摘要：

The conventional LTCC fabrication route requires a series of costly molding equipment and a complicated manufacturing process. If it is achievable to fabricate ceramics using three-dimensional inkjet printing (IJP) technology, it is anticipated that LTCC components could be designed as a more efficient and flexible additive manufacturing route using IJP technology to co-print ceramic and conductive layers and co-fire them. This research represents the first attempt to utilize IJP technology in the field of LTCC, where we developed a stable SiO 2 -H 3 BO 3 nanoceramic ink that can be continuously printed through a piezoelectric nozzle with an array of spray holes. The ink was supplemented with selected photosensitive resins to facilitate the curing of the printed layer under ultraviolet light irradiation. Green bodies are sintered at 950° for two hours to obtain ceramic sheets with good surface flatness and microscopic sintering degrees. The tested samples have an ultra-low dielectric constant ( ε r ) of about 2.485 and a low dielectric loss (tan δ ) of about 0.0038 (at 1MHz), while being stable at high temperatures ( 2 O 3 , TiO 2 have been reported [6], [7]. These two techniques are either limited in accuracy or only applicable to the single fabrication of ceramic substrates, which undoubtedly restricts electrical functionality. Clearly, forming LTCC using a single IJP device is undoubtedly the most efficient route, but the first issue that needs to be addressed is the preparation and sintering of nanoceramic inks. In this regard, an attempt was made to explore the molding and sintering route of silica-based LTCC using IJP technology. We developed a well-dispersed silica-based nano-ceramic ink that was continuously printed by an array nozzle and UV-curable molding. Silica has been widely used as the matrix phase in the LTCC field due to its superior electrical performance, while H 3 BO 3 was chosen as the co-sintering phase in this study due to its proven density-enhancing effect [8] and its inherent excellent dielectric properties [9]. The high surface energy of silica nanoparticles dispersed in ink droplets, enhanced by the H 3 BO 3 sintering aid, enables the SiO 2 -H 3 BO 3 ceramic combination to sinter at 950°. Tests including surface and microscopic morphology results demonstrate good sintering phenomena and component tests prove the phase structure. Additionally, its superior dielectric properties demonstrate the potential for use in microwave dielectrics. Such an innovative attempt paves the way for integrated molding of LTCC components using IJP equipment. Section snippets Materials To maintain experimental consistency, we used 35wt% silica nanoparticle sol provided by Shanghai Jiute Nanomaterial Technology Co., Ltd. The silica nanoparticles were surface grafted with acrylate molecules, which have the same functional groups as the acrylate polymer monomers selected for this work, leading to better compatibility and dispersion. As shown in Table 1, a few sol product parameters were evaluated. Three low-viscosity photosensitive resins, 1, 6-Hexanediol diacrylate (HDDA), Results and discussion According to the previous statement, the ink properties should first be adapted to the piezoelectric nozzle. To judge ink suitability, an observation device has been applied to capture the flight trajectory of micro-droplets from a piezoelectric single nozzle, and specific device information can be found in Ref [10]. The formation and dropping process of the configured ceramic ink droplets was captured using this device as shown in Fig. 2. It could be seen that new droplets start forming from Conclusion In this work, we configured a silicon-based LTCC nanoceramic ink for IJP technology to achieve stable, long-lasting jetting across a piezoelectric array nozzle. The selected photosensitive elements provide a viable print curing pathway while ensuring ink stability, through which the ceramic green bodies were successfully printed and deposited. Due to the sintering aid of the H 3 BO 3 component of the ink, the green bodies were

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