The adoption of additive manufacturing technology is gaining interest for processing precious metals. In this study, the capability of inkjet printing was explored to fabricate macroscopic parts from commercial silver nanoparticle ink (AgNPs). A bespoke JETx® three dimensional (3D) inkjet printing machine was used to print and subsequently sinter up to 1000 layers of AgNPs using an infrared source. Examination of the sample using X-ray computed tomography and scanning electron microscopy revealed the existence of both micro- and nano-scale pores within the structure. Pinning effect, residual surface temperature, insufficient droplet overlap and surface defects were the key factors contributing to the voids. Elemental mapping confirmed the structure to be composed of 87% of silver along with carbon and oxygen. The 750 dpi sample showed a 25% reduction in nanopores and 77% lower micro-pores compared to the 600 dpi sample. In terms of hardness, the 750 dpi sample was 29% harder than the 600 dpi sample, showcasing samples with higher print resolution can contribute towards less voids and improved mechanical properties. Thus by demonstrating the possibility to fabricate dense parts from AgNPs using inkjet technology, this study opens a novel route for processing nano-scale particulates and precious metals in 3D.

中文翻译：

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银纳米粒子宏观结构的 3 维喷墨打印

采用增材制造技术对加工贵金属越来越感兴趣。在这项研究中，探索了喷墨打印的能力，以从商业银纳米粒子墨水 (AgNPs) 制造宏观部件。使用定制的 JETx® 三维 (3D) 喷墨印刷机打印并随后使用红外源烧结多达 1000 层的 AgNP。使用 X 射线计算机断层扫描和扫描电子显微镜检查样品发现结构中存在微米级和纳米级孔。钉扎效应、残余表面温度、液滴重叠不足和表面缺陷是导致空洞的关键因素。元素映射证实该结构由 87% 的银以及碳和氧组成。与 600 dpi 样品相比，750 dpi 样品的纳米孔减少了 25%，微孔减少了 77%。在硬度方面，750 dpi 样品比 600 dpi 样品硬 29%，展示具有更高打印分辨率的样品有助于减少空隙并改善机械性能。因此，通过展示使用喷墨技术从 AgNPs 制造致密部件的可能性，这项研究开辟了一条新的途径来处理 3D 纳米级颗粒和贵金属。