WO2020155732A1

WO2020155732A1 - Non-stick hard coating for injection mold and preparation method thereof

Info

Publication number: WO2020155732A1
Application number: PCT/CN2019/116155
Authority: WO
Inventors: 陈君; 乐务时
Original assignee: 苏州涂冠镀膜科技有限公司
Priority date: 2019-01-29
Filing date: 2019-11-07
Publication date: 2020-08-06
Also published as: CN109594042B; CN109594042A

Abstract

Disclosed are a non-stick hard coating for an injection mold and a preparation method thereof. The method comprises depositing a layer of a composite coating, which comprises a hard metal, a hard ceramic phase and a carbon material, onto a surface of an inner chamber of the mold, and subjecting the coating to surface modification and structural design to provide the same with low surface energy, thereby resolving the issue in which a hot injected mass sticks easily, and also meets the need for a wear-resistant surface, without using a mold release agent, and thus eliminates the process of brushing or spraying a mold release agent. The non-stick hard coating for an injection mold and the preparation method thereof integrate technical fields, such as metal surface coating preparation and plasma modification, to construct a heterogeneous composite coating structure and modify an outer surface of the coating so as to provide a hard composite coating capable of preventing a hot injected mass sticking to a surface of an injection mold. The composite coating thus enables the surface of the injection mold to have high wear resistance and good non-stick performance at the same time.

Description

Anti-adhesion hard coating for injection mold and preparation method thereof

This application claims the priority of the Chinese patent application whose application date is January 29, 2019 and the application number is 201910082754.9, the entire content of which is incorporated into this application by reference.

Technical field

The invention relates to an anti-adhesion hard coating for an injection mold and a preparation method thereof, and belongs to the technical field of metal surface treatment.

Background technique

With the rapid development of the plastics industry and the promotion and application of plastic products in various fields such as industrial production and life, the production of plastic products has become more and more stringent for injection molds. At present, the service life of injection molds is often short, especially the dimensional accuracy and surface roughness of the mold surface are destroyed quickly. An important reason for the damage is that the contact between the hot blank and the mold surface will produce a very strong adhesion phenomenon, resulting in high friction, causing damage to the cavity surface of the mold. In addition, the adhesion of the blank to the surface of the mold cavity will cause defects in the product produced when the mold is used again.

The use of release agent can reduce the adhesion between the surface of the injection molded part and the surface of the mold cavity, prevent the two from sticking to each other, thereby improving the surface quality of the plastic part. The anti-adhesion effect of the release agent is affected by both chemical effects and physical conditions. Since the molding blanks and molding conditions are different, the selection and dosage of the release agent must be determined according to the specific conditions. If used improperly, it often fails to produce a good anti-adhesion effect. The effective working temperature of fatty oil release agent should generally not exceed 150℃, and it cannot be used when the injection temperature is high; the working temperature of silicone oil and metal soap release agent is generally 150～250℃; the working temperature of polytetrafluoroethylene release agent The working temperature can reach above 260°C, and its working temperature range is large. Especially under high temperature conditions, it is the release agent with the best anti-adhesion effect.

From the perspective of thermodynamics, the essential reason for the adhesion of the hot blank on the mold surface is that the surface energy of the mold material is too high. The principle of using a release agent to prevent adhesion is also to form a thin layer of low surface energy between the mold and the hot blank, so that the hot blank and the mold are incompatible, thereby inhibiting adhesion. The reason for the good anti-adhesion effect of PTFE-based mold release agents is that in addition to its high thermal stability, the more important reason is that its molecular structure has a large number of -CF ₃ groups, and the surface energy of this group is as low as Only 6.7mJ/m ² . If a release agent is used to prevent adhesion, a process of painting or spraying the release agent needs to be added in the injection molding production process, which will increase labor and economic costs.

In addition, according to the theory of Young's equation, increasing the external specific surface area while reducing the surface energy can further reduce the adhesion and possibility of the hot blank on the mold surface. Therefore, under the premise of ensuring that the surface of the mold is macroscopically uniform and flat, increasing the roughness of the micro-scale is also conducive to the improvement of the mold's anti-adhesion performance.

Based on the above situation, the present invention is proposed.

Summary of the invention

The purpose of the present invention is to provide an anti-adhesion hard coating for injection molds and a preparation method thereof, wherein a layer deposited on the surface of the cavity of the mold is composed of hard metal/hard ceramic phase/carbon material The composite coating with low surface energy and structural design is implemented on the coating, so as to solve the problem of easy adhesion of injection molding hot blanks without using mold release agent and omitting the process of painting/spraying mold release agent And the problem of surface wear.

