阅读说明：本技术 一种制备内cvd沉积立体式复合陶瓷加热器的方法 (method for preparing internal CVD deposition three-dimensional composite ceramic heater ) 是由 刘汝强 王殿春 孙蕾 吴思华 赵旭荣 于 2019-10-21 设计创作，主要内容包括：本发明涉及一种制备内CVD沉积立体式复合陶瓷加热器的方法,属于加热器技术领域,加热器包含PBN基体、PG涂层电路以及PBN涂层保护层；通过化学气相沉积制备PBN基体,再在PBN基体内表面沉积PG涂层,通过雕刻PG涂层制备电路,再沉积PBN涂层保护层,最终得到内表面加热的加热器,大幅度提高加热器加热的均匀性,热量损失小,耗能低。(The invention relates to a method for preparing an internal CVD deposition three-dimensional composite ceramic heater, belonging to the technical field of heaters, wherein the heater comprises a PBN substrate, a PG coating circuit and a PBN coating protective layer; the heater with the heating inner surface is finally obtained by preparing a PBN substrate through chemical vapor deposition, then depositing a PG coating on the inner surface of the PBN substrate, preparing a circuit through engraving the PG coating, and then depositing a PBN coating protective layer, so that the heating uniformity of the heater is greatly improved, the heat loss is low, and the energy consumption is low.)

1. A method for preparing an internal CVD deposition three-dimensional composite ceramic heater is characterized in that the heater comprises a PBN substrate, a PG coating circuit and a PBN coating protective layer from outside to inside, the PBN substrate is hollow, the PG coating circuit is arranged on the inner wall of the PBN substrate, and the PBN coating protective layer is attached to the PG coating circuit, and the preparation method comprises the following steps:

(1) Preparing a heater PBN matrix: introducing gas containing a nitrogen source and a boron source into a chemical vapor deposition furnace, and depositing on the surface of a mold to form a PBN matrix;

(2) And (3) deposition of a PG coating: demoulding the PBN substrate discharged from the furnace, wrapping the outer surface of the PBN substrate by using a tool, putting the PBN substrate into a chemical vapor deposition furnace, introducing methane or propane, and depositing a PG coating on the inner surface of the PBN substrate;

(3) Engraving a circuit pattern: finely carving a PG coating circuit pattern on the PG coating on the inner surface of the PBN by using a laser or machining mode;

(4) depositing a PBN coating protective layer: and (4) placing the heater semi-finished product with the circuit pattern carved in the step (3) into a chemical vapor deposition furnace, and depositing a PBN coating protective layer.

2. The method of claim 1, wherein in the step (1), the temperature is 1800 ℃, the pressure is 200Pa, and the gas ratio is NH 3: BCl3 ═ 2: 1, chemical vapor deposition was performed.

3. The method of claim 1, wherein in the step (1), the PBN substrate made by the mold is cylindrical or hollow truncated cone or cylindrical with variable diameter.

4. The method of claim 1, wherein in the step (1), the PBN substrate has a diameter of 30mm to 300mm, a height of 50mm to 500mm, a thickness of 0.1mm to 5mm, and an inner diameter deviation of 0.05mm or less.

5. The method of claim 1, wherein the PG coating is deposited at 1700 ℃ and 500Pa in step (2).

6. The method of claim 1, wherein the PG coating is deposited to a thickness of 100 μm in step (2).

7. The method according to claim 1, wherein in step (3), the PG coating circuit pattern comprises a strip-shaped circuit which is folded back and forth, the folded back portion of the strip-shaped circuit is a folded back portion, the PG coating circuit comprises at least two folded back portions, two adjacent folded back portions are not communicated with each other, a gap is left between the two adjacent folded back portions, and two ends of the strip-shaped circuit are provided with electrodes.

8. The method of claim 7, wherein in the step (3), the widths of the bar circuits of the PG coating circuit patterns are both 12mm, the gaps between two adjacent bar circuits are both 2mm, there are 6 folded portions, and the gaps between two adjacent folded portions are both 3 mm; two end points of the circuit are respectively provided with a circular through hole electrode, the outer diameter of the circular through hole electrode is 20mm, and the diameter of the circular through hole electrode is 8 mm.

9. The method for preparing an internal CVD deposited three-dimensional composite ceramic heater according to claim 1, wherein in the step (4), the PBN coating protection layer is deposited under the following conditions: temperature 1600 ℃, pressure 100Pa, gas ratio BCl 3: NH3 is 1: 3.

10. the method of claim 1, wherein in step (4), the PBN coating protective layer has a thickness of 50-500 μm.

Technical Field

The invention relates to a method for preparing an internal CVD deposition three-dimensional composite ceramic heater, in particular to a Pyrolytic Boron Nitride (PBN) -Pyrolytic Graphite (PG) three-dimensional composite heater, and belongs to the technical field of heaters.

