CN211471534U

CN211471534U - Cobalt-containing hard alloy cutter

Info

Publication number: CN211471534U
Application number: CN202020025420.6U
Authority: CN
Inventors: 李伟秋; 颜炳姜; 彭继华
Original assignee: South China University of Technology SCUT; Conprofe Technology Group Co Ltd; Smartguy Intelligent Equipment Co Ltd Guangzhou Branch
Current assignee: South China University of Technology SCUT; Conprofe Technology Group Co Ltd; Smartguy Intelligent Equipment Co Ltd Guangzhou Branch
Priority date: 2020-01-07
Filing date: 2020-01-07
Publication date: 2020-09-11
Anticipated expiration: 2030-01-07

Abstract

The utility model relates to a cobalt-containing hard alloy cutter, which comprises a cutter base body, a cobalt nitride in-situ conversion layer and a diamond film coating, wherein the cobalt phase in the surface layer of the base body of the cutter base body is converted into a cobalt nitride phase in situ to form the cobalt nitride in-situ conversion layer, the diamond film coating is coated outside the cobalt nitride in-situ conversion layer, so the cobalt phase in the surface layer of the base body is converted into a cobalt nitride phase with stable high temperature, these cobalt nitrides do not diffuse during the preparation of the diamond film coating and, due to this transformation, result in a tighter bond between the cobalt-containing nitride phase and the tool substrate, the outward diffusion of the unconverted cobalt phase at the deep layer of the sub-surface forms a barrier, and on the other hand, the cobalt phase in the surface layer of the substrate is converted into the cobalt nitride phase in situ, so that the surface layer structure is compact, the hardness is increased, and the diamond film coating with high bonding force can be obtained on the surface. Therefore, the working efficiency of the cobalt-containing hard alloy cutter can be greatly improved, and the service life of the cobalt-containing hard alloy cutter can be prolonged.

Description

Cobalt-containing hard alloy cutter

Technical Field

The utility model relates to a cutter technical field especially relates to a contain cobalt carbide cutter.

Background

The hard alloy cutter is a common cutting tool for machining nonferrous metals, hard and brittle materials, composite materials and the like. In the advanced manufacturing field, the requirement of the manufacturing industry for the cutter is higher and higher, so that the main stream of the development of the hard alloy cutter is high precision, high efficiency, high reliability and specialization.

The use amount of WC-based hard alloy cutters bonded by cobalt is getting larger, and particularly, the hard alloy with high cobalt content is used as a cutter base material, has good bending strength and impact resistance and is widely applied in various fields. Compared with low-cobalt or cobalt-free hard alloy, the surface hardness and wear resistance of the high-cobalt hard alloy are reduced, so that the surface coating of the superhard diamond film coating is the mainstream technology for exerting the high toughness and improving the wear resistance of the superhard diamond film coating. However, when the diamond film coating is prepared, the cobalt weakens the film-substrate bonding force of the diamond film coating and damages the quality of the diamond film coating, which becomes a technical bottleneck that the industry must break through.

The traditional method adopts an acid-base etching two-step method to carry out surface pretreatment on the high-cobalt-content hard alloy coated diamond, on one hand, the cobalt on the surface is difficult to remove completely, on the other hand, the surface is seriously crisp, so that a high-quality diamond film coating cannot be obtained, and the prepared cobalt-containing hard alloy cutter has low working efficiency and short service life.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide a cobalt-containing cemented carbide tool that can greatly improve the work efficiency and prolong the service life.

A cobalt-containing cemented carbide tool comprising:

a tool substrate having a substrate surface layer, a cobalt phase within the substrate surface layer being converted in situ to a cobalt nitride phase to form a cobalt nitride in situ conversion layer; and

and the diamond film coating is coated outside the cobalt nitride in-situ conversion layer, so that the cobalt nitride in-situ conversion layer is positioned between the cutter substrate and the diamond film coating.

In one embodiment, the cobalt nitride in-situ conversion layer has a thickness of 5 μm to 10 μm.

In one embodiment, the cobalt nitride in-situ conversion layer has a thickness of 6 μm to 8 μm.

In one embodiment, the diamond film coating has a thickness of 2 μm to 10 μm.

In one embodiment, the diamond film coating has a thickness of 4 μm to 8 μm.

In one embodiment, the material of the tool base body is tungsten-cobalt cemented carbide using cobalt as a binder.

In one embodiment, the cobalt nitride in-situ conversion layer contains trace of one or more of cerium, lanthanum and praseodymium.