In order to achieve the above objective, the present invention provides the following technical solutions: an anti-adhesion hard coating for injection molds, the anti-adhesion hard coating includes a bonding layer directly combined with the mold, and is arranged on the bonding A transition layer on the layer and a hard anti-adhesion functional layer disposed on the transition layer; the bonding layer includes a metallic chromium layer (Cr), the transition layer includes a chromium nitride layer, and the hard anti-adhesion layer The additional functional layer includes chromium-nickel nitride ((Cr, Ni)N), -CF ₃ group surface graft modification diamond-like amorphous carbon (DLC-CF ₃ ) and -CF ₃ group surface graft modification A composite layer of three types of carbon nanotubes (CNTs-CF ₃ ).

Further, the thickness of the anti-adhesion hard coating is 6.5-17 μm.

Further, the thickness of the bonding layer is 1.5-3 μm.

Further, the thickness of the transition layer is 2 to 4 μm.

The present invention also provides a method for preparing the anti-adhesion hard coating used for injection molds, which includes the following steps:

S1. Depositing the bonding layer, that is, the Cr layer, on the surface of the mold by a deposition method, and the thickness of the bonding layer is 1.5-3 μm;

S2. Depositing the transition layer, that is, a CrN layer, on the bonding layer by a deposition method, and the thickness of the transition layer is 2 to 4 μm;

S3. Depositing a first composite layer on the transition layer by a deposition method, the first composite layer includes a (Cr, Ni)N/DLC layer, and the thickness of the first composite layer is 3-10 μm;

S4. Heat treatment in a protective atmosphere to make the first composite layer form a second composite layer, the second composite layer including a (Cr, Ni)N/DLC/CNTs layer;

S5. The second composite layer is modified by glow discharge plasma to form the hard anti-adhesion functional layer, that is, the (Cr, Ni)N/DLC-CF3/CNTs-CF3 layer. The thickness of the adhered hard coat layer is 6.5 to 17 μm.

Further, in step S1, the deposition method is a magnetron sputter ion plating deposition method, and the deposition of the transition layer specifically includes the following steps:

Put the mold into the furnace body, evacuate to a vacuum degree of 0.8×10 ^-3 or more, and introduce argon gas with a purity of 99.99% and a pressure control of 0.1-1pa. Among them, the Cr target current is 0.6-2.2A. The negative bias voltage is 60-180V, and the bias frequency is 150-300kHz.

Further, in step S2, the deposition method is a magnetron sputter ion plating deposition method, and the deposition of the transition layer specifically includes the following steps:

Evacuate to a vacuum degree of 0.8×10 ^-3 or more, and pass in nitrogen with a purity of 99.999% and a pressure of 0.3～1.6pa. Among them, the Cr target current is 0.3～1.2A, the negative bias voltage is 30～100V, and the bias voltage The frequency is 50～120kHz.

Further, in step S3, the deposition method is a magnetron sputtering ion plating deposition method, and depositing the first composite layer specifically includes the following steps:

It is evacuated to a vacuum degree above 0.8×10 ^-3 , the purity of the nitrogen is 99.999%, the pressure is controlled at 0.1～1.0pa, and three targets are used for sputtering. Among them, the target current of Cr is 0.2～1.4A, Ni The target current is 0.04～0.3A, the C target current is 0.8～3A, the negative bias voltage is 30～150V, and the bias frequency is 50～180kHz.

Further, step S4 specifically includes the following steps:

Use argon as the protective atmosphere, its purity is 99.99%, the pressure is normal pressure, and the heating rate in the furnace body is 1-20℃/min, the holding temperature is 600-800℃, and the holding time is 2-10h. Cool down to room temperature.

Further, step S5 specifically includes the following steps:

Evacuate to a vacuum degree above 1×10 ^-2 ～10Pa, and pass in a mixed gas including argon and carbon tetrafluoride gas, the purity of which is greater than 99.9%, and the volume percentage of CF ₄ in the mixed gas is 30 ～100%, atmospheric pressure at normal pressure, gas flow at 20～200ml/min, glow discharge power at 40～400W, treatment time at 10～120min.

