陶瓷排胶过程在制备工艺中能耗占比约20%，传统排胶过程具有耗时长耗能高的缺点。探索一种快速、低能耗、适应不同烧结技术的排胶技术，具有重要的科学价值和实际意义。介质阻挡放电（DBD）技术，以其结构简单和能产生低温等离子体的特性，已经在有机物去除领域得到了广泛应用。本文提出基于介质阻挡放电的陶瓷生坯排胶技术，旨在寻找一种高效、节能的排胶新方案。首先，通过介质阻挡放电实现了氧化锌陶瓷生坯的排胶，将生坯中碳原子含量从1.39%降低至0.08%。在电源频率12 kHz、电压峰峰值22 kV及气隙宽度1 mm的条件下，15 min的DBD处理可达到与传统排胶相当的减重比，同时将耗时和单位体积样品耗能分别降至传统方法的5%和10%。针对排胶过程的作用机理研究表明，气体放电功率和高频电场下生坯介质损耗功率对排胶过程中生坯的温升和粘结剂的去除有显著影响，为后续的工艺改进提供了理论指导。其次，研究了不同电气参数、陶瓷体系、粘结剂体系、成型方式和成型参数对排胶效率的影响规律。实验结果表明，若以样品和介质板均无损坏为前提，以15min内生坯最大减重百分比为目标进行优化，优化的处理参数为电源频率12 kHz，电压峰峰值22 kV，气隙宽度1 mm。若以最大能量利用效率为优化目标，则应在电源谐振频率下进行排胶。对于2 mm厚样品，DBD排胶技术对氧化锌、氧化铝、钛酸钡陶瓷生坯，聚乙烯醇水溶液和聚乙烯醇缩丁醛乙醇溶液作为粘结剂时，均可在20 min内达到与传统排胶相当的减重。在50至150 MPa范围内改变压片压强对氧化锌生坯的DBD排胶效率影响较小，但压强增至200 MPa时，达到稳定减重比所需时间从20 min延长至35 min。对于3D打印氧化锆陶瓷生坯，在传统排胶10%耗时内达到其85%的粘结剂去除。最后，研究了DBD排胶对生坯显微结构及传统烧结、闪烧后微观性能的影响。结果显示，相对于传统排胶，DBD排胶能有效提高氧化锌样品的氧空位浓度，增加介孔体积，减小平均孔径，以及降低表面粗糙度，减弱钛酸钡陶瓷生坯低频色散现象。DBD排胶的氧化锌样品在加热烧结后展现出与传统排胶后加热烧结样品相近的晶粒电阻，但晶界电阻仅为后者的1/4。DBD排胶后氧化锌在稳态电压25 V时室温闪烧3 min，得到致密度超过94%的样品。DBD排胶后闪烧样品相对传统排胶后闪烧样品存在更粗晶粒尺寸和更多气孔残留的问题。
In the preparation process of ceramics, debinding accounts for approximately 20% of the energy consumption. Traditional debinding processes are characterized by long durations and high energy consumption. The exploration of a rapid, low-energy consumption, and versatile debinding technology adaptable to different sintering techniques holds significant scientific value and practical significance. Dielectric Barrier Discharge (DBD) technology, known for its simple structure and ability to generate low-temperature plasma, has been widely applied in the removal of organic substances. This paper proposes a ceramic debinding technology based on DBD technology, aiming to find a new efficient and energy-saving debinding solution.Initially, debinding of zinc oxide ceramic green bodies was achieved through DBD, reducing the carbon content in the green bodies from 1.39% to 0.08%. Under the conditions of a power frequency of 12 kHz, a peak-to-peak voltage of 22 kV, and a gas gap width of 1 mm, a 15-minute DBD treatment could achieve a weight reduction ratio comparable to that of traditional debinding, while reducing the time and energy consumption per unit volume of the sample to 5% and 10% of the traditional method, respectively. Studies on the mechanism of action in the debinding process indicate that both the gas discharge power and the power loss in the green body under a high-frequency electric field significantly affect the temperature rise of the green body and the removal of adhesives during the debinding process. This provides theoretical guidance for subsequent process improvements.Furthermore, the study examined the effects of different electrical parameters, ceramic systems, binder systems, molding methods, and molding parameters on debinding efficiency. The results indicated that, under the premise of no damage to the sample and the dielectric plate, optimizing the treatment parameters to achieve the maximum weight reduction percentage within 15 minutes resulted in an optimal parameter set of a 12 kHz power frequency, 22 kV peak-to-peak voltage, and a 1 mm gap width. If maximizing energy efficiency is the goal, debinding should be conducted at the resonant frequency of the power supply. The DBD debinding technology, applied to zinc oxide, alumina, and barium titanate ceramic green bodies, using polyvinyl alcohol aqueous solution and polyvinyl alcohol butyral ethanol solution as binders, achieved a weight reduction comparable to traditional debinding within 20 minutes. Altering the pressing pressure within the range of 50-150 MPa had a minor impact on the efficiency of DBD debinding of green bodies, but increasing the pressure to 200 MPa extended the time required to achieve a stable weight reduction ratio from 20 to 35 minutes. For 3D printed zirconia ceramics, 85% of the binder was removed within 10% of the time required by traditional debinding methods.Lastly, the effects of DBD debinding on the microstructure of green bodies and their micro-properties after traditional sintering and flash sintering were examined. The results showed that DBD debinding effectively increased the oxygen vacancy concentration, increased the mesopore volume, reduced the average pore size, and decreased the surface roughness in zinc oxide samples, in addition to reducing the low-frequency dispersion phenomenon in barium titanate ceramic green bodies. The zinc oxide samples debinded by DBD exhibited a grain boundary resistance that was only one-fourth of that in samples debinded by traditional methods after heat sintering, while the grain resistance remained similar. Flash sintering for 3 minutes at a steady voltage of 25 V after DBD debinding resulted in zinc oxide samples with a densification exceeding 94%. Samples subjected to flash sintering after DBD debinding exhibit larger grain sizes and more residual porosity compared to samples that undergo traditional debinding followed by flash sintering.
