CN109082625B

CN109082625B - Spraying fixture for spring part arranged in separation rocket and spraying method for thermal barrier coating

Info

Publication number: CN109082625B
Application number: CN201811272081.5A
Authority: CN
Inventors: 王海斗; 刘明; 马国政; 邢志国; 赵福长; 刘天寅
Original assignee: Baoji Xinfuquan Machinery Technology Co ltd
Current assignee: Baoji Xinfuquan Machinery Technology Co ltd
Priority date: 2018-10-30
Filing date: 2018-10-30
Publication date: 2020-10-20
Anticipated expiration: 2038-10-30
Also published as: CN109082625A

Abstract

The invention discloses a spraying fixture for a spring part arranged in a separation rocket, which comprises a spring part supporting rod, wherein the center of the upper end of the spring part supporting rod is provided with a connecting hole along the axial direction; and the pressing cap comprises a pressing end and a connecting rod, wherein the connecting rod penetrates through a central hole of the spring part arranged in the separation rocket and is connected in the connecting hole in a matching manner, and the pressing cap presses the spring part arranged in the separation rocket to the upper end of the spring part supporting rod. The invention also discloses a spraying method of the thermal barrier coating of the spring part arranged in the separation rocket, which comprises the following steps: firstly, performing sand blasting coarsening on the surface of the spring part; fixing the spring part on a rotary table rotating at a constant speed by adopting a spraying clamp provided by the invention; step three, spraying a metal bonding layer, wherein the distance between a spray gun and the spring part is controlled to be 100 +/-5 mm in the spraying process; step four, spraying the heat-proof layer, wherein the distance between a spray gun and the spring part is controlled to be 110 +/-5 mm in the spraying process; the thermal barrier coating sprayed by the method is uniform and stable and has better toughness.

Description

Spraying fixture for spring part arranged in separation rocket and spraying method for thermal barrier coating

Technical Field

The invention belongs to the technical field of surface machining and thermal spraying, and particularly relates to a spraying clamp for separating a spring part arranged in a rocket and a spraying method for a thermal barrier coating.

Background

The main function of the spring element in the rocket for separation is to fix the fuel in the rocket for separation in one stage. The spring element substrate is made of 65Mn material, the diameter is 137.5 +/-0.3 mm, the thickness is 1.5 +/-0.1 mm, and the spring element substrate is circular (see figures 1 and 2). The melting point of the 65Mn material is about 1400 ℃, which is far lower than the working temperature. When the rocket is separated, the temperature rises to more than 2000 ℃ instantly within 0.5 second, so that the spring part ablates slag and splashes around to damage the rocket body, and unpredictable potential safety hazards are generated. If no other thermal protection measures are available, the working requirements cannot be met.

Thermal Barrier Coatings (TBCs) are compositions of a metallic bond coat and a ceramic thermal protective functional coating that is heat resistant and thermally insulating. The surface ceramic working layer is bonded to the superalloy substrate by a metallic bond layer between the substrate and the ceramic layer. The bonding layer has good bonding performance with the surface ceramic layer and the matrix metal material, can improve the thermal matching between the ceramic and the metal material, slow down the interface stress, improve the use temperature, improve the thermal shock resistance and prolong the service life.

MCrAlY coatings can perform high temperature oxidation resistance at higher temperatures and are commonly used as metallic bond coats for Thermal Barrier Coating (TBCs) systems. MCrAlY can be NiCoCrAlY, NiCrAlY, CoCrAlY, NiCrAl and the like powder, and the MCrAlY can adopt the technologies of supersonic flame, supersonic plasma, vacuum plasma and the like to prepare the coating.

The oxide ceramic material has the advantages of high melting point, low thermal conductivity, small thermal radiance, high reflectivity, high coating hardness, good high-temperature and high-speed gas erosion and abrasion resistance and the like, and becomes a main material for a thermal barrier coating. In particular stabilized ZrO₂The ceramic coating can effectively improve the thermal shock resistance of the coating. With ZrO₂The ceramic coating material based on has y₂O₃-ZrO₂、CaO-ZrO₂、MgO-ZrO₂、CeO-ZrO₂Etc. can be used as a surface heat shield. The coating can be prepared by adopting the technologies of common plasma, vacuum plasma, supersonic plasma, vapor deposition and the like.

The existing thermal barrier coating preparation method is complex, and the prepared thermal barrier coating has poor structural uniformity.

