High-temperature-oxidation-resistant wear-resistant composite coating on cast high-temperature alloy surface and preparation method thereof

Abstract

The invention discloses a cast superalloy surface high-temperature-oxidation-resistant and wear-resistant composite coating. The composite coating comprises an Al metal transition layer, an AlSi high-temperature-oxidation-resistant layer and a TiCN wear-resistant layer which are sequentially deposited on the surface of a nickel-based cast superalloy from inside to outside. The invention further discloses a preparation method of the composite coating, ion bombardment cleaning is conducted on the base body, then the Al coating, the AlSi coating and the TiCN coating are deposited on the surface of the base body in sequence, each deposition process comprises a low-power weak ionization stage and a high-power strong ionization stage, and high-temperature heating treatment is conducted on the base body before the TiCN coating is deposited. The composite coating disclosed by the invention has excellent high-temperature oxidation resistance and wear resistance; and the preparation method disclosed by the invention has the characteristics of high deposition efficiency, relatively low internal stress between prepared heterogeneous coatings, relatively high binding force and high surface quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface coating and protection of cast metal parts, and relates to a high-temperature oxidation resistant and wear-resistant composite coating on the surface of a cast high-temperature alloy. The present invention also relates to a preparation method of the above-mentioned high-temperature oxidation resistant and wear-resistant composite coating. Background Art

[0002] Nickel-based cast high-temperature alloy refers to a high-temperature alloy material with nickel as the main component and parts directly prepared by casting method. It has excellent comprehensive mechanical properties such as high-temperature strength, fatigue stability and fracture toughness, and is widely used in key fields such as aerospace, automobiles, gas turbines, etc. However, while nickel-based cast high-temperature alloy has good high-temperature mechanical properties, its high-temperature oxidation resistance and wear resistance are difficult to take into account. Therefore, coating the surface of the base material with excellent high-temperature mechanical properties with a high-temperature oxidation-resistant and wear-resistant composite coating is an effective way to solve this contradiction.

[0003] AlSi coating is an excellent high-temperature oxidation resistant coating with good wear resistance. TiCN coating has both amorphous carbon and nanocrystalline structure. Compared with traditional TiC and TiN coatings, it has higher hardness, better toughness and lower friction coefficient. It is a wear-resistant protective coating that is widely used on metal surfaces. AlSi-TiCN composite coating can be prepared by physical vapor deposition method, but relevant patents and literature show that there are few successful cases, which is mainly limited by the limitations of various physical vapor deposition coating preparation methods. Current physical vapor deposition mainly includes magnetron sputtering, multi-arc ion plating, high-power pulsed magnetron sputtering, etc. Magnetron sputtering uses the principle of gas glow discharge to achieve low-temperature deposition of high-surface quality coatings, but the deposition efficiency is low and the coating uniformity is poor for complex parts; multi-arc ion plating uses the principle of gas arc discharge to achieve efficient deposition of coatings, but there are many large molten particles with a diameter of about 2~20μm in the coating, which seriously reduces the mechanical properties of the coating; high-power pulsed magnetron sputtering is a magnetron sputtering technology with a high metal ionization rate. Its working principle is to adopt a high-power pulse power supply control mode, and obtain an instantaneous high metal ionization rate by reasonably adjusting the electric field parameters such as frequency and duty cycle, thereby achieving high ionization. It has significant advantages in improving the density and uniformity of the coating and improving the overall performance of the coating, but its average deposition rate is low, only 15%~50% of that of ordinary magnetron sputtering, and the residual stress of the prepared coating is large.

[0004] Therefore, how to design and prepare a high-temperature oxidation-resistant and wear-resistant composite coating with a dense structure and good bonding between heterogeneous coatings becomes the key to solving the surface protection of nickel-based cast high-temperature alloy parts. Summary of the invention

[0005] The purpose of the present invention is to provide a high-temperature oxidation-resistant and wear-resistant composite coating on the surface of a cast high-temperature alloy, which is an Al-AlSi-TiCN composite coating with excellent high-temperature oxidation resistance and wear resistance.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned composite coating, which has the characteristics of high deposition efficiency, lower internal stress and higher bonding strength between the prepared heterogeneous coatings, and high surface quality.

[0007] The technical solution adopted by the present invention is that the high temperature oxidation resistant and wear resistant composite coating on the surface of the cast high temperature alloy includes an Al metal transition layer, an AlSi high temperature oxidation resistant layer and a TiCN wear resistant layer deposited sequentially from the inside to the outside on the surface of the nickel-based cast high temperature alloy.

