Mold and method for preparing ceramic matrix composite coil spring of SiC fiber

A helical spring and composite material technology, which is applied in the field of ceramic matrix composite helical spring molds, can solve the problems of poor reliability and short life, and achieve the effects of high molding efficiency, high molding precision, and shortened production cycle

Inactive Publication Date: 2019-09-27
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to avoid the deficiencies of the prior art, the present invention proposes a mold and method for preparing SiC fiber cerami

Method used

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  • Mold and method for preparing ceramic matrix composite coil spring of SiC fiber
  • Mold and method for preparing ceramic matrix composite coil spring of SiC fiber
  • Mold and method for preparing ceramic matrix composite coil spring of SiC fiber

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preparation example Construction

[0032] The technical scheme adopted by the present invention to solve its technical problems: a method for preparing a ceramic matrix composite coil spring based on SiC fibers, which is characterized in that it includes the following steps:

[0033] Step 1, quasi-one-dimensional fiber rope parameter design. According to the spring specifications, determine the diameter of the fiber rope, based on this to design and determine the number of SiC fiber bundles.

[0034] Step 2: Prepare a round tube mold, and the diameter of the round tube refers to the size specification of the coil spring. Holes are made on the surface of the circular tube mold as a guide channel for the deposition gas of the ceramic matrix, and the mold material is made of high-temperature resistant graphite material.

[0035] Step 3: Wrap the quasi-one-dimensional fiber rope in the spiral groove of the high-temperature mold and fix it to complete the shaping of the coil spring.

[0036] Step 4, preparing a BN...

Embodiment 1

[0043] (1) Prepare a quasi-one-dimensional fiber rope with a diameter of 2 mm.

[0044] (2) Prepare a circular tube-shaped high-temperature mold with a diameter of 30 mm, and wrap the fiber rope in the spiral groove on the surface of the mold to complete the preparation of the coil spring preform.

[0045] (3) Place the prefabricated blank in the CVI deposition furnace, keep a vacuum of 10-3Pa, deposit a BN interface layer on the surface of the SiC fiber, NH3 is used as a nitrogen source, BCl3 provides a boron source, H2 is a dilution gas, NH3, The volume flows of BCl3 and H2 are 500ml / min, 1000ml / min and 2000ml / min respectively, the deposition temperature is 1200℃, the deposition time is 20h, and the thickness of deposited BN is 50μm.

[0046] (4) Place the prefabricated body prepared in step (3) in the CVI deposition furnace, keep the gas pressure in the deposition furnace at 10-2Pa, and start the densification preparation of the SiC matrix. The deposition temperature is 11...

Embodiment 2

[0052] (1) Prepare a quasi-one-dimensional fiber rope with a diameter of 0.7mm.

[0053] (2) Prepare a circular tube-shaped high-temperature mold with a diameter of 20 mm, and wrap the fiber rope in the spiral groove on the surface of the mold to complete the preparation of the coil spring preform.

[0054] (3) Place the prefabricated blank in the CVI deposition furnace, keep a vacuum of 10-3Pa, deposit a BN interface layer on the surface of the SiC fiber, NH3 is used as a nitrogen source, BCl3 provides a boron source, H2 is a dilution gas, NH3, The volume flows of BCl3 and H2 are 500ml / min, 1000ml / min and 2000ml / min respectively, the deposition temperature is 1100℃, the deposition time is 30h, and the thickness of deposited BN is 80μm.

[0055] (4) Place the prefabricated body prepared in step (3) in the CVI deposition furnace, keep the gas pressure in the deposition furnace at 10-2Pa, and start the densification preparation of the SiC matrix. The deposition temperature is 1...

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Abstract

The invention relates to a mold and method for preparing a ceramic matrix composite coil spring of SiC fiber. The method comprises the following steps: firstly, adopting silicon carbide fiber to prepare a quasi-one-dimensional fiber braided rope, and adopting the SiC fiber rope to prepare a coil spring preform; preparing a BN interfacial layer on the surface of the SiC fiber of the preform by adopting a chemical vapor infiltration method, then pre-densifying the coil spring preform, and processing coil spring blades on a multi-axis CNC machine tool by adopting special cutters of cubic boron nitride or diamond; finally preparing an anti-oxidation coating. The beneficial effects that the structure is simple, the designability is strong, the molding efficiency is high, the preparation cost is low, and the like are achieved. The coil spring provided by the invention is molded by near-size, and is high in molding precision and less in removal amount of blank materials; the diameter of prepared SiC/SiC spiral filament is 0.5-5 mm, and the shear strength range of a spring spiral filament material is 200-500 MPa; the coefficient of the spring stiffness is 10-50 N/mm.

Description

technical field [0001] The invention belongs to a method for preparing a helical spring, and relates to a mold and a method for preparing a helical spring of SiC fiber ceramic matrix composite material. Background technique [0002] With the development of high-speed aircraft, the heat that the aircraft's thermal protection system bears increases sharply. The high-temperature seal between the outer heat-shielding panels of an aircraft plays a decisive role in the safety of the aircraft. Springs are common parts that provide prestress between heat shield panels. At present, the temperature resistance of traditional metal elastic materials will not exceed 800°C, and the stiffness of metal elastic elements will drop sharply as the temperature increases, seriously affecting the safety of equipment in service; [0003] Ceramic matrix composites have the advantages of low density, high specific stiffness, excellent wear resistance, high service temperature, high thermal conducti...

Claims

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Application Information

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IPC IPC(8): C04B35/573C04B35/628C04B35/80C04B41/87
CPCC04B35/806C04B35/573C04B35/62868C04B35/62884C04B35/62897C04B41/009C04B41/5059C04B41/87C04B2235/5244C04B2235/616C04B2235/96C04B41/4529
Inventor 刘持栋刘小冲王东董宁孙肖坤涂建勇陈旭何江怡王义洪王东英郭宏强成来飞
Owner NORTHWESTERN POLYTECHNICAL UNIV
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