Etching method for improving cutting performance of TiCN metal ceramic coating cutter

Abstract

The invention discloses an etching method for improving the cutting performance of a TiCN metal ceramic coating tool. The etching method comprises the steps that firstly, the surface of TiCN-based metal ceramic is cleaned; then, the cleaned TiCN-based metal ceramic is subjected to plasma etching treatment; the gas used in the plasma etching treatment is mixed gas of argon and nitrogen in a flow ratio of 1: 1 or high-purity nitrogen, and the total cavity pressure is 1-2Pa. Plasma used for plasma etching is generated by an ion source cathode in the coating furnace, argon is ionized to generate argon ions and electrons, the electrons move towards the anode under the guidance of the anode, the electrons ionize argon and nitrogen in the cavity in the moving process, and therefore the mixed plasma atmosphere containing the argon ions and the nitrogen ions is formed. By means of the etching method, the surface roughness of a base body can be improved, the surface hardness can be improved, and the abrasion resistance and the cutting performance of the tool with the deposited CrAl / CrAlBN coating etched through the method are obviously improved compared with those of a tool with a pure argon etching coating.

Description

Technical Field

[0001] The invention relates to the technical field of metal ceramics, in particular to an etching method for improving the cutting performance of a TiCN metal ceramic coating tool. Background Art

[0002] TiCN-based cermets are widely used in wear-resistant fields and cutting tools due to their good high-temperature resistance and wear resistance. In the field of cutting tools, cermets are mostly used for dry high-speed cutting of medium-soft steel, and the processing temperature usually exceeds 600°C. In order to meet increasingly complex processing needs and improve the service life of tools, surface coating technology is becoming more and more widely used in cermet tools. However, due to the complex composition system of TiCN cermets and the large lattice mismatch between the substrate and the coating, the coating performance is poor, which to a certain extent limits the application of coated cermet tools. The cutting performance of TiCN-based cermet coated tools needs to be improved.

[0003] A crucial step before coating preparation is plasma etching. This process not only cleans the substrate, activates the surface, and achieves a certain surface roughness, but also preferentially removes the metallic bonding phase within the substrate, exposing a hard phase that is more conducive to the adsorption and growth of the nitride coating. This reduces internal stress in the coating and effectively improves the adhesion between the coating and the substrate, ensuring that the surface hard coating provides adequate protection for the tool substrate. Therefore, in order to improve the cutting performance of TiCN-based cermet-coated tools, in-depth research on plasma etching methods is necessary. Summary of the Invention

[0004] The object of the present invention is to provide an etching method for improving the cutting performance of a TiCN metal ceramic coating tool.

[0005] The etching method for improving the cutting performance of TiCN metal ceramic coating tools provided by the present invention mainly uses argon / nitrogen mixed gas or high-purity nitrogen as the plasma discharge atmosphere for plasma etching. The specific method is as follows:

[0006] First, the surface of the TiCN-based cermet is cleaned, including sequentially performing ethanol spraying treatment, rinsing in different degreasing agents, multiple ultrasonic cleanings, and finally drying to obtain the cleaned TiCN-based cermet.

[0007] Then, the cleaned TiCN-based cermet is subjected to plasma etching, wherein the gas used in the plasma etching is a mixed gas of argon and nitrogen with a flow ratio of 1:1 or high-purity nitrogen, and the overall chamber pressure is 1-2 Pa.

[0008] Before plasma etching, the furnace needs to be loaded and heated. Specifically, the TiCN-based cermet is placed in the coating furnace and vacuumed to less than 3×10 -3Pa, and then the cavity is heated to 300 ° C and hydrogen is introduced to heat the cavity until it is heated to 480 ° C.

[0009] The plasma used in the plasma etching process is generated by the cathode of the ion source in the coating furnace. The filament generates a large amount of heat under high current, ionizing the argon gas to produce argon ions and electrons. The electrons are guided by the anode and move toward the anode. During this movement, the electrons ionize the argon and nitrogen in the chamber, forming a mixed plasma atmosphere containing argon and nitrogen ions. The cathode filament current is 180A, the anode guide current is 200A, and a bias voltage of -200 to -400V is applied to the workpiece holder. Each etching process takes one hour.

[0010] After the above plasma etching method, a CrA / lCrAlBNN multilayer coating is deposited on the surface of the TiCN-based metal ceramic. The target material used is Cr with a purity of 99.9%. 30 Al 70 and Cr 27 Al 63 B 10 Alloy target, target current 160A, frequency 30kHz, duty cycle 75%, substrate -40~-150V, nitrogen bias, chamber pressure 4Pa, total deposition time 3 hours, and then cooled to room temperature in the furnace to obtain the coated tool.

[0011] Compared with the prior art, the present invention is beneficial in that:

[0012] (1) The present invention is based on a plasma discharge process and adopts a mixture of argon and nitrogen or high-purity nitrogen as the plasma discharge gas. The nitrogen-containing mixed discharge gas can achieve the dual effects of plasma nitriding and etching. Since it contains a large amount of nitride-forming element Ti, TiCN-based metal ceramics can form a nitrogen-rich layer in a nitrogen-rich atmosphere, achieve surface modification, and then adjust the surface coating performance of TiCN-based metal ceramics.

