JP4967505B2 - Covering member - Google Patents

Description

  The present invention relates to a covering member in which a surface of a base material such as a sintered alloy, ceramics, cBN sintered body, diamond sintered body, etc. is coated. In particular, the present invention relates to a covering member suitable for a cutting tool represented by a tip, a drill, an end mill, various wear-resistant tools, and wear-resistant parts.

A coated member formed by coating a surface of a base material such as a sintered alloy, ceramics, cBN sintered body, diamond sintered body with a coating such as TiC, TiCN, TiN, (Ti, Al) N, Al ₂ O ₃ Because of the high strength, high toughness of the base material, and excellent wear resistance, oxidation resistance, lubricity, and welding resistance of the coating, it is frequently used as a cutting tool, wear-resistant tool, and wear-resistant part. Yes. Until now, in order to fully exhibit the characteristics of the coating, the hardness and oxidation resistance of the coating have been improved.

  As a conventional hard coating, there is a hard coating for cutting tools made of (Ti, Al, Cr) (C, N) (see, for example, Patent Document 1). Moreover, there exists an Al-Cr-N-type film | membrane as a film | membrane excellent in oxidation resistance (for example, refer nonpatent literature 1). However, due to changes in the work material, cutting conditions, etc., there has been a problem that a long tool life cannot be obtained with a cutting tool coated with these films.

JP 2003-71610 A Yukio Ide and three others, "Development of Al-Cr-N-based coatings with excellent high-temperature oxidation resistance", "Materia" Vol. 40, No. 9, 2001, p.815-816

  In recent years, severe cutting conditions such as severe cutting conditions such as high speed and high feed and high hardness of the work material have been increasing in cutting, and cutting tools made of conventional coated materials meet the recent severe processing demands. It has become impossible. The present invention has been made in view of such circumstances, and in a cutting process with severe processing conditions such as high-speed machining, high-feed machining, and machining of a high-hardness work material, a covering member that realizes a long life is provided. For the purpose of provision.

  The present inventor has been working on improving the cutting performance of a covering member coated with a hard film such as (TiAl) N, (CrAl) N, (TiAlCr) N, etc. As a result, the hard film has Mn, Cu, Ni, Co. , B, Si, S, the addition of at least one additive element reduces the crystallite size of the hard film, increases the stability of the crystal, increases the high-temperature hardness, and wear resistance. In addition to the knowledge that the non-metallic elements contained in the hard film are increased, the knowledge that the oxidation resistance is improved can be obtained. Since the covering member coated with the hard film of the present invention is excellent in wear resistance and oxidation resistance, it has been found that a long life can be realized when used as a cutting tool.

That is, the covering member of the present invention has (M _a L _b ) X _c (where M is Cr, Al, Ti, Hf, V, Zr, Ta, Mo, W, Y) on the surface of the base material. L represents at least one selected metal element, L represents at least one additive element selected from Mn, Cu, Ni, Co, B, Si, and S, and X represents C, N, or O At least one nonmetallic element selected from the above, a represents the atomic ratio of M to the sum of M and L, b represents the atomic ratio of L to the total of M and L, and c represents M And a, b and c are 0.85 ≦ a ≦ 0.99, 0.01 ≦ b ≦ 0.15, a + b = 1, respectively. A coating containing a hard film satisfying 1.00 <c ≦ 1.20 is coated.

  Specific examples of the base material of the covering member of the present invention include sintered alloys, ceramics, cBN sintered bodies, diamond sintered bodies, and the like. Among these, sintered alloys are preferable because they are excellent in fracture resistance and wear resistance, and among these, cemented carbides are more preferable.

The hard film of the present invention has (M _a L _b ) X _c (where M is at least one metal selected from Cr, Al, Ti, Hf, V, Zr, Ta, Mo, W, and Y). L represents an element, L represents at least one additive element selected from Mn, Cu, Ni, Co, B, Si, and S, and X represents at least one element selected from C, N, and O A represents the atomic ratio of M to the sum of M and L, b represents the atomic ratio of L to the sum of M and L, and c represents the ratio of X to the sum of M and L. A, b, and c are 0.85 ≦ a ≦ 0.99, 0.01 ≦ b ≦ 0.15, a + b = 1, and 1.0 <c ≦ 1. Satisfy 2 The hard film of the present invention is excellent in wear resistance and oxidation resistance. When a is less than 0.85, the oxidation resistance decreases, and when a exceeds 0.99, the hardness of the hard film decreases, so 0.85 ≦ a ≦ 0.99. When b is less than 0.01, there is no effect of adding L, the crystallite becomes large, and the hardness of the hard film decreases. When b exceeds 0.15, the oxidation resistance is not improved, so 0.01 ≦ b ≦ 0.15. When c exceeds 1.00, the oxidation resistance is improved, and when c exceeds 1.20, the hardness of the hard film decreases, so 1.00 <c ≦ 1.20.

