阅读说明：本技术 一种氮化硅陶瓷基材表面高反射防激光膜层的制备方法 (Preparation method of high-reflection anti-laser film layer on surface of silicon nitride ceramic substrate ) 是由 朱嘉琦 汪新智 程珙 宋志超 刘颖 白一杰 杨磊 胡梦玥 任建华 于 2020-12-30 设计创作，主要内容包括：一种氮化硅陶瓷基材表面高反射防激光膜层的制备方法,它涉及一种高反射防激光膜层的制备方法。本发明要解决现有氮化硅材料对于激光吸收率较高,会产生大量的热量,造成结构破坏的问题。制备方法：一、氮化硅陶瓷表面预处理；二、氧化钛纳米浆料的配制；三、氧化钛涂层的制作。本发明用于氮化硅陶瓷基材表面高反射防激光膜层的制备。(A preparation method of a high-reflection laser-proof film layer on the surface of a silicon nitride ceramic substrate relates to a preparation method of a high-reflection laser-proof film layer. The invention aims to solve the problem that the existing silicon nitride material has high laser absorptivity and can generate a large amount of heat to cause structural damage. The preparation method comprises the following steps: firstly, pretreating the surface of silicon nitride ceramic; secondly, preparing titanium oxide nano slurry; and thirdly, manufacturing the titanium oxide coating. The preparation method is used for preparing the high-reflection laser-proof film layer on the surface of the silicon nitride ceramic substrate.)

1. A preparation method of a high-reflection laser-proof film layer on the surface of a silicon nitride ceramic substrate is characterized by comprising the following steps:

firstly, silicon nitride ceramic surface pretreatment:

cleaning and drying the silicon nitride ceramic to obtain pretreated silicon nitride ceramic;

secondly, preparing titanium oxide nano slurry:

mixing nano titanium dioxide, acrylic resin and acetone, magnetically stirring for 1-2 h at the rotation speed of 500-1000 r/min to obtain slurry, ultrasonically oscillating the slurry for 1-2 h in a water bath under the power of 500-1000W, then placing the oscillated slurry in a cell disruption instrument, and ultrasonically oscillating a probe for 3-5 min under the power of 1000-1200W to obtain titanium oxide nano slurry;

the mass ratio of the nano titanium dioxide to the acrylic resin is 1 (100-200); the mass ratio of the nano titanium dioxide to the acetone is 1 (500-1000);

thirdly, manufacturing the titanium oxide coating:

firstly, under the condition that the pressure intensity is 8-10 bar, spraying titanium oxide nano slurry on the surface of the pretreated silicon nitride ceramic by a high-pressure cold spraying method, wherein the spraying time is 10-30 s, the thickness of the coating is 1-2 mu m, and after the spraying is finished, drying the coating in a normal-temperature vacuum box for 8-10 h;

and secondly, repeating the third step for 4-8 times to obtain the silicon nitride ceramic substrate with the high-reflection laser-proof film layer on the surface.

2. The method for preparing a silicon nitride ceramic substrate surface high-reflection laser-proof film according to claim 1, wherein the cleaning in the step one is ultrasonic cleaning in acetone for 1h to 2h under the condition of the ultrasonic power of 500W to 1000W, ultrasonic cleaning in alcohol for 1h to 2h under the condition of the ultrasonic power of 500W to 1000W, and ultrasonic cleaning in deionized water for 1h to 2h under the condition of the ultrasonic power of 500W to 1000W.

3. The method for preparing a high-reflectivity laser-proof film on the surface of a silicon nitride ceramic substrate according to claim 1, wherein the drying in the step one is carried out for 2 hours in a vacuum drying oven at a temperature of 60-100 ℃.

4. The method for preparing the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, wherein the particle size of the nano titanium dioxide in the second step is 50nm to 100 nm.

