Die surface self-lubricating coating and application thereof

Abstract

The invention relates to the technical field of mold coating materials, and discloses a mold surface self-lubricating coating which is prepared from the following raw materials in parts by weight: 10-20 parts of molybdenum disulfide, 5-15 parts of graphite, 15-25 parts of polytetrafluoroethylene, 8-18 parts of boron nitride, 3-8 parts of nanoscale graphene and 2-6 parts of hexagonal aluminum nitride. The self-lubricating coating is prepared through one of chemical vapor deposition, physical vapor deposition, a spraying method or an electroplating technology, the thickness of the self-lubricating coating ranges from 5 micrometers to 50 micrometers, the hardness Hv ranges from 800 to 2500, and the particle size ranges from 1 micrometer to 10 micrometers. A layer of film with good lubricity is formed on the surface of the mold through the self-lubricating coating, and the film effectively reduces friction between the mold and a forming material and reduces the wear rate in the injection molding process, so that the service life of the mold is prolonged, and particularly in a high-speed, high-temperature and high-pressure working environment, friction and wear are reduced, and the service life of the mold is prolonged. And the durability of the mold can be obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mold coating materials, and specifically to a self-lubricating coating for the surface of a mold and its application. Background Art

[0002] A mold is a tool used to make shaped articles. Such a tool is composed of various parts, and different molds are composed of different parts. It mainly realizes the processing of the outer shape of an article by changing the physical state of the formed material. A self-lubricating coating is a surface coating material that can provide a lubricating effect between relatively moving surfaces, reducing friction and wear.

[0003] During the manufacturing process of plastic injection molds and die-casting molds, due to long-term exposure to high temperature, high pressure, and strong friction with the formed material, the molds are prone to wear and corrosion, and their durability is poor. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a self-lubricating coating for the surface of a mold and its application, solving the problems that the mold is prone to wear and corrosion and has poor durability.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A self-lubricating coating for the surface of a mold, comprising the following raw materials in parts by weight: 10-20 parts of molybdenum disulfide, 5-15 parts of graphite, 15-25 parts of polytetrafluoroethylene, 8-18 parts of boron nitride, 3-8 parts of nano-scale graphene, and 2-6 parts of hexagonal aluminum nitride form the self-lubricating coating.

[0006] Preferably, the self-lubricating coating is prepared by one of chemical vapor deposition, physical vapor deposition, spraying method, or electroplating technology.

[0007] Preferably, the thickness of the self-lubricating coating is 5-50 μm, the hardness is Hv800-2500, and the particle size is 1-10 μm.

[0008] Preferably, the chemical vapor deposition includes the following steps: Put the pretreated mold into a vacuum reaction chamber and evacuate to a pressure lower than 10⁻³ Pa; Heat the mold to 500-800 °C; Introduce a gas containing lubricating materials, a mixed gas of molybdenum disulfide vapor, methane, and nitrogen, and control the gas flow rate at 10-50 sccm, and react for 1-3 hours.

[0009] Preferably, the physical vapor deposition includes the following steps: In an environment with a vacuum degree better than 10⁻ 4 Pa; By evaporating a target material containing a lubricating material at an evaporation temperature of 1500 - 2500 °C, or by sputtering a target material containing a lubricating material with a sputtering power of 100 - 500 W; Deposit the lubricating material on the surface of the mold for a deposition time of 2 - 4 hours.

[0010] Preferably, the spraying method includes the following steps: Load the coating material into a high-pressure spray gun and adjust the spray gun pressure to 10 - 20 MPa; Control the spraying distance to be 15 - 30 cm, move the spray gun at a uniform speed, spray the surface of the mold, and the number of spraying times is 3 - 5 times.

[0011] Preferably, the electroplating technique includes the following steps: Use the mold as the cathode and the electroplating solution containing the self-lubricating material as the anode; Control the current density to be 2 - 5 A / dm², the electroplating temperature to be 40 - 60 °C, and the electroplating time to be 1 - 2 hours.

[0012] Application of the self-lubricating coating on the mold surface, where the self-lubricating coating is applied to the mold surface.