  In the hard film of the present invention, the size of the crystallite is reduced by the effect of the additive element, and when the size of the crystallite is 5 to 15 nm, the wear resistance is further improved, which is more preferable.

  The film of the present invention is a single-layer film consisting of only the hard film of the present invention, a multilayer film in which two or more hard films of the present invention having different compositions are laminated, and M is Cr, Al, Ti, Hf, V, Zr. , Ta, Mo, W, Y carbide, nitride, oxide, and a multilayer film obtained by laminating the hard film of the present invention and a film made of at least one of these mutual solid solutions, wear resistance, acid resistance It is preferable because it is excellent in chemical conversion. Among these, a multilayer film in which three or more hard films of the present invention are laminated is more preferable. When the average film thickness of the coating of the present invention is 0.01 μm or more, the wear resistance and oxidation resistance are improved, and when it exceeds 10.0 μm, the fracture resistance is lowered, so the range of 0.01 to 10.0 μm. Is preferred.

  The composition of the coating can be measured using an elemental analyzer such as a secondary ion mass spectrometer (SIMS), an energy dispersive element analyzer (EDS), or a glow discharge type analyzer (GDS).

The coating and hard film of the present invention can be produced using an arc ion plating apparatus (hereinafter referred to as AIP apparatus), a sputtering apparatus or the like. Specifically, an arc discharge voltage of 20 to 100 V, a substrate bias of −30 is used on the surface of the base material in an atmosphere of a base material temperature of 273 to 973 K and a pressure of 0.5 to 2.8 Pa using, for example, arc ion plating. When the hard film is coated under the condition of -200V, the coated member of the present invention is obtained. In order to improve the film quality of the hard film, it is effective to generate a large amount of multivalent ions by increasing the arc voltage. The arc discharge control method includes constant current control and constant voltage control. The constant current control has a problem that when the arc voltage is increased, the arc current also increases and the power supply becomes large. Therefore, the constant voltage control is preferable as the arc discharge control method.

  The covering member of the present invention is excellent in wear resistance and oxidation resistance. When the covering member of the present invention is used as a cutting tool, an effect of realizing a long life is exhibited. Among them, the effect is high in cutting processing with severe processing conditions such as high-speed processing, high-feed processing, and processing of a hard material.

A chip made of cemented carbide equivalent to K20 having a shape of SDKN1203AETN is prepared as a base material. A substrate is loaded into an AIP apparatus capable of mounting a 6-pole target including a metal bombardment electrode, and after evacuation to a pressure of 1 × 10 ⁻³ Pa, The substrate was heated to 773K with a heater. The metal bombardment was performed under the bombardment conditions of pressure: 1 × 10 ⁻² Pa, base material bias potential: −600 V, arc current: 100 A, and time: 6 minutes. A film having a film configuration shown in Tables 1 to 3 was coated. For the coating, a target having a component ratio between the metal element and the additive element of each film is used. If necessary, N ₂ , O ₂ , CH ₄ or a mixed gas thereof is introduced as a reaction gas, and pressure: 0.6 to The coating was performed under coating conditions of 2.5 Pa, arc voltage: DC modulation 30 to 70 V (constant voltage control), and substrate bias voltage: −30 to −80 V. In addition, the metal bombardment in the case of producing a comparative product was made into the same bombardment conditions as the invention product. The comparative product was coated under the coating conditions of pressure: 3.0 Pa, arc current: 120 A (constant current control), and substrate bias voltage: −30V.

  The chemical composition of each film shown in Tables 1 to 3 was measured using a glow discharge analyzer (GDS) capable of rapid elemental analysis in the depth direction. As for the atomic ratio of the nonmetallic element to the total of the metallic elements and the additive elements contained in each coating, the atomic ratio of the nonmetallic element N to the metallic element Ti produced by the thermal CVD method: TiN film with N / Ti = 1 Calculation was performed based on (average film thickness 3 μm).

  Using the coated cemented carbide tools of the inventive products 1-8 and comparative products 1-6, under the conditions of the work material: SCM440, cutting speed: 212 m / min, cutting: 2.0 mm, feed: 0.2 mm / tooth A dry milling test was performed. The tool life was estimated based on the flank wear amount VB = 0.3 mm. When the flank wear amount VB did not reach 0.3 mm by the cutting length of 6 m, the flank wear amount VB at the cutting length of 6 m was measured. These results are shown in Table 4.