Disclosure of Invention

One of the purposes of the invention is to provide a spraying method of a thermal barrier coating of a spring part in a separation rocket, which adopts a supersonic plasma spray gun to prepare the thermal barrier coating, can efficiently finish the spraying process by reasonably controlling the spraying path and the spraying distance of the spray gun, and the prepared thermal barrier coating has the advantages of uniform structure, stable structure, no cracking of the coating and better toughness.

The invention also aims to provide a spraying clamp for the spring part arranged in the separation rocket, which has the advantages of simple structure and convenient assembly and disassembly, can effectively reduce the shielded area in the center of the spring part, and brings convenience for subsequent spraying supplement.

The technical scheme provided by the invention is as follows:

a spray coating fixture for detaching an innerspring element of a rocket, comprising:

the spring part supporting rod is provided with a connecting hole at the center of the upper end along the axial direction;

a pressing cap which comprises a pressing end and a connecting rod,

the connecting rod penetrates through a central hole of the spring part arranged in the separation rocket and is connected in the connecting hole in a matching mode, and the pressing cap presses the spring part arranged in the separation rocket to the upper end of the spring part supporting rod.

Preferably, the compressing end is in a circular truncated cone shape, and the small-diameter end of the compressing end is connected with the connecting rod.

Preferably, the pressing end is stepped, and a small-diameter end of the pressing end is connected with the connecting rod.

A method for spraying a thermal barrier coating of a spring element arranged in a separation rocket comprises the following steps:

firstly, performing sand blasting coarsening on the surface of the spring part;

fixing the spring part on a turntable which rotates at a constant speed by using the clamp;

step three, spraying a metal bonding layer;

wherein, the distance between the nozzle opening of the spray gun and the spring part is controlled within 100 plus or minus 5mm in the spraying process;

step four, spraying a heat-proof layer;

wherein, the distance between the nozzle opening of the spray gun and the spring part is controlled within 110 plus or minus 5mm in the spraying process;

wherein the spraying process of the metal bonding layer and the heat-proof layer comprises the following steps:

enabling the spray gun to be parallel to the surface of the spring part, and spraying the outer edge of the spring part from the side;

tilting the lance relative to the spring member in a first direction to move the lance from the edge of the spring member towards the central region at a speed increasing from a first speed at the edge region to a second speed at the central region; moving the spray gun from the central area to the edge, reducing the moving speed from the second speed of the central area to the first speed of the edge area, and then circularly spraying;

tilting the lance relative to the spring member in a second direction to move the lance from the edge of the spring member towards the central region at an increased velocity from the first velocity in the edge region to the second velocity in the central region; moving the spray gun from the central area to the edge, reducing the moving speed from the second speed of the central area to the first speed of the edge area, and then circularly spraying;

enabling the spray gun to be perpendicular to the spring part, enabling the spray gun to move transversely along the spring part at a third speed for spraying, and enabling the spray gun to move longitudinally for a set distance and then move transversely and reversely for spraying when the spray gun moves to the edge of the spring part; until covering the whole spring element surface;

enabling the spray gun to be perpendicular to the spring part, enabling the spray gun to move longitudinally of the spring part at a third speed for spraying, and enabling the spray gun to move transversely for a set distance and then move longitudinally in the opposite direction for spraying when the spray gun moves to the edge of the spring part; until the entire spring element surface is covered.

Preferably, in the fourth step, the spring member is preheated before the thermal protective layer is sprayed.

Preferably, when preheating the spring element, the preheating parameters of the spray gun are set as follows:

the flow rate of argon gas flow is 150 +/-10L/min, the current is 450 +/-8A, and the voltage is 140 +/-10V.

Preferably, the first speed is 0.75m/min and the second speed is 2.5 m/min.

Preferably, the first direction is perpendicular to the second direction.

Preferably, when spraying the metal bonding layer, the spraying parameters of the spray gun are set as follows:

the flow rate of argon gas flow is 240 +/-20L/min, the current is 400 +/-8A, the voltage is 140 +/-5V, the pressure of powder feeding gas is 0.5 +/-0.05 Mpa, the flow rate of the powder feeding gas is 6 +/-1L/min, and the powder feeding amount is 22 +/-2 g/min;

when the heat-proof layer is sprayed, the spraying parameters of the spray gun are set as follows:

the flow rate of argon gas flow is 130 +/-10L/min, the current is 450 +/-8A, the voltage is 140 +/-10V, the pressure of powder conveying gas is 0.45 +/-0.05 Mpa, the flow rate of the powder conveying gas is 7 +/-1L/min, and the powder conveying quantity is 26 +/-2 g/min.