[0013] Application of the self-lubricating coating on the mold surface includes the following steps: Step 1: Pretreatment of the mold surface. Grind and polish the mold surface to make its surface roughness reach Ra0.1 - 0.2 μm, and then use ultrasonic cleaning to remove surface oil stains and impurities; Step 2: Select the coating material. By weight, select molybdenum disulfide, graphite, polytetrafluoroethylene, boron nitride, nanoscale graphene, and hexagonal boron nitride and mix them to form a self-lubricating coating; Step 3: Then use plasma-enhanced chemical vapor deposition to form a transition layer on the pretreated mold surface. During the deposition process, the reaction gases are silane and ammonia, the deposition temperature is 400 - 500 °C, the working pressure is 0.2 - 0.5 Pa, the radio frequency power is 200 - 300 W, the deposition time is 30 - 60 minutes, and the thickness of the transition layer is 1 - 2 μm; Step 4: Use magnetron sputtering technology to deposit a self-lubricating coating on the transition layer. The working pressure is 0.5 - 1.0 Pa, the sputtering power is 300 - 500 W, the deposition time is 1 - 2 hours, and the thickness of the coating is 7 - 13 μm; Step 5: Perform surface treatment on the deposited coating, including ion implantation and low-temperature plasma treatment; Step 6: During the coating preparation process, make the coating have antibacterial properties by doping trace amounts of silver ions, and introduce organosilicon compounds to enhance the antioxidant and corrosion resistance capabilities.

[0014] Preferably, in step five, titanium and chromium elements are ion-implanted with an implantation energy of 20 - 50 keV and an implantation dose of 1×10¹ 6 -5×10¹ 6 ions / cm²; During low-temperature plasma treatment, a mixed gas of argon and oxygen is introduced with a power of 500 - 800 W, a gas pressure of 50 - 100 Pa, and a treatment time of 10 - 20 minutes.

[0015] The present invention provides a self-lubricating coating for the mold surface and its application. It has the following beneficial effects: 1. The present invention forms a film with good lubricity on the mold surface through the self-lubricating coating. This film effectively reduces the friction between the mold and the molding material during the injection molding process, reduces the wear rate, and thus extends the service life of the mold. Especially in the working environment of high speed, high temperature, and high pressure, reducing friction and wear can significantly improve the durability of the mold.

[0016] 2. Due to the reduction of friction in the present invention, the stability of the mold during the molding process is improved, avoiding mold deformation and surface defects caused by friction, thereby improving the accuracy and surface quality of the molded product. Moreover, the self-lubricating coating of the mold can effectively delay the wear and corrosion of the mold, reduce the maintenance frequency of the mold, lower the cost of mold replacement, and improve production efficiency.

[0017] 3. Reducing the friction force in the present invention can not only reduce mold wear but also reduce energy consumption. Since the friction is reduced, the energy loss during the injection molding process is also correspondingly reduced, thereby improving the energy utilization rate of production. The self-lubricating coating has good high-temperature resistance, maintains good lubrication effects at high temperatures, avoids the failure of the lubricant caused by high temperatures, and ensures that the mold can still operate smoothly in a high-temperature working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the method steps for the application of the self-lubricating coating on the mold surface of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0020] Example: Please refer to the attached Figure 1, the embodiments of the present invention provide a self-lubricating coating for the mold surface, which comprises the following raw materials in parts by weight: 10-20 parts of molybdenum disulfide, 5-15 parts of graphite, 15-25 parts of polytetrafluoroethylene, 8-18 parts of boron nitride, 3-8 parts of nano-scale graphene, and 2-6 parts of hexagonal aluminum nitride to form the self-lubricating coating.

[0021] The self-lubricating coating is prepared by one of chemical vapor deposition, physical vapor deposition, spraying method or electroplating technology.

[0022] The thickness of the self-lubricating coating is 5-50 μm, the hardness is Hv800-2500, and the particle size is 1-10 μm.

[0023] Chemical vapor deposition includes the following steps: Put the pretreated mold into the vacuum reaction chamber and evacuate to a pressure lower than 10⁻³ Pa; Heat the mold to 500-800 °C; Introduce the gas containing lubricating materials, a mixed gas of molybdenum disulfide vapor, methane and nitrogen, control the gas flow rate at 10-50 sccm, and react for 1-3 hours.

[0024] Through the chemical reaction of the gas at high temperature, the lubricating materials are deposited on the mold surface and form a uniform coating, which can accurately control the composition and structure of the coating, so as to obtain a coating with good bonding force and performance, which can significantly reduce the friction coefficient of the mold surface, reduce wear, and improve the service life of the mold Physical vapor deposition includes the following steps: In an environment with a vacuum degree better than 10⁻ 4 Pa; Evaporate the target containing lubricating materials, with an evaporation temperature of 1500-2500 °C, or sputter the target containing lubricating materials, with a sputtering power of 100-500 W; Deposit the lubricating materials on the mold surface, and the deposition time is 2-4 hours.

[0025] Using physical processes, evaporation or sputtering, transfer the materials on the target and deposit them on the mold surface, which can achieve precise control of the coating thickness and microstructure, and can form a dense and uniform coating, effectively improving the wear resistance and corrosion resistance of the mold.

