High-temperature-resistant nitride thermal barrier coating with extremely low thermal conductivity as well as preparation method and application of nitride thermal barrier coating

Abstract

The invention relates to a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance and a preparation method and application thereof, the nitride thermal barrier coating is a SiXN coating, the SiXN coating comprises, by atomic fraction, 10%-70% of Si, 1%-30% of X and the balance N, and X is selected from any one or more elements of Ti, Al, Zr or Cr. The minimum thermal conductivity of the nitride thermal barrier coating is 1.5 W / mK, and the nitride thermal barrier coating can bear a high-temperature environment, can be used as a thermal protection coating of a titanium-aluminum alloy and a titanium alloy, can stably work in the high-temperature environment for a short time or a long time, and reduces the surface temperature of a base material.

Description

Technical Field

[0001] The present invention relates to the technical field of surface coating, and particularly to a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and a preparation method and application thereof. Background Art

[0002] Titanium alloys and titanium aluminide alloys are widely used in various technical fields such as aerospace, automotive, and medical due to their high specific strength, strong corrosion resistance, and excellent high-temperature mechanical properties. For example, high-temperature titanium alloys can serve at 600 °C for a long time, can withstand continuous high-temperature working conditions, and can reach a short-term service temperature of 750 °C when dealing with extreme high-temperature working conditions; titanium aluminide alloys can serve in a high-temperature environment of 750 °C for a long time, and their high-temperature stability and creep resistance are superior to those of high-temperature titanium alloys, and the short-term service temperature can reach 950 °C in extreme high-temperature working conditions.

[0003] Despite the high specific strength of titanium aluminide or titanium alloys, their creep properties are relatively poor. Especially when continuously bearing loads at high temperatures, the alloys are prone to large plastic deformation. Compared with nickel-based superalloys, the creep strength of titanium aluminide alloys is lower, which limits their application in some high-temperature and high-stress environments.

[0004] Therefore, there is an urgent need for a new type of thermal protection coating material, which reduces the direct contact between high-temperature gas and the substrate through thermal isolation, thereby reducing the surface temperature of the substrate material, reducing thermal stress and thermal fatigue. Summary of the Invention

[0005] The purpose of the present invention is to provide a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and a preparation method and application thereof. The thermal conductivity of the nitride thermal barrier coating is at least 1.5 W / mK and can withstand high-temperature environments. It can be used as a thermal protection coating for titanium aluminide alloys and titanium alloys, and can work stably in high-temperature environments for short or long periods, reducing the surface temperature of the substrate material.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, the nitride thermal barrier coating is a SiXN coating, and the SiXN coating includes by atomic fraction percentage: Si: 10% - 70%, X: 1% - 30%, and the balance is N.

[0008] Wherein, X is selected from any one or more elements of Ti, Al, Zr, or Cr.

[0009] Further, the thickness of the SiXN coating is 1 - 30 microns.

[0010] Further, the lowest thermal conductivity of the SiXN coating is 1.5 W / mK.

[0011] The present invention also provides a method for preparing a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and the specific steps are as follows:

[0012] Using a Si target and a metal target, magnetron sputtering is carried out on the substrate in an atmosphere of nitrogen and inert gas to obtain a SiXN coating, that is, a nitride thermal barrier coating.

[0013] Furthermore, the inert gas is argon.

[0014] Still further, the flow rate of the argon is 15-40 sccm, and the flow rate of the nitrogen is 5-30 sccm.

[0015] Furthermore, the power of the Si target is 100-900 W.

[0016] Furthermore, the metal target is selected from any one or more of a Ti target, an Al target, a Zr target, or a Cr target.

[0017] Still further, the power of the Ti target is 30-800 W, the power of the Al target is 30-800 W, the power of the Zr target is 30-800 W, and the power of the Cr target is 30-800 W.

[0018] Furthermore, the heating temperature of the substrate is 20-550 °C, and the substrate includes a titanium-aluminum alloy and a titanium alloy.