[0008] The present invention is also characterized in that: The thickness of the Al metal transition layer is 200nm~300nm, the thickness of the AlSi high temperature oxidation resistant layer is 800nm~1500nm, and the thickness of the TiCN wear resistant layer is 1500nm~2000nm; the composite coating is composed of uniform and dense nanocrystals, and the grain size is less than 20nm.

[0009] Another technical solution adopted by the present invention is a method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy, which is specifically implemented according to the following steps: Step 1, under vacuum conditions, argon gas is introduced, the Al target is started and a direct current is loaded to perform ion bombardment cleaning on the nickel-based cast high-temperature alloy substrate; Step 2, turning on the Al target sputtering mode, and depositing an Al metal transition layer on the substrate surface through two stages of weak ionization and strong ionization; Step 3, close the Al target, open the AlSi20at% target, and deposit the AlSi high temperature oxidation resistant coating on the Al metal transition layer through two stages of weak ionization and strong ionization; Step 4, closing the AlSi20at% target and heating the substrate; Step 5, open the TiCN target, and deposit a TiCN wear-resistant layer on the AlSi high-temperature oxidation resistant layer through two stages of weak ionization and strong ionization.

[0010] Another technical solution of the present invention is also characterized in that: In step 1, the vacuum degree is 2.0~3.0×10 -5 Torr, argon flow rate is 40~60mL / min, Al target current is DC 1.0~2.0A, and cleaning time is 5~10min.

[0011] In step 2, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon flow rate is 40~60mL / min, and the deposition time is 10~20min.

[0012] In step 3, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon flow rate is 40~60mL / min, and the deposition time is 20~30min.

[0013] In step 4, the heating temperature is 400-500° C., and the heating time is 10-15 min.

[0014] In step 5, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon gas flow rate is 40~60mL / min, and the deposition time is 40~60min.

[0015] The beneficial effects of the present invention are: (1) The structure of the composite coating of the present invention is an Al metal transition layer, an AlSi high temperature oxidation resistant layer, and a TiCN wear resistant layer. The composite coating of this structure has the advantages of both AlSi and TiCN coatings, and has excellent high temperature oxidation resistance and wear resistance. (2) The method of the present invention first deposits an Al metal transition layer on the surface of the cast high-temperature alloy, and then deposits an AlSi high-temperature oxidation resistant layer and a TiCN wear-resistant layer in sequence. The deposition process of the three coatings is divided into a weak ionization stage and a strong ionization stage. The substrate is heated at high temperature before the TiCN coating is deposited, so that the prepared composite coating has a dense coating structure and a smooth and uniform surface quality. The heterogeneous coatings have lower internal stress and higher bonding strength, which solves the problem that it is currently difficult to obtain a good high-temperature oxidation resistant and wear-resistant composite coating on the surface of a nickel-based cast high-temperature alloy by a physical vapor deposition method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of electric field design for high-power pulsed magnetron sputtering and dual-stage high-power pulsed magnetron sputtering; Figure 2This is a SEM photo of the TiCN wear-resistant coating on the surface of the nickel-based cast high-temperature alloy prepared in Example 1 of the present invention; Figure 3 This is a cross-sectional SEM photograph of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0017] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The high-temperature oxidation-resistant and wear-resistant composite coating on the surface of the cast high-temperature alloy of the present invention consists of an Al metal transition layer, an AlSi high-temperature oxidation-resistant layer and a TiCN wear-resistant layer, wherein the thickness of the Al metal transition layer is 200-300nm, the thickness of the AlSi high-temperature oxidation-resistant layer is 800-1500nm, and the thickness of the TiCN wear-resistant layer is 1500nm-2000nm; the composite coating consists of uniform and dense nanocrystals, and the grain size is less than 20nm.

[0019] The method for preparing the high-temperature oxidation-resistant and wear-resistant composite coating on the surface of a cast high-temperature alloy of the present invention comprises the following steps: a layer of Al metal transition layer is designed before the deposition of the AlSi coating, and a substrate heating box device is used to heat the substrate at high temperature before the deposition of the TiCN coating to reduce internal stress and activate the surface, thereby improving the bonding force between the AlSi and TiCN heterogeneous coatings.