5. The method for preparing the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, characterized in that in the second step, nano titanium dioxide, acrylic resin and acetone are mixed, magnetic stirring is carried out for 2 hours under the condition that the rotating speed is 800 r/min-1000 r/min, slurry is obtained, the slurry is subjected to ultrasonic oscillation for 2 hours through water bath under the condition that the power is 800W-1000W, then the oscillated slurry is placed in a cell disruptor, and the probe is subjected to ultrasonic oscillation for 4 minutes-5 minutes under the condition that the probe power is 1200W, so that titanium oxide nano slurry is obtained.

6. The method for preparing the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, wherein in the second step, the nano titanium dioxide, the acrylic resin and the acetone are mixed, the mixture is magnetically stirred for 2 hours at the rotation speed of 800r/min to obtain slurry, the slurry is ultrasonically oscillated for 2 hours in a water bath under the power of 800W, then the oscillated slurry is placed in a cell disruptor, and the probe is ultrasonically oscillated for 5 minutes under the probe power of 1200W to obtain the titanium oxide nano slurry.

7. The method for preparing the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, wherein the mass ratio of the nano titanium dioxide to the acrylic resin in the second step is 1 (100-150).

8. The method for preparing the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, wherein the mass ratio of the nano titanium dioxide to the acetone in the second step is 1 (500-800).

9. The preparation method of the silicon nitride ceramic substrate surface high-reflection laser-proof film layer according to claim 1, characterized in that in the third step, under the condition of the pressure of 10bar, the titanium oxide nano slurry is sprayed on the pretreated silicon nitride ceramic surface by a high-pressure cold spraying method, the spraying time is 20 s-30 s, the thickness of the coating is 2 μm, and after the spraying is finished, the silicon nitride ceramic substrate surface high-reflection laser-proof film layer is dried in a normal-temperature vacuum box for 8 h-10 h.

10. The method for preparing the high-reflection laser-proof film layer on the surface of the silicon nitride ceramic substrate according to claim 1, wherein the third step is repeated for 5-8 times.

Technical Field

The invention relates to a preparation method of a high-reflection laser-proof film layer.

Background

With the development of aerospace technology, wave-transparent materials are required to have good and stable wave-transparent performance in a wider frequency band, better thermal shock resistance and more excellent weather resistance, and intensive research is carried out on high-temperature wave-transparent materials at home and abroad. Wherein the silicon nitride ceramic material has strong covalent bond force and low thermal expansion coefficient (2.35 multiplied by 10)^-6and/K), the oxidation resistance temperature is high, and the like, and the research hotspot is formed. In recent years, with the successful development of high-power lasers, laser weapons have been developed rapidly. Laser weapons can cause thermal, mechanical, and radiation damage to materials. The common silicon nitride material has high laser absorptivity, and can generate a large amount of heat to cause structural damage.

Disclosure of Invention

The invention provides a preparation method of a high-reflection anti-laser film layer on the surface of a silicon nitride ceramic substrate, aiming at solving the problem that the existing silicon nitride material has high laser absorption rate, can generate a large amount of heat and cause structural damage.

A preparation method of a high-reflection laser-proof film layer on the surface of a silicon nitride ceramic substrate is completed according to the following steps:

firstly, silicon nitride ceramic surface pretreatment:

cleaning and drying the silicon nitride ceramic to obtain pretreated silicon nitride ceramic;

secondly, preparing titanium oxide nano slurry:

mixing nano titanium dioxide, acrylic resin and acetone, magnetically stirring for 1-2 h at the rotation speed of 500-1000 r/min to obtain slurry, ultrasonically oscillating the slurry for 1-2 h in a water bath under the power of 500-1000W, then placing the oscillated slurry in a cell disruption instrument, and ultrasonically oscillating a probe for 3-5 min under the power of 1000-1200W to obtain titanium oxide nano slurry;

the mass ratio of the nano titanium dioxide to the acrylic resin is 1 (100-200); the mass ratio of the nano titanium dioxide to the acetone is 1 (500-1000);

thirdly, manufacturing the titanium oxide coating:

firstly, under the condition that the pressure intensity is 8-10 bar, spraying titanium oxide nano slurry on the surface of the pretreated silicon nitride ceramic by a high-pressure cold spraying method, wherein the spraying time is 10-30 s, the thickness of the coating is 1-2 mu m, and after the spraying is finished, drying the coating in a normal-temperature vacuum box for 8-10 h;

and secondly, repeating the third step for 4-8 times to obtain the silicon nitride ceramic substrate with the high-reflection laser-proof film layer on the surface.

