Pvd coated ceramic substrate

Abstract

Disclosed herein are ceramic substrates having physical vapor deposition coatings. An adhesion layer between the ceramic substrate and the PVD coating provides improved adhesion for the PVD coating. The ceramic substrate can be silicon nitride-based and / or silicon oxide-based. The PVD coating can include a nitride, such as titanium nitride, aluminum nitride, or titanium aluminum nitride. The adhesion layer can include titanium boride, titanium nitride, or a combination thereof. An ion implantation layer can be provided between the ceramic substrate and the adhesion layer.

Description

Technical Field

[0001] The present invention relates to ceramic substrates having a physical vapor deposition coating, the physical vapor deposition coating having improved adhesion. Background Technology

[0002] Ceramic materials are generally more difficult to coat than metal-based substrates due to their poor or non-existent electrical conductivity, as well as the lattice mismatch between the ceramic substrate and the coating material. Summary of the Invention

[0003] This invention provides a ceramic substrate with a physical vapor deposition (PVD) coating. An adhesion layer between the ceramic substrate and the PVD coating provides improved adhesion to the PVD coating. The ceramic substrate may be silicon nitride-based and / or silicon oxide-based. The PVD coating may contain nitrides, such as titanium nitride, aluminum nitride, or titanium aluminum nitride. The adhesion layer may contain titanium boride, titanium nitride, or a combination thereof. An ion implantation layer may be disposed between the ceramic substrate and the adhesion layer.

[0004] One aspect of the present invention is to provide a coated ceramic substrate comprising: a ceramic substrate, and an adhesion layer located on at least a portion of the ceramic substrate, the adhesion layer comprising Ti(B) x N 2-x ), and a PVD coating located on at least a portion of the adhesive layer.

[0005] Another aspect of the present invention provides a method for physical vapor deposition of a coating on a ceramic substrate, comprising: depositing a coating containing Ti(B) X N 2-X An adhesion layer is deposited on a ceramic substrate, and a PVD coating is physically vapor-deposited onto at least a portion of the adhesion layer.

[0006] These and other aspects of the invention will become more apparent from the following description. Attached Figure Description

[0007] Figure 1 This is a schematic diagram showing a ceramic substrate with an adhesion layer and a PVD coating. Detailed Implementation

[0008] Figure 1A ceramic substrate 10 having a physical vapor deposition (PVD) coating 20, an intermediate adhesion layer 16, and an optional ion implantation layer 14 is schematically shown. The ceramic substrate 10 may comprise nitrides, oxides, carbides, borides, and combinations thereof. As used herein, when referring to a substrate, the term "ceramic" includes ceramic materials and ceramic-containing materials that include a large amount of ceramics, such as cermet composites. Examples of nitrides include silicon nitride, aluminum nitride, aluminum silicon nitride, etc. Examples of oxides include alumina, silicon oxide, silicon alumina, etc.

[0009] The ceramic substrate 10 can be based on silicon nitride and / or silicon oxide, such as silicon nitride (SiN). X ), silicon aluminum nitride (Si / AlN) X ), silicon dioxide (SiO) X ), silicon aluminum oxide (Si / AlO) X Examples of suitable ceramic substrates include silicon nitride (SiAlON) doped with aluminum and oxygen. Alternatively, the ceramic substrate 10 may comprise an alumina-based ceramic, such as alumina (AlO). X ), alumina silicon (Al / SiO) X )wait.

[0010] The ceramic substrate 10 may have a crystal structure that does not match the crystal structure of the PVD coating 20 to be applied to the ceramic substrate. For example, the SiAlON ceramic substrate material may have a hexagonal crystal structure (P6 group), unlike the non-hexagonal crystal structure of the PVD coating, such as a cubic titanium aluminum nitride coating. This crystal structure mismatch, for example, between the SiAlON ceramic substrate and the TiAlN PVD coating, may result in poor adhesion of the coating to the substrate.

[0011] The deposited adhesion layer 16 may comprise borides, nitrides, and combinations thereof. Examples of borides include titanium boride, zirconium boride, chromium boride, vanadium boride, molybdenum boride, other transition metal borides, or combinations thereof. Examples of nitrides include titanium nitride, zirconium nitride, chromium nitride, vanadium nitride, molybdenum nitride, other transition metal nitrides, or combinations thereof.

