Additive manufacturing of zirconia ceramics by material jetting

The possibility of additive manufacturing of ceramics has been reported widely in scientific literature. This study investigates the potential of direct inkjet printing or material jetting of 3Y-TZP ceramics by assessing the microstructure and mechanical properties of the sintered printed parts. The technique allows to print in layers of 10.5 μm, with an as-printed green density of 58 % and nearly fully sintered density of 6.03 ± 0.1 g/cm³ (99.7 % TD). The dimensions of the green and sintered parts were highly accurate but showed an anisotropic roughness in function of the building direction, mainly due to the support structures. The biaxial bending and 4-point bending strength of the sintered material was found to be substantially higher in the XY direction than in the building (Z) direction. SEM and X-Ray computed tomography revealed the presence of delamination cracks, agglomerates and spherical pores, which were identified as fracture origins on fractured surfaces.     

Preparation of NaYF4:Yb3+,Tm3+@NaGdF4:Ce3+,Eu3+ double-jacket microtubes for dual-mode fluorescent anti-counterfeiting

Novel hydrophilic NaYF₄:Yb³⁺,Tm³⁺@NaGdF₄:Ce³⁺,Eu³⁺ double-jacket microtubes (DJMTs) with upconversion/ downconversion dual-mode luminescence were designed and prepared through epitaxial growth of NaGdF₄:Ce³⁺, Eu³⁺ shell onto the NaYF₄:Yb³⁺,Tm³⁺ microtube via poly(acrylic acid) (PAA) mediated hydrothermal method. It is demonstrated that PAA ligand played an important role in guiding the direct growth of NaGdF₄:Ce³⁺,Eu³⁺ shell onto the surface of NaYF₄:Yb³⁺,Tm³⁺ parent microtubes. The growth of NaGdF₄:Ce³⁺,Eu³⁺ shell experienced a crystal phase transition from β-NaGdF₄ and β-NaYF₄ mixture to β-NaYF₄@NaGdF₄ composite crystal, and morphology evolution from mixture of β-NaGdF₄:Ce³⁺,Eu³⁺ nanorods and β-NaYF₄:Yb³⁺,Tm³⁺ microtubes to NaYF₄:Yb³⁺,Tm³⁺@NaGdF₄: Ce³⁺,Eu³⁺ DJMTs. The formation mechanism of DJMTs was the dissolution−renucleation of β-NaGdF₄:Ce³⁺,Eu³⁺ nanorods and the growth of β-NaGdF₄:Ce³⁺,Eu³⁺ shell via the classical Ostwald ripening mechanism. The as-prepared DJMTs could exhibit blue upconversion and red downconversion luminescence, which was further made into environmentally benign luminescent inks for creating highly secured and fluorescent-based anti-counterfeiting patterns via inkjet printing.     

陶瓷印刷技术变革—喷墨印花技术应用与前景

喷墨印花技术所制备的陶瓷制品以其绚丽多彩的图案、灵活多变的设计、仿实逼真的效果而获得人们的喜爱,也使得陶瓷装饰技术迎来了第三次变革。喷墨印花技术在我国引入和应用只有短短的几年,技术的更新和进步却非常迅速,极大地刺激了我国建筑陶瓷工业的发展。鉴于此,本文将对陶瓷装饰技术的发展历程、喷墨印花技术在我国的应用与前景等方面进行阐述分析,并对今后的发展之路提出一些见解,以便更好地推动喷墨印花技术在我国陶瓷工业中的应用发展。     

喷墨打印头陶瓷喷孔的皮秒激光加工研究

喷墨打印头的喷孔直径一般为几十微米,材料一般是有机薄膜、不锈钢薄片等。针对有机膜等作为喷嘴板材料的缺陷,采用氧化锆陶瓷代替,以提高耐磨能力和耐腐蚀性。采用皮秒激光打孔方法,可在多种材料上加工出直径几十微米的小孔,包括聚酰亚胺（厚度50μm）、氧化锆陶瓷（厚度120μm）和铜片（厚度70μm）。通过控制不同的参数变化,可制备出孔径约20μm、孔间距为140μm的喷孔阵列。对比不同参数下喷孔尺寸和微观形貌发现,较高功率密度、较低单点停留时间有助于得到圆孔,减少重铸层。     

不同还原体系银油墨打印对聚酰亚胺基板化学镀铜制备印制电路板的影响

先在普通打印机上用活化导电银油墨将线路图打印在聚酰亚胺(PI)基板上,固化后再化学镀铜制得印制电路板(PCB)。研究了导电银油墨的还原剂对不同体系镀液化学镀铜层厚度、导电性、结合力和抗氧化性的影响。结果表明,油墨的还原剂相同时,甲醛体系化学镀铜层的综合性能优于乙醛酸镀液。导电银油墨的最佳还原剂为丙酸,即油墨的最佳配方为:丙酸0.5 mol/L,Ag NO3 0.5 mol/L,10%(质量分数)OP乳化剂适量。采用0.5 mol/L丙酸油墨–甲醛镀液体系制得厚度为3.10μm的铜镀层,其抗氧化时间为44 s,电阻率为1.00×10-7?·m,与PI基板间的结合力良好,综合性能最佳。     

银膜换能元的喷墨打印及其性能表征

针对常用薄膜换能元的沉积和成型方法耗时长、成本高、材料利用率低等问题,采用喷墨打印制备了银膜换能元,并采用扫描电镜（SEM）和原子力学显微镜（AFM）对换能元形貌及厚度进行了表征,对银膜桥的发火性能进行了研究。结果表明,银膜换能元厚度为2.1μm,表面平整,在不同输入能量下存在电热、电爆两种情况。银膜桥更容易产生等离子体;蘸有斯蒂芬酸铅（LTNR）的银膜桥在47μF脉冲放电下50%发火电压为6.65 V,脚-脚间可以耐受25 kV静电放电（放电电容为500 pF,串联5 kΩ电阻）,可通过钝感电火工品1A1W5min测试。