Meshed porous electric heating material for built-in porous heater and manufacturing method thereof

Abstract

The invention discloses a meshed porous electric heating material for a built-in porous heater and a manufacturing method thereof. The manufacturing method includes: processing a nickel foam plate into bar-type helical nickel foam, chromizing the bar-type helical nickel foam via solid phase chromizing method, and subjecting the chromized bar-type helical nickel foam to vacuum heat treatment to obtain the meshed porous electric heating material, or subjecting the bar-type helical nickel foam to vacuum heat treatment after the nickel foam is chromized and aluminized to obtain the meshed porous electric heating material. The manufactured electric heating material is a three-dimensional meshed porous structure formed by mutually communicated hollow thin-wall metal edges, is high in porosity, uniform in aperture size and distribution and large in specific surface area, the pores are mutually communicated and good in air permeability , thickness of the thin-wall metal is controllable, and a higher electrical resistivity can be obtained. The meshed porous electric heating material can be used for manufacturing the integrated heating core of the built-in porous heater.

Description

technical field

[0001] The invention relates to an electrothermal material in a thermal control facility of an aerospace vehicle attitude and orbit control thruster and a preparation method thereof, in particular to a mesh porous electrothermal material used for a built-in porous heater and a preparation method thereof. Background technique

[0002] my country Aerospace Science and Technology Corporation began to launch a series of space vehicles including earth observation satellites and spacecrafts at the end of the 20th century. Some of them are low-orbit, long-life, three-axis stable earth observation satellites. At present, most of these satellites use single-component propulsion However, in the catalytic decomposition of hydrazine, the requirements for the catalyst are strict, not only must it have catalytic activity and a large surface area, but also require high temperature resistance, thermal shock resistance, and non-poisoning , usually using porous ceramic particles...

Examples

preparation example Construction

[0024] 1. Preparation of mesh porous nickel-chromium alloy electric heating material:

[0025] 1. Preparation and processing of nickel foam board

[0026] According to the internal space size and technical index requirements of the foam heater, determine the specifications of the foamed nickel plate through calculation, that is, surface density, pore size, thickness, porosity, etc., determine the apparent resistivity of the foamed nickel, and select a good quality foamed nickel plate . CNC wire cutting machine is used to process it into thin strips of the required size. During the cutting process, it is necessary to ensure that the nickel foam plate remains flat to ensure the uniformity of the size of the strip-shaped nickel foam; tap water is used as the cutting fluid, and nickel foam should be avoided as much as possible. Contamination, manual feeding, increased cutting rate. After the nickel foam is cut, wind it into a spiral shape, then add it to the boiling water contai...

Embodiment 1

[0045] Preparation of mesh porous nickel-chromium alloy electrothermal material with chromium mass fraction of 20%:

[0046] The internal size of the built-in porous heater is only Φ15×25mm, and the resistance of the mesh porous electric heating material in this space should reach 36.5±3.5Ω. The selected area density is 320g / m 2 1. A nickel foam plate with a pore diameter of 110PPI, a porosity of 97.6%, and a size of 1000mm×500mm×1.5mm has a resistivity of about 8.66μΩ.m. It is processed into a thin strip of 1000mm×1.2mm×1.5mm by a CNC wire cutting machine, and then wound into a spiral shape on a thin ceramic tube of Φ1.0mm, with a pitch of 0.5mm and a diameter of 1.0mm. The total length of nickel foam is about 220mm. Clean and dry, weigh and measure the resistance, the resistance value is about 4.5~5.0Ω.

[0047] Chromizing at 1000°C. The penetrating agent used is composed of 1200-mesh high-purity alumina powder, 300-mesh high-purity chromium powder and analytically pure ...

