Automated preparation method of a SiC.SUB.f./SiC composite flame tube

Abstract

An automated preparation method of a SiC.sub.f/SiC composite flame tube, comprising the following steps: preparing an interface layer for a SiC fiber by a chemical vapor infiltration process, and obtaining the SiC fiber with a continuous interface layer; laying a unidirectional tape on the SiC fiber with the continuous interface layer and winding the SiC fiber with the continuous interface layer to form and obtaining a preform of a net size molding according to a fiber volume and a fiber orientation obtained in a simulation calculation; and adopting a reactive melt infiltration process and the chemical vapor infiltration process successively for a densification and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way. The SiC.sub.f/SiC composite flame tube prepared by the present disclosure not only has a high temperature resistance, but also has a low thermal expansion coefficient, high thermal conductivity and high thermal shock resistance.

Claims

1. A method for the preparation of a silicon carbide ceramic (SiC.sub.f/SiC) matrix composite flame tube, comprising the steps of: 1) preparing an interface layer for a SiC fiber by a chemical vapor infiltration process, and obtaining the SiC fiber having a continuous interface layer; 2) laying a prepreg unidirectional tape on the SiC fiber having the continuous interface layer obtained in step 1) and winding the SiC fiber having the continuous interface layer obtained in step 1) to form and obtain a preform of a net size molding; 3) performing densification on the preform obtained in step 2) by adopting a reactive melt infiltration (RMI) process and a chemical vapor infiltration process in sequence until the mass ratio of a SiC matrix formed by the chemical vapor infiltration process to a SiC matrix formed by the reactive melt infiltration process is 1:1; 4) preparing an environmental barrier coating on a surface of the preform obtained in step 3), wherein a thickness of the environmental barrier coating is between 60 μm to 150 μm; and 5) preparing a thermal barrier coating on the surface of the preform obtained in step 4), thereby obtaining the SiC.sub.f/SiC composite flame tube, wherein a thickness of the thermal barrier coating is between 100 μm to 150 μm.

2. The method according to claim 1, wherein the interface layer in step 1) is one or more of PyC, SiC, B.sub.4C, ZrC, HfC, TaC, Si.sub.3N.sub.4, BN.

3. The method according to claim 1, wherein the chemical vapor infiltration process in step 1) comprises the steps of: placing the SiC fiber into a chemical vapor infiltration furnace and choosing a precursor for preparing the interface layer in step 1); introducing a gas into the chemical vapor infiltration furnace by a bubble method by maintaining a temperature ranges from about 500° C.-1400° C. for a time period of about 60 minutes to 600 minutes and a pressure ranges from about 0.5 KPa to 12 KPa, wherein the gas is a mixture of hydrogen and argon, wherein the thickness of the infiltration interface layer obtained in step 1) ranges from about 100 nm to 2 μm; wherein the precursor is selected from the group consisting of methane, methyltrichlorosilane, boron chloride, zirconium chloride, tantalum chloride, silicon chloride, boron halide, and ammonia.

4. The method according to claim 1, wherein the step 2) of laying the unidirectional tape and winding of the SiC fiber having the continuous interface layer to form the perform comprises the steps of: S1: cleaning the surface of a flame tube mold by acetone to remove impurities attached on the surface and coating the surface of the flame tube mold uniformly with an epoxy resin release agent, and heating the flame tube mold at a temperature range from about 30° C. to 50° C.; S2: laying said SiC fiber with a volume content of about 40%-65% and the prepreg unidirectional tape with the epoxy resin release agent on the surface of the flame tube mold; S3: winding said SiC fiber with a volume content of 50% to 70% and the prepreg unidirectional tape with the epoxy resin release agent on the surface of the flame tube mold in step S2) through a winding machine; S4: putting the wounded SiC fiber obtained in S3 into a curing furnace for curing and forming-at a temperature ranges from about 90° C.-165° C.; and S5: demolding and obtaining the preform of the net size molding.

5. The method according to claim 1, wherein the reactive melt infiltration process in step 3) is a molten silicon infiltration process, which is carried out using at least any one of a vacuum atmospheric infiltration furnace and a vacuum siliconizing furnace at a temperature ranges from about 1400° C. to 1800° C. and pressure of 2 Pa.