The invention has the beneficial effects that:

the silicon nitride ceramics have a porous structure in the microcosmic aspect, the surface roughness is large, the uniform film coating on the surface is difficult to realize in normal process engineering, and the film layer is easy to fall off. According to the invention, the bonding performance of the titanium dioxide nano-size is enhanced by adding the acrylic resin, on one hand, the acrylic resin has stable physicochemical characteristics such as light and color retention, water and chemical resistance and the like, and has good adhesion, on the other hand, the nano-titanium dioxide has stronger reflectivity in a visible light range, and the titanium dioxide nano-size used in the invention is ensured to realize the function of laser reflection. In addition, the invention removes impurities and non-hydrophilic groups on the surface of the silicon nitride ceramic through surface pretreatment, further ensures the dispersibility of titanium dioxide in the spraying process through a high-pressure cold spraying method, strengthens the combination of titanium dioxide nano particles and a substrate, realizes the uniform deposition of the titanium dioxide nano particles on the silicon nitride substrate, improves the surface flatness and enhances the reflectivity of the structure to visible light.

The titanium oxide coating with uniform thickness and stable performance is obtained on the surface of the silicon nitride ceramic, and the reflectivity of the ceramic surface to incident light (532nm wavelength) is improved from < 10% to > 70%.

The invention relates to a preparation method of a high-reflection laser-proof film layer on the surface of a silicon nitride ceramic substrate.

Drawings

FIG. 1 is a schematic view of a silicon nitride ceramic composition without any treatment;

FIG. 2 is a diagram of a silicon nitride ceramic substrate with a high-reflectivity anti-laser film layer on the surface thereof according to the first embodiment;

FIG. 3 is a graph of the reflectivity of a silicon nitride ceramic without any treatment;

fig. 4 is a reflectivity diagram of a silicon nitride ceramic substrate with a high-reflectivity laser-blocking film layer on the surface prepared in the first embodiment.

Detailed Description

The first embodiment is as follows: the embodiment is a preparation method of a high-reflection laser-proof film layer on the surface of a silicon nitride ceramic substrate, which is completed by the following steps:

firstly, silicon nitride ceramic surface pretreatment:

cleaning and drying the silicon nitride ceramic to obtain pretreated silicon nitride ceramic;

secondly, preparing titanium oxide nano slurry:

mixing nano titanium dioxide, acrylic resin and acetone, magnetically stirring for 1-2 h at the rotation speed of 500-1000 r/min to obtain slurry, ultrasonically oscillating the slurry for 1-2 h in a water bath under the power of 500-1000W, then placing the oscillated slurry in a cell disruption instrument, and ultrasonically oscillating a probe for 3-5 min under the power of 1000-1200W to obtain titanium oxide nano slurry;

the mass ratio of the nano titanium dioxide to the acrylic resin is 1 (100-200); the mass ratio of the nano titanium dioxide to the acetone is 1 (500-1000);

thirdly, manufacturing the titanium oxide coating:

firstly, under the condition that the pressure intensity is 8-10 bar, spraying titanium oxide nano slurry on the surface of the pretreated silicon nitride ceramic by a high-pressure cold spraying method, wherein the spraying time is 10-30 s, the thickness of the coating is 1-2 mu m, and after the spraying is finished, drying the coating in a normal-temperature vacuum box for 8-10 h;

and secondly, repeating the third step for 4-8 times to obtain the silicon nitride ceramic substrate with the high-reflection laser-proof film layer on the surface.