Compared with the prior art, the beneficial effects of the present invention are: the anti-adhesion hard coating for injection molds of the present invention and the preparation method thereof deposit a layer of hard metal/hard ceramics on the surface of the mold cavity. A composite coating composed of phase/carbon material, and the coating is subjected to low surface energy surface modification and structural design, so as to avoid the use of mold release agents and omit the process of painting/spraying mold release agents. Solve the problem of easy adhesion of injection molding hot blanks and surface wear resistance. The anti-adhesion hard coating for injection molds and its preparation method are closely combined with metal surface coating preparation technology, plasma modification technology and other fields, through the construction of a heterogeneous composite coating structure, and the outer surface of the coating The further modification of the injection mold forms a hard composite coating that prevents the adhesion of hot blanks on the surface of the injection mold. The composite coating can make the surface of the injection mold have high wear resistance and obtain good anti-adhesion performance.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and implement it in accordance with the content of the description, the preferred embodiments of the present invention are described in detail below with the accompanying drawings.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the anti-adhesion hard coating for injection molds of the present invention;

Figure 2 is a diagram showing the contact angle test results of the sample in Example 1 of the present invention.

detailed description

The specific embodiments of the present invention will be described in further detail below in conjunction with the drawings and embodiments. The following examples are used to illustrate the present invention, but not to limit the scope of the present invention.

It should be noted that the terms "upper", "lower", "left", "right", "inner", "outer" and other terms in the present invention are only used to describe the present invention with reference to the drawings, and are not used as limiting terms.

The preparation method of the anti-adhesion hard coating for injection molds of the present invention is based on the following considerations:

First of all, metal nitride ceramics have high hardness and excellent wear resistance, and diamond-like amorphous carbon materials (DLC) also have the characteristics of high hardness and low friction coefficient. The synergy produced when the hard nitride ceramic phase is combined with DLC can further improve its wear resistance. At the same time, the surface energy of DLC is lower than that of nitride ceramics, and the two can have a lower surface energy after being combined. Secondly, through the heat treatment of DLC, under the catalysis of nickel element (Ni), the structure of sp ² bonded carbon in DLC can be reformed, and then carbon nanotube (CNTs) structure can be grown on DLC, thereby expanding The specific surface area of the DLC (ie micro-roughness). At the same time, CNTs themselves have higher wear resistance. In addition, the graft modification of -CF ₃ groups on the surface of the carbon material can greatly reduce the surface energy of the carbon material.

Specifically, it includes the following steps:

S1. Clean and dry the mold substrate, and deposit the metal Cr layer (bonding layer) by magnetron sputtering ion plating: evacuate to a vacuum degree above 0.8×10 ^-3 Pa (preferably, 0.8×10 ^-3 ～10Pa ), and then argon gas (Ar, purity 99.99%), the pressure is controlled at 0.1～1pa, the Cr target current is 0.6～2.2A, the negative bias voltage is 60～180V, the bias frequency is 150～300kHz, the thickness of the deposited layer is controlled At 1.5～3μm, its function is to improve the bonding force between the coating and the substrate;

S2. On the basis of the previous step, the CrN layer (transition layer) is deposited by magnetron sputtering ion plating: evacuated to a vacuum degree above 0.8×10 ^-3 Pa (preferably, 0.8×10 ^-3 ～10 Pa), and then Nitrogen (N ₂ , purity of 99.999%) is introduced, the pressure is controlled at 0.3～1.6pa, the Cr target current is 0.3～1.2A, the negative bias voltage is 30～100V, the bias frequency is 50～120kHz, and the thickness of the deposited layer is controlled at 2～4μm, its function is to reduce the structural mismatch between the outermost hard anti-adhesion functional layer and the metal Cr layer;

S3. On the basis of the previous step, use magnetron sputtering ion plating to deposit the first composite layer, namely the (Cr, Ni)N/DLC layer: evacuated to a vacuum degree above 0.8×10 ^-3 Pa (preferably, 0.8×10 ^-3 ～10Pa), and then pass in nitrogen (N ₂ , purity of 99.999%), the pressure is controlled at 0.1～1.0pa, using three targets co-sputtering, Cr target current 0.2～1.4A, Ni target current 0.04～0.3A, C target current 0.8～3A, negative bias voltage 30～150V, bias frequency 50～180kHz, the thickness of the first composite layer is controlled within 3～10μm;

