the same size, but there are cases where the arrangement length is excessive or insufficient depending on the edge position of the modified region of the base material 1. In the peripheral part of the region, the length T adjusted in the above range is used.

The material of the ceramic chip 2 may be any material that can maintain strength at a high temperature when the material to be modified is used. For example, borides such as CrB ₂ , TiB ₂ , ZrB ₂ , Cr ₃ C ₂ , W ₂ C Carbides such as WC, SiC, nitrides such as Si ₃ N ₄ , AlN and ZrN, oxides such as Al ₂ O ₃ and ZrO ₂ , silicides such as NbSi ₂ , WSi ₂ and CrSi ₂ , sialon [Si _{6 -Z Al Z O Z N 8-} Z, Si 6-Z (Al, Y) Z O Z N 8-Z] (0>Z> 6), cordierite _{(MgO-Al 2 O 3 -SiO} 2) And alumina-graphite. Among these, TiB ₂ , Cr ₃ C ₂ , W ₂ C, WC, SiC, Si ₃ N ₄ , sialon, cordierite, and alumina-graphite are preferable because they are high in hardness and excellent in strength. It is. Furthermore, Si ₃ N ₄ and sialon, which are excellent in heat insulation and thermal shock resistance, are particularly suitable because they have a wide application range.

  In addition, as these ceramic chips 2, you may use together multiple types from which a material differs. On the other hand, the metal material of the substrate 1 is not particularly limited, but usually heat-resistant steel is used.

  As the filler material, an alloy material generally known for overlay welding can be used. In particular, an alloy material having a melting point of 1150 ° C. or higher is preferable, and a melting point of 1350 ° C. is particularly suitable for use in a high temperature atmosphere around 1250 ° C. Alloy materials above ℃ are recommended. Such a high melting point alloy material is not particularly limited. For example, 25Cr-20Ni—Fe alloy (melting point 1400 ° C.) known as HK40 (ASTM standard = JIS SCH22), 28Cr-48Ni-5W—Fe alloy ( Cr-Ni heat-resistant alloy such as 28 ° C-50Co-Fe alloy (melting point 1388 ° C) known as UMCo50 (developed by the Belgian National Metallurgical Research Center), 80Cr-Fe alloy (melting point 1388 ° C) Fe-Cr heat-resistant alloy and the like having a melting point of 1650 ° C. The size of the powder 30 of the filler material is not particularly limited, but the average particle size is preferably in the range of 20 to 200 μm, and spherical particles having an average particle size of 20 to 100 μm are particularly recommended from the viewpoint of excellent fluidity.

  The arrangement of the ceramic chip 2 on the surface 1a to be modified of the substrate 1 may be a vertical and horizontal arrangement as shown in FIG. 3A for applications where the surface 1a to be modified receives only a compressive load. On the other hand, in an application where the surface to be modified 1a receives friction in addition to a compressive load, in order to develop high wear resistance by the ceramic chip 2 with high hardness, as shown in FIG. , F2 as an array in which the positions of the ceramic chips 2 in each row in the orthogonal direction are sequentially shifted by less than 1 pitch (illustrated staggered array with a half-pitch shift), the load sliding contact is ceramics at any position in the width direction. It is preferable that the chip 2 is scraped. In this staggered arrangement, the length of the array is excessive or insufficient at the edge position of the modified region every other row, so that ceramic 2 'having a short length is used at both ends of the every other row as shown.

  In the surface modification method of the present invention, as means for filling the gaps 4 between the ceramic chips 2 arranged and fixed on the surface 1a to be modified of the base material 1 with the melted solidified material 3 of the filler material, FIG. The laser overlay welding technique is used as shown in FIG. That is, if the laser beam 6a is used as a heat source, the irradiation spot can be easily narrowed to a diameter of 0.5 to 5 mm corresponding to the gap G of the gap 4 and heated at a high energy density by focus adjustment by an optical system such as a lens. Therefore, even if the filler material is an alloy material with a very high melting point, it can be joined efficiently at a high speed, the penetration width of the filler material is small, and the length per length compared to gas welding or arc welding is small. Since the amount of heat input is remarkably small, it is difficult to cause cracks in the ceramic chip 2 during welding and thermal adverse effects on the base material 1, and the high-quality surface modified layer 7 can be formed.