The beneficial effects of the embodiment are as follows:

the silicon nitride ceramics have a porous structure in the microcosmic aspect, the surface roughness is large, the uniform film coating on the surface is difficult to realize in normal process engineering, and the film layer is easy to fall off. The embodiment strengthens the bonding performance of the titanium dioxide nano-size by adding the acrylic resin, so that the acrylic resin has stable physicochemical characteristics such as light and color retention, water and chemical resistance and the like and has good adhesion, and the nano-titanium dioxide has stronger reflectivity in a visible light range, thereby ensuring that the titanium dioxide nano-size used in the invention can realize the function of laser reflection. In addition, according to the embodiment, impurities and non-hydrophilic groups on the surface of the silicon nitride ceramic are removed through surface pretreatment, the dispersibility of titanium dioxide in the spraying process is ensured by a high-pressure cold spraying method, the combination of titanium dioxide nanoparticles and a substrate is strengthened, the uniform deposition of the titanium dioxide nanoparticles on the silicon nitride substrate is realized, the surface flatness is improved, and the reflectivity of the structure to visible light is enhanced.

The titanium oxide coating with uniform thickness and stable performance is obtained on the surface of the silicon nitride ceramic, and the reflectivity of the ceramic surface to incident light (532nm wavelength) is improved from < 10% to > 70%

The second embodiment is as follows: the first difference between the present embodiment and the specific embodiment is: the cleaning in the step one is that under the condition that the ultrasonic power is 500W-1000W, the glass is placed in acetone for ultrasonic cleaning for 1 h-2 h, then under the condition that the ultrasonic power is 500W-1000W, the glass is placed in alcohol for ultrasonic cleaning for 1 h-2 h, and finally under the condition that the ultrasonic power is 500W-1000W, the glass is placed in deionized water for ultrasonic cleaning for 1 h-2 h. The rest is the same as the first embodiment.

The third concrete implementation mode: this embodiment is different from the first or second embodiment in that: the drying in the step one is vacuum drying for 2 hours in a vacuum drying oven at the temperature of 60-100 ℃. The other is the same as in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment mode and one of the first to third embodiment modes is: the particle size of the nano titanium dioxide in the second step is 50 nm-100 nm. The others are the same as the first to third embodiments.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: and step two, mixing the nano titanium dioxide, the acrylic resin and the acetone, magnetically stirring for 2 hours at the rotating speed of 800-1000 r/min to obtain slurry, ultrasonically oscillating the slurry for 2 hours in a water bath under the power of 800-1000W, then placing the oscillated slurry in a cell disruption instrument, and ultrasonically oscillating the probe for 4-5 minutes under the power of 1200W to obtain the titanium oxide nano slurry. The rest is the same as the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is: and step two, mixing the nano titanium dioxide, the acrylic resin and the acetone, magnetically stirring for 2 hours at the rotating speed of 800r/min to obtain slurry, ultrasonically oscillating the slurry for 2 hours in a water bath under the power of 800W, then placing the oscillated slurry in a cell disruption instrument, and ultrasonically oscillating the probe for 5 minutes under the power of 1200W to obtain the titanium oxide nano slurry. The rest is the same as the first to fifth embodiments.

The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: the mass ratio of the nano titanium dioxide to the acrylic resin in the second step is 1 (100-150). The others are the same as the first to sixth embodiments.

The specific implementation mode is eight: the present embodiment differs from one of the first to seventh embodiments in that: the mass ratio of the nano titanium dioxide to the acetone in the second step is 1 (500-800). The rest is the same as the first to seventh embodiments.

The specific implementation method nine: the present embodiment differs from the first to eighth embodiments in that: and thirdly, spraying the titanium oxide nano slurry on the surface of the pretreated silicon nitride ceramic by a high-pressure cold spraying method under the condition that the pressure is 10bar, wherein the spraying time is 20-30 s, the thickness of the coating is 2 microns, and after the spraying is finished, drying the coating in a normal-temperature vacuum box for 8-10 h. The other points are the same as those in the first to eighth embodiments.

The detailed implementation mode is ten: the present embodiment differs from the first to ninth embodiments in that: and step III, repeating the step III for 5 to 8 times. The other points are the same as those in the first to ninth embodiments.