S4. On the basis of the previous step, heat treatment in protective atmosphere is used to cause the structural reformation of sp ² bonded carbon in DLC under the catalysis of Ni element, which spontaneously occurs on the surface of the (Cr, Ni)N/DLC composite layer Grow CNTs and transform them into a second composite layer, namely (Cr, Ni)N/DLC/CNTs composite layer: Put the sample obtained in the previous step into a protective atmosphere furnace for heat treatment, and the protective atmosphere is argon (Ar , The purity is 99.99%), the air pressure is normal pressure, the heating rate is 1-20°C/min, the holding temperature is 600-800°C, the holding time is 2-10h, and the furnace cools down to room temperature;

S5. On the basis of the previous step, using glow discharge plasma modification, part of the sp ² type bonded carbon that has not undergone structural reformation in DLC and the surface of CNTs are grafted with -CF ₃ groups to form (Cr, Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite layer (hard anti-adhesion functional layer): Put the sample obtained in the previous step into the reaction chamber and vacuum to 1×10 ^-2 Vacuum degree above Pa, the mixed gas of argon and carbon tetrafluoride gas (Ar/CF ₄ , purity greater than 99.9%), the volume percentage of CF ₄ in the Ar/CF ₄ mixed gas is 30-100%, The air pressure is normal pressure, the gas flow rate is 20-200ml/min, the glow discharge power is 40-400W, and the treatment time is 10-120min.

After the above steps, an anti-adhesion hard coating with high wear resistance and good anti-adhesion performance can be prepared: Cr→CrN→(Cr,Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite coating .

Refer to Figure 1. The composite coating is divided into three layers from the inside to the outside (the side close to the mold base is "in", that is, the direction indicated by arrow A): the first layer is directly bonded to the outer surface of the mold 1 The bonding layer 2 is a metallic chromium (Cr) layer; the second layer is a transition layer 3 arranged on the bonding layer 2, which is a chromium nitride (CrN) layer; the third layer is arranged on the transition layer 3 The hard anti-adhesion functional layer 4 is the surface of chromium nickel nitride (Cr, Ni) N, -CF ₃ group grafted modified diamond-like amorphous carbon (DLC-CF3), -CF ₃ group surface A composite layer of three substances of graft-modified carbon nanotubes (CNTs-CF ₃ ), and the total thickness of the anti-adhesion hard coating is 6.5-17 μm.

The present invention will be further described in detail below in conjunction with specific embodiments.

Example one

First, the mold base is cleaned and dried;

Next, the metal Cr layer (bonding layer) is deposited by magnetron sputtering ion plating: evacuated to a vacuum degree above 0.8×10 ^-3 Pa, and then introduced argon (Ar, purity of 99.99%), and the pressure is controlled at 0.3 ~0.8pa, Cr target current 1.2A, negative bias voltage 120V, bias voltage frequency 180kHz, and the thickness of the deposited layer is about 2μm.

Next, use magnetron sputtering ion plating to deposit the CrN layer (transition layer): vacuum 0.8×10 ^-3 Pa or more, and then pass in nitrogen (N ₂ , purity of 99.999%), and control the pressure at 0.8～ 1.2pa, Cr target current 0.6A, negative bias voltage 60V, bias voltage frequency 60kHz, and the thickness of the deposited layer is about 3μm.

Next, the (Cr, Ni)N/DLC composite layer is deposited by magnetron sputtering ion plating: vacuum 0.8×10 ^-3 Pa or more, and then pass in nitrogen (N ₂ , purity 99.999%), The air pressure is controlled at 0.1-0.4pa, and three targets are used for co-sputtering, the Cr target current is 0.8A, the Ni target current is 0.1A, the C target current is 1.5A, the negative bias voltage is 80V, the bias frequency is 120kHz, and the thickness of the deposited layer is about 8μm.

Next, the (Cr, Ni)N/DLC/CNTs composite layer is prepared by heat treatment in a protective atmosphere: the protective atmosphere is argon (Ar, purity is 99.99%), the air pressure is normal pressure, the heating rate is 2°C/min, and the heat preservation The temperature is 650℃, the holding time is 4h, and the furnace cools down to room temperature.

Next, use glow discharge plasma modification to prepare (Cr, Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite layer (hard anti-adhesion functional layer): vacuum 1×10 ^-2 Pa or more Vacuum degree, the mixed gas of argon and carbon tetrafluoride gas (Ar/CF ₄ , the purity is greater than 99.9%), the volume percentage of CF ₄ in the Ar/CF4 mixed gas is 80%, and the pressure is normal pressure. The gas flow rate is 30ml/min, the glow discharge power is 120W, and the treatment time is 20min.

