阅读说明：本技术 一种改进的碳化硅蜂窝陶瓷单元体快速烧成方法 (Improved silicon carbide honeycomb ceramic unit body rapid firing method ) 是由 梁瑞 蔡凯 沈琴娟 于 2021-11-16 设计创作，主要内容包括：本发明公开了一种改进的碳化硅蜂窝陶瓷单元体快速烧成方法,包括以下步骤：将碳化硅蜂窝陶瓷单元体放入烧制炉；在烧制炉中营造烧制环境；进行烧制,以6.0℃/min的升温速率从室温升温至800℃；以2.0℃/min的升温速率从室温升温至1100℃,保温2 h；以0.8℃/min的升温速率升温至1400℃,保温1 h；以0.2℃/min的升温速率升温至1460℃,保温2 h；停止加热,随炉冷却至室温。采用本发明的设计,整体升温时间时间为20.9小时,相对于现有技术的32.5小时,大大提高了烧成效率。(The invention discloses an improved silicon carbide honeycomb ceramic unit body rapid firing method, which comprises the following steps: putting the silicon carbide honeycomb ceramic unit body into a firing furnace; building a firing environment in a firing furnace; firing, and heating from room temperature to 800 ℃ at the heating rate of 6.0 ℃/min; heating from room temperature to 1100 ℃ at the heating rate of 2.0 ℃/min, and keeping the temperature for 2 h; heating to 1400 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 1 h; heating to 1460 ℃ at the heating rate of 0.2 ℃/min, and keeping the temperature for 2 hours; stopping heating, and cooling to room temperature along with the furnace. By adopting the design of the invention, the integral temperature rise time is 20.9 hours, and compared with the 32.5 hours in the prior art, the firing efficiency is greatly improved.)

1. An improved method for quickly firing a silicon carbide honeycomb ceramic unit body is characterized by comprising the following steps: the method comprises the following steps:

1) putting the silicon carbide honeycomb ceramic unit bodies into a baffle splicing structure and putting the baffle splicing structure into a firing furnace;

2) building a firing environment in a firing furnace;

3) heating from room temperature to 800 ℃ at a heating rate of 6.0 ℃/min;

4) heating from room temperature to 1100 ℃ at the heating rate of 2.0 ℃/min, and keeping the temperature for 2 h;

5) heating to 1400 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 1 h;

6) heating to 1460 ℃ at the heating rate of 0.2 ℃/min, and keeping the temperature for 2 hours;

7) stopping heating, and cooling to room temperature along with the furnace.

2. The improved silicon carbide honeycomb ceramic unit cell fast firing method according to claim 1, characterized in that: in the step 1), the baffle splicing structure is used by uniformly distributing a plurality of silicon carbide honeycomb ceramic unit bodies and then stacking the silicon carbide honeycomb ceramic unit bodies layer by layer, and comprises partition plates for separating upper and lower layers of silicon carbide honeycomb ceramic unit bodies and baffle surrounding parts for separating silicon carbide honeycomb ceramic unit body areas on adjacent partition plates on the same layer.

3. The improved silicon carbide honeycomb ceramic unit cell fast firing method according to claim 1, characterized in that: and in the step 2), a refrigerator provided by the firing furnace is started, the temperature of the refrigerator is set to be 20 ℃, an air compressor and an electromagnetic vacuum gauge of the firing furnace are started, then a vacuum pump and a vacuum valve of the firing furnace are started, and when the reading of the electromagnetic vacuum gauge reaches 60 Pa, the vacuum valve and the vacuum pump are sequentially closed.

4. The improved silicon carbide honeycomb ceramic unit cell fast firing method according to claim 3, characterized in that: in the step 2), after the indication of the electromagnetic vacuum gauge reaches 60 Pa, the inflation control cabinet is opened, the argon flow is set to be 100L/min, the methane flow is set to be 900 mL/min, simultaneously, the air valves of the argon and the methane, which are communicated with the furnace body, are opened, the mixed gas of the methane and the argon is inflated into the furnace body, and when the large pressure of the furnace body reaches 0.035 MPa, the air valves of the argon and the methane are closed.

5. The improved silicon carbide honeycomb ceramic unit cell fast firing method according to claim 1, characterized in that: in the step 3), before the temperature is increased, the temperature of the refrigerator is set to 30 ℃, and then ignition firing is carried out.

Technical Field

The invention relates to a honeycomb ceramic sintering method, in particular to an improved silicon carbide honeycomb ceramic unit body rapid sintering method.

Background

The development of industrialization of the automobile industry brings increasingly serious tail gas pollution. With the stricter and stricter control standards of automobile exhaust emission, the exhaust emission of diesel vehicles in various countries including China in the world is becoming stricter.

The method adopted by the honeycomb ceramic firing in the prior art has a slow heating rate, and in order to meet the requirement of a new product of silicon carbide honeycomb ceramic unit body, the firing efficiency needs to be improved on the premise of not reducing the product quality, and the firing purpose of each step needs to be researched so as to pertinently improve the sintering process.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to solve the problem of low firing efficiency of the existing silicon carbide honeycomb ceramic unit body.