[0012] For example, the adhesion layer 16 may contain titanium boride (TiB). X Titanium nitride (TiN) X ) or a combination thereof (Ti(B) X N 2-X Ti(B) X N 2-XThe stoichiometry of the adhesion layer can be constant or variable throughout its thickness. For example, the adhesion layer may initially be boron-rich when deposited on a ceramic substrate and can be converted to n-rich during subsequent depositions, such as first depositing TiB2 followed by Ti(B)2. X N 2-X ( ) deposition, followed by TiN deposition, to form a graded adhesion layer.

[0013] The composition of the adhesion layer 16 can be controlled to produce a crystalline structure that promotes the adhesion of the subsequently deposited PVD coating 20. For example, the adhesion layer 16 may have a cubic crystal structure, a hexagonal crystal structure, or a crystal structure that transitions from a hexagonal structure adjacent to the ceramic substrate to a cubic structure adjacent to the PVD coating. For instance, when the ceramic substrate contains SiAlON and the PVD coating contains TiAlN, the adhesion layer may contain TiB2 with a hexagonal crystal structure adjacent to the SiAlON ceramic substrate or ion implantation layer, transitioning to a cubic Ti(B2) structure adjacent to the TiAlN PVD coating. X N 2-X TiB2 is either TiN or TiB2. TiB2 is very similar to non-cubic SiAlON (i.e., hexagonal, P6 group) in lattice structure.

[0014] The adhesion layer 16 can have a typical thickness of 0.001 to 0.3 micrometers, for example, 0.005 to 0.2 micrometers. The PVD coating 20 can be deposited directly on the deposited adhesion layer, or the adhesion layer 16 can be further processed before the PVD coating is deposited, for example by additional etching by applying a pulsed voltage or preferably a constant voltage on the substrate stage.

[0015] As measured by EDS as described below, the adhesive layer 16 may have a titanium concentration of at least 0.5 atomic%, or at least 1 atomic%, or at least 2 atomic%, or at least 3 atomic%, and at most 5 or 10 atomic% or more.

[0016] The adhesion layer 16 can be deposited on at least a portion of the ceramic substrate 10 by: evacuating the coating chamber to at least 5 mPa, heating it to at least 500°C for at least 1 hour, backfilling the chamber with argon working gas to a pressure of 0.1 to 0.5 Pa, etching it by applying a bipolar pulsed voltage (e.g., a negative peak voltage of 650 V at a frequency of 240 kHz) to the substrate for 20-60 minutes, followed by evaporation of at least one sputtering target, for example, at an average power of 2 to 10 kW and a frequency of 0.1 to 5 kHz, while applying a constant, unipolar or bipolar pulsed voltage, for example, 20 to 100 V, to the substrate. The coating deposition can be performed in a non-reactive mode or in a reactive mode filled with nitrogen or other suitable gases. In the non-reactive process mode, the target material can contain the hard compound to be deposited, such as TiN and / or TiB2. In reactive process modes, the target material can be a pure metal or alloy, such as Ti, Cr, or TiAl, which is evaporated under a sufficient nitrogen flow to form a hard compound on the substrate. Depending on the adjusted parameters, the deposition step may take, for example, 1 to 2 hours.

[0017] The PVD coating 20 may comprise nitrides, borides, oxides, carbides, and combinations thereof. Examples of nitrides include titanium nitride (TiN). X Aluminum nitride (AlN) X Titanium aluminum nitride (Ti / AlN) X Such nitride PVD coatings can have a cubic crystal structure, which typically does not adhere well to non-cubic ceramic substrates. However, improved adhesion can be achieved by providing the adhesion layer 16 of the present invention.

[0018] The PVD coating 20 can have a typical thickness of 0.5 to 5 micrometers, such as 1 to 3 micrometers, or 1.5 to 2.5 micrometers.

[0019] Physical deposition processes can be performed using standard procedures known to those skilled in the art. For example, PVD coatings can be produced using commercial PVD equipment such as the CemeCon CC800 or Balzers Ingenia via pulsed sputtering deposition.