[0026] The spraying method includes the following steps: Load the coating material into the high-pressure spray gun and adjust the spray gun pressure to 10-20 MPa; Control the spraying distance to be 15-30 cm, move the spray gun at a uniform speed, spray the mold surface, and the number of spraying times is 3-5 times.

[0027] The coating material is atomized and sprayed onto the mold surface under high pressure to form a coating. The operation is relatively simple, suitable for large-area coating construction, and can quickly provide a certain thickness of coating for the mold, playing a role in protection and lubrication.

[0028] The electroplating technology includes the following steps: The mold is used as the cathode, and the electroplating solution containing the self-lubricating material is used as the anode; The current density is controlled at 2 - 5 A / dm², the electroplating temperature is 40 - 60 °C, and the electroplating time is 1 - 2 hours.

[0029] Application of the self-lubricating coating on the mold surface, the self-lubricating coating is applied to the mold surface.

[0030] By using the electrolytic action, the self-lubricating material in the electroplating solution is deposited on the mold surface to form a coating, which can achieve uniform coating deposition on the surface of complex-shaped molds and can provide good adhesion and protective performance.

[0031] Application of the self-lubricating coating on the mold surface includes the following steps: Step 1: Pretreatment of the mold surface. The mold surface is polished and buffed to make its surface roughness reach Ra0.1 - 0.2 μm, and then ultrasonic cleaning is used to remove surface oil stains and impurities; The unevenness and defects on the surface are removed by grinding and polishing, and ultrasonic cleaning uses high-frequency vibration to remove tiny pollutants, thereby improving the bonding force between the coating and the mold surface, creating good conditions for the uniform adhesion of the subsequent coating, and avoiding the influence of defects and impurities on the coating performance; Step 2: Select the coating material. By weight, molybdenum disulfide, graphite, polytetrafluoroethylene, boron nitride, nano-scale graphene, and hexagonal boron nitride are selected and mixed to form a self-lubricating coating; Step 3: Then, plasma-enhanced chemical vapor deposition is used to form a transition layer on the pretreated mold surface. During the deposition process, the reaction gases are silane and ammonia, the deposition temperature is 400 - 500 °C, the working pressure is 0.2 - 0.5 Pa, the radio frequency power is 200 - 300 W, the deposition time is 30 - 60 minutes, and the thickness of the transition layer is 1 - 2 μm; The reaction gases are excited by plasma to promote chemical reactions to deposit a transition layer on the mold surface. By controlling the process parameters, the transition layer has good adhesion and performance, effectively improving the bonding strength between the coating and the mold substrate and enhancing the stability and durability of the coating; Step 4: Use magnetron sputtering technology to deposit a self-lubricating coating on the transition layer. The working pressure is 0.5 - 1.0 Pa, the sputtering power is 300 - 500 W, the deposition time is 1 - 2 hours, and the thickness of the coating is 7 - 13 μm; Under the action of a magnetic field, ions are bombarded onto the target material, and the sputtered material is deposited on the surface of the mold to form a coating. By adjusting parameters to control the growth process of the coating, a dense, uniform and excellent-performance self-lubricating coating can be obtained, significantly reducing the friction and wear on the surface of the mold; Step Five: Perform surface treatment on the deposited coating, including ion implantation and low-temperature plasma treatment; Ion implantation incorporates elements into the coating by bombarding with high-energy ions to change its properties; low-temperature plasma treatment improves its surface characteristics through the interaction between the plasma and the coating surface. Strictly control the treatment parameters to achieve the desired effect, further enhancing the hardness, wear resistance, corrosion resistance and bonding strength of the coating; Step Six: During the coating preparation process, make the coating have antibacterial properties by doping trace silver ions, and introduce silicone compounds to enhance the antioxidant and corrosion resistance capabilities.

[0032] The presence of silver ions inhibits the growth and reproduction of bacteria, and the protective film formed by silicone compounds improves the antioxidant and corrosion resistance capabilities. Precisely control the doping and introduction amounts to avoid adverse effects on other properties of the coating, making the coating multifunctional and adaptable to different working conditions and requirements, thereby better protecting the mold and improving its service performance.

[0033] In Step Five, implant titanium and chromium elements by ion implantation, with an implantation energy of 20 - 50 keV and an implantation dose of 1×10¹ 6 -5×10¹ 6 ions / cm²; During low-temperature plasma treatment, introduce a mixed gas of argon and oxygen, with a power of 500 - 800 W, a gas pressure of 50 - 100 Pa, and a treatment time of 10 - 20 minutes.