[0020] The method of the present invention adopts a self-developed two-stage high-power pulse magnetron sputtering device loaded with a substrate heating box device, that is, on the basis of the original high-power pulse magnetron sputtering device, the high-power pulse power supply is changed to a two-stage high-power pulse power supply including a weak ionization electric field and a strong ionization electric field gradient design, and a substrate heating box device is loaded to heat the substrate. The two-stage high-power pulse magnetron sputtering device can provide two power supply modes: ordinary DC and two-stage high-power pulse. The maximum power of the pulse power supply is 12kW, the duty cycle τ is adjustable in the range of 8% to 100%, and the pulse conduction width T on , pulse off width T off Can be set as needed.

[0021] like Figure 1As shown, it is a schematic diagram of the electric field design of high-power pulsed magnetron sputtering and dual-stage high-power pulsed magnetron sputtering. The present invention proposes a design concept of increasing the duty cycle τ and reducing the peak target current in order to improve the deposition efficiency. The electric field mode is designed to be segmented or stepped, that is, there are two continuous and independently adjustable pulse stages in one pulse conduction cycle, and the duty cycle τ can reach 10%~100%. In the first pulse stage, a lower power is applied to initially ionize the Ar gas to form a low-density plasma, which is defined as the weak ionization stage; and in the second pulse stage, a higher power is applied to further ionize the atoms to form a high-density plasma, which is defined as the strong ionization stage. The pre-ionization process in the weak ionization stage is used to reduce internal stress and improve the film-substrate bonding, and the strong ionization process in the strong ionization stage is used to significantly improve the deposition efficiency. The substrate heating box device is used to improve the bonding between heterogeneous coatings.

[0022] The method for preparing the high temperature oxidation resistant and wear resistant composite coating on the surface of the cast high temperature alloy of the present invention is specifically implemented according to the following steps: First, a metal Al target with a purity of 99.99%, an AlSi20at% target with a Si content of 20%, and a TiCN target are installed in a double-stage high-power pulsed magnetron sputtering chamber, and a nickel-based cast high-temperature alloy substrate is installed on a substrate rotating frame. The rotation speed is preferably 3-8 rpm, and more preferably 5 rpm.

[0023] Step 1, ion cleaning: Turn on the double-stage high-power pulse power supply, and after the vacuum degree in the vacuum chamber reaches a certain value, introduce high-purity argon gas, start the aluminum target and load direct current, and use high-energy argon ions to bombard the nickel-based cast high-temperature alloy substrate to improve the surface cleanliness of the substrate and activate the surface. The vacuum degree in the vacuum chamber is 2.0~3.0×10 -5 Torr, preferably 2.0×10 -5 Torr; argon flow rate is 40~60mL / min, preferably 45mL / min; aluminum target current is DC 1.0~2.0A, preferably 1.5A; cleaning time is 5~10min.

[0024] Step 2, Al metal transition layer deposition: After the ion cleaning is completed, the Al target sputtering mode is turned on, and the peak voltages of the weak ionization and strong ionization stages, the pulse conduction widths of the weak ionization and strong ionization stages, the pulse off widths, the negative bias voltage, the frequency, the argon gas flow rate and other related parameters are set to deposit a layer of pure metal Al transition layer on the substrate. Among them, the peak voltages of the weak ionization and strong ionization stages are 200~250V and 600~750V, respectively, the pulse conduction widths of the weak ionization and strong ionization stages are 4~8ms and 6~8ms, respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, preferably -60V, the frequency is 40~60Hz, preferably 50Hz, the argon gas flow rate is 40~60mL / min, preferably 55mL / min, and the deposition time is 10~20min.

[0025] Step 3, AlSi high temperature resistant oxide layer deposition: After the Al transition layer is deposited, the Al target is turned off, the AlSi20at% target is turned on, and the peak voltages of the weak ionization and strong ionization stages, the pulse conduction widths of the weak ionization and strong ionization stages, the pulse off widths, the negative bias voltage, the frequency, the argon gas flow rate and other related parameters are set to deposit the AlSi high temperature oxidation resistant coating on the Al metal transition layer. Among them, the peak voltages of the weak ionization and strong ionization stages are 200~250V and 600~750V, respectively, the pulse conduction widths of the weak ionization and strong ionization stages are 4~8ms and 6~8ms, respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, preferably -60V, the frequency is 40~60Hz, preferably 50Hz, the argon gas flow rate is 40~60mL / min, preferably 55mL / min, and the deposition time is 20~30min.