[0019] In addition, the present invention also provides an application of a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and the nitride thermal barrier coating is used to prepare a thermal protection coating on the surfaces of a titanium-aluminum alloy and a titanium alloy.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The nitride thermal barrier coating provided by the present invention has extremely low thermal conductivity and good high temperature stability, and can provide good thermal protection for aeroengine titanium-aluminum alloy or titanium alloy and related devices in the microelectronics field.

[0022] 2. The preparation method of the nitride thermal barrier coating in the present invention is simple, the coating has strong bonding force, and is suitable for large-scale industrial applications.

[0023] 3. The present invention realizes the low thermal conductivity and high temperature resistance of the nitride thermal barrier coating by precisely regulating the structure of SiXN and the proportion of each element. The SiXN coating prepared by adopting the microstructure precise control technology has a minimum thermal conductivity of 1.5 W / mK. The present invention can achieve thermal protection for a titanium-aluminum alloy or a titanium alloy at 300-1000 °C, and can greatly increase the service temperature of a titanium-aluminum alloy or a titanium alloy in hot end components such as aeroengines. Description of the Drawings

[0024] Figure 1 This is a schematic structural diagram of the nitride thermal barrier coating of the present invention. Specific embodiments

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0026] Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0027] Example 1

[0028] This embodiment provides a method for preparing a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and the specific steps are as follows:

[0029] S1. Place the titanium-aluminum alloy substrate in the sample fixture of the magnetron sputtering chamber and fix it, evacuate to about 8.5×10 - 6 mBar or below; apply a bias voltage of -500V to the substrate, and introduce argon at a flow rate of 40 sccm. After 20 minutes, turn off the bias voltage to obtain the titanium-aluminum alloy substrate bombarded by argon ions.

[0030] S2. Deposit a nitride thermal barrier coating on the surface of the titanium-aluminum alloy substrate bombarded by argon ions in step S1:

[0031] Set the powers applied to the Si target and the Ti target to 900W and 30W respectively. The substrate rotates self-rotationally at a speed of 5 r / min to achieve the co-deposition of Si and Ti. At this time, the argon gas flow rate is 40 sccm, and the nitrogen gas is 5 sccm. At the same time, the set heating temperature of the substrate is 200°C. After 2 hours, turn off the power supply to obtain the nitride thermal barrier coating, that is, the SiTiN coating.

[0032] Take out the SiTiN coating sample, and use the time-domain thermoreflectance method to measure the thermal conductivity of the SiTiN coating on the substrate surface. The thermal conductivity is 2.5 W / mK.

[0033] Example 2

[0034] This embodiment provides a method for preparing a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance, and the specific steps are as follows:

[0035] S1. Place the titanium alloy and the titanium-aluminum alloy substrate in the sample fixture of the magnetron sputtering chamber and fix it, evacuate to 8.5×10 -6around or below mBar; Apply a bias voltage of -500V to the substrate, and introduce argon gas at a flow rate of 35 sccm. After 20 minutes, turn off the bias voltage to obtain titanium alloy and titanium aluminide alloy substrates bombarded by argon ions.

[0036] S2. Deposit a nitride thermal barrier coating on the surfaces of the titanium alloy and titanium aluminide alloy substrates bombarded by argon ions obtained in step S1:

[0037] Set the powers applied to the Si target and Zr target to be 200W and 200W respectively. The substrate rotates self at a speed of 5 r / min to achieve co-deposition of Si and Zr. At this time, the argon gas flow rate is 35 sccm, the nitrogen gas is 30 sccm, and the set heating temperature of the substrate is 500°C. After 2 hours, turn off the power supply to obtain a nitride thermal barrier coating, that is, a SiZrN coating.

[0038] Take out the SiZrN coating sample, and measure the thermal conductivity of the SiZrN coating on the titanium alloy surface by the time-domain thermoreflectance method. The thermal conductivity is 2.7 W / mK.

[0039] Example 3

[0040] This example provides a method for preparing a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance. The specific steps are as follows:

[0041] S1. Place the titanium alloy and titanium aluminide alloy substrates in the sample fixture of the magnetron sputtering chamber and fix them. Pump the vacuum to around 8.5×10 -6 mBar or below; Apply a bias voltage of -500V to the substrate, and introduce argon gas at a flow rate of 30 sccm. After 20 minutes, turn off the bias voltage to obtain titanium alloy and titanium aluminide alloy substrates bombarded by argon ions.