Incidentally, the energy density of the laser beam 6a can be easily set to 100 kW / cm ² or more. In the modification method of the present invention, when the gap 4 is filled with the molten solidified material 3 of the filler material by the laser beam 6a, for example, when a semiconductor laser is used, the laser output is in the range of 0.3 to 3 kW, The moving speed can be adjusted in the range of 20 to 1000 mm / min. In addition, although a high energy density can be set also by electron beam welding, since it carries out under a high vacuum, supply of a filler material is difficult and it is difficult to apply to overlay welding.

  It is recommended that supply of the powder 30 of the filler material into the gap 4 is sent into the irradiation spot of the laser beam 6a through a shielding gas, as in general laser welding. Although the supply position may be one, it is preferable to provide two or more locations facing the irradiation spot in order to supply the entire gap 4 evenly. In the above-described embodiment, the filler material is supplied as the powder 30. However, the filler material may be supplied in the form of a rod, a strip, a line, or the like.

  By this surface modification method, the surface 1a to be modified of the base material 1 used at a high temperature was arranged with a gap G of 0.5 to 5 mm between them as shown in FIG. 1 (d). It is three-dimensionally densely covered by a surface modification layer 7 composed of a large number of ceramic chips 2 and a melt-solidified material 3 of a filler material in which gaps 4 that are continuous in a net pattern between the chips are arranged. This surface modification layer 7 is obtained by separating the surface modification material ceramics into small chips 2 that are independent of each other. The stress distribution in each chip 2 is good, and stress deformation and thermal deformation exist around the chip. Since it is absorbed by the toughness of the melted and solidified material 3, cracks due to changes in load and changes in temperature and changes in temperature are unlikely to occur. Moreover, since the melted and solidified material 3 of the filler material in the surface modified layer 7 is continuous in a net shape with a specific width of 0.5 to 5 mm corresponding to the gap G, many ceramic chips 2 are melted and solidified. The entire surface modified layer 7 is firmly integrated by the object 3 and thus the joint strength between the surface modified layer 7 and the substrate 1 is high. In addition, since the ratio of the area covered by the ceramic chip of the surface 1a to be modified of the substrate 1 / the area of the substrate surface exposed between the ceramic chips is in a specific range of 40/60 to 96/4, Both the heat resistance and heat insulation action by the ceramics and the fixing strength by the melted solidified product 3 of the filler material are sufficiently exhibited. Accordingly, the surface-modified base material 1 has high heat resistance and high durability capable of maintaining sufficient strength even in a severe use environment that receives a compressive load or friction in a high temperature atmosphere. .

  When the gap G between the gaps 4 between the ceramic chips 2 becomes smaller than 0.5 mm, it becomes difficult to uniformly melt the filler material up to the deep part of the gap 4, and the surface modification layer 7 and the substrate The bonding strength with 1 is insufficient. On the other hand, if the gap G of the gap 4 is larger than 5 mm, the area ratio and volume ratio of the ceramic in the surface modification layer 7 become too small, and the heat resistance and wear resistance become insufficient. Further, if the above-mentioned area ratio of the ceramic chip 2 covering the surface 1a to be modified of the base material 1 is less than 40/60, the heat resistance and heat insulating action by the ceramics cannot be sufficiently exhibited. The adhesion strength of the surface modification layer 7 to the surface 1a to be modified of the material 1 becomes insufficient.

  On the other hand, as described above, it is recommended that the ceramic chip 2 has a bottom width W in a range of 5 to 15 mm, a length L in a range of 5 to 30 mm, and a thickness T in a range of 3 to 30 mm. . That is, if any one of these bottom width W, length L, and thickness T is too large, the stress dispersion upon receiving a compressive load is deteriorated, and cracking is likely to occur. On the contrary, if any of the bottom width W, length L, and thickness T is too small, the heat resistance and wear resistance are insufficient, and the work efficiency is also reduced due to the increase in the length of the joint.

  If a ceramic chip 2 having a trapezoidal cross section in the width direction and / or longitudinal direction is used, the cross section in the width direction of the melt-solidified material 3 of the filler material filling the gap 4 between the chips 2 is shown in FIG. Therefore, the binding force of the ceramic chip 2 by the molten solidified material 3 is remarkably increased. Therefore, even if the ceramic chip 2 is made of a material having poor wettability with respect to the filler material, the ceramic chip 2 can be reliably prevented from peeling off or dropping out. Therefore, in view of the restraining force, it is recommended that at least the cross section in the width direction is a trapezoid that is narrow on the front side and wide on the bottom side. In such a ceramic chip 2 having a trapezoidal cross section in the width direction, the ratio of the bottom width W to the top width D (see FIG. 2A) is preferably about 0.6 to 0.9 as D / W. .

