JP2011068960A - Surface-coated member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-coated member having high adhesion and wear resistance and for use in such as a cutting tool. <P>SOLUTION: The surface-coated member is for the cutting tool 1 or the like and has high adhesion and wear resistance. The surface-coated member is made of a constitution wherein the surface of a substrate 6 made of Al<SB>2</SB>O<SB>3</SB>-rich ceramics is coated with an Al<SB>2</SB>O<SB>3</SB>layer 7 as a first layer, the Al<SB>2</SB>O<SB>3</SB>layer 7 has an α type crystal structure, also, in the X-ray diffraction analysis measured from the surface of the Al<SB>2</SB>O<SB>3</SB>layer 7, the peak belonging to the (116) face is the strongest peak. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a surface coating member in which a coating layer is formed on the surface of a substrate.

  At present, for members that require wear resistance, slidability, and fracture resistance, such as cutting tools, wear-resistant members, and sliding members, sintered alloys such as cemented carbide and cermet, diamond, and cBN (cubic boron nitride) A method of improving the wear resistance, slidability, and fracture resistance by forming a coating layer on the surface of a high-hardness sintered body and a substrate made of a ceramic such as alumina or silicon nitride is used. Among them, ceramic tools are used for cutting high-hardness materials because they are inexpensive and have excellent wear resistance.

For example, Patent Document 1 discloses a coated ceramic tool in which an Al ₂ O ₃ layer is provided as a first layer on a surface of an Al ₂ O _{3 based} ceramic substrate with chamfer honing by a known chemical vapor deposition method.

On the other hand, various developments have been made on the coating layer, and Patent Document 2 discloses a cutting tool in which the surface of a cBN substrate is coated with an Al ₂ O ₃ layer having various orientation indices Tc, and Tc (116). A coating layer of 1.0 or more is described. Patent Document 3 discloses a configuration in which an inner layer made of TiN, TiCN, TiC, TiB ₂ or the like is formed on the surface of a cemented carbide substrate, and an Al ₂ O ₃ layer is formed on the upper surface of the inner layer. A coating layer having an orientation index TCa (116) of 1.6 and a TCa (104) of 1.3 of the Al ₂ O ₃ layer is described.

JP-A-5-169302 JP 2000-44370 A Japanese Patent Laid-Open No. 11-124672

However, in the configuration of Patent Document 1 in which an Al ₂ O ₃ layer is provided as a first layer on the surface of an Al ₂ O ₃ ceramic substrate by a known chemical vapor deposition method, when a difficult-to-cut material such as cast iron is cut, Al ₂ There was a problem that the O ₃ layer was partially peeled off and satisfactory wear resistance could not be obtained.

Further, as in Patent Document 2 and Patent Document 3, in the configuration in which the surface of a cBN substrate or cemented carbide substrate is coated with an Al ₂ O ₃ layer having various crystal plane orientation indices as the first layer (116 ) The Al ₂ O ₃ layer having a high orientation index of the surface did not show high cutting performance as compared with others.

In particular, when used for severe cutting such as cutting at a high speed on a hard work material, the Al ₂ O ₃ layer may peel off or chipping (flaking) at the cutting edge. The tool performance was insufficient. In addition, since the surface of the ceramic substrate is high in hardness and inferior in toughness, there is a possibility that it will be lost in the initial stage when the coating layer is impacted.

Therefore, an object of the surface covering member of the present invention is to provide a cutting tool having a longer life with Al ₂ O ₃ ceramics as a base.

The surface covering member of the present invention has a structure in which an Al ₂ O ₃ layer is coated as a first layer on the surface of a substrate made of Al ₂ O ₃ ceramics, and the Al ₂ O ₃ layer has an α-type crystal structure, and The peak attributed to the (116) plane in the X-ray diffraction analysis measured from the surface of the Al ₂ O ₃ layer is the strongest peak.

Here, in the above configuration, it is desirable that the organization coefficient Tc (116) represented by the following formula is 1.5 to 1.8.
Tc (116) = {I (116) / I ₀ (116)} / {(1/6) Σ [I (hkl) / I ₀ (hkl)]}
However,
(Hkl) plane: (012), (104), (110), (113), (024) and (116) plane I (hkl): The peak intensity of the X-ray diffraction peak attributed to the (hkl) plane Measurement value I ₀ (hkl): Standard X-ray diffraction peak intensity on the (hkl) plane of JCPDS card number 10-173 Σ [I (hkl) / I ₀ (hkl)]: (012), (104), (110 ), (113), (024), (116) plane total [value of measured X-ray diffraction peak intensity / standard X-ray diffraction peak intensity] Further, in the above configuration, the Al ₂ O _{3 based} ceramics may contain ZrO. ₂ is preferably contained at a ratio of 10 to 30% by mass.