6. The method according to claim 1, wherein a precursor used in the chemical vapor infiltration process is methyltrichlorosilane.

7. The method according to claim 1, wherein the environmental barrier coating in step 4) includes a Si bonding layer, a rare earth monosilicate (Re.sub.2SiO.sub.5) surface layer, and a ytterbium disilicate (Yb.sub.2Si.sub.2O.sub.7) intermediate layer located between the Si bonding layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer, wherein a thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer, and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer is 1-2:1-2:1-3; and wherein the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer is selected from at least one of Y.sub.2SiO.sub.5, Sc.sub.2SiO.sub.5, Gd.sub.2SiO.sub.5, Er.sub.2SiO.sub.5, Tm.sub.2SiO.sub.5, Yb.sub.2SiO.sub.5, Lu.sub.2SiO.sub.5.

8. The method according to claim 1, wherein the environmental barrier coating is prepared by a process, comprising the steps of: (1): grinding Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the ground particle size is between 20 μm to 80 μm, thereby obtaining Yb.sub.2Si.sub.2O.sub.7 powder and Re.sub.2SiO.sub.5 powder; (2): putting the preform into an inert protective atmosphere and heating at a temperature ranges of about 1450° C. to 1800° C. for a time period of about 1 hour to 4 hours to form a Si bonding layer; (3): spraying Yb.sub.2Si.sub.2O.sub.7 powder obtained in step (1) on the preform with the Si bonding layer by adopting a plasma spraying method to form an intermediate layer; and (4): spraying Re.sub.2SiO.sub.5 powder on the preform with the bonding layer and the intermediate layer by adopting a plasma spraying method to obtain the environmental barrier coating.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram of preparation process of the SiC.sub.f/SiC composite flame tube;

(2) FIG. 2 is a scanning electron micrograph of the PyC/Si.sub.3N.sub.4/BN multi-layer interface layer in the embodiment 3;

(3) FIG. 3 is a scanning electron micrograph of MI SiC/CVI SiC matrix;

(4) FIG. 4 is a scanning electron micrograph of the environmental barrier coating (EBC);

(5) FIG. 5 is the enlarged view of the EBC surface;

(6) FIG. 6 is a schematic diagram of laying and winding the unidirectional tape in the present disclosure;

(7) FIG. 7 is a stereograph of the SiC.sub.f/SiC composite flame tube in the present disclosure;

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) The following describes the present disclosure in detail with reference to the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

(9) The preparation method of a SiC.sub.f/SiC composite flame tube will be described in detail below in conjunction with specific preferred embodiments.

Embodiment 1

(10) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(11) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, and making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 500° C., the infiltration pressure is 12 KPa, the infiltration time is 600 min and the thickness of an infiltration interface layer is 100 nm; and after the SiC fiber cooling in the furnace, SiC fiber with continuous PyC interface layer is obtained;

(12) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(13) S1: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 2 times, and heating the flame tube mold to 30° C.;

(14) S2: laying the SiC fiber with a volume content of 40% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(15) S3: winding the SiC fiber with a volume content of 50% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 30°, a winding velocity is 0.3 m/s, the winding tension is 2N/cm and a winding thickness is 1 mm;

(16) S4: putting the SiC fiber with the volume content of 50% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 90° C. and a curing time is 4 hours;

(17) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(18) 3): for the preform of the net size molding in step 2), adopting a reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1400° C., the infiltration pressure is normal pressure and the siliconizing time is 300 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 900° C., the infiltration pressure is 5 KPa and the infiltration time is 6000 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:1.

(19) 4): preparing a 60 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(20) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 20 um;

(21) (2): putting the preform into an inert protective atmosphere and heating at 1450° C. for 4 hours to form the Si bonding layer;

(22) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 1:1:1 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 60 slpm, the flow rate of the helium is 40 slpm, the powder feeding rate is 10 r/min, and a spraying distance is 90 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(23) 5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—Al.sub.2O.sub.3, whose thickness is 100 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Embodiment 2

(24) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(25) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, and making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1400° C., the infiltration pressure is 0.5 KPa, the infiltration time is 60 min and the thickness of an infiltration interface layer is 2 um; and after the SiC fiber cooling in the furnace, SiC fiber with continuous interface layer is obtained.