[0020] like Figure 1 As shown, the ion implantation layer 14 can be disposed between the ceramic substrate 10 and the adhesion layer 16. The ions used to generate the ion implantation layer 14 can contain Ti, B, or a combination thereof. The atomic ratio of Ti to B can be determined by the source material (“target”) used for deposition (non-reactive mode). A common stoichiometric composition of the target material is TiB2, but other compositions are also possible. For example, the Ti:B atomic ratio can be in the range of 2:1 to 1:2, such as TiB2. X, where X is between 0.5 and 2.

[0021] The ion implantation layer 14 can extend into the ceramic substrate 10 by a penetration distance or thickness of 0.001 to 0.05 micrometers, for example, 0.005 to 0.01 micrometers.

[0022] The ion-implanted layer 14 can be produced by: evacuating the coating chamber to at least 5 mPa, heating it to >500°C for at least 1 hour, backfilling the chamber with argon working gas to a pressure of 0.1 to 0.5 Pa, applying a unipolar or bipolar pulsed voltage (e.g., a peak negative voltage of 800-1200 V, e.g., a frequency of 0.1 to 5 kHz) to the substrate stage, and evaporating at least one sputtering target, e.g., at an average power of 2 to 10 kW and a frequency of 0.1 to 5 kHz, for a duration of, for example, 1 to 30 minutes. The ion implantation process can be performed using the PVD equipment described above.

[0023] The ion-implanted layer 14 may include defects in the crystal structure of the ceramic substrate caused by the ion implantation process. While not intended to be strictly theoretical, the ion-implanted layer 14 may contain doped ceramic material with atomic substitutions at A-sites and / or B-sites. For example, in a SiAlON ceramic substrate implanted with Ti and B ions, the Si and / or Al at the A-sites may be partially substituted by Ti, while the N and / or O at the B-sites may be partially substituted by B.

[0024] The following examples are intended to illustrate various aspects of the invention and are not intended to limit the scope of the invention.

[0025] Example

[0026] The ceramic substrates were processed within the time periods (minutes) listed in Table 1 through steps including ion implantation, adhesion layer deposition, etching, and PVD coating. The ceramic substrates of the listed samples contained SiAlON and were in the form of Kennametal KYS30 grade CNMG blades with polished surfaces.

[0027] Table 1

[0028]

[0029] The PVD coating contains AlTiN (Al:Ti elemental ratio of approximately 1.5:1) and is approximately 3 micrometers thick, and is deposited in a reactive mode by pulse sputtering as described above.

[0030] Table 2 lists the Ti concentration and critical load measurements obtained for samples 1, 2, 3, 5, and 6 in Table 1. The titanium concentration was measured by energy-dispersive X-ray spectroscopy (EDS) prior to the PVD coating step. Adhesion or critical load was determined on PVD-coated samples with the same processing sequence, for example, by continuing to use the same samples after EDS measurement and cleaning, or by using different samples but with the same etching sequence followed by PVD coating. The critical load was measured by a diamond stylus scratch test conforming to ASTM C1624-22. The scratch test is commonly used for evaluating and grading PVD coatings and for determining the maximum vertical load the coating can withstand before it begins to peel off from a sufficiently hard substrate, such as ceramic.

[0031] Table 2

[0032]

[0033] According to Table 2, when vertical and shear loads are applied, the sample with a Ti concentration of approximately 3.5 atomic% exhibits the highest critical load value (i.e., best adhesion) on the AlTiN coating on the SiAlON ceramic substrate.

[0034] Longitudinal turning tests were performed on comparative samples and samples of the present invention using SiAlON substrate material. Table 3 lists the cutting parameters used. The workpiece material was IN718 with a hardness of 385 HBN, and an external coolant was applied.

[0035] Table 3

[0036]

[0037] Table 4 lists the tool life in minutes obtained in the two tests. KYS30 is the uncoated baseline ceramic insert (without the pretreatment of this invention). AlTiN represents the coated KYS30 insert, which has a coating thickness similar to the variant of this invention, but without any injection or adhesion layers. Sample 5 is the variant of this invention defined by processing steps 10-20-10-60 as described in Table 1 (values ​​in minutes).

[0038] Table 4

[0039]

[0040] As shown in Table 4, the process of the present invention not only gives uncoated cutting tools a longer tool life, but also gives PVD-coated cutting tools that do not use the process steps of the present invention a longer tool life.