[0042] S2. Deposit a nitride thermal barrier coating on the surfaces of the titanium alloy and titanium aluminide alloy substrates bombarded by argon ions obtained in step S1:

[0043] Set the powers applied to the Si target, Zr target, and Al target to be 500W, 300W, and 100W respectively. The substrate rotates self at a speed of 5 r / min to achieve co-deposition of Si, Zr, and Al. At this time, the argon gas flow rate is 30 sccm, the nitrogen gas is 30 sccm, and the set heating temperature of the substrate is 100°C. After 2 hours, turn off the power supply to obtain a nitride thermal barrier coating, that is, a SiZrAlN coating.

[0044] Take out the SiZrAlN coating sample, and measure the thermal conductivity of the SiZrAlN coating on the titanium alloy surface by the time-domain thermoreflectance method. The thermal conductivity is 1.5 W / mK.

[0045] Example 4

[0046] This embodiment provides a method for preparing a nitride thermal barrier coating with extremely low thermal conductivity and high temperature resistance. The specific steps are as follows:

[0047] S1. Place the titanium-aluminum alloy substrate in the sample fixture of the magnetron sputtering chamber and fix it. Evacuate the chamber to about 8.5×10 - 6 mBar or below. Apply a bias voltage of -500V to the substrate and introduce argon at a flow rate of 15 sccm. After 20 minutes, turn off the bias voltage to obtain the titanium-aluminum alloy substrate bombarded by argon ions.

[0048] S2. Deposit a nitride thermal barrier coating on the surface of the titanium-aluminum alloy substrate bombarded by argon ions obtained in step S1:

[0049] Set the powers applied to the Si target and the Cr target to 600W and 150W respectively. The substrate rotates self at a speed of 5 r / min to achieve the co-deposition of Si and Cr. At this time, the argon flow rate is 15 sccm and the nitrogen is 5 sccm. At the same time, the set heating temperature of the substrate is 30°C. After 2 hours, turn off the power supply to obtain the nitride thermal barrier coating, that is, the SiCrN coating.

[0050] Take out the SiCrN coating sample and measure the thermal conductivity of the SiCrN coating on the substrate surface by the time-domain thermoreflectance method. The thermal conductivity is 2.8 W / mK.

[0051] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. Obviously, those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A very low thermal conductivity and high temperature resistant nitride thermal barrier coating, characterized in that: The nitride thermal barrier coating is a SiXN coating, which includes, by atomic fraction percentage: Si: 10% to 70%, X: 1% to 30%, and the remainder is N. Wherein, X is selected from any one or more elements of Ti, Al, Zr or Cr.

2. The extremely low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 1, characterized in that: The thickness of the SiXN coating is 1 to 30 microns.

3. A method for preparing the extremely low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 1 or claim 2, characterized in that: The specific steps are as follows: The SiXN coating, i.e., the nitride thermal barrier coating, is obtained by multi-target magnetron sputtering of the substrate using Si target and metal target in a nitrogen and inert gas atmosphere.

4. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 3, characterized in that: The inert gas is argon.

5. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 4, characterized in that: The flow rate of the argon gas is 15 to 40 sccm, and the flow rate of the nitrogen gas is 5 to 30 sccm.

6. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 3, characterized in that: The power of the Si target is 100-900W.

7. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 3, characterized in that: The metal target is selected from any one or more of a Ti target, an Al target, a Zr target or a Cr target.

8. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 7, characterized in that: The power of the Ti target is 30-800W, the power of the Al target is 30-800W, the power of the Zr target is 30-800W, and the power of the Cr target is 30-800W.

9. The method for preparing a very low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 3, characterized in that: The heating temperature of the substrate is 20-550° C., and the substrate includes titanium-aluminum alloy and titanium alloy.

10. An application of the extremely low thermal conductivity and high temperature resistant nitride thermal barrier coating according to claim 1 or claim 2, characterized in that: The nitride thermal barrier coating is used for preparing thermal protection coatings on the surfaces of titanium-aluminum alloys and titanium alloys.

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