烧成陶瓷用微波烧成炉

采用微波烧成炉进行陶瓷烧成试验。微波加热是利用材料自身的发热进行加热的方法，与原来的外部加热法不同，一是加热速度比电阻加热或烧气体燃料加热快；二是能对材料进行选择加热。利用微波烧成的砖质量与用气体燃料烧成的相同或更高。另外，从内部加热特性来看，它能缩短保温时间。在混合炉中进行了氧化铝陶瓷烧成试验，利用气体燃料和微波并用的烧成效果，可以促进脱结合剂，烧成时间比只采用气体燃料烧成或只采用微波烧成大幅度缩短了。     

ZTA陶瓷微波烧结研究

采用２．４５ＧＨＺ，５ＫＷ功率源的多模腔微波烧结装置对１５％（按质量计，下同）ＺｒＯ２（２．５％ｍｏｌ）Ｙ２Ｏ３＋８５％Ａｌ２Ｏ３的ＺＴＡ陶瓷的微波加热烧结特性，显微结构和力学性能作了较系统的研究，并与常规烧结进行比较，通过合理的保温结构设计和良好的爱人本负载阻抗匹配实现了微波快速绕结。实验发现：在多模腔中ＺＴＡ陶瓷坯体经微波加热约３０ｍｉｎ至１５４０℃保温２０ｍｉｎ（共约５０ｍｉｎ），其密度可达     

微波加热技术应用于陶瓷行业需要解决的几个问题

较详细地讨论了微波加热技术应用于陶瓷行业需要解决的几个问题,指出了微波加热技术在陶瓷行业的应用前景.     

陶瓷材料微波焊接装置研制

利用微波能在高温下焊接陶瓷是近年迅速发展的一门新技术。微波焊接具有接强度高升温速度快，局部加热，易于控制温度等优点。我们在吸收和消化国外近十年在微波焊接技术方面精华的基础上加以改进，研制成功了一台微波焊接装置，并利用这套装置成功地进行了氧化铝陶瓷的微波焊接研究。     

利用普通微波炉日生产出超导陶瓷

今年在日本静冈县滨松市召开的超导体研讨会上，日本东北大学工科教授小池洋工的科研小组发表了他们利用一般家用微波炉制造超导体的实验结果。以往生产高温超导陶瓷，都是将组成超导的陶瓷材料在近］000C高温的电炉中加热合成，这种合成法很难生产电线、线圈一类的线形超导陶瓷。微波炉是利用微波这种电磁波，使包含在食品中的水分子进行振动，从而达到加热食品的目的。同样，微波也可以使构成高温超导体最重要的氧化铜分子发生振动，所以过去曾研究过微波加热制造超导体。微波加热均匀，效率又好，但加热中，热量容易从材料表面散失，因…     

陶瓷的微波烧结及进展

综述了近年来微波技术在陶瓷烧结领域的一些最新研究进展,包括微波加热烧结、微波等离子烧结和微波等离子分步烧结。     

微波助热隧道窑

英国（EATechnology）技术公司已开发出微波助热隧道赛。这种窑既有电加热或煤气加热，又有微波加热。在加热过程中，微波加热产品内部，传统的热能加热窑炉和产品外部。这种复合式加热使产品内外温度均匀，并且烧成效率高，减少了产品变形和开裂。这种窑既可间歇操作，也可连续操作。这种窑复合加热方式使烧成过程中能置费用节省4O％以上，与传统加热方式相比，生产能力提高3倍。这种窑已成功地用于烧成砖、日用陶瓷、卫生陶瓷、高技术陶瓷、耐火材料等。微波助热隧道窑@李荔寅     

陶瓷的微波烧结及进展

综述了近年来微波技术在陶瓷烧结领域的一些最新研究进展,包括微波加热烧结、微波等离子烧结和微波等离子分步烧结。     

日用陶瓷坯体微波干燥技术的研究

微波加热的特点是表里一致,加热均匀,效率高、质量好、时间短,有选择性、易于实现自动控制。采用微波加热干燥陶瓷坯体应该是比较理想的方法。根据这样的设想,我们在北京市第一轻工业研究所的帮助下开展了“日用陶瓷坯体微波干燥技术”的研究。实验结果表明:微波加热是目前最优越的陶瓷坯体干燥方法。通过对宣化第一瓷厂大中小四种型号的     