[0026] Step 4, substrate heating: After the deposition of the AlSi high temperature oxidation resistant coating is completed, the AlSi20at% target is turned off, and the substrate is heated by a substrate heating box device to reduce residual stress and improve the bonding strength of the AlSi and TiCN heterogeneous coatings. The heating temperature is 400-500°C, preferably 450°C, and the heating time is 10-15 minutes, preferably 10 minutes.

[0027] Step 5, TiCN wear-resistant layer deposition: After heating, the substrate heating box device is turned off, the TiCN target is turned on, and the peak voltages of the weak ionization and strong ionization stages, the pulse conduction widths of the weak ionization and strong ionization stages, the pulse off widths, the negative bias voltage, the frequency, the argon flow rate and other related parameters are set to deposit the TiCN wear-resistant layer on the AlSi high temperature oxidation layer. Among them, the peak voltages of the weak ionization and strong ionization stages are 200~250V and 600~750V, respectively, the pulse conduction widths of the weak ionization and strong ionization stages are 4~8ms and 6~8ms, respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, preferably -60V, the frequency is 40~60Hz, preferably 55Hz, the argon flow rate is 40~60mL / min, preferably 55mL / min, and the deposition time is 40~60min.

[0028] Finally, a high-temperature oxidation-resistant and wear-resistant composite coating with dense structure and excellent performance was prepared on the surface of the nickel-based cast high-temperature alloy substrate.

[0029] Example 1 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.0×10 -5 Torr, high-purity argon gas with a flow rate of 45 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0030] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 220V and 600V respectively, the pulse on width of the weak ionization and strong ionization stages to 4ms and 6ms respectively, the pulse off width to 12ms, the negative bias voltage to -60V, the frequency to 50Hz, the argon gas flow rate to 45mL / min, the deposition time to 10min, and deposit a layer of pure metal Al primer transition layer on the substrate.

[0031] Step 3, deposition of AlSi high temperature resistant oxide layer: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of weak ionization and strong ionization stages to 220V and 600V respectively, the pulse on width of weak ionization and strong ionization stages to 4ms and 6ms respectively, the pulse off width to 12ms, the negative bias voltage to -60V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 20min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0032] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 450°C and a heating time of 10 minutes.

[0033] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 220V and 600V, the pulse on width of the weak ionization and strong ionization stages to 4ms and 6ms respectively, the pulse off width to 12ms, the negative bias voltage to -60V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 40min, and deposit the TiCN coating on the AlSi high temperature oxidation resistant layer.

[0034] Figure 2 This is a SEM photo of the TiCN wear-resistant coating on the surface of the nickel-based cast high-temperature alloy. It can be seen that the surface is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. Figure 3 This is a cross-sectional SEM photo of the Al-AlSi-TiCN composite coating on the surface of a nickel-based cast high-temperature alloy. It can be seen that the thickness of the Al transition layer is 210nm, the thickness of the AlSi high-temperature oxidation layer is 825nm, and the thickness of the TiCN wear-resistant layer is 1956nm. In addition, the test results show that the oxidation weight gain per unit area of ​​the composite coating at 1000℃ constant temperature oxidation for 500h is 0.765mg. 2 cm -4 , the oxidation rate is 2.86×10 -4 mg 2 cm -4 ·h -1 Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.13, and the mass wear rate is 1.02×10 -4 g / s.

[0035] In summary, the composite coating obtained in this embodiment has a dense overall structure and excellent performance.

[0036] Example 2 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.5×10 -5 Torr, high-purity argon gas with a flow rate of 50 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0037] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 200V and 650V respectively, the pulse on width of the weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -60V, the frequency to 50Hz, the argon gas flow rate to 50mL / min, the deposition time to 10min, and deposit a layer of pure metal Al base transition layer on the substrate.

[0038] Step 3, AlSi high temperature resistant oxide layer deposition: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of the weak ionization and strong ionization stages to 200V and 650V respectively, the pulse on width of the weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -60V, the frequency to 50Hz, the argon flow rate to 50mL / min, the deposition time to 30min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0039] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 500°C and a heating time of 10 minutes.

[0040] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 200V and 650V, the pulse on width of the weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width is 10ms, the negative bias voltage is -60V, the frequency is 50Hz, the argon flow rate is preferably 50mL / min, the deposition time is 40min, and the TiCN coating is deposited on the AlSi high temperature oxidation resistant layer.

[0041] Through testing, it can be seen that the surface of the TiCN wear-resistant coating in this embodiment is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. The thickness of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy is 3450nm. The oxidation weight gain of the composite coating at 1000℃ constant temperature oxidation for 500h is 0.745mg 2 cm -4 , the oxidation rate is 2.48×10 -4 mg 2 cm -4 ·h -1 Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.125, and the mass wear rate is 0.98×10 -4 g / s.