[0013] (2) The present invention uses a mixture of argon and nitrogen or high-purity nitrogen as the plasma discharge gas. After etching, a certain surface roughness can be obtained while increasing the surface hardness of the substrate. The interface between the coating and the substrate is tightly bonded, effectively improving the bonding strength between the coating and the substrate, and improving the wear resistance and cutting performance of the coating sample. Experimental studies have shown that the wear resistance and cutting performance of the CrAl / CrAlBN coated tool after etching by this method are significantly improved compared to the coated tool etched with pure argon.

[0014] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Surface morphology of samples after etching in different embodiments and comparative examples.

[0016] Figure 2 These are morphology images of the substrate and coating cross sections after argon ion polishing in different embodiments.

[0017] Figure 3 1 and 2 are graphs showing the friction coefficient and volume wear results of the reciprocating friction and wear test of the coating samples of each embodiment, wherein (a) is the friction coefficient graph and (b) is the volume wear graph.

[0018] Figure 4 The figures are the cutting results of GH4169 high-temperature alloy processed by coated tools of different embodiments. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0020] Example 1

[0021] An etching method for improving the cutting performance of a TiCN metal ceramic coating tool, comprising the following steps:

[0022] (1) Sample preparation: After cleaning and drying, the TiCN-based cermet sample is placed on the workpiece holder and loaded into the furnace.

[0023] (2) Heating: Vacuum to 3×10 -3 After pa, turn on the resistance heating module and heat to 300℃.

[0024] (3) Hydrogen heating: Keep the resistance heating module working, introduce a certain amount of hydrogen and argon mixed gas, turn on the ion source, apply a certain bias voltage to the workpiece, and heat it to 480℃.

[0025] (4) Argon ion etching: high-purity argon gas was introduced, the chamber pressure was maintained at 1 Pa, the argon flow rate was 350 sccm, the ion source was turned on, the cathode filament current was 180 A, the guide anode current was 200 A, a -200 V bias was applied to the substrate, and etching was performed for 1 hour after the bias current was stable.

[0026] A CrA / lCrAlBNN multilayer coating is deposited on the surface of the TiCN metal ceramic after etching in step (4), and the furnace is cooled to room temperature and then taken out of the furnace.

[0027] Example 2

[0028] An etching method for improving the cutting performance of a TiCN metal ceramic coating tool, comprising the following steps:

[0029] (1) Sample preparation: After cleaning and drying, the TiCN-based cermet sample is placed on the workpiece holder and loaded into the furnace.

[0030] (2) Heating: Vacuum to 3×10 -3 After pa, turn on the resistance heating module and heat to 300℃.

[0031] (3) Hydrogen heating: Keep the resistance heating module working, introduce a certain amount of hydrogen and argon mixed gas, turn on the ion source, apply a certain bias voltage to the workpiece, and heat it to 480℃.

[0032] (4) Mixed gas plasma etching: first pass a certain amount of argon gas, then pass nitrogen gas, the argon and nitrogen flow ratio is 1:1, each gas flow is 200 sccm, the chamber pressure is maintained at 1 Pa, turn on the ion source, the cathode filament current is 180A, the guide anode current is 200A, and a -400V bias is applied to the substrate. After the bias current stabilizes, etching is carried out for 1 hour.

[0033] A CrA / lCrAlBNN multilayer coating is deposited on the surface of the TiCN metal ceramic after etching in step (4), and the furnace is cooled to room temperature and then taken out of the furnace.

[0034] Example 3

[0035] An etching method for improving the cutting performance of a TiCN metal ceramic coating tool, comprising the following steps:

[0036] (1) Sample preparation: After cleaning and drying, the TiCN-based cermet sample is placed on the workpiece holder and loaded into the furnace.

[0037] (2) Heating: Vacuum to 3×10 -3 After pa, turn on the resistance heating module and heat to 300℃.

[0038] (3) Hydrogen heating: Keep the resistance heating module working, introduce a certain amount of hydrogen and argon mixed gas, turn on the ion source, apply a certain bias voltage to the workpiece, and heat it to 480℃.

[0039] (4) Mixed gas plasma etching: first pass a certain amount of argon gas, then pass nitrogen gas, the argon and nitrogen flow ratio is 1:1, each gas flow is 200 sccm, the chamber pressure is maintained at 1 Pa, turn on the ion source, the cathode filament current is 180A, the guide anode current is 200A, and a -400V bias is applied to the substrate. After the bias current stabilizes, etching is carried out for 1 hour.

[0040] (5) Argon ion etching: high-purity argon gas was introduced, the chamber pressure was maintained at 1 Pa, the ion source was turned on, the cathode filament current was 180 A, the anode current was guided to 200 A, a -200 V bias was applied to the substrate, and etching was performed for 1 hour after the bias current was stable.

[0041] A CrA / lCrAlBNN multilayer coating is deposited on the surface of the TiCN metal ceramic after etching in step (5), and the furnace is cooled to room temperature and then taken out of the furnace.