(26) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(27) S1: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 3 times, and heating the flame tube mold to 50° C.;

(28) S2: laying the SiC fiber with a volume content of 65% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(29) S3: winding the SiC fiber with a volume content of 70% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 90°, a winding velocity is 0.7 m/s, the winding tension is 10N/cm and a winding thickness is 5 mm;

(30) S4: putting the SiC fiber with the volume content of 70% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 165° C. and the curing time is 8 h;

(31) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(32) 3): for the preform of the net size molding in step 2), adopting the reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1800° C., the infiltration pressure is 2 Pa and the siliconizing time is 30 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 1200° C., the infiltration pressure is 0.5 KPa and the infiltration time is 60 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:2.

(33) 4): preparing a 150 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(34) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 80 um;

(35) (2): putting the preform into an inert protective atmosphere and heating at 1800° C. for 1 h to form the Si bonding layer;

(36) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 2:2:3 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 80 slpm, the flow rate of the helium is 60 slpm, the powder feeding rate is 35 r/min, and a spraying distance is 200 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(37) 5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—Al.sub.2O.sub.3, whose thickness is 150 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Embodiment 3

(38) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(39) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, and making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1000° C., the infiltration pressure is 8 KPa, the infiltration time is 300 min and the thickness of an infiltration interface layer is 1 um; and after the SiC fiber cooling in the furnace, SiC fiber with continuous interface layer is obtained.

(40) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(41) 51: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 2 times, and heating the flame tube mold to 40° C.;

(42) S2: laying the SiC fiber with a volume content of 55% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(43) S3: winding the SiC fiber with a volume content of 60% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 60°, a winding velocity is 0.5 m/s, the winding tension is 6N/cm and a winding thickness is 3 mm;

(44) S4: putting the SiC fiber with the volume content of 70% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 120° C. and the curing time is 6 hours;

(45) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(46) 3): for the preform of the net size molding in step 2), adopting the reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1600° C., the infiltration pressure is 1 Pa and the siliconizing time is 180 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 1000° C., the infiltration pressure is 3 KPa and the infiltration time is 4800 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:1.5.

(47) 4): preparing a 100 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(48) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 50 um;

(49) (2): putting the preform into an inert protective atmosphere and heating at 1600° C. for 3 h to form the Si bonding layer;

(50) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 1:2:1 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 70 slpm, the flow rate of the helium is 50 slpm, the powder feeding rate is 20 r/min, and a spraying distance is 120 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(51) 5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—Al.sub.2O.sub.3, whose thickness is 120 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Embodiment 4

(52) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(53) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, Si.sub.3N.sub.4 interface layer and BN interface layer, and introducing PyC/Si.sub.3N.sub.4/BN multi-interface layer, specifically introducing the PyC interface layer. In the PyC interface layer, making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 500° C., the infiltration pressure is 12 KPa, the infiltration time is 600 min and the thickness of an infiltration interface layer is 100 nm; and in the Si.sub.3N.sub.4 interface layer, making Trichloromethylsilane and ammonia gas as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 500° C., the infiltration pressure is 0.5 KPa, the infiltration time is 600 min and the thickness of an infiltration interface layer is 100 nm; and in the BN interface layer, making boron chloride and ammonia as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 500° C., the infiltration pressure is 12 KPa, the infiltration time is 600 min and the thickness of an infiltration interface layer is 100 nm; and after the SiC fiber cooling in the furnace, SiC fiber with multi-layer continuous interface layer is obtained.