Please refer to Figure 2. Figure 2 is a test result diagram of the contact angle of the sample at 146.2°C. The instrument used is the DSA100 video optical contact angle meter from Germany KRUSS.

Example two

The mold base is cleaned and dried as in the first embodiment.

According to the method of the first embodiment, a metal Cr layer (bonding layer) is deposited.

According to the method of the first embodiment, a CrN layer (transition layer) is deposited.

Next, the (Cr, Ni)N/DLC composite layer is deposited by magnetron sputtering ion plating: vacuum 0.8×10 ^-3 Pa or more, and then pass in nitrogen (N ₂ , purity 99.999%), The air pressure is controlled at 0.1-0.4pa, and three targets are used for co-sputtering, the Cr target current is 0.6A, the Ni target current is 0.15A, the C target current is 2.5A, the negative bias voltage is 120V, the bias frequency is 120kHz, and the thickness of the deposited layer is about 6μm.

According to the method in the embodiment, the (Cr, Ni)N/DLC/CNTs composite layer was prepared.

Next, use glow discharge plasma modification to prepare (Cr, Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite layer (hard anti-adhesion functional layer): vacuum 1×10 ^-2 Pa or more Vacuum degree, the mixed gas of argon and carbon tetrafluoride gas (Ar/CF ₄ , the purity is greater than 99.9%), the volume percentage of CF ₄ in the Ar/CF ₄ mixed gas is 60%, and the pressure is normal pressure , The gas flow rate is 40ml/min, the glow discharge power is 800W, and the treatment time is 40min.

Example three

The mold base is cleaned and dried as in the first embodiment.

According to the method of the first embodiment, a (Cr, Ni)N/DLC composite layer was deposited.

Next, the (Cr, Ni)N/DLC/CNTs composite layer is prepared by heat treatment in a protective atmosphere: the protective atmosphere is argon (Ar, purity is 99.99%), the air pressure is normal pressure, the heating rate is 2°C/min, and the heat preservation The temperature is 760°C, the holding time is 8h, and the furnace cools down to room temperature.

According to the method of Example 1, the (Cr, Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite layer (hard anti-adhesion functional layer) was prepared by modification.

Example four

The mold base is cleaned and dried as in the first embodiment.

According to the method of the second embodiment, a (Cr, Ni)N/DLC composite layer was deposited.

According to the method of Example 3, a (Cr, Ni)N/DLC/CNTs composite layer was prepared.

According to the method of Example 2, the (Cr, Ni)N/DLC-CF ₃ /CNTs-CF ₃ composite layer (hard anti-adhesion functional layer) was prepared by modification.

The surface hardness of the hard anti-adhesion functional layer in the above examples was measured by a Vickers hardness meter, and the anti-adhesion performance of the hard anti-adhesion functional layer in the above examples was judged by a contact angle measuring instrument (the greater the contact angle The better the performance, the contact angle is deionized water as the test medium), the test results are shown in Table 1.

Table 1. Analysis and characterization test results of samples

According to the results in Table 1, it can be seen that the technology of the present invention can make the surface of the injection mold have high wear resistance and at the same time obtain good heat-proof blank adhesion performance.

To sum up: the anti-adhesion hard coating for injection molds of the present invention and the preparation method thereof deposit a layer composed of hard metal/hard ceramic phase/carbon material on the surface of the mold cavity Coating, and implement low surface energy surface modification and structural design on the coating, so as to solve the problem of easy adhesion of the injection molding hot blank and the surface without the use of mold release agent and omission of the brushing/spraying mold release agent process. The problem of wear resistance. The anti-adhesion hard coating for injection molds and its preparation method are closely combined with metal surface coating preparation technology, plasma modification technology and other fields, through the construction of a heterogeneous composite coating structure, and the outer surface of the coating The further modification of the injection mold forms a hard composite coating that prevents the adhesion of hot blanks on the surface of the injection mold. The composite coating can make the surface of the injection mold have high wear resistance and obtain good anti-adhesion performance.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several embodiments of the present invention, and the descriptions are more specific and detailed, but they should not be interpreted as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