Embodiment 2

[0050] Preparation of mesh-like porous nickel-chromium-aluminum alloy electrothermal material with chromium mass fraction of 20% and aluminum mass fraction of 5%:

[0051] On the basis of Example 1, the mesh porous nickel-chromium alloy sample without vacuum heat treatment after solid-phase chromizing is placed in the aluminizing agent for aluminizing, and the used infiltrating agent consists of 1200 mesh high-purity alumina powder, chemical Pure aluminum-nickel alloy powder and analytically pure ammonium chloride were mixed and ground thoroughly, the mass ratio was 82:15:3, and the basic operation was the same as that in Example 1. Insulate at 750°C for 30 minutes, wash and dry the sample after cooling, and weigh it; calculate the aluminum mass fraction to be 5-6%, measure the resistance and size, the resistance value is about 15-19Ω, and the calculated resistivity is 33-37μΩ.m; then Put the aluminized sample into a vacuum furnace with a vacuum degree of 5×10-3Pa, raise the t...

technical field

[0001] The invention relates to an electrothermal material in a thermal control facility of an aerospace vehicle attitude and orbit control thruster and a preparation method thereof, in particular to a mesh porous electrothermal material used for a built-in porous heater and a preparation method thereof. Background technique

[0002] my country Aerospace Science and Technology Corporation began to launch a series of space vehicles including earth observation satellites and spacecrafts at the end of the 20th century. Some of them are low-orbit, long-life, three-axis stable earth observation satellites. At present, most of these satellites use single-component propulsion However, in the catalytic decomposition of hydrazine, the requirements for the catalyst are strict, not only must it have catalytic activity and a large surface area, but also require high temperature resistance, thermal shock resistance, and non-poisoning , usually using porous ceramic particles...

Examples

preparation example Construction

[0024] 1. Preparation of mesh porous nickel-chromium alloy electric heating material:

[0025] 1. Preparation and processing of nickel foam board

[0026] According to the internal space size and technical index requirements of the foam heater, determine the specifications of the foamed nickel plate through calculation, that is, surface density, pore size, thickness, porosity, etc., determine the apparent resistivity of the foamed nickel, and select a good quality foamed nickel plate . CNC wire cutting machine is used to process it into thin strips of the required size. During the cutting process, it is necessary to ensure that the nickel foam plate remains flat to ensure the uniformity of the size of the strip-shaped nickel foam; tap water is used as the cutting fluid, and nickel foam should be avoided as much as possible. Contamination, manual feeding, increased cutting rate. After the nickel foam is cut, wind it into a spiral shape, then add it to the boiling water contai...

Embodiment 1

[0045] Preparation of mesh porous nickel-chromium alloy electrothermal material with chromium mass fraction of 20%:

[0046] The internal size of the built-in porous heater is only Φ15×25mm, and the resistance of the mesh porous electric heating material in this space should reach 36.5±3.5Ω. The selected area density is 320g / m 2 1. A nickel foam plate with a pore diameter of 110PPI, a porosity of 97.6%, and a size of 1000mm×500mm×1.5mm has a resistivity of about 8.66μΩ.m. It is processed into a thin strip of 1000mm×1.2mm×1.5mm by a CNC wire cutting machine, and then wound into a spiral shape on a thin ceramic tube of Φ1.0mm, with a pitch of 0.5mm and a diameter of 1.0mm. The total length of nickel foam is about 220mm. Clean and dry, weigh and measure the resistance, the resistance value is about 4.5~5.0Ω.

[0047] Chromizing at 1000°C. The penetrating agent used is composed of 1200-mesh high-purity alumina powder, 300-mesh high-purity chromium powder and analytically pure ...

Embodiment 2

[0050] Preparation of mesh-like porous nickel-chromium-aluminum alloy electrothermal material with chromium mass fraction of 20% and aluminum mass fraction of 5%:

[0051] On the basis of Example 1, the mesh porous nickel-chromium alloy sample without vacuum heat treatment after solid-phase chromizing is placed in the aluminizing agent for aluminizing, and the used infiltrating agent consists of 1200 mesh high-purity alumina powder, chemical Pure aluminum-nickel alloy powder and analytically pure ammonium chloride were mixed and ground thoroughly, the mass ratio was 82:15:3, and the basic operation was the same as that in Example 1. Insulate at 750°C for 30 minutes, wash and dry the sample after cooling, and weigh it; calculate the aluminum mass fraction to be 5-6%, measure the resistance and size, the resistance value is about 15-19Ω, and the calculated resistivity is 33-37μΩ.m; then Put the aluminized sample into a vacuum furnace with a vacuum degree of 5×10-3Pa, raise the t...

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