The following examples were used to demonstrate the beneficial effects of the present invention:

the first embodiment is as follows:

firstly, silicon nitride ceramic surface pretreatment:

cleaning and drying the silicon nitride ceramic to obtain pretreated silicon nitride ceramic;

secondly, preparing titanium oxide nano slurry:

mixing nano titanium dioxide, acrylic resin and acetone, magnetically stirring for 2 hours at the rotating speed of 800r/min to obtain slurry, carrying out ultrasonic oscillation on the slurry for 2 hours in a water bath under the condition of the power of 800W, then placing the oscillated slurry in a cell disruption instrument, and carrying out ultrasonic oscillation on a probe for 5 minutes under the condition of the probe power of 1200W to obtain titanium oxide nano slurry;

the mass ratio of the nano titanium dioxide to the acrylic resin is 1: 100; the mass ratio of the nano titanium dioxide to the acetone is 1: 500;

thirdly, manufacturing the titanium oxide coating:

firstly, under the condition that the pressure intensity is 10bar, spraying titanium oxide nano slurry on the surface of the pretreated silicon nitride ceramic by a high-pressure cold spraying method for 30s, wherein the thickness of the coating is 2 mu m, and after the spraying is finished, drying the silicon nitride ceramic in a normal-temperature vacuum box for 10 h;

and secondly, repeating the third step for 5 times to obtain the silicon nitride ceramic substrate with the high-reflection laser-proof film layer on the surface.

The cleaning in the step one is ultrasonic cleaning for 1h in acetone under the condition that the ultrasonic power is 800W, ultrasonic cleaning for 1h in alcohol under the condition that the ultrasonic power is 800W, and finally ultrasonic cleaning for 1h in deionized water under the condition that the ultrasonic power is 800W.

The drying in the step one is vacuum drying for 2 hours in a vacuum drying oven at the temperature of 80 ℃.

The particle size of the nano titanium dioxide in the second step is 50 nm.

FIG. 1 is a schematic view of a silicon nitride ceramic composition without any treatment; FIG. 2 is a diagram of a silicon nitride ceramic substrate with a high-reflectivity anti-laser film layer on the surface thereof according to the first embodiment; as can be seen from the figure, the surface of the sample is white, which is mainly the function of titanium dioxide nanoparticles in the film layer material, a compact particle deposition layer is formed on the surface of the sample, and the high-pressure spraying can ensure the uniform dispersion of the particles due to the small particle size, so that the surface of the silicon nitride ceramic is smoother, the spectral reflectivity of the silicon nitride ceramic is enhanced, the reflectivity of the ceramic is modified by utilizing the strong reflectivity of the titanium dioxide in a visible light region, and finally the spectral reflectivity of the silicon nitride ceramic is adjusted.

And respectively carrying out absorbance characterization on the silicon nitride ceramic without any treatment and the silicon nitride ceramic substrate with the high-reflection laser-proof film layer on the surface. The reflectance of the sample in the wavelength range of 400nm to 800nm was measured using an ultraviolet-visible-near infrared spectrophotometer (PerkinElmer, Lambda750, USA).

FIG. 3 is a graph of the reflectivity of a silicon nitride ceramic without any treatment; FIG. 4 is a graph of the reflectivity of a silicon nitride ceramic substrate with a high-reflectivity anti-laser film layer on the surface prepared in the first embodiment;

as can be seen from the graph, the silicon nitride ceramics without any treatment had a low reflectance, and the average reflectance in the range of 400nm to 800nm was less than 10%. The reflectance of the silicon nitride ceramic without any treatment was 5.48% at a wavelength of 532 nm. The transmittance of the sample in this band is almost 0, so the average absorption of the sample in this band is > 90%. Such a high absorption rate would be detrimental to laser protection. The reflectivity of the sample after coating is obviously improved, and the average reflectivity in the range of 400 nm-800 nm is far higher than 50%. At the wavelength of 532nm, the reflectivity can reach 76.92 percent and is higher than 70 percent. The high reflectivity is beneficial to enhancing the laser reflection and improving the laser resistance.