Further, in the above structure, an average particle size of the _Al 2 _{O 3} particles when observing the _{the Al} 2 _{O 3} layer from the surface it is desirable that 0.3～1Myuemu.

According to the surface covering member of the present invention, the Al ₂ O ₃ layer is directly coated on the surface of the substrate made of Al ₂ O ₃ ceramic, and the Al ₂ O ₃ layer has an α-type crystal structure, and The structure is oriented in the (116) plane with respect to the surface. With this configuration, the reason is unknown, but the Al ₂ O ₃ layer has excellent adhesion and wear resistance. In particular, it is desirable that the organization coefficient Tc (116) represented by the above formula is 1.5 to 1.8 in terms of improvement in adhesion to the substrate and wear resistance.

Here, in the above structure, when ZrO ₂ is contained in a proportion of 10 to 30 mass%, the particle size of the _Al 2 _{O 3} particles constituting the _{the Al} 2 _{O 3} layer is reduced to _Al 2 _{O 3} quality ceramics There is a tendency. As a result, since the hardness and strength of the Al ₂ O ₃ layer are improved, wear resistance and chipping resistance as a tool are improved. At this time, when the Al ₂ O ₃ layer is observed from the surface, the average particle diameter of the Al ₂ O ₃ particles is preferably 0.3 to 1 μm from the viewpoint of improvement in wear resistance and fracture resistance.

An example of the cutting tool which is a suitable example of the surface covering member of this invention is shown, (a) A schematic perspective view and (b) A schematic sectional drawing. The the Al ₂ O ₃ layer constituting the surface-coated tool of the present invention is a scanning electron micrograph showing an example of observation of the surface.

  An example of the cutting tool which is a suitable example of the surface covering member of the present invention will be described based on (a) a schematic perspective view and (b) a schematic sectional view of FIG.

As shown in FIG. 1 (a), the cutting tool 1 of the present invention has a shape in which the intersecting ridge line between the rake face 2 and the flank 3 is the cutting edge 4, and as shown in FIG. 1 (b), Al The surface of a substrate (hereinafter simply referred to as “substrate”) 6 made of ₂ O ₃ ceramics is covered with a coating layer 8 having an Al ₂ O ₃ layer 7 as a first layer.

The Al ₂ O ₃ ceramics forming the substrate 6 may include Mg, Ca, Si, Zr, Cr, Ti, Ni, Co, Y and rare earth element oxides, Ti, if desired, in a matrix of Al ₂ O ₃ particles. , Si carbide, nitride, carbonitride, and carbonitride oxide.

Here, in the above composition, the _Al 2 _{O 3} quality ceramics to be contained in a proportion of ZrO ₂ is 10 to 30 _mass%, the particle size of the _Al 2 _{O 3} particles constituting the the Al 2 _{O 3} layer is This tends to be small, and is desirable because the hardness and strength of the Al ₂ O ₃ layer 7 are improved and the wear resistance and chipping resistance of the cutting tool 1 are improved. At this time, as shown in the scanning electron micrograph of FIG. 2, when the Al ₂ O ₃ layer 7 is observed from the surface, the average particle diameter of the Al ₂ O ₃ particles is 0.3 to 1 μm. It is desirable in terms of improvement in wear resistance and fracture resistance.

The average particle size of the _Al 2 _{O 3} particles contained in _Al 2 _{O 3} quality ceramics are base 6, wear resistance, 0.05 to 3 [mu] m from the strength point, preferably 0.1 to 0. It is desirable to be in the range of 5 μm. The particle size measurement of _Al 2 _{O 3} particles and other compound particles may be measured according to the measurement method of the average particle size of the defined cemented carbide CIS-019D-2005.

On the other hand, the coating layer 8 has an α 2 crystal structure on the surface of the substrate 6 and an Al ₂ O ₃ layer 7 whose peak attributed to the (116) plane is the strongest peak in the X-ray diffraction analysis measured from the surface. Covered as a first layer. With this configuration, the Al ₂ O ₃ layer 7 is excellent in adhesiveness and wear resistance. In particular, it is desirable that the organization coefficient Tc (116) represented by the following formula is 1.5 to 1.8 in terms of improvement in adhesion to the substrate 6 and wear resistance.
Tc (116) = {I (116) / I ₀ (116)} / {(1/6) Σ [I (hkl) / I ₀ (hkl)]}
However,
(Hkl) plane: (012), (104), (110), (113), (024) and (116) plane I (hkl): The peak intensity of the X-ray diffraction peak attributed to the (hkl) plane Measurement value I ₀ (hkl): Standard X-ray diffraction peak intensity on the (hkl) plane of JCPDS card number 10-173 Σ [I (hkl) / I ₀ (hkl)]: (012), (104), (110 ), (113), (024), (116) The total of [X-ray diffraction peak intensity measurement value / standard X-ray diffraction peak intensity] values in the plane Note that the desirable range of the film thickness of the Al ₂ O ₃ layer 7 is 0.5-5 μm. Here, when the Al ₂ O ₃ layer 7 is observed from the surface, the average particle diameter of the Al ₂ O ₃ particles is preferably 0.3 to 1 μm from the viewpoint of improvement in wear resistance and fracture resistance. In calculating the average particle diameter, the shape of each particle is specified from a micrograph, and the area of each particle is obtained by an image analysis method. Then, the particle diameter when each particle is assumed to be a circle is calculated, and the average value is defined as the average particle diameter.