The technical scheme is as follows: the invention provides the following technical scheme:

an improved silicon carbide honeycomb ceramic unit body rapid firing method comprises the following steps:

1) putting the silicon carbide honeycomb ceramic unit bodies into a baffle splicing structure and putting the baffle splicing structure into a firing furnace;

2) building a firing environment in a firing furnace;

3) heating from room temperature to 800 ℃ at a heating rate of 6.0 ℃/min;

4) heating from room temperature to 1100 ℃ at the heating rate of 2.0 ℃/min, and keeping the temperature for 2 h;

5) heating to 1400 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 1 h;

6) heating to 1460 ℃ at the heating rate of 0.2 ℃/min, and keeping the temperature for 2 hours;

7) stopping heating, and cooling to room temperature along with the furnace.

The temperature rise rate of 6.0 ℃/min is increased from room temperature to 800 ℃, the temperature rise rate is increased, the temperature rise time from room temperature to 800 ℃ is shortened, and meanwhile, the performance of the product is not obviously influenced.

The temperature is raised from room temperature to 1100 ℃ at the temperature raising rate of 2.0 ℃/min, the temperature is kept for 2 h, the temperature raising rate is accelerated, the reaction temperature of oxygen, water vapor and methane is shortened, and the heat preservation is favorable for full reaction of methane, water vapor and oxygen.

The temperature is raised to 1400 ℃ at the heating rate of 0.8 ℃/min, the temperature is kept for 1 h, the added alumina component can react with the silicon oxide on the surface of the silicon carbide, so that the silicon carbide is exposed as far as possible and is fully combined with the liquid metal silicon, and compared with the old sintering curve, the temperature is raised and combined step by step, the sintering time is shortened, and meanwhile, the product performance is not obviously influenced.

The temperature is increased to 1460 ℃ at the heating rate of 0.2 ℃/min, the temperature is kept for 2 h, the silicon metal begins to melt and absorb a large amount of heat, the temperature in the furnace is uniformly and slowly increased by slowing down the heating rate, the molten silicon metal can be filled into capillary holes accumulated by the silicon carbide to achieve the effect of adhering silicon carbide particles, the heating rate is not too slow, and the molten silicon metal can be excessively filled into the pore channels to cause large holes and small holes to appear, so that the filtering performance of the product is not favorable.

Further, in step 1), the baffle mosaic structure is used by uniformly distributing a plurality of silicon carbide honeycomb ceramic unit bodies and then superposing the silicon carbide honeycomb ceramic unit bodies layer by layer, and the baffle mosaic structure comprises partition plates for separating an upper layer of silicon carbide honeycomb ceramic unit bodies and a lower layer of silicon carbide honeycomb ceramic unit bodies and a baffle surrounding part for separating the silicon carbide honeycomb ceramic unit bodies on the same layer of adjacent partition plates.

Due to different technical problems, the enclosure structure independently applies for invention patents.

Further, in the step 2), a refrigerator of the firing furnace is opened, the temperature of the refrigerator is set to be 20 ℃, an air compressor and an electromagnetic vacuum gauge of the firing furnace are opened, then a vacuum pump and a vacuum valve of the firing furnace are opened, and when the reading of the electromagnetic vacuum gauge reaches 60 Pa, the vacuum valve and the vacuum pump are closed in sequence.

Further, in the step 2), after the indication number of the electromagnetic vacuum gauge reaches 60 Pa, the inflation control cabinet is opened, the flow of argon is set to 100L/min, the flow of methane is set to 900 mL/min, simultaneously, the gas valves of argon and methane leading to the furnace body are opened, mixed gas such as methane and argon is inflated into the furnace body, and when the large pressure of the furnace body reaches 0.035 MPa, the gas inlet valves of argon and methane are closed.

Further, in the step 3), before the temperature is increased, the temperature of the refrigerator is set to 30 ℃, and then the firing is carried out.

Has the advantages that: compared with the prior art, the invention has the advantages that:

by adopting the technical scheme of the invention, the overall time consumption in the firing stage is 20.9 hours, and compared with 32.5 hours in the prior art, the improvement efficiency is more than 50%.

Drawings

FIG. 1 is a broken line schematic view of a heating portion of the present invention;

fig. 2 is a broken line schematic diagram of a heating part of the prior art.

Detailed Description

The present invention is further illustrated by the following figures and specific examples, which are to be understood as illustrative only and not as limiting the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalent modifications thereof which may occur to those skilled in the art upon reading the present specification.

Examples

As shown in fig. 1, an improved silicon carbide honeycomb ceramic unit body rapid firing method comprises the following steps:

1) putting the silicon carbide honeycomb ceramic unit bodies into a baffle splicing structure and putting the baffle splicing structure into a firing furnace;

baffle mosaic structure for with a plurality of carborundum honeycomb ceramic cell units evenly distributed back successive layer stack baffle mosaic structure that uses, baffle mosaic structure is including being used for with the division board of two-layer carborundum honeycomb ceramic cell units from top to bottom to and enclose fender portion that separates the carborundum honeycomb ceramic cell unit district on the adjacent division board of same layer.

