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CN-121990818-A - High-temperature quick firing method for alumina ceramic

CN121990818ACN 121990818 ACN121990818 ACN 121990818ACN-121990818-A

Abstract

The invention relates to the technical field of advanced ceramic material preparation, in order to solve the problems that the sintering period of the traditional gas furnace is too long and can not meet the urgent production requirement, and the quality problem occurs when the traditional process is directly transplanted to an electric furnace, the invention provides a high-temperature quick-sintering method of alumina ceramic, which adopts the heating rate of 1-3 ℃ per minute to ensure that the transition from room temperature to target sintering temperature is completed in a short time, simultaneously ensures the stable progress of the densification, grain growth and other processes of ceramic materials through accurate temperature control in each stage, realizes the short-period high-quality sintering from green bodies to finished products, can complete the preparation of high-quality products in 72-96 hours, and is particularly suitable for the production mode of small batch, multiple varieties and urgent orders; the parameter adjustment is flexible, can be rapidly optimized according to the product requirement, and has strong adaptability to the type and specification of the electric furnace.

Inventors

  • WU JIANGHAO
  • CHENG DONGYUAN
  • WANG FU
  • ZHANG WEN
  • WU YUNKAI

Assignees

  • 浙江富乐德半导体材料科技有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The high-temperature rapid-firing method for the alumina ceramic is characterized by comprising the following steps of: Adding an organic binder and a sintering aid into alumina powder, and performing spray granulation, and then adopting dry pressing and isostatic pressing to prepare a green body, wherein the density of the green body reaches 45-65% of theoretical density; step two, placing the green body into a high-temperature electric furnace, and executing the following continuous temperature program; and thirdly, grinding, polishing and finishing as required after sintering.
  2. 2. The method for high-temperature rapid firing of alumina ceramic according to claim 1, wherein the alumina powder has a purity of not less than 95% and an average particle diameter of 0.5-3.0 μm.
  3. 3. The method for high-temperature rapid firing of alumina ceramic according to claim 1, wherein the organic binder is selected from polyvinyl alcohol or polyacrylic acid, and the use amount is 0.5-2% of the mass of the alumina powder.
  4. 4. The method for high-temperature rapid firing of alumina ceramic according to claim 1, wherein the sintering aid is selected from magnesium oxide and is used in an amount of 0.5-1% by mass of the alumina powder.
  5. 5. The method according to claim 1, wherein the second step comprises a de-binding stage, a medium-speed heating stage, a preliminary densification stage, a grain growth stage, and a rapid cooling stage.
  6. 6. The method according to claim 1 or 5, wherein the de-binding stage is performed by heating from room temperature to 120 ℃ at a rate of 1-3 ℃ per minute, heating from 120 ℃ to 350 ℃ at a rate of 1-3 ℃ per minute, heating from 350 ℃ to 800 ℃ at a rate of 1-3 ℃ per minute, and maintaining for 300-420 minutes.
  7. 7. The method for quickly heating the alumina ceramic at high temperature according to claim 1 or 5, wherein the medium-speed heating stage is to heat up to 1100 ℃ at a rate of 1-3 ℃ per minute, and the heat-preserving time is 2-4 hours.
  8. 8. A method of high temperature rapid firing of alumina ceramic according to claim 1 or 5 wherein the preliminary densification stage is heated to 1450 ℃ at a rate of 1-3 ℃ per minute for a period of 2-4 hours.
  9. 9. The method for rapid firing of alumina ceramic according to claim 1 or 5, wherein the grain growth stage is to heat up to 1640 ℃ at a rate of 1-3 ℃ per minute, and the holding time is 0.5-2 hours.
  10. 10. A method for rapid firing of alumina ceramics at high temperature according to claim 1 or 5, wherein the rapid cooling stage is to decrease the sintering temperature from 3-6deg.C/min to 1550 deg.C, keep the temperature for 8-12 hours, and then decrease the temperature from 1550 deg.C to room temperature at 1-3deg.C/min.