The cobalt-containing hard alloy cutter at least has the following advantages:

the cobalt phase in the surface layer of the base body of the cutter base body is converted into the cobalt nitride phase in situ to form a cobalt nitride in-situ conversion layer, the diamond film coating is coated outside the cobalt nitride in-situ conversion layer, so the cobalt phase in the surface layer of the base body is converted into the cobalt nitride phase stable at high temperature, the cobalt nitride is not diffused in the preparation process of the diamond film coating, and due to the conversion, the cobalt-containing nitride phase is more tightly combined with the cutter base body, and the outward diffusion of the unconverted cobalt phase at the sub-surface deep layer forms a barrier, and on the other hand, the cobalt phase in the surface layer of the base body is converted into the cobalt nitride phase in situ, the surface layer has a compact structure and increased hardness, and the high-. Therefore, the method is suitable for the hard alloy with wide cobalt content (the cobalt content is more than 6%), can avoid the surface of the hard alloy substrate from being crisp, and can greatly improve the working efficiency and prolong the service life of the cobalt-containing hard alloy cutter.

Drawings

Fig. 1 is a partial cross-sectional view of a cobalt-containing cemented carbide insert according to an embodiment.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention can be embodied in many different forms other than those specifically described herein, and it will be apparent to those skilled in the art that similar modifications can be made without departing from the spirit and scope of the invention, and it is therefore not to be limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

Referring to fig. 1, one embodiment of a cobalt-containing cemented carbide tool includes a tool substrate 01, a cobalt nitride in-situ conversion layer 02, and a diamond thin film coating 03. The tool may be a milling cutter or the like. The material of the tool base 01 is a tungsten-cobalt cemented carbide using cobalt as a binder.

The tool base 01 has a base surface layer in which a cobalt phase is converted in situ into a cobalt nitride phase to form a cobalt nitride in-situ conversion layer 02. The diamond film coating 03 is coated outside the cobalt nitride in-situ conversion layer 02, so that the cobalt nitride in-situ conversion layer 02 is positioned between the cutter substrate 01 and the diamond film coating 03.

The cobalt-containing hard alloy cutter at least has the following advantages:

the cobalt phase in the surface layer of the base body of the cutter base body 01 is converted into the cobalt nitride phase in situ to form a cobalt nitride in-situ conversion layer 02, the diamond film coating 03 is coated outside the cobalt nitride in-situ conversion layer 02, so the cobalt phase in the surface layer of the base body is converted into the cobalt nitride phase stable at high temperature, the cobalt nitride is not diffused in the preparation process of the diamond film coating 03, and the cobalt nitride phase is more tightly combined with the cutter base body 01 due to the conversion, and a barrier is formed for the outward diffusion of the unconverted cobalt phase in the sub-surface deep layer, on the other hand, the cobalt phase in the surface layer of the base body is converted into the cobalt nitride phase in situ, the surface layer has a compact structure and increased hardness, and the high-bonding-force diamond. Therefore, the method is suitable for the hard alloy with wide cobalt content (the cobalt content is more than 6%), can avoid the surface of the hard alloy substrate from being crisp, and can greatly improve the working efficiency and prolong the service life of the cobalt-containing hard alloy cutter.

Specifically, the thickness of the cobalt nitride in-situ conversion layer 02 ranges from 5 μm to 10 μm. Therefore, the cobalt phase is converted into the cobalt nitride phase within a certain thickness range of the surface layer of the cutter base body 01, and the thickness of the cobalt nitride in-situ conversion layer 02 is smaller than the total thickness of the cutter base body 01. Further, the thickness of the cobalt nitride in-situ conversion layer 02 is 6 μm to 8 μm.

Specifically, the thickness of the diamond thin film coating 03 is 2 μm to 10 μm. The thickness of the diamond thin film coating 03 is different according to the growth time of the diamond thin film coating 03. Further, the thickness of the diamond thin film coating 03 is 4 μm to 8 μm.

Further, the cobalt nitride in-situ conversion layer 02 contains one or a mixture of a plurality of trace rare earths of cerium, lanthanum and praseodymium. This is because, during the conversion process, the rapid and efficient nitriding treatment of the cobalt phase in the surface layer of the substrate is achieved with a rare earth mixture.

In order to prepare the cobalt-containing hard alloy cutter, the method specifically comprises the following steps:

1) obtaining a cobalt-containing cemented carbide tool with a clean surface: and removing oil stains on the surface of the cobalt-containing hard alloy cutter by using a commercially available metal cleaning agent, rinsing and drying for later use.

2) Placing the cobalt-containing hard alloy cutter into a vacuum treatment device: fixing a clean cobalt-containing hard alloy cutter on a workpiece rotating stand of a vacuum treatment device; placing 1 g of rare earth mixture powder on an auxiliary sample machine of an ion source; starting the rotation of the workpiece rotating frame, starting the vacuum pumping, and pumping the air pressure in the vacuum processing device to a vacuum degree lower than 7.5x10^-3Pa, starting the auxiliary heating device, and raising the temperature in the vacuum chamber to 200-400 ℃.