2) Building a firing environment in a firing furnace;

and (3) opening a refrigerator of the firing furnace, setting the temperature of the refrigerator to be 20 ℃, opening an air compressor and an electromagnetic vacuum gauge of the firing furnace, then opening a vacuum pump and a vacuum valve of the firing furnace, and closing the vacuum valve and the vacuum pump in sequence when the reading of the electromagnetic vacuum gauge reaches 60 Pa.

And after the indication of the electromagnetic vacuum gauge reaches 60 Pa, opening an inflation control cabinet, setting the flow of argon at 100L/min and the flow of methane at 900 mL/min, simultaneously opening the air valves of argon and methane leading to the furnace body, inflating mixed gas of methane and argon into the furnace body, and closing the air inlet valves of argon and methane when the large pressure of the furnace body reaches 0.035 MPa.

After completion, the refrigerator temperature was set to 30 ℃.

3) Heating from room temperature to 800 ℃ at a heating rate of 6.0 ℃/min;

the temperature rise rate of 6.0 ℃/min is increased from room temperature to 800 ℃, the temperature rise rate is increased, the temperature rise time from room temperature to 800 ℃ is shortened, and meanwhile, the performance of the product is not obviously influenced.

4) Heating from room temperature to 1100 ℃ at the heating rate of 2.0 ℃/min, and keeping the temperature for 2 h;

the temperature is raised from room temperature to 1100 ℃ at the temperature raising rate of 2.0 ℃/min, the temperature is kept for 2 h, the temperature raising rate is accelerated, the reaction temperature of oxygen, water vapor and methane is shortened, and the heat preservation is favorable for full reaction of methane, water vapor and oxygen.

5) Heating to 1400 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 1 h;

the temperature is raised to 1400 ℃ at the heating rate of 0.8 ℃/min, the temperature is kept for 1 h, the added alumina component can react with the silicon oxide on the surface of the silicon carbide, so that the silicon carbide is exposed as far as possible and is fully combined with the liquid metal silicon, and compared with the old sintering curve, the temperature is raised and combined step by step, the sintering time is shortened, and meanwhile, the product performance is not obviously influenced.

6) Heating to 1460 ℃ at the heating rate of 0.2 ℃/min, and keeping the temperature for 2 hours;

the temperature is increased to 1460 ℃ at the heating rate of 0.2 ℃/min, the temperature is kept for 2 h, the silicon metal begins to melt and absorb a large amount of heat, the temperature in the furnace is uniformly and slowly increased by slowing down the heating rate, the molten silicon metal can be filled into capillary holes accumulated by the silicon carbide to achieve the effect of adhering silicon carbide particles, the heating rate is not too slow, and the molten silicon metal can be excessively filled into the pore channels to cause large holes and small holes to appear, so that the filtering performance of the product is not favorable.

7) Stopping heating, and cooling to room temperature along with the furnace.

The overall time of the embodiment is 20 hours and 58 minutes, and the product yield reaches 93 percent.

Comparative example

As shown in fig. 2, a method for firing a silicon carbide honeycomb ceramic unit body comprises the following steps:

1) heating from room temperature to 800 ℃ at a heating rate of 3.5 ℃/min;

2) heating to 1100 deg.C at a heating rate of 1.0 deg.C/min;

3) heating to 1300 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 2 h;

4) heating to 1380 ℃ at a heating rate of 0.5 ℃/min;

5) heating to 1410 ℃ at the heating rate of 0.2 ℃/min;

6) heating to 1460 ℃ at the heating rate of 0.08 ℃/min, and keeping the temperature for 2 hours;

7) stopping heating, and cooling to room temperature along with the furnace.

Heating to 1100 deg.C at a heating rate of 1.0 deg.C/min; the trace oxygen and water in the furnace will start to react with the reducing gas methane.

Heating to 1300 ℃ at the heating rate of 0.8 ℃/min, and keeping the temperature for 2 h; the added aluminum oxide component reacts with silicon oxide on the surface of the silicon carbide, so that the silicon carbide is exposed as far as possible and is fully combined with liquid metal silicon

Heating to 1380 ℃ at a heating rate of 0.5 ℃/min; the furnace temperature is more uniform when the temperature rise rate is reduced.

Heating to 1410 ℃ at the heating rate of 0.2 ℃/min; when the temperature is close to the melting point of silicon, the temperature of the furnace is further reduced at a temperature rise rate, and the temperature is more uniform.

Heating to 1460 ℃ at the heating rate of 0.08 ℃/min, preserving heat for 2 hours, melting the metal silicon to absorb a large amount of heat, slowing the heating rate to ensure that the temperature in the furnace is uniformly and slowly increased, and preserving heat to ensure that the molten metal silicon can be filled into capillary holes accumulated in the silicon carbide to achieve the effect of adhering silicon carbide particles.

The whole time of the comparative example is 32 hours and 25 minutes, and the product yield reaches 92 percent.