陶瓷微波加热过程模型研究

建立了ＴＦ１０Ｎ单模微波烧结腔中陶瓷同波烧结加热过程的有限元数学模型，并对小尺寸圆柱形和长方柱形氧化铝陶瓷试体分别用二维轴对和二维模型进行了加热过程的数值模拟，所得结果能基本准确地反映实际过程，文中还讨论了材料物性参数，介电损耗因子、热导率等对加热过程的影响作用。     

Evidence for the Microwave Effect During the Annealing of Zinc Oxide

A microwave/conventional hybrid furnace has been used to anneal virtually fully dense zinc oxide ceramics under pure conventional and a microwave/conventional hybrid heating regime with a view to obtaining evidence for the "microwave effect" during the resulting grain growth. In each case it was ensured that each sample within a series had an identical thermal history in terms of its temperature/time profile. The results showed that grain growth was enhanced during hybrid heating compared with pure conventional heating; the greatest enhancement, a factor of ∼3 increase in average grain size, was observed in the range 1100°–1150°C. The grain growth exponent decreased from 3 during conventional heating to 1.4 during hybrid heating in this temperature range, suggesting an acceleration of the diffusional processes involved. Temperature gradients within the samples were found to be too small to explain the results. This suggests that clear evidence has been found to support the existence of a genuine "microwave effect."     

Influence of microwave sintering on electrical properties of BCTZ lead free piezoelectric ceramics

Barium titanate doped with calcium and zirconium (BCTZ) could be used at low temperature to replace lead based piezoelectric ceramics (PZT). The classical way to obtain BCTZ is the solid-state route coupled with conventional sintering, but this step is time-consuming. To reduce the duration of this process, microwave heating was used for sintering. It is a fast sintering method and the heating rate was around 200 °C/min in this study. Slightly better electrical properties with finer microstructures (d₃₃* = 706 pm/V, grain size about 42.1 ± 14.2 μm) were obtained for samples sintered by microwave heating during 50 min compared to the conventional sintering (d₃₃* = 622 pm/V, 22.6 ± 4.4 μm). The main result of this study is that by using microwave heating, the sintering step duration (including heating, dwell time and cooling) was drastically reduced: 1.5 h for microwave sintering against 12.5 h for conventional sintering.     

Fast synthesis of SrFe12O19 hexaferrite in a single-mode microwave cavity

The M-type SrFe₁₂O₁₉ hexaferrite has been synthesized by a microwave solid state reaction process – a fast heating process – in a home-made 2.45 GHz single-mode microwave cavity. Starting from SrCO₃ and Fe₂O₃ mixtures (1:6 ratio), cold pressed samples have been heated up in the microwave electric field without needing any susceptor, demonstrating the good coupling of the precursors with this microwave mode in our experimental setup.After optimization of the experimental conditions, the properties of the obtained ceramics, including structure, microstructure and magnetic properties, are compared with those of ceramics synthesized by conventional solid state reaction. With that microwave process, it is found that SrFe₁₂O₁₉ ceramics prepared in less than 30 min exhibit magnetic properties similar to those of the same compound produced by a conventional process. This highlights the potentialities of the technique to synthesize hexaferrite ceramics.     

Evidence for the Microwave Effect During Hybrid Sintering

A microwave/conventional hybrid furnace has been used to sinter three ceramics with different microwave absorption characteristics under pure conventional and a range of microwave/conventional hybrid heating regimes. The precursor powder particle size was also varied for each material. In each case it was ensured that every sample within a series had an identical thermal history in terms of its temperature/time profile. An increase in both the onset of densification and the final density achieved was observed with an increasing fraction of microwave energy used during sintering, the effect being greatest for the materials that absorbed microwaves most readily. Twenty-three percent greater densification was observed for submicron zinc oxide powder, the material with the largest microwave absorption capability, when sintered using hybrid heating involving 1 kW of microwave power compared with pure conventional power under otherwise identical conditions. For the ceramic with the lowest microwave absorption characteristic, alumina, the increase in densification was extremely small; partially stabilized zirconia, a moderate microwave absorber, was intermediate between the two. Temperature gradients within the samples, a potential cause of the effect, were assessed using two different approaches and found to be too small to explain the results. Hence, it is believed that clear evidence has been found to support the existence of a genuine "microwave effect."     