(54) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(55) S1: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 2 times, and heating the flame tube mold to 30° C.;

(56) S2: laying the SiC fiber with a volume content of 40% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(57) S3: winding the SiC fiber with a volume content of 50% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 30°, a winding velocity is 0.3 m/s, the winding tension is 2N/cm and a winding thickness is 1 mm;

(58) S4: putting the SiC fiber with the volume content of 50% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 90° C. and the curing time is 4 hours;

(59) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(60) 3): for the preform of the net size molding in step 2), adopting the reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1400° C., the infiltration pressure is 2 Pa and the siliconizing time is 300 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 900° C., the infiltration pressure is 5 KPa and the infiltration time is 60 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:1.

(61) 4): preparing a 60 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(62) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 20 um;

(63) (2): putting the preform into an inert protective atmosphere and heating at 1450° C. for 4 hours to form the Si bonding layer;

(64) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 1:1:1 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 60 slpm, the flow rate of the helium is 40 slpm, the powder feeding rate is 10 r/min, and a spraying distance is 90 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(65) 5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—ZrO.sub.2—CeO.sub.2, whose thickness is 100 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Embodiment 5

(66) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(67) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, Si.sub.3N.sub.4 interface layer and BN interface layer, and introducing PyC/Si.sub.3N.sub.4/BN multi-interface layer, specifically introducing the PyC interface layer. In the PyC interface layer, making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1400° C., the infiltration pressure is 0.5 KPa, the infiltration time is 60 min and the thickness of an infiltration interface layer is 2 um; and in the Si.sub.3N.sub.4 interface layer, making Trichloromethylsilane and ammonia gas as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1400° C., the infiltration pressure is 0.5 KPa, the infiltration time is 60 min and the thickness of an infiltration interface layer is 2 um; and in the BN interface layer, making boron chloride and ammonia as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1400° C., the infiltration pressure is 0.5 KPa, the infiltration time is 60 min and the thickness of an infiltration interface layer is 2 um; and after the SiC fiber cooling in the furnace, SiC fiber with multi-layer continuous interface layer is obtained.

(68) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(69) S1: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 2 times, and heating the flame tube mold to 50° C.;

(70) S2: laying the SiC fiber with a volume content of 65% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(71) S3: winding the SiC fiber with a volume content of 70% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 90°, a winding velocity is 0.7 m/s, the winding tension is 10N/cm and a winding thickness is 5 mm;

(72) S4: putting the SiC fiber with the volume content of 70% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 90° C. and the curing time is 4 hours;

(73) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(74) 3): for the preform of the net size molding in step 2), adopting the reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1800° C., the infiltration pressure is normal pressure and the siliconizing time is 30 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 1200° C., the infiltration pressure is 0.5 KPa and the infiltration time is 6000 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:2.

(75) 4): preparing a 150 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(76) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 80 um;

(77) (2): putting the preform into an inert protective atmosphere and heating at 1800° C. for 1 h to form the Si bonding layer;

(78) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 2:2:3 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 80 slpm, the flow rate of the helium is 60 slpm, the powder feeding rate is 35 r/min, and a spraying distance is 200 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(79) (5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—ZrO.sub.2—CeO.sub.2, whose thickness is 150 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Embodiment 6

(80) The automated preparation method of the SiC.sub.f/SiC composite flame tube, wherein, comprising the following steps:

(81) 1): placing the SiC fiber in an electric resistance furnace at the corresponding chemical vapor infiltration temperature of the PyC interface layer, Si.sub.3N.sub.4 interface layer and BN interface layer, and introducing PyC/Si.sub.3N.sub.4/BN multi-interface layer, specifically introducing the PyC interface layer. In the PyC interface layer, making methane as the precursor, hydrogen as the reaction gas, and argon as the dilution gas, introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1000° C., the infiltration pressure is 8 KPa, the infiltration time is 300 min and the thickness of an infiltration interface layer is 1 um; and in the Si.sub.3N.sub.4 interface layer, making Trichloromethylsilane and ammonia gas as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1000° C., the infiltration pressure is 8 KPa, the infiltration time is 300 min and the thickness of an infiltration interface layer is 1 um; and in the BN interface layer, making boron chloride and ammonia as precursors, hydrogen as the reaction gas, and argon as the dilution gas, and introducing the gas is into the chemical vapor infiltration furnace by the bubbling method, and the infiltration temperature is 1000° C., the infiltration pressure is 8 KPa, the infiltration time is 300 min and the thickness of an infiltration interface layer is 1 um; and after the SiC fiber cooling in the furnace, SiC fiber with multi-layer continuous interface layer is obtained.