[0042] Example 3 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.5×10 -5 Torr, high-purity argon gas with a flow rate of 50 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0043] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 250V and 680V respectively, the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 12ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon gas flow rate to 45mL / min, the deposition time to 15min, and deposit a layer of pure metal Al base transition layer on the substrate.

[0044] Step 3, deposition of AlSi high temperature resistant oxide layer: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of weak ionization and strong ionization stages to 250V and 680V respectively, the pulse on width of weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 20min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0045] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 400°C and a heating time of 15 minutes.

[0046] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 250V and 680V, ​​the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 50min, and deposit the TiCN coating on the AlSi high temperature oxidation resistant layer.

[0047] Through testing, it can be seen that the surface of the TiCN wear-resistant coating in this embodiment is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. The thickness of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy is 2860nm. The oxidation weight gain of the composite coating at 1000℃ constant temperature oxidation for 500h is 0.766mg 2 cm -4 , the oxidation rate is 2.93×10 -4 mg 2 cm -4 ·h -1 Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.131, and the mass wear rate is 1.05×10 -4 g / s.

[0048] Example 4 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.5×10 -5 Torr, high-purity argon gas with a flow rate of 48 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0049] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 230V and 700V respectively, the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 12ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon gas flow rate to 45mL / min, the deposition time to 15min, and deposit a layer of pure metal Al base transition layer on the substrate.

[0050] Step 3, deposition of AlSi high temperature resistant oxide layer: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of weak ionization and strong ionization stages to 230V and 700V respectively, the pulse on width of weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 20min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0051] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 450°C and a heating time of 10 minutes.

[0052] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 230V and 700V, the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width is 10ms, the negative bias voltage is -55V, the frequency is 50Hz, the argon flow rate is preferably 45mL / min, the deposition time is 45min, and the TiCN coating is deposited on the AlSi high temperature oxidation resistant layer.

[0053] Through testing, it can be seen that the surface of the TiCN wear-resistant coating in this embodiment is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. The thickness of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy is 2914nm. The oxidation weight gain of the composite coating at 1000℃ constant temperature oxidation for 500h is 0.783mg 2 cm -4 , the oxidation rate is 2.89×10 -4 mg 2 cm -4 ·h -1Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.128, and the mass wear rate is 1.01×10 -4 g / s.

[0054] Example 5 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.5×10 -5 Torr, high-purity argon gas with a flow rate of 50 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0055] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 240V and 720V respectively, the pulse on width of the weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width to 12ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 20min, and deposit a layer of pure metal Al primer transition layer on the substrate.

[0056] Step 3, deposition of AlSi high temperature resistant oxide layer: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of weak ionization and strong ionization stages to 240V and 720V respectively, the pulse on width of weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width to 12ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 25min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0057] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 500°C and a heating time of 10 minutes.

[0058] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 240V and 720V, the pulse on width of the weak ionization and strong ionization stages to 6ms and 8ms respectively, the pulse off width is 12ms, the negative bias voltage is -55V, the frequency is 50Hz, the argon flow rate is preferably 45mL / min, the deposition time is 55min, and the TiCN coating is deposited on the AlSi high temperature oxidation resistant layer.

[0059] Through testing, it can be seen that the surface of the TiCN wear-resistant coating in this embodiment is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. The thickness of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy is 2976nm. The oxidation weight gain of the composite coating at 1000℃ constant temperature oxidation for 500h is 0.788mg 2 cm -4 , the oxidation rate is 2.87×10 -4 mg 2 cm -4 ·h -1 Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.126, and the mass wear rate is 1.0×10 -4 g / s.

[0060] Example 6 Step 1, ion cleaning: When the vacuum degree in the vacuum chamber reaches 2.0×10 -5 Torr, high-purity argon gas with a flow rate of 50 mL / min was introduced, the aluminum target was started and a direct current of 1.5 A was loaded to carry out ion bombardment on the nickel-based cast high-temperature alloy substrate for 5 minutes.

[0061] Step 2, Al metal transition layer deposition: turn on the Al target sputtering mode, set the peak voltage of the weak ionization and strong ionization stages to 210V and 750V respectively, the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 12ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon gas flow rate to 45mL / min, the deposition time to 20min, and deposit a layer of pure metal Al base transition layer on the substrate.