Background

With the continuous development of the industrial level, the requirement of the heater heating uniformity in many technical fields is higher and higher. The three-dimensional composite heaters on the market are heated on the outer surface of a base body, the heating mode has the defects of more heat dissipation of the outer surface and high energy consumption of the heater, and the temperature uniformity of an internal heating area of the heater is poor due to the difference of heat conduction of different areas of the base body and the difference of heat dissipation of different areas of the outer surface. The present applicant has also filed a patent application (application No. 201810752512.1) disclosing a cylindrical composite heater, which is not meeting the market demand, and there is a need to find another method for improving the heating uniformity of the three-dimensional composite heater.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the method for preparing the internal CVD deposition three-dimensional composite ceramic heater, and the heater prepared by the method can obviously improve the heating uniformity of the heater, and simultaneously can reduce the heat loss and the energy consumption.

The technical scheme of the invention is as follows:

A method for preparing an internal CVD deposition three-dimensional composite ceramic heater, wherein the heater comprises a PBN substrate, a PG coating circuit and a PBN coating protective layer from outside to inside, the PBN substrate is hollow, the inner wall of the PBN substrate is provided with the PG coating circuit, and the PBN coating protective layer is attached to the PG coating circuit, and the preparation method comprises the following steps:

(1) Preparing a heater PBN matrix: introducing gas containing a nitrogen source and a boron source into a chemical vapor deposition furnace, and depositing on the surface of a mold to form a PBN matrix;

(2) And (3) deposition of a PG coating: demoulding the PBN substrate discharged from the furnace, wrapping the outer surface of the PBN substrate by using a tool, putting the PBN substrate into a chemical vapor deposition furnace to prevent the PG coating from being coated on the outer surface of the PBN substrate, then introducing methane or propane, and depositing the PG coating on the inner surface of the PBN substrate;

(3) Engraving a circuit pattern: finely carving a PG coating circuit pattern on the PG coating on the inner surface of the PBN by using a laser or machining mode;

(4) Depositing a PBN coating protective layer: and (4) placing the heater semi-finished product with the circuit pattern carved in the step (3) into a chemical vapor deposition furnace, and depositing a PBN coating protective layer to protect the PG coating circuit.

Preferably, in step (1), the reaction is carried out at a temperature of 1800 ℃, a pressure of 200Pa, a gas ratio NH 3: BCl3 ═ 2: 1, chemical vapor deposition was performed.

Preferably, in the step (1), the PBN substrate manufactured by the mold is cylindrical, hollow truncated cone-shaped, or cylindrical with a variable diameter.

Preferably, in the step (1), the PBN matrix has a diameter of 30mm-300mm, a height of 50mm-500mm and a thickness of 0.1mm-5mm, and the deviation of the inner diameter can be controlled within 0.05mm by controlling the PBN matrix mould

preferably, in step (2), the PG coating is deposited at 1700 ℃ and 500 Pa.

Preferably, in step (2), the PG coating is deposited to a thickness of 100 microns.

preferably, in step (3), the PG coating circuit pattern includes a bar circuit that is folded back and forth, the folded back portion of the bar circuit is a folded back portion, the PG coating circuit includes at least two folded back portions, two adjacent folded back portions are not connected, a gap is left between the two adjacent folded back portions, and two end points of the bar circuit are provided with electrodes.

Except the folding part, other strip circuits are arranged along the circumference of the PBN substrate or in the direction similar to the circumference, the widths of the strip circuits can be the same or different, and gaps among the strip circuits can be the same or different.

preferably, in the step (3), the widths of the strip circuits of the PG coating circuit pattern are both 12mm, the gaps between two adjacent strip circuits are both 2mm, there are 6 folded portions, and the gaps between two adjacent folded portions are both 3 mm; two end points of the circuit are respectively provided with a circular through hole electrode, the outer diameter of the circular through hole electrode is 20mm, and the diameter of the circular through hole electrode is 8 mm.

preferably, in the step (4), the conditions for depositing the PBN coating protective layer are as follows: temperature 1600 ℃, pressure 100Pa, gas ratio BCl 3: NH3 is 1: 3.

preferably, in step (4), the thickness of the PBN coating protective layer is 50 microns to 500 microns.

The invention has the beneficial effects that:

1. by using the preparation method, the inner surface of the PBN substrate does not need to be polished, the inner diameter can reach the deviation within 0.05mm, the surface damage caused by polishing of the PBN substrate is avoided, the risk of cracking and delamination of the heater is reduced, the yield of the heater is greatly improved, the polishing step is omitted, and the cost and the time are reduced and shortened.

2. The PG coating circuit is positioned on the inner surface of the PBN substrate, the PG coating heating circuit is closer to a heated area, the uniformity of heat of an internal heating area is better controlled, the PG coating circuit is prepared by engraving the circuit, and simultaneously, the heat generated by the PG coating circuit is greatly reduced due to the action of the PBN substrate, so that the heating uniformity of the heater is greatly improved, the heat loss is low, and the energy consumption is low.

Drawings

FIG. 1 is a view showing the overall construction of a heater prepared according to the present invention;

FIG. 2 is an expanded view of a heater PG coating pattern prepared in accordance with the present invention;

Wherein, 1, electrode, 2, folded part.

Detailed Description

the present invention will be further described by way of examples, but not limited thereto, with reference to the accompanying drawings.