Preferably, in the second step, the rotating speed of the turntable is 75 +/-15 r/min.

The invention has the beneficial effects that:

the spraying method of the thermal barrier coating of the spring part arranged in the separation rocket has high spraying efficiency and stable process; the thermal influence on the matrix is small, and the prepared thermal barrier coating has the advantages of uniform structure, stable structure, no cracking of the coating after burning and better toughness.

The spraying method of the thermal barrier coating of the spring part arranged in the separation rocket is simple in process, is not limited by the size of the workpiece, and has the prospect of being popularized to parts in other fields for protection.

The spring part spraying clamp provided by the invention has the advantages that the structure is simple and reasonable, the installation and the disassembly are convenient, the shielded area in the center of the spring part can be effectively reduced, and the convenience is brought to the subsequent spray supplement; the top is compressed tightly by the nut, and a gap is left between the nut and the spring part after the compression, so that the adhesion of the coating can be prevented.

Drawings

FIG. 1 is a front view of the spring plate of the present invention.

FIG. 2 is a side view of the spring plate of the present invention.

Fig. 3 is a schematic structural diagram of a spraying jig according to a first embodiment of the present invention.

Fig. 4 is a schematic view of a spring plate of a spray jig according to a first embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a second embodiment of a spray coating fixture according to the present invention.

Fig. 6 is a schematic view of a spring plate of a spray jig according to a first embodiment of the present invention.

FIG. 7 is a diagram illustrating a first operation according to the present invention.

FIG. 8 is a diagram illustrating a second operation according to the present invention.

Fig. 9 is a schematic diagram of a third operation according to the present invention.

Fig. 10 is a diagram illustrating a fourth operation according to the present invention.

FIG. 11 is a schematic view of a center post-spray area of a spring element according to the present invention.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

The invention provides a spraying fixture for spring elements in a separation rocket, which comprises a spring element support rod 110, wherein the center of the upper end of the spring element support rod is provided with a connecting hole 111 along the axial direction, as shown in figures 3-6; the lower end of the pressing cap 120 is provided with a threaded connecting rod 121 (thread M10 × 1.5) matched with the connecting hole 111, and the top end of the pressing cap 120 is a pressing end 122. When the spring member 130 needs to be fixed, the connecting rod 121 passes through the center hole of the spring member 130, and then the lower end of the connecting rod 121 is placed in the connecting hole 111, and the pressing cap 120 is pressed downward, so that the spring member 130 is fixed on the supporting rod 110. After compressing tightly, the lower surface of spring part 130 supports and leans on the upper end of spring part bracing piece 110, and there is the clearance about 1mm between the top of the end 122 that compresses tightly of nut 120 and the upper surface of spring part 130, can effectively prevent the coating adhesion. Among them, the spray jig has various embodiments.

In a first embodiment, as shown in fig. 3 to 4, the pressing end 122 of the pressing cap 120 of the spraying fixture is a circular truncated cone, a small diameter end of the circular truncated cone is connected with the connecting rod 121, and a middle portion of the circular truncated cone is clamped in a central hole of the spring member 130, so that the spring member 130 is fixed on the connecting rod 121. The upper end of the connection hole 111 is provided with a circular truncated cone hole matched with the lower end of the pressing end 122, and the lower end part of the pressing end 122 is inserted into the connection hole 111, so that the fixing effect of the spring member 130 is better.

5-6, the pressing end of the pressing cap 120 of the spray coating fixture is stepped, and includes a first step 123 at the lower end and a second step 124 at the upper end, wherein the diameter of the first step 123 is smaller than that of the second step 124. The first step 123 is in the shape of a circular truncated cone, and the first step 123 of the pressing cap is engaged with the center hole of the spring member 130 to fix the spring member 130 to the connecting rod 121. The upper end of the connection hole 111 is provided with a circular truncated cone hole matched with the lower end of the first step 123, and the lower end of the first step 123 is inserted into the connection hole 111 to enable the fixing effect of the spring member 130 to be better.

After the spring part is stably fixed on the clamp and does not shake, the spring part supporting rod 110 is clamped on the three-jaw chuck. During clamping, the supporting rod 110 is determined to be just in time at the coaxial central position of the chuck, so that when the chuck rotates, the clamping apparatus drives the spring part to rotate stably, and the situation of shaking up and down, left and right is avoided.

