High-strength high-temperature-ablation-resistant high-wave-transmission silicon nitride-based composite ceramic and preparation method thereof

文档序号：335377 发布日期：2021-12-03 浏览：57次中文

阅读说明：本技术 高强度耐高温烧蚀高透波氮化硅基复合陶瓷及其制备方法 (High-strength high-temperature-ablation-resistant high-wave-transmission silicon nitride-based composite ceramic and preparation method thereof ) 是由鲍崇高王克杰宋索成卢秉恒于 2021-08-05 设计创作，主要内容包括：一种高强度耐高温烧蚀高透波氮化硅基复合陶瓷及其制备方法,先将氮化硅粉末、二氧化硅粉、氮化硼短纤维、氧化钇粉、氧化铝粉、酚醛树脂组成的复合陶瓷粉末和酒精混合均匀后球磨处理烘干得到预制粉；再将预制粉过筛,随后造粒再过筛；然后将过筛后的试样进行模压成型；再将模压后的试样进行脱脂；最后将脱脂后的试样在气压炉中进行液相烧结得到氮化硅基复合陶瓷,氮化硅基复合陶瓷强度达到450～600MPa,介电常数为2.8～3.3,耐高温烧蚀温度为2500℃以上,线烧蚀率为0.007～0.03；本发明制备的氮化硅基复合陶瓷通过优化材料组分、纤维增强和优化制备工艺等,提高了复合陶瓷强度、高温烧蚀性能和介电性能。(A high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic and a preparation method thereof are disclosed, wherein composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin is uniformly mixed with alcohol, and then is subjected to ball milling treatment and drying to obtain pre-prepared powder; sieving the prefabricated powder, granulating and sieving; then carrying out compression molding on the sieved sample; degreasing the molded sample; finally, performing liquid phase sintering on the degreased sample in a gas pressure furnace to obtain the silicon nitride-based composite ceramic, wherein the strength of the silicon nitride-based composite ceramic reaches 450-600 MPa, the dielectric constant is 2.8-3.3, the high temperature ablation resistance temperature is more than 2500 ℃, and the line ablation rate is 0.007-0.03; the silicon nitride-based composite ceramic prepared by the invention improves the strength, high-temperature ablation performance and dielectric performance of the composite ceramic by optimizing material components, fiber reinforcement, optimizing preparation process and the like.)

1. The high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic is characterized in that the raw materials of the composite ceramic consist of composite ceramic powder and a binder;

the composite ceramic powder consists of 58-85% of silicon nitride powder, 7-30% of silicon dioxide powder, 4-8% of boron nitride short fiber, 3-6% of yttrium oxide powder and 1-3% of aluminum oxide powder, wherein the silicon nitride powder is in the mass of the composite ceramic powder;

the adhesive is phenolic resin, and the content of the phenolic resin is 0.2-4% of the mass of the composite ceramic powder.

2. The silicon nitride-based composite ceramic with high strength, high temperature ablation resistance and high wave transmission according to claim 1, wherein the silicon nitride powder is spherical-like powder with d 50-100-800 nm;

the silicon dioxide powder is spherical-like powder with d50 being 20-600 nm;

the boron nitride short fiber is a wire material with d50 being 4-8 nm and length L being 5-10 mm;

the yttrium oxide powder is spherical-like powder with d50 being 100-800 nm;

the alumina powder is spherical-like powder with d50 being 100-20000 nm.

3. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 1, characterized by comprising the following steps of:

step 1, taking silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin as a binder, wherein the silicon nitride powder accounts for 58-85% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 7-30% of the mass of the composite ceramic powder, the boron nitride short fibers account for 4-8% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3-6% of the mass of the composite ceramic powder, and the aluminum oxide powder accounts for 1-3% of the mass of the composite ceramic powder; the content of the phenolic resin is 0.2 to 4 percent of the mass of the composite ceramic powder;

step 2, uniformly mixing composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, phenolic resin and alcohol, and then performing ball milling treatment and drying to obtain pre-prepared powder, wherein the mass of the alcohol is 1.5-2.5 times of that of the composite ceramic powder;

step 3, sieving the pre-prepared powder with a 50-70-mesh sieve, then granulating and sieving with a 50-70-mesh sieve;

step 4, carrying out compression molding on the sieved sample;

step 5, degreasing the molded sample;

and 6, carrying out liquid phase sintering on the degreased sample in a gas pressure furnace to obtain the silicon nitride-based composite ceramic.

4. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 3, characterized in that: and in the step 2, after the composite ceramic powder and the alcohol are uniformly mixed, ball-milling the mixture for at least 18 hours on a ball mill at the rotating speed of 240-380 r/min.

5. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 3, characterized in that: the pressure for the compression molding in the step 4 is 120-250MPa, and the pressure maintaining time is 1-3 min.

6. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 3, characterized in that: the temperature for degreasing in the step 5 is 540-.

7. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 3, characterized in that: in the step 6, the sintering atmosphere is nitrogen, the pressure is 1 MPa-3 MPa, the sintering temperature is 1450-1800 ℃, and the heat preservation time is 0.5-3 hours.

8. The high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic is characterized in that the raw materials of the composite ceramic consist of composite ceramic powder and a binder;

the composite ceramic powder consists of 85% of silicon nitride powder, 7% of silicon dioxide powder, 4% of boron nitride short fiber, 3% of yttrium oxide powder and 1% of aluminum oxide powder, wherein the silicon nitride powder is in the mass of the composite ceramic powder;

the binder is phenolic resin, and the content of the phenolic resin accounts for 1 percent of the mass of the composite ceramic powder;

the silicon nitride powder is spherical-like powder with d 50-100 nm;

the silicon dioxide powder is spherical powder with d 50-20 nm;

the boron nitride short fiber is a wire with d50 equal to 4nm and length L equal to 5 mm;

the yttrium oxide powder is spherical-like powder with d 50-100 nm;

the alumina powder is spheroidal powder with d50 being 100 nm.

9. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 8, characterized by comprising the following steps of:

step 1, taking silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin as a binder, wherein the silicon nitride powder accounts for 85% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 7% of the mass of the composite ceramic powder, the boron nitride short fibers account for 4% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3% of the mass of the composite ceramic powder, and the aluminum oxide powder accounts for 1% of the mass of the composite ceramic powder; the content of the phenolic resin is 1 percent of the mass of the composite ceramic powder;

step 2, uniformly mixing composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, phenolic resin and alcohol, wherein the mass of the alcohol is 1.5 times that of the composite ceramic powder; ball milling for 18 hours, and drying to obtain pre-prepared powder, wherein the rotating speed is 240 r/min;

step 3, sieving the pre-prepared powder with a 50-mesh sieve, then granulating and sieving with the 50-mesh sieve;

step 4, carrying out compression molding on the sieved sample, keeping the pressure at 150MPa for 1 min;

step 5, degreasing the molded sample, wherein the degreasing temperature is 540 ℃, the heat preservation time is 1.5h, and the heating rate is 1 ℃/min;

and 6, performing liquid phase sintering on the degreased sample in a nitrogen atmosphere, wherein the pressure is 3MPa, the sintering temperature is 1800 ℃, and the heat preservation time is 3 hours, so as to obtain the silicon nitride-based composite ceramic.

10. The high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic is characterized in that the raw materials of the composite ceramic consist of composite ceramic powder and a binder;

the composite ceramic powder consists of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, wherein the silicon nitride powder accounts for 82% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 8% of the mass of the composite ceramic powder, the boron nitride short fibers account for 5% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3% of the mass of the composite ceramic powder, and the aluminum oxide powder accounts for 2% of the mass of the composite ceramic powder;

the binder is phenolic resin, and the content of the phenolic resin accounts for 1 percent of the mass of the composite ceramic powder;

the silicon nitride powder is spherical-like powder with d 50-300 nm;

the silicon dioxide powder is spherical powder with d 50-100 nm;

the boron nitride short fiber is a wire with d50 equal to 4.5nm and length L equal to 6 mm;

the yttrium oxide powder is quasi-spherical powder with d 50-300 nm;

the alumina powder is spherical powder with d 50-1000 nm.

11. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 10, characterized by comprising the following steps of:

step 1, taking silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin as a binder, wherein the silicon nitride powder accounts for 82% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 8% of the mass of the composite ceramic powder, the boron nitride short fibers account for 5% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3% of the mass of the composite ceramic powder, and the aluminum oxide powder accounts for 2% of the mass of the composite ceramic powder; the content of the phenolic resin is 1 percent of the mass of the composite ceramic powder;

step 2, uniformly mixing composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, phenolic resin and alcohol, wherein the mass of the alcohol is 2.0 times of that of the composite ceramic powder; ball milling for 18 hours, and drying to obtain pre-prepared powder, wherein the rotating speed is 300 r/min;

step 3, sieving the pre-prepared powder with a 60-mesh sieve, then granulating and sieving with the 60-mesh sieve;

step 4, carrying out compression molding on the sieved sample, keeping the pressure at 180MPa for 2 min;

step 5, degreasing the molded sample, wherein the degreasing temperature is 550 ℃, the heat preservation time is 1.2h, and the heating rate is 1.5 ℃/min;

and 6, performing liquid phase sintering on the degreased sample in a nitrogen atmosphere at the pressure of 1MPa and the sintering temperature of 1450 ℃ for 0.5 hour to obtain the silicon nitride-based composite ceramic.

12. The high-strength high-temperature ablation-resistant high-wave-permeability silicon nitride-based composite ceramic is characterized in that: the raw materials of the ceramic powder composite material consist of composite ceramic powder and a binder;

the composite ceramic powder consists of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, wherein the content of the silicon nitride powder is 67% of the mass of the composite ceramic powder, the content of the silicon dioxide powder is 21% of the mass of the composite ceramic powder, the content of the boron nitride short fibers is 6% of the mass of the composite ceramic powder, the content of the yttrium oxide powder is 3% of the mass of the composite ceramic powder, and the content of the aluminum oxide powder is 3% of the mass of the composite ceramic powder;

the binder is phenolic resin, and the content of the phenolic resin accounts for 1 percent of the mass of the composite ceramic powder;

the silicon nitride powder is spherical-like powder with d 50-600 nm;

the silicon dioxide powder is spherical powder with d 50-300 nm;

the boron nitride short fiber is a wire with d50 being 5nm and length L being 7 mm;

the yttrium oxide powder is spherical-like powder with d 50-500 nm;

the alumina powder is sphere-like powder with d50 being 10000 nm.

13. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 12, characterized by comprising the following steps of:

step 1, taking silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin as a binder, wherein the silicon nitride powder accounts for 67% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 21% of the mass of the composite ceramic powder, the boron nitride short fibers account for 6% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3% of the mass of the composite ceramic powder, the aluminum oxide powder accounts for 3% of the mass of the composite ceramic powder, the binder is phenolic resin, and the phenolic resin accounts for 1% of the mass of the composite ceramic powder;

step 2, uniformly mixing composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, phenolic resin and alcohol, wherein the mass of the alcohol is 2.0 times of that of the composite ceramic powder; ball milling for 18 hours and drying to obtain pre-prepared powder, wherein the rotating speed is 350 r/min;

step 3, sieving the pre-prepared powder with a 70-mesh sieve, then granulating and sieving with a 60-mesh sieve;

step 4, carrying out compression molding on the sieved sample, keeping the pressure at 250MPa for 3 min;

step 5, degreasing the molded sample, wherein the degreasing temperature is 560 ℃, the heat preservation time is 1h, and the heating rate is 1.2 ℃/min;

and 6, performing liquid phase sintering on the degreased sample in a nitrogen atmosphere at the sintering temperature of 1750 ℃ under the pressure of 1MPa for 0.5 hour to obtain the silicon nitride-based composite ceramic.