Further, the coating layer 8 is coated with another coating layer 9 selected from one of carbides, nitrides and carbonitrides of Group 4, 5 and 6 metals of the periodic table as an upper layer of the Al ₂ O ₃ layer 7. A multilayer structure may be used. The total thickness of the coating layer 8 is preferably 0.5 to 10 μm → 1 to 7 μm because it can prevent film peeling and chipping of the coating layer 8 and maintain sufficient wear resistance. In particular, when used as a cutting tool for high-speed rough cutting, the thickness of the coating layer 8 is 1.0 μm to 5.0 μm. When used as a cutting tool for machining cast iron, the thickness of the coating layer 8 is 2. It is desirable that it is 0 micrometer-7.0 micrometers.

  Further, the surface covering member of the present invention is not limited to the above cutting tool, and can be suitably used for a member that requires wear resistance and fracture resistance, such as an abrasion resistant member and a sliding member.

(Production method)
Next, the manufacturing method of the tool mentioned above is demonstrated.

For example, additive raw material powders such as Al ₂ O ₃ raw material powder having a predetermined average particle diameter in the range of 0.2 to ₃ μm and ZrO ₂ powder having an average particle diameter of 0.1 to ₂ μm as the raw material powder have a specific composition And weigh and mix.

Then, the mixed powder is formed into a predetermined shape. For molding, known molding means such as press molding, injection molding, cast molding, and extrusion molding can be used. Thereafter, the molded body is subjected to binder removal treatment, and then fired at 1500 to 1750 ° C. in the air or in a non-oxidizing atmosphere, preferably in a non-oxidizing reduced pressure atmosphere such as argon (Ar) gas. If desired, the surface of the obtained base 6 made of Al ₂ O ₃ ceramics is ground, and if desired, chamfer honing or R honing is applied to the cutting edge portion.

  The processed substrate is preferably washed with an acid solution or an alkali solution and then rinsed with pure water or alcohol.

Next, the coating layer 8 is formed on the surface of the substrate 6. As a method for forming the Al ₂ O ₃ layer 7, first, the substrate 6 is set in a chemical vapor deposition apparatus, and the temperature is raised to 980 to 1050 ° C. while the chamber is replaced with an H ₂ or Ar atmosphere. At this time, the temperature is maintained until the inside of the chamber is soaked within 10 ° C.

Then, hydrogen (H ₂ ) and hydrogen chloride (HCl) gas are flowed into the chamber for 3 to 10 minutes. Then, the hydrogen (H ₂ ) and hydrogen chloride (HCl) gas in the chamber is replaced with hydrogen (H ₂ ) and aluminum chloride (AlCl ₃ ) gas. By this step, uniform and fine Al ₂ O ₃ layer nuclei are formed on the surface of the substrate 6.

Thereafter, aluminum trichloride (AlCl ₃ ) gas is 0.5 to 5.0% by volume, hydrogen chloride (HCl) gas is 0.5 to 3.5% by volume, and carbon dioxide (CO ₂ ) gas is 0.5 to 5.0%. Using a mixed gas consisting of 5.0% by volume, hydrogen sulfide (H ₂ S) gas in an amount of 0.0 to 0.5% by volume, and the remainder being hydrogen (H ₂ ) gas, the film forming temperature is 950 to 1100 ° C., and the pressure The Al ₂ O ₃ layer 7 is formed to a thickness of 5 to 10 kPa.

Using Al ₂ O ₃ powder having an average particle size of 0.5 μm, ZrO ₂ powder having an average particle size of 1.0 μm, MgO powder, SiC powder, TiCN powder, TiC powder and Co powder, the powders were prepared as shown in Table 1, and this powder was prepared. The body was mixed for 72 hours in a ball mill using alumina balls.