The invention also provides a spraying method of the thermal barrier coating of the spring part arranged in the separation rocket, wherein the metal bonding layer MCrAlY can be one of NiCoCrAlY, NiCrAlY, CoCrAlY, NiCrAl and other powders; the coating may be prepared using one of the techniques of supersonic flame, supersonic plasma, vacuum plasma, etc. The surface heat-shielding layer may be Y₂O₃-ZrO₂、CaO-ZrO₂、MgO-ZrO₂、CeO-ZrO₂One of (1); the coating can be prepared by one of the technologies of common plasma, vacuum plasma, supersonic plasma, vapor deposition and the like.

Preferably, NiCoCrAlY is selected as the metal bonding layer, y₂O₃-ZrO₂(8% yttria-stabilized zirconia) as a surface heat shield; and a supersonic plasma spray gun is adopted as spraying equipment; the prepared thermal barrier coating has the advantages of uniform structure, stable structure, no cracking of the coating after burning and better toughness. The structure of the spring element is shown in fig. 1-2, and the specific preparation method comprises the following steps:

taking the spring part by wearing the rubber gloves, and cleaning oil stains and spots on the surface of the spring part by clamping absorbent cotton with tweezers and dipping absolute ethyl alcohol with the purity of more than 99.7%.

And step two, measuring the thickness of the substrate (A, B, C position) by using a micrometer, and recording the measured thickness. Wherein, the A position is positioned near the edge of the spring piece, the C position is positioned near the center of the spring piece, and the B position is positioned between the A position and the C position. As shown in fig. 1, the thicknesses at positions a1, a2, and A3 were averaged, the thicknesses at positions B1, B2, and B3 were averaged, and the thicknesses at positions C1, C2, and C3 were averaged.

Step three, adopting a sand blasting machine, and roughening the surface of the spring piece by using 16-20# white corundum sand; setting the sand blasting air pressure to be 0.6 +/-0.1 MPa; the sand blasting distance is 30 +/-5 mm; the sand blasting angle is 70 +/-10 degrees. And sand blasting is carried out until the surface of the spring part is obviously coarsened, and no bright surface or no bright surface is observed under sunlight or lamplight.

After blasting, the substrate (A, B, C position) thickness was measured with a micrometer and the measured thickness was recorded.

And step four, the spring part is fixed on the turntable chuck by adopting the spring part spraying clamp arranged in the separation rocket, so that the spring part is stable and does not shake during rotation, and the rotating speed of the turntable is set to be 75 +/-15 r/min.

And step five, spraying a metal bonding layer.

Firstly, setting the spraying parameters of a spray gun as follows: ar flow rate: 240. + -. 20L/min, current: 400 ± 8A, voltage: 140 plus or minus 5V, powder feeding gas pressure: 0.5 +/-0.05 Mpa, powder feeding gas flow: 6 +/-1L/min, powder feeding amount: 22 + -2 g/min.

Then setting the spraying distance of a spray gun, wherein the spraying distance of the metal bonding layer is 100 +/-5 mm; thereafter, the robot completes the following actions:

the first action is shown in fig. 7: the robot program was set to spray the outer edge of the spring element from the side with the spray gun 200 parallel to the surface of the spring element 130 for a spray time of 10S.

The second action is shown in fig. 8: setting a robot program to enable the spray gun 200 to be inclined to the spring part 130, wherein the nozzle opening of the spray gun 200 and the surface of the spring part form an included angle of 45 +/-5 degrees; the longitudinal motion is changed linearly from one side to the other side through the center. The lance movement speed increased from 0.75m/min in the edge region to 2.5m/min in the central region and then decreased from 2.5m/min in the central region to 0.75m/min in the edge region.

The third action is shown in fig. 9: setting a robot program to enable the spray gun 200 to be inclined to the spring part 130, wherein the nozzle opening of the spray gun 200 and the surface of the spring part form an included angle of 45 +/-5 degrees; the lateral motion is changed linearly from one side to the other side through the center. The lance movement speed increased from 0.75m/min in the edge region to 2.5m/min in the central region and then decreased from 2.5m/min in the central region to 0.75m/min in the edge region.

The above actions are mainly spraying the adhesive layer to the outer edge of the spring element, all the holes and the side edges of the teeth, and the thickness of the adhesive layer coating is up to 0.05 +/-0.01 mm.