14. The high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic is characterized in that the raw materials of the composite ceramic consist of composite ceramic powder and a binder;

the composite ceramic powder consists of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, wherein the content of the silicon nitride powder is 58% of the mass of the composite ceramic powder, the content of the silicon dioxide powder is 30% of the mass of the composite ceramic powder, the content of the boron nitride short fibers is 7% of the mass of the composite ceramic powder, the content of the yttrium oxide powder is 3% of the mass of the composite ceramic powder, the content of the aluminum oxide powder is 2% of the mass of the composite ceramic powder, the binder is phenolic resin, and the content of the phenolic resin is 4% of the mass of the composite ceramic powder;

the silicon nitride powder is spherical-like powder with d 50-800 nm;

the silicon dioxide powder is spherical powder with d 50-600 nm;

the boron nitride short fiber is a wire with d50 being 6nm and length L being 8 mm;

the yttrium oxide powder is spherical-like powder with d 50-800 nm;

the alumina powder is spherical-like powder with d50 ═ 20000 nm.

15. The preparation method of the high-strength high-temperature-ablation-resistance high-wave-transmission silicon nitride-based composite ceramic according to claim 14, characterized by comprising the following steps of:

step 1, taking silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder, aluminum oxide powder and phenolic resin as a binder, wherein the silicon nitride powder accounts for 58% of the mass of the composite ceramic powder, the silicon dioxide powder accounts for 30% of the mass of the composite ceramic powder, the boron nitride short fibers account for 7% of the mass of the composite ceramic powder, the yttrium oxide powder accounts for 3% of the mass of the composite ceramic powder, the aluminum oxide powder accounts for 2% of the mass of the composite ceramic powder, the binder is phenolic resin, and the phenolic resin accounts for 4% of the mass of the composite ceramic powder;

step 2, uniformly mixing composite ceramic powder consisting of silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder, phenolic resin and alcohol, wherein the mass of the alcohol is 2.5 times that of the composite ceramic powder; ball milling for 18 hours and drying to obtain pre-prepared powder, wherein the rotating speed is 380 r/min;

step 3, sieving the pre-prepared powder with a 60-mesh sieve, then granulating and sieving with the 60-mesh sieve;

step 4, carrying out compression molding on the sieved sample, keeping the pressure at 200MPa for 1 min;

step 5, degreasing the molded sample, wherein the degreasing temperature is 550 ℃, the heat preservation time is 1.3h, and the heating rate is 1.3 ℃/min;

and 6, performing liquid phase sintering on the degreased sample in a nitrogen atmosphere, wherein the pressure is 3MPa, the sintering temperature is 1450 ℃, and the heat preservation time is 3 hours, so as to obtain the silicon nitride-based composite ceramic.

Technical Field

The invention belongs to the technical field of preparation of silicon nitride functional ceramic materials, and particularly relates to a high-strength high-temperature ablation-resistant high-wave-permeability silicon nitride-based composite ceramic and a preparation method thereof.

Background

The silicon nitride ceramic has thermal shock resistance, high temperature resistance and ablation resistance, is an electromagnetic window material with the greatest development prospect in a high-temperature extreme environment, is excellent in thermal stability and high temperature performance, has a reinforcing effect on boron nitride short fibers, and is outstanding in wave-transmitting performance of silicon dioxide ceramic.

The silicon nitride ceramic applied to the missile radome at present is difficult to meet the comprehensive characteristics of high strength, high-temperature ablation resistance and high wave transmission. How to meet the functional requirements of the protective material is as follows: the technical problem which needs to be solved urgently at present is to improve the strength of the material on the premise of lower dielectric constant, lower mass ablation rate and lower line ablation rate.