Next, the mixed powder was press-molded into a throwaway tip shape of JIS / CNGA120408 at a pressure of 98 MPa. This molded body was treated to remove the binder and then fired at 1650 ° C. in a non-oxidizing atmosphere of argon (Ar) gas 0.04 MPa to obtain Al ₂ O ₃ ceramics. Both the main surfaces of the alumina ceramic substrate were ground and the cutting edge portion of the substrate was subjected to a blade edge treatment using a diamond wheel to form a 0.2 mm × 20 ° chamfer honing on the cutting blade.

The substrate thus prepared was washed with an acid solution and an alkali solution, rinsed with pure water and alcohol, and then a coating layer was formed by chemical vapor deposition (CVD). As a specific film forming method, after pre-processing under the pre-processing conditions shown in Table 2, the film was formed at the film-forming temperature shown in Table 1. In forming each layer, AlCl ₃ : 1.5% by volume, HCl: 2% by volume, CO ₂ : 4% by volume, H ₂ S: 0.3% by volume, H ₂ : the remaining mixed gas is flowed. the _{the Al} 2 _{O 3} layer Te, TiCl _4: 5.0 by _volume%, N 2: 20 vol%, _CH 4: 9 vol%, _{H 2:} the TiCN layer with a mixed gas of residual, TiCl _4: 3.0 by volume %, N ₂ : 30% by volume, H ₂ : TiN layer was formed with the remaining mixed gas.

About the obtained throw-away tip, X-ray diffraction measurement is performed from the surface of the coating layer, the crystal structure and diffraction peak of the Al ₂ O ₃ layer are identified, and the structure is determined from the peak intensity of the peak attributed to the (116) plane. The conversion factor Tc (116) was calculated. Further, the surface and section of the coating layer was observed with a scanning electron microscope to calculate the thickness of the average particle diameter and the coating layer of Al ₂ O ₃ particles when viewed the Al ₂ O ₃ layer from the surface. When measuring the average particle size of the first layer of the coating layer in a structure in which two layers are laminated, the color mapping of each particle is performed by measuring the crystal orientation by the EBSD (EBS Diffraction) method on the polished surface from which the upper layer is polished and removed. The particle diameter of each particle was estimated, and the average particle diameter when the crystal was assumed to be a circle was calculated from the image analysis method. The results are shown in Table 3.

Next, a cutting test was performed using the throwaway tip under the following cutting conditions. The results are shown in Table 3.
Cutting method: Peripheral workpiece: SKD11
Cutting speed: 150 m / min Feed: 0.5 mm / rev
Cutting depth: 0.5mm
Cutting state: Dry evaluation method: Time for flank wear to be 0.3 mm or more

From the results shown in Tables 1 to 3, Sample No. _{2 in which} the Al ₂ O ₃ layer does not have an α-type crystal structure. No. 7 resulted in poor wear resistance. In addition, Sample No. in which the strongest peak of the Al ₂ O ₃ layer is not a peak attributed to the (116) plane is obtained. In No. 8, flaking occurred during cutting, and the tool life was short. Furthermore, sample No. 1 with the TiCN layer as the first layer was formed. In No. 6, the adhesion of the coating layer was lowered and delamination occurred.

  On the other hand, the composition of the hard layer is within the range of the present invention. 1 to 5 exhibited excellent wear resistance and good fracture resistance. As a result, the tool life was long.

1 cutting tool 2 rake face 3 flank 4 cutting edge 6 base 7 _Al 2 _{O 3} layer 8 covering layer 9 other coating layer

Claims (4)

A surface of a base made of Al ₂ O ₃ ceramic is coated with an Al ₂ O ₃ layer as a first layer, the Al ₂ O ₃ layer has an α-type crystal structure, and the Al ₂ O ₃ layer A surface-coated member in which the peak attributed to the (116) plane is the strongest peak in the X-ray diffraction analysis measured from the surface. The surface covering member according to claim 1 whose organization factor Tc (116) denoted by a following formula is 1.5-1.8.
Tc (116) = {I (116) / I ₀ (116)} / {(1/6) Σ [I (hkl) / I ₀ (hkl)]}
However,
(Hkl) plane: (012), (104), (110), (113), (024) and (116) plane I (hkl): The peak intensity of the X-ray diffraction peak attributed to the (hkl) plane Measurement value I ₀ (hkl): Standard X-ray diffraction peak intensity on the (hkl) plane of JCPDS card number 10-173 Σ [I (hkl) / I ₀ (hkl)]: (012), (104), (110 ), (113), (024), (116) plane [total X-ray diffraction peak intensity measurement value / standard X-ray diffraction peak intensity] value The surface covering member according to claim 1 or 2, wherein ZrO ₂ is contained in the Al ₂ O _{3 based} ceramic in a proportion of 10 to 30% by mass. Surface-coated member according to claim 3, wherein an average particle size of the _Al 2 _{O 3} particles are 0.3~1μm when observing the _{the Al} 2 _{O 3} layer from the surface.