Enhanced dielectric and ferroelectric properties of BaTiO3 ceramics prepared by microwave assisted radiant hybrid sintering

Structural, dielectric and ferroelectric properties of polycrystalline BaTiO₃ (BTO) ceramics prepared with hybrid sintering i.e., microwave assisted radiant heating (MARH) are reported. It is observed that the permittivity (ε) and true switched ferroelectric charge density (Q_SW) of BTO ceramics can be enhanced by employing MARH. An enhancement of 58% in ε and 17% in Q_SW is observed for the BTO sample prepared with 30% microwave power applied during MARH as compared to the conventional radiant heating. The results are explained in terms of microstructure resulting from the microwave assisted sintering.     

Heating parameter optimization and optical properties of Nd:YAG transparent ceramics prepared by microwave sintering

Nd-doped YAG transparent ceramics were prepared by microwave sintering. In this paper, the green bodies from high-purity commercial powders were sintered from 900 °C to 1750 °C for different lengths of time (0.5–2 h) by microwave heating. By optimizing the microwave heating parameters (the heating rate at different stages of microwave sintering, sintering temperature and holding time), the microstructures and optical properties of transparent ceramics can be effectively improved. The phase transformation, densification process and optical properties of Nd:YAG transparent ceramics were discussed. The liquid phases strongly absorb microwave radiation and affect the sintering results of samples during microwave sintering. The highest in-line transmittances of Nd:YAG transparent ceramic fabricated at 1750 °C for 2 h were 76.5% at 400 nm and 80.6% at 1064 nm. The fluorescence emission spectra and lifetime depending on different heating conditions were also discussed.     

Sintering of Partially Stabilized Zirconia by Microwave Heating Using ZnO–MnO2–Al2O3 Plates in a Domestic Microwave Oven

Partially stabilized zirconia (PSZ) powders were fully densified by microwave heating using a domestic microwave oven. Pressed powder compacts of PSZ were sandwiched between two ZnO–MnO₂–Al₂O₃ ceramic plates and put into the microwave oven. In the first step, PSZ green pellets were heated by self-heating of ZnO–MnO₂–Al₂O₃ ceramics (1000°C). In the second step, the heated PSZ pellets absorbed microwave energy and self-heated up to a higher temperature (1250°C), leading to densification. The density of PSZ obtained by heating in the microwave oven for 16 min was 5.7 g/cm³, which was approximately equal to the density of bodies sintered at 1300°C for 4 h or 1400°C for 16 min by the conventional method. The average grain size of the sample obtained by this method was larger than the average grain size of samples sintered by the conventional method with a similar heating process.     

Effect of Microwave Processing on the Crystallization and Energy Density of BaO‐Na2O‐Nb2O5‐SiO2‐B2O3 Glass‐Ceramics

Barium sodium niobate (BNN) glass‐ceramics were successfully synthesized through a controlled crystallization method, using both a conventional and a microwave hybrid heating process. The dielectric properties of glass‐ceramics devitrified at different temperatures and conditions were measured. It was found that the dielectric constant increased with higher crystallization temperature, from 750°C to 1000°C, and that growth of the crystalline phase above 900°C was essential to enhancing the relative permittivity and overall energy storage properties of the material. The highest energy storage was found for materials crystallized conventionally at 1000°C with a discharge energy density of 0.13 J/cm³ at a maximum field of 100 kV/cm. Rapid microwave heating was found to not give significant enhancement in dielectric properties, and coarsening of the ferroelectric crystals was found to be critical for higher energy storage.     

High-performance Al2O3 ceramics prepared by DCC-HVCI via microwave heating

A novel and rapid fabrication method for Al₂O₃ ceramics by the DCC-HVCI method via microwave heating was proposed. Effects of microwave heating temperature on coagulation time, micromorphology, as well as performance of the green body and ceramic sample were studied. As the microwave heating temperature rises, the coagulation time gradually reduced and compressive strength of green sample decreased while relative density and flexural strength of ceramics rose at the beginning and then dropped. The 50 vol.% Al₂O₃ suspension was coagulated and demolded after treating at 60°C for 800 s by microwave heating. The compressive strength of green samples reached 1.12 ± 0.13 MPa. The relative density of Al₂O₃ ceramic samples reached 99.39%. And the flexural strength of Al₂O₃ ceramics reached 334.55 ± 26.41 MPa. The Weibull modulus of Al₂O₃ ceramics reached 19. In contrast with the ceramic samples heated through water bath, the ceramic samples treated through microwave possessed uniform microstructures. Microwave heating could reduce the coagulation time by 77%. Meanwhile, it could significantly raise the compressive strength of green bodies by 65%. Additionally, it could increase the flexural strength of ceramics by 30%.