(82) 2): laying a unidirectional tape on the SiC fiber with the continuous interface layer obtained in step 1) and winding the SiC fiber with the continuous interface layer obtained in step 1) according to a fiber volume and a fiber orientation obtained in a simulation calculation, comprising the following steps:

(83) S1: cleaning a surface of a flame tube mold by acetone to a state where no impurities are attached, coating the surface of the flame tube mold evenly with epoxy resin release agent for 2 times, and heating the flame tube mold to 40° C.;

(84) S2: laying the SiC fiber with a volume content of 55% and a prepreg unidirectional tape with a residual of resin on the surface of the flame tube mold respectively;

(85) S3: winding the SiC fiber with a volume content of 60% and the prepreg unidirectional tape with the residual of resin on the surface of the flame tube mold in S2 through a winding machine, winding from the inside to the outside in a way of a gradient decreasing of a winding tension, a winding angle is 60°, a winding velocity is 0.5 m/s, the winding tension is 6N/cm and a winding thickness is 3 mm;

(86) S4: putting the SiC fiber with the volume content of 60% and the prepreg unidirectional tape with the residual of resin wound on the surface of the flame tube mold in S3 into a curing furnace for curing and forming, a curing temperature is 120° C. and the curing time is 6 hours;

(87) S5: demoulding a preform after curing in S4, and then finish processing the preform after curing by a combination of a grinding processing and a laser processing after demolding, and obtaining the preform of the net size molding.

(88) 3): for the preform of the net size molding in step 2), adopting the reactive melt infiltration process and the chemical vapor infiltration process successively for a densification. Carrying out low-temperature vacuum siliconizing first, and regarding the binary alloy of Si and Ta as the silicon source, and the argon is the diluent gas, the infiltration temperature is 1600° C., the infiltration pressure is 1 Pa and the siliconizing time is 180 min, after cooling with the furnace, repeating the step once. And then, carrying out the chemical vapor infiltration, and the methyltrichlorosilane is the precursor, the hydrogen is the reactant gas, the argon is the diluent gas, and introducing the hydrogen and the argon into the chemical vapor infiltration furnace by the bubble method, the infiltration temperature is 1000° C., the infiltration pressure is 3 KPa and the infiltration time is 4800 min, after cooling with the furnace, repeating the step once until the mass ratio of the SiC matrix formed by the chemical vapor infiltration process to the SiC matrix formed by the reactive melt infiltration process is 1:1.5.

(89) 4): preparing a 100 um-thick environmental barrier coating on the surface of the preform obtained in step 3), the preparation method of the environmental barrier coating, comprising the following steps:

(90) (1): ball milling Yb.sub.2Si.sub.2O.sub.7 and Re.sub.2SiO.sub.5 respectively until the particle size is 60 um;

(91) (2): putting the preform into an inert protective atmosphere and heating at 1600° C. for 2 h to form the Si bonding layer;

(92) (3): preparing the intermediate layer and the surface layer according to the thickness ratio of the Si bonding layer, the Yb.sub.2Si.sub.2O.sub.7 intermediate layer and the rare earth monosilicate Re.sub.2SiO.sub.5 surface layer of 1:2:1 by adopting the plasma spraying method. As for the plasma spraying method, plasma gas includes argon and helium, the flow rate of the argon is 70 slpm, the flow rate of the helium is 50 slpm, the powder feeding rate is 20 r/min, and a spraying distance is 150 mm And spraying Yb.sub.2Si.sub.2O.sub.7 powder and Yb.sub.2Si.sub.2O.sub.5 powder on the preform in turn to obtain a high-density and fully intelligent SiC.sub.f/SiC composite flame tube.

(93) (5): preparing the thermal barrier coating on the surface of the preform obtained in step 4), and the thermal barrier coating is R.sub.2O.sub.3—ZrO.sub.2—CeO.sub.2, whose thickness is 120 um, and obtaining a high-density SiC.sub.f/SiC composite flame tube in a full intelligent way.