  In this surface modification method, the bonding strength between the substrate 1 and the ceramic chip 2 is substantially borne by bonding with a filler material. Therefore, the ceramic chip 2 may be fixed to the modified surface 1a of the base material 1 at the previous stage by temporary fixing to prevent misalignment during bonding, depending on the properties of the ceramic chip 2 and the like. Various fixing methods can be employed. For example, the following first to third fixing methods are recommended as methods that can be fixed particularly easily and reliably in operation.

  In the first fixing method, when the ceramic chip 2 is an electrically conductive carbide or boride, as shown in FIGS. 4 (a) and 4 (b), a convex portion 21 such as a bowl is provided on the lower surface side. In a state where the ceramic chip 2 is placed on the surface 1a to be modified of the base material 1, the energization E with a required strength is performed between the upper surface side and the base material 1, thereby This is a method of fusing to the substrate 1 by resistance heat generation at the tip portion. In this case, the height S of the convex portion 21 is preferably about 0.1 to 0.5 mm. If it is too low, the fusion force is insufficient. A gap is formed between the surface to be modified 1a and the peel strength of the surface modified layer 7 is lowered.

  In the second fixing method, when the ceramic chip 2 is non-conductive such as nitride, a conductive metal layer 22 is provided on the peripheral surface thereof as shown in FIGS. In a state where the ceramic chip 2 is placed on the surface 1a to be modified of the base material 1, a current E with a required strength is applied to the base material 1 through the conductive metal layer 22, thereby In this method, the conductive metal layer 22 is fused to the substrate 1 in the same manner as described above. The conductive metal layer 22 is formed on the peripheral surface of the ceramic chip 2 with a thickness of about 50 to 500 μm made of a highly conductive metal such as Ni, Ni—Cr, or Ni—W by plating or spraying. do it.

  The third fixing method is a method in which a concave portion is formed on the surface 1a to be modified of the substrate 1, and the ceramic chip 2 is fitted into the concave portion and mechanically fixed. In this case, as shown in FIGS. 6 (a) and 6 (b), the concave portion of the surface 1a to be modified of the substrate 1 is a dovetail groove 11, and the ceramic chip 2 having a trapezoidal cross section in the width direction is used. A method of sliding the ceramic chip 2 in the groove 11 from the groove side end and crimping both side edges of the dovetail groove 11 at a predetermined fitting position is particularly simple. As a mechanical fixing means other than this caulking method, for example, there is a method in which the ceramic chip 2 is fitted into the recess and then a wedge-shaped metal piece is driven or press-fitted into the gap between the recess and the ceramic chip. In addition, the depth of the recessed part in the case of performing this mechanical fixation is good about 1-10 mm. In this case, the position G of the ceramic chip 2 between the ceramic chips 2 and the area ratio of the ceramics are based on the position of the surface 1a to be modified of the substrate 1.

Example 1
<Base material> It consists of a heat-resistant steel plate having a width of 50 mm, a length of 100 mm, and a thickness of 12.5 mm.
The modified surface has a width of 43 mm and a length of 87 mm, and a height of 7 mm around the surface to be modified.
Has a ridge.
<Ceramic Chip> TiB ₂ consists (boron, titanium), in the width direction cross-section base width
A 7 mm trapezoid with an upper end width of 6 mm, a length of 25 mm and a thickness of 7 mm Underside
On both sides in the longitudinal direction, there are bowl-shaped convex portions having a height of 0.2 mm.
On the surface to be modified of the base material, 12 ceramic chips are placed in a vertical and horizontal arrangement (3 × 4 rows) as shown in FIG. By performing, each ceramic chip was fixed to the base material (the area ratio of the ceramic to the surface to be modified: 57.8%). Then, using a laser overlay welding apparatus (semiconductor laser), a powder of UMCo50 (supra) with an average particle size of 50 μm is added as a filler material through a shielding gas (argon) in the gap between the ceramic chips on the substrate. While continuously supplying from three directions, the laser beam (output 1 kW, irradiation spot diameter 3 mm) is irradiated so that the gap is filled with the melt of the filler material, and is built up at a welding speed of 300 mm / min. The surface modification layer was formed by joining by a welding method. Then, by polishing the surface of the surface modification layer with a diamond grindstone, the excess portion of the filler metal protruding from the surface is removed including the surface layer portion of the ceramic chip, and the surface of the surface modification layer is flattened. Turned into.

