Carbon-doped hafnium nitride nanocrystalline film and preparation method thereof

Abstract

The invention discloses a carbon-doped hafnium nitride nanocrystalline film. The chemical formula of the carbon-doped hafnium nitride nanocrystalline film is HfCxN1-x, wherein the value of x ranges from 0.09 to 0.1. The invention also discloses a preparation method of the carbon-doped hafnium nitride nanocrystalline film, which adopts a magnetron co-sputtering method and specifically comprises the following steps: putting a pure hafnium target and a graphite target into a chamber, and vacuumizing to 4 * 10 <-4 > Pa; and continuously introducing nitrogen and argon into the chamber, controlling the sputtering current of the pure hafnium target and the graphite target, and depositing the HfCxN1-x film on the substrate. According to the invention, the C element is introduced into HfN, so that the hafnium carbonitride nanocrystalline film with extremely low infrared emissivity and excellent durability is prepared.

Description

Technical Field

[0001] The invention relates to a carbon-doped hafnium nitride nanocrystalline film and also relates to a method for preparing the hafnium nitride nanocrystalline film. Background Art

[0002] Traditional infrared stealth film materials are mainly pure metals such as aluminum, silver, gold and copper. Although these materials have very low infrared emissivity, they have poor environmental durability such as low hardness, low melting point and corrosion resistance. Although transition metal nitrides such as HfN have excellent durability such as high hardness, high melting point and wear resistance and corrosion resistance, their infrared emissivity is much higher than that of pure metals, showing poor infrared stealth performance, so they cannot be directly used as infrared stealth materials. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a carbon-doped hafnium nitride nanocrystalline film. When it is used as an infrared stealth material, the hafnium nitride nanocrystalline film has high hardness, high melting point, good wear resistance and corrosion resistance, as well as extremely low infrared emissivity; another purpose of the present invention is to provide a method for preparing the above-mentioned hafnium nitride nanocrystalline film.

[0004] Technical solution: The carbon-doped hafnium nitride nanocrystalline film of the present invention has a chemical formula of HfC x N 1-x ; Among them, x ranges from 0.09 to 0.1.

[0005] The material of the present invention is a film composed of three elements: Hf, C and N. x N 1-x The membrane has a single-phase rock salt solid solution structure.

[0006] Among them, HfC x N 1-x The average grain size of the film is less than 10 nm.

[0007] Among them, HfC x N 1-x In the film, the content of C element is 9 at. % to 10 at. %, preferably 9 at. %.

[0008] The preparation method of the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method, specifically, placing a pure hafnium target and a graphite target in a chamber, evacuating the chamber to a vacuum of 4×10 -4 Pa; nitrogen and argon are continuously introduced into the chamber to control the sputtering current of the pure hafnium target and graphite target to deposit HfC on the substrate x N 1-x membrane.

[0009] The flow ratio of nitrogen to argon is 0.1 to 1:40.

[0010] Among them, both the pure hafnium target and the graphite target use a DC medium-frequency pulse power supply. The sputtering current of the pure hafnium target is 0.4-0.5A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz; the sputtering current of the graphite target is 0.1-0.2A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz.

[0011] The sputtering conditions are as follows: the distance between the target and the sample stage is 110-120 mm, the substrate temperature is 500-550° C., the working gas pressure is 0.8-0.85 Pa, the sample stage rotation speed is 10-12 r / min, and the sputtering time is 100-120 min.

[0012] The present invention introduces C element into HfN to prepare a carbon / hafnium nitride nanocrystalline film with extremely low infrared emissivity and excellent durability. After C doping, the bonding strength between Hf and N can be effectively improved, which can not only improve the hardness of hafnium nitride to 33.5Gpa, but also weaken the material's absorption intensity of infrared light, thereby greatly reducing the material's infrared emissivity.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: the average infrared emissivity of the hafnium carbonitride nanocrystalline film material prepared by the present invention in the infrared bands of 3-5 μm and 8-14 μm is 0.08 and 0.03 respectively, the hardness is 33.5 GPa, and the self-corrosion current density in 3.5 wt.% NaCl solution is ~1×10 -7 A.cm -2 , indicating that the nanocrystalline film material of the present invention not only has extremely low infrared emissivity, but also has excellent durability. It is expected to be used as an infrared stealth durable film in harsh environments such as high-speed solid-liquid particle impact, high temperature and the presence of corrosive liquid gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the infrared emissivity of the hafnium carbonitride nanocrystalline film obtained in Example 1;