[0034] The following is introduced in combination with specific examples: Example One: The self-lubricating coating on the mold surface consists of the following raw materials in parts by weight: 10 parts of molybdenum disulfide, 5 parts of graphite, 15 parts of polytetrafluoroethylene, 8 parts of boron nitride, 3 parts of nanoscale graphene and 2 parts of hexagonal aluminum nitride to form the self-lubricating coating.

[0035] The self-lubricating coating is prepared by chemical vapor deposition, and the chemical vapor deposition includes the following steps: Put the pretreated mold into a vacuum reaction chamber, evacuate to a pressure below 10⁻³ Pa; heat the mold to 500 °C, introduce a gas containing lubricating materials, a mixed gas of molybdenum disulfide vapor, methane and nitrogen, control the gas flow rate at 10 sccm, and react for 1 hour.

[0036] The application of the self-lubricating coating on the mold surface includes the following steps: Step 1: Pretreat the mold surface. Grind and polish the mold surface to make its surface roughness reach Ra0.1μm, and then use ultrasonic cleaning to remove surface oil stains and impurities; Step 2: Select coating materials. By weight, select molybdenum disulfide, graphite, polytetrafluoroethylene, boron nitride, nanoscale graphene, and hexagonal boron nitride and mix them to form a self-lubricating coating; Step 3: Then use plasma-enhanced chemical vapor deposition to form a transition layer on the pretreated mold surface. During the deposition process, the reaction gases are silane and ammonia, the deposition temperature is 400°C, the working pressure is 0.2 Pa, the radio frequency power is 200 W, the deposition time is 30 minutes, and the thickness of the transition layer is 1μm; Step 4: Use magnetron sputtering technology to deposit a self-lubricating coating on the transition layer. The working pressure is 0.5 Pa, the sputtering power is 300 W, the deposition time is 1 hour, and the thickness of the coating is 7μm; Step 5: Perform surface treatment on the deposited coating, perform ion implantation and low-temperature plasma treatment. Ion implant titanium and chromium elements, the implantation energy is 20 keV, and the implantation dose is 1×10¹ 6 ions / cm². When performing low-temperature plasma treatment, introduce a mixed gas of argon and oxygen, the power is 500 W, the pressure is 50 Pa, and the treatment time is 10 minutes; Step 6: During the coating preparation process, make the coating have antibacterial properties by doping trace silver ions, and introduce organosilicon compounds to enhance antioxidant and corrosion resistance capabilities.

[0037] Example 2: The self-lubricating coating on the mold surface comprises the following raw materials by weight: 20 parts of molybdenum disulfide, 15 parts of graphite, 25 parts of polytetrafluoroethylene, 18 parts of boron nitride, 8 parts of nanoscale graphene, and 6 parts of hexagonal boron nitride to form a self-lubricating coating.

[0038] The self-lubricating coating is prepared by physical vapor deposition, and the physical vapor deposition includes the following steps: In an environment with a vacuum better than 10⁻ 4 Pa, by evaporating the target material containing lubricating materials, the evaporation temperature is 2500°C, or by sputtering the target material containing lubricating materials, the sputtering power is 500 W, so that the lubricating materials are deposited on the mold surface, and the deposition time is 4 hours.

[0039] The application of the self-lubricating coating on the mold surface includes the following steps: Step 1: Pretreat the mold surface. Grind and polish the mold surface to make its surface roughness reach Ra0.2μm, and then use ultrasonic cleaning to remove surface oil stains and impurities; Step 2: Select coating materials. By weight, select molybdenum disulfide, graphite, polytetrafluoroethylene, boron nitride, nanoscale graphene, and hexagonal boron nitride and mix them to form a self-lubricating coating; Step 3: Then, use plasma-enhanced chemical vapor deposition to form a transition layer on the surface of the pretreated mold. During the deposition process, the reaction gases are silane and ammonia, the deposition temperature is 500 °C, the working pressure is 0.5 Pa, the radio frequency power is 300 W, the deposition time is 60 minutes, and the thickness of the transition layer is 2 μm; Step 4: Use magnetron sputtering technology to deposit a self-lubricating coating on the transition layer. The working pressure is 1.0 Pa, the sputtering power is 500 W, the deposition time is 2 hours, and the thickness of the coating is 13 μm; Step 5: Perform surface treatment on the deposited coating, including ion implantation and low-temperature plasma treatment. Ion implant titanium and chromium elements, the implantation energy is 50 keV, and the implantation dose is 5×10¹ 6 ions / cm². When performing low-temperature plasma treatment, introduce a mixed gas of argon and oxygen, the power is 800 W, the pressure is 100 Pa, and the treatment time is 20 minutes.