An anti-adhesion hard coating for injection molds, characterized in that the anti-adhesion hard coating includes a bonding layer directly combined with the mold, a transition layer provided on the bonding layer, and The hard anti-adhesion functional layer on the transition layer; the bonding layer includes a metallic chromium layer (Cr), the transition layer includes a chromium nitride layer, and the hard anti-adhesion functional layer includes chromium nitride Nickel ((Cr,Ni)N), -CF 3 group surface graft modified diamond-like amorphous carbon (DLC-CF 3 ) and -CF 3 group surface grafted modified carbon nanotubes (CNTs- CF 3 ) A composite layer of three substances.
The anti-adhesion hard coating for injection molds according to claim 1, wherein the thickness of the anti-adhesion hard coating is 6.5-17 μm.
The anti-adhesion hard coating for injection molds according to claim 2, wherein the thickness of the bonding layer is 1.5 to 3 μm.
The anti-adhesion hard coating for injection molds of claim 2 or 3, wherein the thickness of the transition layer is 2 to 4 μm.
A method for preparing an anti-adhesion hard coating for injection molds according to any one of claims 1 to 4, characterized in that it comprises the following steps:

S1. Depositing the bonding layer, that is, the Cr layer, on the surface of the mold by a deposition method, and the thickness of the bonding layer is 1.5-3 μm;

S2. Depositing the transition layer, that is, a CrN layer, on the bonding layer by a deposition method, and the thickness of the transition layer is 2 to 4 μm;

S3. Depositing a first composite layer on the transition layer by a deposition method, the first composite layer includes a (Cr, Ni)N/DLC layer, and the thickness of the first composite layer is 3-10 μm;

S4. Heat treatment in a protective atmosphere to make the first composite layer form a second composite layer, the second composite layer including a (Cr, Ni)N/DLC/CNTs layer;

S5. The second composite layer is modified by glow discharge plasma to form the hard anti-adhesion functional layer, namely (Cr, Ni)N/DLC-CF 3 /CNTs-CF 3 layer, so The thickness of the anti-adhesion hard coating is 6.5-17 μm.
The method for preparing an anti-adhesion hard coating for injection molds according to claim 5, wherein, in step S1, the deposition method is a magnetron sputter ion plating deposition method, and the transition layer is deposited Specifically include the following steps:

Put the mold into the furnace body, evacuate to a vacuum degree of 0.8×10 -3 or more, and introduce argon gas with a purity of 99.99% and a pressure control of 0.1-1pa. Among them, the Cr target current is 0.6-2.2A. The negative bias voltage is 60-180V, and the bias frequency is 150-300kHz.
The method for preparing an anti-adhesion hard coating for injection molds according to claim 5, wherein in step S2, the deposition method is a magnetron sputtering ion plating deposition method, and the transition layer is deposited Specifically include the following steps:

Evacuate to a vacuum degree above 0.8×10 3 ～10Pa, and pass in nitrogen with a purity of 99.999% and a pressure of 0.3～1.6pa. Among them, the Cr target current is 0.3～1.2A, and the negative bias voltage is 30～100V. Compression frequency is 50～120kHz.
The method for preparing an anti-adhesion hard coating for injection molds according to claim 5, wherein, in step S3, the deposition method is a magnetron sputtering ion plating deposition method, and the first The composite layer specifically includes the following steps:

It is evacuated to a vacuum degree above 0.8×10 -3 , the purity of the nitrogen is 99.999%, the pressure is controlled at 0.1～1.0pa, and three targets are used for sputtering. Among them, the target current of Cr is 0.2～1.4A, Ni The target current is 0.04～0.3A, the C target current is 0.8～3A, the negative bias voltage is 30～150V, and the bias frequency is 50～180kHz.
The method for preparing an anti-adhesion hard coating for injection molds according to claim 5, wherein step S4 specifically includes the following steps:

Use argon as the protective atmosphere, its purity is 99.99%, the pressure is normal pressure, and the heating rate in the furnace body is 1-20℃/min, the holding temperature is 600-800℃, and the holding time is 2-10h. Cool down to room temperature.
The method for preparing an anti-adhesion hard coating for injection molds according to claim 5, wherein step S5 specifically includes the following steps:

Evacuate to a vacuum degree above 1×10 -2 10Pa, and pass in a mixed gas including argon and carbon tetrafluoride gas, the purity of which is greater than 99.9%, and the volume percentage of CF 4 in the mixed gas is 30～ 100%, atmospheric pressure is normal pressure, gas flow rate is 20-200ml/min, glow discharge power is 40-400W, treatment time is 10-120min.