Description

High-temperature quick firing method for alumina ceramic Technical Field The invention relates to the technical field of advanced ceramic material preparation, in particular to a method for rapidly sintering alumina ceramic by adopting a high-temperature electric furnace. Background Alumina ceramic is used as important engineering ceramic material and is widely used in electronic, mechanical, chemical and other fields. Although the traditional gas furnace sintering process can obtain products with stable performance, the sintering period is usually 10-14 days, and the sintering period comprises a plurality of stages of slow temperature rise, long-time heat preservation, sectional cooling and the like. The long-period sintering mode has the following remarkable defects that 1. The production efficiency is low, and the requirements of modern manufacturing such as emergency orders, rapid sample trial production, small batch and multiple varieties can not be met. 2. The energy consumption is large, a large amount of energy is consumed in the long-time heat preservation stage, and the production cost is increased. 3. The response speed is slow, and the service life from order receiving to product delivery is too long, so that the customer satisfaction degree and the market competitiveness are affected. 4. The process flexibility is poor, the traditional process parameters are solidified, and the rapid adjustment according to the specification of the product is difficult. In the prior art, for example, chinese patent document CN 107032765B discloses a method for rapidly sintering alumina ceramics at high temperature, which realizes rapid high-temperature solid-phase sintering under a non-pressure condition to obtain the alumina ceramics, wherein the temperature rising speed of the patent is 500-600 ℃ per second, the rapid temperature rising time is 3-4 s, and the short heat preservation time is 1-2 min. However, the rapid temperature rise causes cracking of the blank, and the insufficient heat preservation time causes incomplete densification and other problems. Along with the development of the high-temperature electric furnace technology, the high-temperature electric furnace has the advantages of (1) high temperature rising speed which can reach 10-20 ℃ per minute, (2) accurate temperature control, and can realize accurate execution of a complex temperature curve, (3) natural air environment of furnace atmosphere without an additional atmosphere control system, and (4) long-term stable operation of a heating element (silicon-molybdenum rod) in an oxidizing atmosphere. However, when the conventional long-period sintering process is directly applied to the rapid sintering of an electric furnace, the problems of (1) cracking of a blank caused by rapid temperature rise, (2) incomplete densification caused by insufficient heat preservation time, (3) thermal stress cracking caused by too rapid cooling, and (4) uneven microstructure and unstable performance can occur. Therefore, development of a rapid sintering method of aluminum oxide ceramics specially aiming at the characteristics of a high-temperature electric furnace is urgently needed, the sintering period is shortened to 3-4 days from the traditional two weeks on the premise of ensuring the product quality, and the requirement of the modern manufacturing industry on rapid response is met. Disclosure of Invention In order to solve the problems that the sintering period of the traditional gas furnace is too long and the emergency production requirement cannot be met, and the quality problem occurs when the traditional process is directly transplanted to an electric furnace, the invention provides the high-temperature rapid sintering method for the alumina ceramic, which can finish the preparation of high-quality products within 72-96 hours. The technical scheme of the invention is as follows, the high-temperature rapid firing method of the alumina ceramic is based on the firing method of the alumina ceramic, in the air environment of a high-temperature electric furnace, a rapid temperature system is adopted, the temperature rising rate of 1-3 ℃ per minute is adopted, the transition from room temperature to target sintering temperature is ensured to be completed in a short time, meanwhile, the stable progress of the densification, grain growth and other processes of ceramic materials is ensured through accurate temperature control in each stage, and the short-period high-quality sintering from a green body to a finished product is realized, and the method specifically comprises the following steps: Step one, preparing raw materials and a green body Adding an organic binder and a sintering aid into alumina powder, and performing spray granulation, and then adopting dry pressing and isostatic pressing to prepare a green body, wherein the density of the green body reaches 45-65% of theoretical density. Preferably, the purity of the alumina powder is more than or equ