The fourth action is shown in fig. 10: the robot program was set so that the nozzle opening of the spray gun 200 was perpendicular to the spring element 130, the spray gun moved at a speed of 20m/min, from the left edge of the spring element laterally to the right edge, to the right edge end point and then longitudinally moved 3mm, from the right edge back to the left edge, to the left edge end point and then longitudinally moved 3 mm. The nozzle reciprocates not from top to bottom until the coating covers the entire front face of the spring member. The spray gun moves longitudinally from the upper edge of the spring part to the lower edge at the moving speed of 20m/min, then moves transversely for 3mm when reaching the end point of the lower edge, returns to the upper edge from the lower edge, and then moves transversely for 3mm when reaching the end point of the upper edge. From left to right until the coating covers the entire front face of the spring element. The distance between the position of the spray gun nozzle opening and the position of the starting point and the position of the ending point of the spring part is 3cm, and the fact that the jet flow is not on the spring part when the jet flow is at the position of the starting point and the position of the ending point is guaranteed. The fourth action is mainly spraying the front surface of the spring part, and the thickness of the coating of the bonding layer is up to 0.1 +/-0.03 mm.

Then, the robot is operated to perform a metal bonding layer coating on the central shaded area 131 (shown in fig. 11) with the nut pressed tightly, wherein the coating thickness is 0.03 +/-0.01 mm.

After the spray coating was completed, the thickness of the metal bond coat (A, B, C location) and the thickness of the central after-spray area coating were measured with a micrometer and the measured thicknesses were recorded.

In the process of spraying the metal bonding layer, the spraying distance is kept unchanged according to the spraying path, and all surfaces of the spring part are coated with the coating.

And step six, spraying a heat-proof layer.

Before the heat-proof layer is sprayed, the spring part needs to be preheated. The preheating parameters are as follows: ar flow rate: 150. + -. 10L/min, current: 450 ± 8A, voltage: 140 + -10V.

After preheating, spraying a heat-proof layer. Wherein, preheating and spraying are continuously completed, and if the spraying process is forced to be stopped, preheating is needed again to perform spraying.

The spraying parameters of the heat-proof layer are as follows: ar flow rate: 130 + -10L/min, current: 450 ± 8A, voltage: 140 +/-10V, powder feeding gas pressure: 0.45 +/-0.05 Mpa, powder feeding gas flow: 7 +/-1L/min, powder feeding amount: 26 plus or minus 2 g/min.

Setting the spraying distance of the heat-proof layer as 110 +/-5 mm, and then completing the following actions by the robot:

The second action is shown in fig. 8: setting a robot program to enable the spray gun 200 to be inclined to the spring part 130, wherein the nozzle opening of the spray gun 200 and the surface of the spring part form an included angle of 45 +/-5 degrees; the front face of the spring element, the holes and the inner sides of the teeth are sprayed from the side. The longitudinal motion is changed linearly from one side to the other side through the center. The lance movement speed increased from 0.75m/min in the edge region to 2.5m/min in the central region and then decreased from 2.5m/min in the central region to 0.75m/min in the edge region.

The third action is shown in fig. 9: setting a robot program to enable the spray gun 200 to be inclined to the spring part 130, wherein the nozzle opening of the spray gun 200 forms an included angle of 45 +/-5 degrees with the surface of the spring part; the front face of the spring element, the holes and the inner sides of the teeth are sprayed from the side. The lateral motion is changed linearly from one side to the other side through the center. The lance movement speed increased from 0.75m/min in the edge region to 2.5m/min in the central region and then decreased from 2.5m/min in the central region to 0.75m/min in the edge region.

The heat-proof layer is sprayed to the outer edges, all holes and the side edges of the teeth of the spring element, and the thickness of the single-side coating reaches 0.1 +/-0.01 mm.

The fourth action is shown in fig. 10: the robot program was set so that the spray gun 200 was perpendicular to the spring element 130, the spray gun moved at a speed of 20m/min, moved from the left edge of the spring element laterally to the right edge, moved 3mm longitudinally to the end point of the right edge, returned from the right edge to the left edge, and moved 3mm longitudinally to the end point of the left edge. And spraying from top to bottom in a transverse reciprocating mode until the coating covers the whole front face of the spring piece. The spray gun moves from the upper edge of the spring part to the lower edge longitudinally at the moving speed of 20m/min, then moves transversely for 3mm when reaching the end point of the lower edge, returns to the upper edge from the lower edge, and then moves transversely for 3mm when reaching the end point of the upper edge. And longitudinally spraying from left to right until the coating covers the whole front surface of the spring element. The distance between the position of the spray gun nozzle opening and the position of the starting point and the position of the ending point of the spring part is 3cm, and the fact that the jet flow is not on the spring part when the jet flow is at the position of the starting point and the position of the ending point is guaranteed. The fourth action is mainly spraying the front surface of the spring part, and the thickness of the single-side heat-proof layer is up to 0.4 +/-0.05 mm.