Test Embodiment

(94) Carrying out the performance test of the SiC.sub.f/SiC composite flame tube prepared in embodiment 1 to embodiment 6, and a conventional flame tube was used as a comparative example, and the details are as follows:

(95) 1. High Temperature Oxidation Resistance

(96) Test method: samples were taken from the SiC.sub.f/SiC composite flame tube prepared in embodiment 1 to embodiment 6, and made into mechanical properties parts with a size of 3×4×40 (mm), and then process the piece in aerobic environment, normal temperature and high temperature environment for 500 h, among which the high temperature environment was 1400° C. and 1600° C. respectively.

(97) Test result: the test results of bending strength are shown in Table 1 below:

(98) TABLE-US-00001 TABLE 1 bending strength of SiC.sub.f/SiC composite flame tube at different temperatures: Bending strength(MPa) normal pressure 1400° C. 1600° C. Embodiment 1 823 617 431 Embodiment 2 836 624 426 Embodiment 3 829 614 435 Embodiment 4 854 626 415 Embodiment 5 848 618 424 Embodiment 6 839 622 421 Contrast ratio 716 523 293

(99) 2. Density and Porosity

(100) Test method: the SiC.sub.f/SiC composite flame tube prepared in embodiment 1 to embodiment 6 were tested according to GB/T 1966-1996 “Test Method for Apparent Porosity and Capacity of Porous Ceramics”.

(101) Test result: the volume density of the prepared SiC.sub.f/SiC composite flame tube is 2.75 g/m3, and the apparent porosity is 0.65%.

(102) 3. Thermal and Seismic Resistance Performance

(103) Test method: cutting the specimens on the SiC.sub.f/SiC composite flame tube prepared in Examples 1 to 6, and place them in a completely enclosed space, respectively, and heat them to 1100° C., 1200° C., and 1300° C., and then placing them in 20° C. water, repeating the heating and cooling process, and visually check whether there is cracking.

(104) Test result: the thermal and seismic resistance performance of the SiC.sub.f/SiC composite flame tube is shown in Table 2 below:

(105) TABLE-US-00002 TABLE 2 thermal and seismic resistance performance of SiC.sub.f/SiC composite flame tube at different temperatures: Thermal and seismic resistance performance 1100° C. 1200° C. 1300° C. Embodiment 1 786 685 145 Embodiment 2 779 688 151 Embodiment 3 791 679 147 Embodiment 4 789 683 152 Embodiment 5 794 690 143 Embodiment 6 790 687 148 Contrast ratio 347 163  31

(106) The pros and cons of thermal and seismic resistance performance are expressed by the number of heating and cooling treatments, that is, the more times, the better the thermal and seismic resistance performance. It can be seen from Table 2 that the thermal and seismic resistance performance of the embodiment 1 to embodiment 6 is more excellent.

(107) 4. Thermal Conductivity

(108) Test method: testing the SiC.sub.f/SiC composite flame tube according to GB/T 17911.8-2002 “Test Method for Thermal Conductivity of Refractory Ceramic Fiber Products”.

(109) Test method: the average thermal conductivity of the prepared SiC.sub.f/SiC composite flame tube is 30 W/(m.Math.K).

(110) 5. Coefficient of Thermal Expansion

(111) Test method: testing the SiC.sub.f/SiC composite flame tube according to GB/T16535-1996 “Test Method for Thermal Expansion Coefficient of Engineering Ceramics”.

(112) Test result: the coefficient of thermal expansion of the prepared SiC.sub.f/SiC composite flame tube is 3.65×10.sup.−6 m/K.

(113) Although the embodiments of the present disclosure have been disclosed above, the present disclosure is not limited to the applications listed in the specification and embodiments, and it can be applied to various fields suitable for the present disclosure. For those skilled in the art, for those of ordinary skill in the art, various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principles of the present disclosure, and therefore, without departing from the rights under the general concept defined by the requirements and equivalent scope, the present disclosure is not limited to specific details.