3) And (2) performing ion nitriding on the surface of the hard alloy in the vacuum treatment device by adopting an auxiliary ion source: keeping the temperature in the vacuum chamber within the range of 200-400 ℃, introducing argon into the vacuum chamber to enable the air pressure of the vacuum chamber to reach 0.1Pa, starting an auxiliary ion source, adjusting the current of an electron gun to be 90-120A, introducing nitrogen working gas into the vacuum chamber after electron beams are stabilized to enable the air pressure of the vacuum chamber to reach 5-8 Pa, starting a bias voltage power supply, adjusting the bias voltage to 400-600V, closing the electron gun, the bias voltage power supply, the working gas and heating after ion nitriding is finished for 2-4 hours, closing the vacuum pump when the temperature in the vacuum chamber is reduced to be below 100 ℃, opening a vacuum treatment device door, and taking out a workpiece.

4) Carrying out crystal planting pretreatment on the surface of the cobalt-containing hard alloy cutter: placing the cobalt-containing hard alloy cutter subjected to nitriding treatment in a suspension containing diamond powder for ultrasonic grinding; diamond powder in suspension: ethylene glycol: the proportion of ethanol is 5-20 g: 5-10 ml: 1000ml, ultrasonic frequency of 28kHz, ultrasonic power of 30-50W/liter and ultrasonic time of 10-20 minutes; and (3) putting the cobalt-containing hard alloy cutter into pure ethanol for secondary ultrasound, wherein the ultrasound parameters are frequency of 28kHz, ultrasound power of 30-50W/liter, and ultrasound time of 10-20 minutes.

5) Carrying out vapor deposition on a diamond film coating on the surface of the cobalt-containing hard alloy cutter: placing the cobalt-containing hard alloy cutter subjected to the crystal planting treatment into an HFCVD device, and adopting methane: the mixed working gas of hydrogen gas accounts for 2 percent to 98 percent of the mass flow, the surface temperature of the sample is 800 ℃, the growth pressure is 1K to 5KPa, and the mixed working gas is introduced into the reaction chamber, and the thickness of the grown diamond film coating is 2 to 10 mu m.

Therefore, the technical means of high energy and high density ion source assistance and rare earth catalytic infiltration are adopted to convert the cobalt phase on the surface of the tungsten-cobalt hard alloy into the cobalt nitride Co with high temperature stability in situ under the conditions of low temperature and low pressure at the temperature lower than 400 DEG C₄N not only densifies the structure of the surface layer of the hard alloy, but also can inhibit the diffusion of cobalt during the subsequent growth of the diamond coating, and is suitable for the tungsten-cobalt hard alloy with wide cobalt content. And secondly, depositing a high-quality diamond coating on the basis of cobalt nitride by adopting a hot wire chemical vapor deposition method, thereby being beneficial to obtaining the diamond coating with high bonding force on the surface. The invention does not relate to the application of harmful substances to the environment, and realizes clean preparation in the whole process.

In the preparation process, when the light rare earth mixture powder on the surface of the auxiliary anode is bombarded by the plasma beam, a small amount of rare earth elements are volatilized into working gas, so that the cobalt phase in the surface layer of the hard alloy sample is quickly and efficiently nitrided and pretreated, and is converted into a high-temperature stable Co-N compound phase (Co)₄N), then preparing a diamond coating on the surface of the hard alloy sample by adopting ultrasonic grinding crystal implantation and hot wire chemical vapor deposition, wherein the surface cobalt phase is converted into highThe cobalt nitride phase is stable at temperature, so the cobalt nitride does not diffuse in the preparation process of the diamond coating, and the cobalt-containing nitride phase is more tightly combined with the hard alloy matrix due to the transformation, the outward diffusion of the untransformed cobalt phase at the deep layer of the subsurface is blocked, and on the other hand, the cobalt phase on the surface layer is converted into the Co phase in situ₄And N, the surface layer has a compact structure and increased hardness, and is beneficial to obtaining a diamond coating with high binding force on the surface. Therefore, it is suitable for use in a wide range of cobalt content (cobalt content)>6%) and avoiding the surface of the hard alloy matrix from being crisp.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A cobalt-containing cemented carbide tool, comprising:

2. The cobalt-containing cemented carbide tool of claim 1, wherein the cobalt nitride in-situ conversion layer has a thickness of 5-10 μ ι η.

3. The cobalt-containing cemented carbide tool of claim 2, wherein the cobalt nitride in-situ conversion layer has a thickness of 6-8 μ ι η.

4. The cobalt-containing cemented carbide tool of claim 1, wherein the diamond film coating has a thickness of 2-10 μ ι η.

5. The cobalt-containing cemented carbide tool of claim 4, wherein the diamond film coating has a thickness of 4-8 μm.

6. The cobalt-containing cemented carbide tool according to claim 1, wherein the tool base is made of a tungsten-cobalt cemented carbide using cobalt as a binder.