Then, the operating robot performs the additional spraying of the heat-proof layer on the central shaded area 131 (shown in fig. 11) which is tightly pressed by the nut, wherein the thickness of the coating is 0.05 +/-0.01 mm.

After the spraying was completed, the thickness of the heat-shielding layer (A, B, C position) and the thickness of the central after-spraying area were measured with a micrometer, and the measured thicknesses were recorded.

After the spraying of the front surface of the spring part is finished, the back surface of the spring part is fixed, and then the spraying method provided by the invention is used for spraying the back surface of the spring part.

After the spraying on both sides is finished, the thermal barrier coating prepared by the preparation method of the thermal barrier coating provided by the invention is inspected. The method comprises the following steps: and (3) inspecting the appearance, the coating thickness, the bonding strength, the porosity, the microhardness and the ablation resistance of the coating, and performing flattening test to judge whether the working service performance of the spring piece can be met. As shown in fig. 1, positions D1, D2 and D3 are cutting positions, and after grinding and polishing, the coating thickness, microhardness and porosity were measured at the cross-sectional positions, and the average values were taken as final data. In the figure, positions of B1, B2, B3, E1, E2 and E3 represent the weakest parts of the spring element, and ablation resistance tests are carried out at the positions, and the average values are respectively taken as final test data.

In this embodiment, the performance indexes of the thermal barrier coating prepared on the surface of the spring element are as follows: the appearance is grey white, and the local part is dark grey; the thickness of the single-side coating is 0.5 +/-0.05 mm (the thickness of the metal bonding layer is 0.1 +/-0.02 mm, and the thickness of the heat-proof layer is 0.4 +/-0.05 mm); microhardness is 800 +/-200 HV; the bonding strength is more than or equal to 30 Mpa; porosity 9% ± 3%; the ablation resistance is more than 2S (supersonic speed plasma spray gun is adopted, the experimental parameters are 380 plus or minus 5 current, 135 plus or minus 3 voltage, 120 plus or minus 5L/Min main gas and 50 plus or minus 3mm ablation distance). The spring part flattening test is repeatedly carried out for 10 times, and the coating does not peel off and has no cracks on the surface. Through inspection, the thermal barrier coating prepared by the embodiment can ensure that the spring part can normally work in a high-temperature state.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims

1. A method for spraying a thermal barrier coating of a spring element arranged in a separation rocket is characterized by comprising the following steps:

firstly, performing sand blasting coarsening on the surface of the spring part;

fixing the spring part on a turntable rotating at a constant speed by adopting a clamp;

wherein, the anchor clamps include:

a pressing cap which comprises a pressing end and a connecting rod,

the connecting rod penetrates through a central hole of the spring part arranged in the separation rocket and is connected in the connecting hole in a matching manner, and the pressing cap presses the spring part arranged in the separation rocket to the upper end of the spring part supporting rod;

the pressing end is in a circular truncated cone shape, and the small-diameter end of the pressing end is connected with the connecting rod;

the middle part of the circular truncated cone is clamped in the central hole of the spring part, and the spring part is fixed on the connecting rod; a clearance of about 1mm is formed between the top end of the compressing end and the upper surface of the spring part;

step three, spraying a metal bonding layer;

step four, spraying a heat-proof layer;

2. The method of applying a thermal barrier coating to a spring element housed in a breakaway rocket as recited in claim 1 wherein in step four, the spring element is preheated prior to applying the thermal barrier layer.

3. A method of applying a thermal barrier coating to a spring element housed in a rocket launcher according to claim 2, wherein the preheating parameters of the spray gun are set to:

4. A method of applying a thermal barrier coating to a spring element built-in a rocket according to claim 3 wherein said first speed is 0.75m/min and said second speed is 2.5 m/min.

5. The method of applying a thermal barrier coating to a spring insert within a breakaway rocket as claimed in claim 4 wherein the first direction is perpendicular to the second direction.

6. A method of applying a thermal barrier coating to a spring element built-in a rocket according to claim 5 wherein the spray parameters of the spray gun are set to:

7. The method for thermal barrier coating of a spring element built in a rocket according to claim 6, wherein in step two, the rotation speed of said turntable is 75 ± 15 r/min.