[0041] As used herein, the terms “including” and “containing” should be understood in the context of this application as synonymous with “comprising”, and are therefore open-ended, not excluding the presence of additional undescribed or unlisted elements, materials, stages, or method steps. As used herein, “consisting of” should be understood in the context of this application as excluding the presence of any unspecified elements, materials, stages, or method steps. As used herein, “consisting substantially of” should be understood in the context of this application as including specified elements, materials, stages, or method steps (if applicable), and also including any unspecified elements, materials, stages, or method steps that do not materially affect the basic or novel characteristics of the invention.

[0042] Although the numerical ranges and parameters describing the broad scope of this invention are approximate, the values ​​described in specific examples are reported as accurately as possible. However, any value inherently contains a certain degree of error, which is necessarily caused by standard variations found in the corresponding test measurements.

[0043] Similarly, it should be understood that any numerical range listed herein is intended to include all subranges contained therein. For example, the range “1 to 10” is intended to include all subranges between the minimum value 1 and the maximum value 10 (and including both the minimum and the maximum), i.e., a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0044] In this application, unless specifically stated otherwise, the use of the singular includes the plural and the plural encompasses the singular. Additionally, in this application, unless explicitly stated otherwise, the use of “or” means “and / or,” even if “and / or” may be explicitly used in certain circumstances. In this application and the appended claims, unless explicitly and clearly limited to a single referent, the articles “a,” “an,” and “described” include plural referents.

[0045] While specific embodiments of the invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that many variations in the details of the invention may be made without departing from the invention as defined in the appended claims.

Claims

1. A coated ceramic substrate comprising: Ceramic substrate; An adhesion layer is located on at least a portion of the ceramic substrate, the adhesion layer comprising Ti(B) x N 2-x );as well as A PVD coating located on at least a portion of the adhesive layer.

2. The coated ceramic substrate according to claim 1, wherein x is in the range of 2 to 0.

3. The coated ceramic substrate according to claim 1, wherein x is in the range of 2 to 0.

1.

4. The coated ceramic substrate according to claim 1, wherein x is 2.

5. The coated ceramic substrate according to claim 1, wherein the adhesive layer has a substantially uniform composition over the entire thickness of the adhesive layer.

6. The coated ceramic substrate according to claim 1, wherein the adhesive layer has a non-uniform composition over the entire thickness of the adhesive layer.

7. The coated ceramic substrate of claim 6, wherein the adhesion layer comprises TiB2 adjacent to the ceramic substrate and TiN adjacent to the PVD coating.

8. The coated ceramic substrate according to claim 1, wherein the adhesion layer has a thickness of 0.005 to 0.2 micrometers.

9. The coated ceramic substrate of claim 1, wherein the adhesion layer comprises a titanium concentration of at least 1 atomic percent as measured by energy-dispersive X-ray spectroscopy.

10. The coated ceramic substrate according to claim 9, wherein the titanium concentration is at least 3 atoms.

11. The coated ceramic substrate according to claim 1, wherein the ceramic substrate comprises silicon nitride, aluminum silicon nitride, silicon oxide, aluminum silicon oxide, silicon nitride doped with aluminum and oxygen, aluminum oxide, silicon alumina, or a combination thereof.

12. The coated ceramic substrate of claim 1, wherein the PVD coating comprises titanium nitride, aluminum nitride, aluminum titanium nitride, or a combination thereof.

13. The coated ceramic substrate of claim 1, further comprising an ion implantation layer located between the ceramic substrate and at least a portion of the adhesion layer.

14. The coated ceramic substrate of claim 13, wherein the ion implantation layer comprises Ti, B, or a combination thereof.

15. The coated ceramic substrate of claim 14, wherein the ion implantation layer has a thickness of 0.001 to 0.05 micrometers.

16. A method for depositing a coating physical vapor deposition on a ceramic substrate, comprising: Will contain Ti(B) X N 2-X An adhesion layer is deposited on a ceramic substrate; and The PVD coating is physically vapor-deposited onto at least a portion of the adhesion layer.

17. The method of claim 16, further comprising ion implantation of a layer on the ceramic substrate prior to depositing the adhesion layer.

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