Example 2
The same 10 ceramic chips as in Example 1 and 4 similar ones except that the length is different from 11 mm are used, and these ceramic chips are formed on the surface to be modified of the same substrate as in Example 1. Are placed in a zigzag arrangement as shown in FIG. 3B with a space of 3 mm between each other in the vertical and horizontal directions, and electricity is applied between the upper surface of each ceramic chip and the base material in the same manner as in Example 1. Each ceramic chip was fixed to a base material (area ratio of ceramics to the surface to be modified: 52.3%). Then, using the same laser overlay welding apparatus as in Example 1, the surface of the ceramic substrate was irradiated with a laser beam while supplying the powder of UMCo50 to the gap between the ceramic chips on the substrate in the same manner as in Example 1. After forming the modified layer, the surface was polished and planarized in the same manner as in Example 1.

Example 3
The ceramic chip is made of Si ₃ N ₄ (silicon nitride), has a bottom width of 8 mm, a length of 25 mm, a thickness of 10 mm and a cross section in the width direction of a trapezoid (top width 6 mm). As described in Example 1, four dovetail grooves with a bottom width of 8.5 mm are provided in parallel on the surface to be modified of the same base material as in Example 1, and a ceramic chip is slid into each dovetail groove from the groove side end. After being fitted and arranged at predetermined positions, the ceramic chips were fixed in the same vertical and horizontal arrangement as in Example 1 by crimping the groove edges on both sides of each ceramic chip. The distance between the ceramic chips in the vertical and horizontal arrangement is set to 3 mm in both the vertical and horizontal directions at the position of the surface of the substrate to be modified (area ratio of the ceramic to the surface to be modified: 57.8%). Then, after the surface modified layer is formed by irradiating the laser beam while supplying the powder of UMCo50 in the same manner as in Example 1, the surface is polished and planarized in the same manner as in Example 1. did.

1 Substrate 1a Surface to be modified 11 Dovetail (concave)
2,2 'Ceramic chip 21 Convex part 22 Conductive coating layer 3 Molten solidified material 30 Powder of filler metal 4 Gap 6a Laser beam 7 Surface modification layer f1, f2 Friction direction G Distance between ceramic chips L Length of ceramic chip T Ceramic chip thickness W Ceramic chip bottom width

Claims (8)

  The surface of the base material made of metal and the surface of the base material exposed between the ceramic chips with an area of 0.5 to 5 mm between the ceramic chips and the area covered with the ceramic chips. Are fixed so that the area ratio is in the range of 40/60 to 96/4, and a laser beam is supplied while continuously supplying a filler material into a net-like gap formed between the arranged ceramic chips. A surface modification method using ceramics characterized in that, by irradiation, the filler material is melted and filled to fill the gap.   The ceramic chip has a bottom width of 5 to 15 mm, a length of 5 to 30 mm, and a thickness of 3 to 30 mm, and a chip whose length is adjusted in the above range is used at the periphery of the surface of the base material to be modified. A surface modification method using ceramics according to claim 1.   The surface modification method using ceramics according to claim 1 or 2, wherein the ceramic chip has a trapezoidal cross section in the width direction and / or the longitudinal direction. The ceramic _{chip, TiB 2, Cr 3 C 2} , W 2 C, WC, SiC, Si 3 N 4, sialon, cordierite, alumina - claim 1 comprising at least one selected from graphite The surface modification method by ceramics as described in 2.   The surface modification method using ceramics according to claim 1, wherein the filler material is made of an alloy material having a melting point of 1150 ° C. or higher.   A convex part having a height of 0.1 to 0.5 mm is formed on the lower surface of the ceramic chip having electrical conductivity, and this ceramic chip is placed on the surface to be modified of the base material and energized to thereby apply the base material to the base material. On the other hand, the ceramic surface modification method according to any one of claims 1 to 5, wherein the ceramic chip is fused and fixed at the convex portion.   A conductive metal layer is formed on the peripheral surface of the ceramic chip having no electrical conductivity, and the ceramic chip is placed on the surface to be modified of the base material and energized, whereby the ceramic chip is attached to the base material. The surface modification method using ceramics according to any one of claims 1 to 5, wherein the conductive metal layer is fused and fixed. 6. The surface modification method using ceramics according to any one of claims 1 to 5, wherein a concave portion having an expanded bottom surface is formed on the surface of the substrate to be modified, and the ceramic chip is fitted into the concave portion and mechanically fixed.

Images