[0042] Comparative Example

[0043] A conventional surface polishing method comprises the following steps:

[0044] (1) Diamond grinding: Metal ceramics are ground with diamond grinding discs to remove surface oxide scale and level the surface.

[0045] (2) Polishing: Polish with oily 0.5 μm diamond polishing paste until the sample surface becomes mirror-like.

[0046] (3) Cleaning: Clean in anhydrous ethanol solution using an ultrasonic cleaner for 10 minutes.

[0047] (4) Drying: After ultrasonic cleaning, the sample is placed in a drying phase at 60°C for drying.

[0048] The TiCN cermet after drying in step (4) was used as the original surface reference.

[0049] The surface roughness and hardness of the samples of Examples 1-3 and the comparative example were measured, and the test results of the surface roughness of the samples after coating are shown in Table 1.

[0050] Table 1. Roughness and hardness test data of samples of Examples 1-3 and Comparative Examples

[0051]

[0052] As can be seen from the data in Table 1, the roughness of the sample etched by the etching method of the present invention is significantly improved compared to the roughness of the comparative example, and the hardness is also significantly improved. After etching, the coating is performed, and the roughness of the coated sample is also significantly improved.

[0053] Figure 1 Figures 2 and 3 show the surface morphology of samples after etching in different examples and comparative examples. Compared to the samples after etching in the comparative example, the surfaces of the samples after plasma etching in Examples 1-3 exhibit an undulating surface, with the metal bonding phase preferentially removed, leaving behind TiCN hard particles. The edges of the hard phase on the surfaces of Examples 1 and 3 are rounded, with no fine particles remaining. However, the surface of Example 2 exhibits a relatively large number of fine particles, representing the residual broken bonding phase. This indicates that the etching effect of Example 2 is less severe than that of Examples 1 and 3.

[0054] Figure 2 The following are the morphology images of the substrate and coating sections after argon ion polishing in different examples. It can be seen that in Example 1, the substrate surface has local cracks, in Example 2, the coating and substrate interface is tightly bonded, and in Example 3, there is a clear delamination between the coating and substrate.

[0055] Figure 3Figure 2 shows the friction coefficient and volume wear results of the coating samples from various examples during reciprocating friction and wear tests. (a) shows the friction coefficient, and (b) shows the volume wear. Experimental parameters: load 5N, grinding balls 6mm diameter Si3N4 ceramic balls, wear scar length 5mm, sliding speed 200mm / min, and test time 90 minutes. The results show that Example 2 has the lowest friction coefficient and volume wear.

[0056] Figure 4 The following are the cutting results of GH4169 high-temperature alloy using coated tools from different embodiments. Cutting parameters: cutting speed 100 m / min, cutting depth 0.5 mm, feed 0.1 mm / r, cutting time 5 min. In the figure, the grayscale image on the right is the fitting result of the blade after cutting. Green represents the original blade position; red represents adhesion above the original blade position; blue represents wear below the original blade position. The results show that Example 1 has the most severe tip damage, while Example 2 has the least adhesion and the least tip damage.

[0057] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An etching method for improving the cutting performance of a TiCN metal ceramic coating tool, characterized in that: First, the surface of the TiCN-based metal ceramic is cleaned; then, the cleaned TiCN-based metal ceramic is subjected to plasma etching treatment; the gas used in the plasma etching treatment is a mixed gas of argon and nitrogen with a flow ratio of 1:1 or high-purity nitrogen, and the overall chamber pressure is 1-2 Pa.

2. The etching method for improving the cutting performance of a TiCN metal ceramic coating tool according to claim 1, characterized in that: Before plasma etching, the furnace needs to be loaded and heated. Specifically, the TiCN-based cermet is placed in the coating furnace and vacuumed to less than 3×10 -3 Pa, and then the cavity is heated to 300 ° C and hydrogen is introduced to heat the cavity until it is heated to 480 ° C.

3. The etching method for improving the cutting performance of a TiCN metal ceramic coating tool according to claim 2, characterized in that: The plasma used for plasma etching is generated by the cathode of the ion source in the coating furnace, which ionizes the argon gas to produce argon ions and electrons. The electrons move toward the anode under the guidance of the anode. During the movement, the electrons ionize the argon and nitrogen in the cavity, thereby forming a mixed plasma atmosphere containing argon ions and nitrogen ions.

4. The etching method for improving the cutting performance of a TiCN metal ceramic coating tool according to claim 3, characterized in that: The cathode filament current is 180A, the anode guide current is 200A, a bias voltage of -200 to -400V is applied to the workpiece holder, and the etching time for each etching process is 1 hour.

5. The etching method for improving the cutting performance of a TiCN metal ceramic coating tool according to claim 1, characterized in that: The method for cleaning the surface of the TiCN-based cermet before etching includes sequentially performing ethanol spraying treatment, rinsing in different degreasing agents, multiple ultrasonic cleanings, and finally drying.

6. The etching method for improving the cutting performance of a TiCN metal ceramic coating tool according to any one of claims 1 to 5, characterized in that: Used in the etching process before depositing CrA / lCrAlBNN multilayer coating on the surface of TiCN-based metal ceramics.

Images