Tidén Simon, Taher Mamoun, Vennström Marie, Jansson Ulf
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden.
Graphmatech AB, Mältargatan 17, SE-753 18 Uppsala, Sweden.
Materials (Basel). 2023 Jul 25;16(15):5216. doi: 10.3390/ma16155216.
Additive manufacturing of Cu is interesting for many applications where high thermal and electric conductivity are required. A problem with printing of Cu with a laser-based process is the high reflectance of the powder for near-infrared wavelengths making it difficult to print components with a high density. In this study, we have investigated laser bed fusion (L-PBF) of Cu using graphene oxide (GO)-coated powder. The powder particles were coated in a simple wet-chemical process using electrostatic attractions between the GO and the powder surface. The coated powder exhibited a reduced reflectivity, which improved the printability and increased the densities from ~90% for uncoated powder to 99.8% using 0.1 wt% GO and a laser power of 500 W. The coated Cu powders showed a tendency for balling using laser powers below 400 W, and increasing the GO concentration from 0.1 to 0.3 wt.% showed an increase in spattering and reduced density. Graphene-like sheet structures could be observed in the printed parts using scanning electron microscopy (SEM). Carbon-filled inclusions with sizes ranging from 10-200 nm could also be observed in the printed parts using transmission electron microscopy (TEM). The GO treatment yielded parts with higher hardness (75.7 HV) and electrical conductivity (77.8% IACS) compared to the parts printed with reference Cu powder.
对于许多需要高导热性和导电性的应用而言，铜的增材制造很有意义。基于激光的工艺打印铜时存在的一个问题是，粉末对近红外波长的高反射率使得难以打印出高密度的部件。在本研究中，我们研究了使用氧化石墨烯（GO）包覆粉末的铜激光粉末床熔融（L-PBF）工艺。粉末颗粒通过GO与粉末表面之间的静电引力，采用简单的湿化学工艺进行包覆。包覆后的粉末反射率降低，这改善了可打印性，并将密度从未包覆粉末的约90%提高到使用0.1 wt% GO和500 W激光功率时的99.8%。当激光功率低于400 W时，包覆的铜粉有球化趋势，将GO浓度从0.1 wt%提高到0.3 wt%会导致飞溅增加且密度降低。使用扫描电子显微镜（SEM）可在打印部件中观察到类石墨烯片状结构。使用透射电子显微镜（TEM）也可在打印部件中观察到尺寸范围为10 - 200 nm的含碳夹杂物。与使用参考铜粉打印的部件相比，GO处理后的部件具有更高的硬度（75.7 HV）和电导率（77.8% IACS）。