Chinese patent publication No. CN1569743A discloses a silicon nitride-boron nitride-silicon dioxide ceramic wave-transparent material and a preparation method thereof, and the obtained properties are as follows: the room-temperature bending strength is 99-286 MPa, the dielectric constant is 3.4-4.8, the temperature resistance is 2500 ℃, and the wire ablation rate is 0.01-0.05. The ceramic material prepared by the patent has low strength, unsatisfactory dielectric property and high ablation rate of high-temperature wires.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic and the preparation method thereof by optimizing material components, fiber reinforcement and preparation processes, so that the strength, the high-temperature ablation performance and the dielectric performance of the composite ceramic are improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic comprises raw materials of composite ceramic powder and a binder;

the binder is phenolic resin, and the content of the phenolic resin is 0.2-4% of the mass of the composite ceramic powder;

the silicon nitride powder is spherical-like powder with d50 being 100-800 nm;

the silicon dioxide powder is spherical-like powder with d50 being 20-600 nm;

the boron nitride short fiber is a wire material with d50 being 4-8 nm and length L being 5-10 mm;

the yttrium oxide powder is spherical-like powder with d50 being 100-800 nm;

the alumina powder is spherical-like powder with d50 being 100-20000 nm.

A preparation method of high-strength high-temperature ablation-resistant high-wave-transmission silicon nitride-based composite ceramic comprises the following steps:

step 3, sieving the pre-prepared powder with a 50-70-mesh sieve, then granulating and sieving with a 50-70-mesh sieve;

step 4, carrying out compression molding on the sieved sample;

step 5, degreasing the molded sample;

and 6, carrying out liquid phase sintering on the degreased sample in a gas pressure furnace to obtain the silicon nitride-based composite ceramic.

And in the step 2, after the composite ceramic powder and the alcohol are uniformly mixed, ball-milling the mixture for at least 18 hours on a ball mill at the rotating speed of 240-380 r/min.

The pressure for the compression molding in the step 4 is 120-250MPa, and the pressure maintaining time is 1-3 min.

The temperature for degreasing in the step 5 is 540-.

In the step 6, the sintering atmosphere is nitrogen, the pressure is 1 MPa-3 MPa, the sintering temperature is 1450-1800 ℃, and the heat preservation time is 0.5-3 hours.

Compared with the prior art, the invention has the following beneficial technical effects:

according to the invention, silicon nitride powder, silicon dioxide powder, boron nitride short fibers, yttrium oxide powder and aluminum oxide powder are added with phenolic resin with specified content as an adhesive, so that the finally prepared silicon nitride-based composite ceramic has the strength of 450-600 MPa, the dielectric constant of 2.8-3.3, the high-temperature ablation resistance temperature of more than 2500 ℃ and the line ablation rate of 0.007-0.03; the silicon nitride-based composite ceramic prepared by the invention has the advantages of ideal dielectric property and high strength.

Drawings

FIG. 1 (a) is a macroscopic view of a sample of pure silicon nitride after being ablated in an oxyacetylene flame at 2500 ℃ for 20 seconds; (b) is a macro topography picture of the sample of the embodiment 1 of the invention after being ablated for 20 seconds under the oxyacetylene flame at the temperature of 2500 ℃; (c) is a macro topography picture of a sample of the embodiment 2 of the invention after being ablated for 20 seconds at 2500 ℃ by oxyacetylene flame; (d) is a macro topography picture of the sample of the embodiment 6 of the invention after being ablated for 20 seconds under the oxyacetylene flame at the temperature of 2500 ℃; (e) the macro topography of the sample of example 9 of the present invention after being ablated in an oxyacetylene flame at 2500 ℃ for 20 seconds is shown.

FIG. 2 shows the results of flexural strength tests of silicon nitride compositions of examples 1, 2, 6 and 9 of the present invention.

FIG. 3 shows the results of dielectric constant measurements for different silicon nitride compositions according to examples 1, 2, 6 and 9 of the present invention.

FIG. 4 shows the results of line ablation rate tests of different silicon nitride compositions of examples 1, 2, 6 and 9 of the present invention.

Detailed Description

The preparation process of the present invention will be described in detail with reference to examples.

Example 1, a high-strength, high-temperature-ablation-resistant, high-wave-transparent silicon nitride-based composite ceramic, the raw materials of which are composed of composite ceramic powder and a binder;