[0015] Figure 2 is the XRD spectrum of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0016] Figure 3 TEM image of the hafnium carbonitride nanocrystalline film prepared in Example 1;

[0017] Figure 4 is the hardness-displacement curve of the hafnium carbonitride nanocrystalline film obtained in Example 1;

[0018] Figure 5 is a potentiodynamic polarization curve of the hafnium carbonitride nanocrystalline film obtained in Example 1;

[0019] Figure 6 The infrared emissivity of the hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 is compared with that in Example 1;

[0020] Figure 7 The hardness of the hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 is compared with that in Example 1;

[0021] Figure 8 The corrosion resistance of the hafnium carbonitride nanocrystalline films prepared in Comparative Examples 1 and 2 is compared with that of Example 1. DETAILED DESCRIPTION

[0022] Example 1

[0023] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C and N, and its chemical formula is HfC x N 1-x ; Among them, x is 0.09, that is, the C content is 9at.%.

[0024] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically comprises the following steps:

[0025] (1) A silicon wafer is selected as a substrate, and the substrate is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0026] (2) Place the pure hafnium target and graphite target into the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500°C, the pure hafnium target used a DC medium-frequency pulse power supply, the sputtering current was set to 0.4A, the pulse width was 4μs, and the pulse frequency was 100kHz; the graphite target also used a DC medium-frequency pulse power supply, the sputtering current was set to 0.1A; the pulse width was 4μs, and the pulse frequency was 100kHz;

[0027] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working pressure was 0.8 Pa, the sample rotation speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and HfC with an x ​​value of 0.09 was obtained after sputtering. x N 1-x membrane.

[0028] like Figure 1 As shown, the average infrared emissivity of the hafnium carbonitride nanocrystalline film material prepared in Example 1 in the infrared bands of 3-5 μm and 8-14 μm is only 0.08 and 0.03, respectively. Figure 2 As shown, the hafnium carbonitride nanocrystalline film material prepared in Example 1 has a face-centered cubic single-phase solid solution structure. Figure 3 As shown, the average grain size of the hafnium carbonitride nanocrystalline film material prepared in Example 1 is only 5 nm. Figure 4 As shown, the hardness of the hafnium carbonitride nanocrystalline film material prepared in Example 1 reaches 33.5 GPa. Figure 5 As shown, the self-corrosion current density of the hafnium carbonitride nanocrystalline film material prepared in Example 1 in a 3.5wt.% NaCl solution is ~1×10 -7 A.cm -2 .

[0029] Example 2

[0030] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C and N, and its chemical formula is HfC x N 1-x ; Among them, x is 0.1, that is, the C content is 10at.%.

[0031] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically comprises the following steps:

[0032] (1) A silicon wafer is selected as a substrate, and the substrate is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0033] (2) Place the pure hafnium target and graphite target into the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500°C, the pure hafnium target used a DC medium-frequency pulse power supply, the sputtering current was set to 0.4A, the pulse width was 4μs, and the pulse frequency was 100kHz; the graphite target also used a DC medium-frequency pulse power supply, the sputtering current was set to 0.1A; the pulse width was 4.5μs, and the pulse frequency was 100kHz;

[0034] (3) Nitrogen and argon are continuously introduced into the chamber, wherein the nitrogen flow rate is 0.5 sccm, the argon flow rate is 40 sccm, the working gas pressure is 0.8 Pa, the sample stage speed is 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film is deposited on the substrate. The sputtering time is 120 min. After sputtering, HfC with an x ​​value of 0.1 is obtained. x N 1-x membrane.

[0035] Comparative Example 1

[0036] A hafnium nitride nanocrystalline film material is composed of two elements, Hf and N, that is, the content of C is 0 at.%.

[0037] The preparation method of the above hafnium nitride nanocrystalline film material adopts a magnetron co-sputtering method, which specifically includes the following steps:

[0038] (1) A silicon wafer is selected as a substrate, and the substrate is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0039] (2) Place the pure hafnium target and graphite target into the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500°C, the pure hafnium target used a DC medium-frequency pulse power supply, the sputtering current was set to 0.4A, the pulse width was 4μs, and the pulse frequency was 100kHz; the graphite target also used a DC medium-frequency pulse power supply, and the sputtering current was set to 0A;

[0040] (3) Nitrogen and argon gases are continuously introduced into the chamber, wherein the nitrogen flow rate is 0.5 sccm, the argon flow rate is 40 sccm, the working gas pressure is 0.8 Pa, the sample stage rotation speed is 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film is deposited on the substrate. The sputtering time is 120 min, and a HfN film is obtained after sputtering.