[0040] Step 6: During the coating preparation process, make the coating have antibacterial properties by doping trace amounts of silver ions, and introduce organosilicon compounds to enhance the antioxidant and corrosion resistance capabilities.

[0041] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. The self-lubricating coating on the mold surface is characterized by: The self-lubricating coating comprises the following raw materials in parts by weight: 10-20 parts of molybdenum disulfide, 5-15 parts of graphite, 15-25 parts of polytetrafluoroethylene, 8-18 parts of boron nitride, 3-8 parts of nanometer-level graphene and 2-6 parts of hexagonal aluminum nitride.

2. The self-lubricating coating on the mold surface according to claim 1, characterized in that: The self-lubricating coating is prepared by chemical vapor deposition, physical vapor deposition, spraying or electroplating technology.

3. The self-lubricating coating on the mold surface according to claim 1, characterized in that: The self-lubricating coating has a thickness of 5-50 μm, a hardness of Hv800-2500, and a particle size of 1-10 μm.

4. The self-lubricating coating on the mold surface according to claim 2, characterized in that: The chemical vapor deposition comprises the following steps: Place the pretreated mold into a vacuum reaction chamber and evacuate it to a pressure lower than 10⁻³Pa; Heat the mold to 500-800℃; A gas containing lubricating material, molybdenum disulfide vapor, a mixed gas of methane and nitrogen is introduced, the gas flow rate is controlled at 10-50 sccm, and the reaction is carried out for 1-3 hours.

5. The self-lubricating coating on the mold surface according to claim 2, characterized in that: The physical vapor deposition comprises the following steps: The vacuum degree is better than 10⁻ 4 In the environment of Pa; By evaporating a target containing a lubricating material at an evaporation temperature of 1500-2500°C, or by sputtering a target containing a lubricating material at a sputtering power of 100-500W; The lubricating material is deposited on the mold surface for 2-4 hours.

6. The self-lubricating coating on the mold surface according to claim 2, characterized in that: The spraying method comprises the following steps: Load the coating material into the high-pressure spray gun and adjust the spray gun pressure to 10-20MPa; Control the spraying distance to 15-30 cm, move the spray gun at a uniform speed, spray the mold surface 3-5 times.

7. The self-lubricating coating on the mold surface according to claim 2, characterized in that: The electroplating technique comprises the following steps: The mold is used as a cathode and the electroplating solution containing the self-lubricating material is used as an anode; The current density is controlled to be 2-5A / dm², the electroplating temperature is 40-60℃, and the electroplating time is 1-2 hours.

8. Application of self-lubricating coating on mold surface, characterized by: The self-lubricating coating is applied to the mold surface.

9. Application of self-lubricating coating on mold surface, characterized by: The self-lubricating coating for the mold surface according to any one of claims 1 to 7 comprises the following steps: Step 1: Pre-treatment of the mold surface: grinding and polishing the mold surface to a surface roughness of Ra0.1-0.2μm, and then using ultrasonic cleaning to remove surface oil and impurities; Step 2: Select coating materials, and select molybdenum disulfide, graphite, polytetrafluoroethylene, boron nitride, nano-graphene and hexagonal aluminum nitride to mix and form a self-lubricating coating by weight; Step 3: Then, plasma enhanced chemical vapor deposition is used to form a transition layer on the pretreated mold surface. During the deposition process, the reaction gases are silane and ammonia, the deposition temperature is 400-500°C, the working pressure is 0.2-0.5Pa, the radio frequency power is 200-300W, the deposition time is 30-60 minutes, and the thickness of the transition layer is 1-2μm; Step 4: Deposit a self-lubricating coating on the transition layer using magnetron sputtering technology, with a working pressure of 0.5-1.0 Pa, a sputtering power of 300-500 W, a deposition time of 1-2 hours, and a coating thickness of 7-13 μm; Step 5: Surface treatment of the deposited coating by ion implantation and low-temperature plasma treatment; Step 6: During the coating preparation process, trace amounts of silver ions are doped to give the coating antibacterial properties, and organic silicon compounds are introduced to enhance antioxidant and corrosion resistance.

10. The use of the self-lubricating coating on the mold surface according to claim 9, characterized in that: In step 5, ion implantation of titanium and chromium elements is performed with an implantation energy of 20-50 keV and an implantation dose of 1×10¹ 6 -5×10¹ 6 ions / cm²; During low-temperature plasma treatment, a mixed gas of argon and oxygen is introduced, the power is 500-800W, the gas pressure is 50-100Pa, and the treatment time is 10-20 minutes.

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