寿命判定：ＶＢ＝０．３ｍｍ

Life judgment: VB = 0.3mm

  As Table 4 shows, invention products 1-8 are excellent in abrasion resistance, and therefore the flank wear amount VB is smaller than comparative products 1-6 even at the same cutting length. It can be seen from Table 4 that the inventive products 1 to 8 have a longer lifetime than the comparative products 1 to 6.

In order to measure the size of the crystallites of the coating, a 5 × 5 × 0.1 mm cemented carbide substrate was prepared, and the surface of this substrate was coated with the coating of Invention 1 and Comparative 1 Produced. Next, using a focused ion beam (FIB), the film was cut in a direction perpendicular to the surface of the sample to obtain a coating cross section. The obtained coating cross section was observed using a transmission electron microscope (TEM). Fig. 1 shows a transmission electron micrograph of the second layer (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 1, and Fig. 2 shows a transmission type of (Ti _0.50 Al _0.50 ) N _1.00 film of Comparative product 1. An electron micrograph is shown. The crystallite size of the second layer (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 1 is 5 to 15 nm, and the crystal of (Ti _0.50 Al _0.50 ) N _1.00 film of Comparative Product 1 It was confirmed that the size of the child was 20 to 100 nm.

A commercially available molybdenum substrate was coated with a (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film to obtain Invention 9. In addition, a commercially available molybdenum substrate was coated with a (Ti _0.50 Al _0.50 ) N _1.00 film to obtain a comparative product 7. In order to evaluate the stabilization of the crystal structure of the coating, it was heated from 500 ° C. to 1000 ° C. in the atmosphere, and the change in the crystal structure was examined by X-ray diffraction. In Invention 9, which covered the (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film, only cubic crystals were observed up to 1000 ° C., and almost no change was observed. On the other hand, in Comparative product 7 coated with a (Ti _0.50 Al _0.50 ) N _1.00 film, the cubic X-ray diffraction peak intensity decreased at 800 ° C. or higher, and a soft hexagonal X-ray diffraction peak was confirmed.

Inventive product 9 and comparative product 7 were subjected to an oxidation test using an atmospheric furnace capable of heating to 1100 ° C. The thickness of the oxide layer was measured from a change in weight by an chemical balance, generation of an oxide by X-ray diffraction or the like, and observation of a cross section of the film by a scanning electron microscope. At 900 ° C., the (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 9 was not oxidized and kept in a good state. On the other hand, an oxide layer having a thickness of 1 μm was confirmed on the surface of the (Ti _0.50 Al _0.50 ) N _1.00 film of Comparative product 7. At 1000 ° C., an oxide layer having a thickness of 0.5 μm was confirmed on the surface of the (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 9. On the other hand, an oxide layer having a thickness of 2 μm was confirmed on the surface of the (Ti _0.50 Al _0.50 ) N _1.00 film of Comparative product 7, and a part of the film was peeled off. At 1100 ° C., the thickness of the oxide layer formed on the surface of the (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 9 was 1 μm. On the other hand, in the comparative product 7, the entire film was oxidized, and a part of the film was removed from the molybdenum substrate.

Transmission electron micrograph of the second layer (Ti _0.20 Cr _0.20 Al _0.57 Si _0.03 ) N _1.09 film of Invention 1 Transmission electron micrograph of (Ti _0.50 Al _0.50 ) N _1.00 film of Comparative product 1 Effect of temperature on indentation hardness of coating in vacuum.

Claims (2)

In the coating member in which the surface of the substrate is coated, at least three layers of the coating are (M _a L _b ) X _c (where M is Cr, Al, Ti, Hf, V, Zr, Ta, Mo, W , Y represents at least one metal element selected from among Y, L represents at least one additive element selected from Mn, Cu, Ni, Co, B, Si, and S, and X represents C , N, O represents at least one nonmetallic element selected from the group consisting of a, M represents an atomic ratio of M to the sum of M and L, and b represents an atomic ratio of L to the sum of M and L. Where c represents the atomic ratio of X with respect to the sum of M and L.), a, b and c are 0.85 ≦ a ≦ 0.99 and 0.01 ≦ b ≦ 0.15, respectively. , a + b = 1,1.00 <I from multilayered film of laminated layers c ≦ 1.20 a different hard film in composition satisfying continuously three or more layers Covering member. The covering member according to claim 1 whose crystallite size of a hard film is 5-15 nm.

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