[0041] Comparative Example 2

[0042] The carbon-doped hafnium nitride nanocrystalline film of the present invention is composed of three elements: Hf, C and N, and its chemical formula is HfC x N 1-x ; Among them, x is 0.26, that is, the C content is 26at.%.

[0043] The method for preparing the carbon-doped hafnium nitride nanocrystalline film adopts a magnetron co-sputtering method and specifically comprises the following steps:

[0044] (1) A silicon wafer is selected as a substrate, and the substrate is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water, and then dried;

[0045] (2) Place the pure hafnium target and graphite target into the chamber, adjust the target-substrate distance to 110 mm, and evacuate to 4 × 10 -4 Pa, the substrate was heated to 500°C, the pure hafnium target used a DC medium-frequency pulse power supply, the sputtering current was set to 0.4A, the pulse width was 4μs, and the pulse frequency was 100kHz; the graphite target also used a DC medium-frequency pulse power supply, the sputtering current was set to 0.2A; the pulse width was 4μs, and the pulse frequency was 100kHz;

[0046] (3) Nitrogen and argon were continuously introduced into the chamber, wherein the nitrogen flow rate was 0.5 sccm, the argon flow rate was 40 sccm, the working gas pressure was 0.8 Pa, the sample stage speed was 10 r / min, and a carbon-doped hafnium nitride nanocrystalline film was deposited on the substrate. The sputtering time was 120 min, and HfC with an x ​​value of 0.26 was obtained after sputtering. x N 1-x membrane.

[0047] Figure 6 The results show that the reflectivity of the sample in comparative example 1 to infrared light with a wavelength of 2000nm is 79%, that is, the emissivity is 0.21, the emissivity of the sample in comparative example 2 to infrared light with a wavelength of 2000nm is 0.16, and the emissivity of the sample in embodiment 1 to infrared light with a wavelength of 2000nm is only 0.12. Figure 7 The results show that the hardness of the sample in Comparative Example 1 is 26.5 GPa, the hardness of the sample in Comparative Example 2 is 28.2 GPa, and the hardness of the sample in Example 1 is 33.5 GPa. Figure 8 The results show that the sample of Example 1 has a more positive corrosion potential and a lower corrosion current density than the samples of Comparative Examples 1 and 2. Figures 6 to 8 By comparison, it can be seen that Example 1 has the lowest infrared emissivity, the highest hardness and the best corrosion resistance. This is because, on the one hand, carbon doping enhances the bonding strength of hafnium nitride and weakens the lattice vibration absorption effect, thereby effectively reducing the infrared emissivity; on the other hand, carbon doping refines the grain size of hafnium nitride, thereby improving the hardness and corrosion resistance of hafnium nitride.

Claims

1. A carbon-doped hafnium nitride nanocrystalline film, characterized in that: Its chemical formula is HfC x N 1-x ; Among them, x ranges from 0.09 to 0.

1.

2. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, characterized in that: HkDJ x N 1-x The membrane has a single-phase rock salt solid solution structure.

3. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, characterized in that: HkDJ x N 1-x The average grain size in the film is less than 10 nm.

4. The carbon-doped hafnium nitride nanocrystalline film according to claim 1, characterized in that: HkDJ x N 1-x In the film, the content of C element is 9 at.%.

5. The method for preparing the carbon-doped hafnium nitride nanocrystalline film according to claim 1, characterized in that: The magnetron co-sputtering method is used, specifically: a pure hafnium target and a graphite target are placed in a chamber and vacuumed to 4×10 -4 Pa; nitrogen and argon are continuously introduced into the chamber to control the sputtering current of the pure hafnium target and graphite target to deposit HfC on the substrate x N 1-x membrane.

6. The preparation method according to claim 5, characterized in that: The flow ratio of the nitrogen gas to the argon gas is 0.1 to 1:

40.

7. The preparation method according to claim 5, characterized in that: Both the pure hafnium target and the graphite target use a DC medium-frequency pulse power supply, wherein the sputtering current of the pure hafnium target is 0.4-0.5A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz; the sputtering current of the graphite target is 0.1-0.2A, the pulse width is 4-5μs, and the pulse frequency is 100-120kHz.

8. The preparation method according to claim 5, characterized in that: The sputtering conditions are as follows: target-substrate distance of 110-120 mm, substrate temperature of 500-550° C., working gas pressure of 0.8-0.85 Pa, sample stage rotation speed of 10-12 r / min, and sputtering time of 100-120 min.

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