[0062] Step 3, deposition of AlSi high temperature resistant oxide layer: turn off the Al target, turn on the AlSi20at% target, set the peak voltage of weak ionization and strong ionization stages to 210V and 750V respectively, the pulse on width of weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 20min, and deposit the AlSi high temperature resistant oxide layer on the Al transition layer.

[0063] Step 4, substrate heating: turn off the AlSi20at% target and use a substrate heating box device to heat the substrate at a heating temperature of 450°C and a heating time of 15 minutes.

[0064] Step 5, TiCN wear-resistant layer deposition: turn off the substrate heating box device, turn on the TiCN target, set the peak voltage of the weak ionization and strong ionization stages to 210V and 750V, the pulse on width of the weak ionization and strong ionization stages to 8ms and 8ms respectively, the pulse off width to 10ms, the negative bias voltage to -55V, the frequency to 50Hz, the argon flow rate to 45mL / min, the deposition time to 60min, and deposit the TiCN coating on the AlSi high temperature oxidation resistant layer.

[0065] Through testing, it can be seen that the surface of the TiCN wear-resistant coating in this embodiment is composed of fine and uniform particles, without obvious defects and impurities, and the surface quality is good. The thickness of the Al-AlSi-TiCN composite coating on the surface of the nickel-based cast high-temperature alloy is 3640nm. The oxidation weight gain of the composite coating at 1000℃ constant temperature oxidation for 500h is 0.778mg 2 cm -4 , the oxidation rate is 2.90×10 -4 mg 2 cm -4 ·h -1 Compared with the existing technology level, the high temperature oxidation resistance of the coating has been significantly improved. The average friction coefficient of the composite coating at room temperature is 0.128, and the mass wear rate is 1.02×10 -4 g / s.

Claims

1. High temperature oxidation resistant and wear resistant composite coating on the surface of cast high temperature alloy, characterized in that: The invention comprises an Al metal transition layer, an AlSi high temperature oxidation resistant layer and a TiCN wear resistant layer which are deposited in sequence from the inside to the outside on the surface of the nickel-based cast high temperature alloy.

2. The high temperature oxidation resistant and wear resistant composite coating on the surface of the cast high temperature alloy according to claim 1, characterized in that: The thickness of the Al metal transition layer is 200nm~300nm, the thickness of the AlSi high temperature oxidation resistant layer is 800nm~1500nm, and the thickness of the TiCN wear-resistant layer is 1500nm~2000nm; the composite coating is composed of uniform and dense nanocrystals, and the grain size is less than 20nm.

3. A method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy, characterized in that: Follow the steps below to implement it: Step 1, under vacuum conditions, argon gas is introduced, the Al target is started and a direct current is loaded to perform ion bombardment cleaning on the nickel-based cast high-temperature alloy substrate; Step 2, turning on the Al target sputtering mode, and depositing an Al metal transition layer on the substrate surface through two stages of weak ionization and strong ionization; Step 3, close the Al target, open the AlSi20at% target, and deposit the AlSi high temperature oxidation resistant coating on the Al metal transition layer through two stages of weak ionization and strong ionization; Step 4, closing the AlSi20at% target and heating the substrate; Step 5, open the TiCN target, and deposit a TiCN wear-resistant layer on the AlSi high-temperature oxidation resistant layer through two stages of weak ionization and strong ionization.

4. The method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy according to claim 3, characterized in that: In step 1, the vacuum degree is 2.0~3.0×10 -5 Torr, argon flow rate is 40~60mL / min, Al target current is DC 1.0~2.0A, and cleaning time is 5~10min.

5. The method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy according to claim 3, characterized in that: In step 2, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon flow rate is 40~60mL / min, and the deposition time is 10~20min.

6. The method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy according to claim 3, characterized in that: In step 3, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon flow rate is 40~60mL / min, and the deposition time is 20~30min.

7. The method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy according to claim 3, characterized in that: In step 4, the heating temperature is 400-500° C., and the heating time is 10-15 min.

8. The method for preparing a high temperature oxidation resistant and wear resistant composite coating on the surface of a cast high temperature alloy according to claim 3, characterized in that: In step 5, the peak voltages in the weak ionization and strong ionization stages are 200~250V and 600~750V respectively, the pulse on widths in the weak ionization and strong ionization stages are 4~8ms and 6~8ms respectively, the pulse off width is 10~20ms, the negative bias voltage is -60~-40V, the frequency is 40~60Hz, the argon gas flow rate is 40~60mL / min, and the deposition time is 40~60min.

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