Some organic additive manufacturing feedstocks can be cohesive and tend to agglomerate in suspensions, which can lead to significant challenges in formulating solids-loaded fluids, like those used in many additive manufacturing processes. By depositing an ultra-thin, layer of a second material conformally with the surface of the feedstock powder, Atomic Layer Deposition (ALD) can be used to uniquely modify the surface and, thereby, cohesion of the powder material without changing the properties of the bulk material. This paper demonstrates low temperature (<115 °C), ALD of aluminum oxide on temperature-sensitive materials: first, on polyimide thin film flats, then, on melamine and nylon organic powder feedstocks with the goal of improving their powder rheology. The process produced amorphous aluminum oxide-hydroxide coatings that are both uniform and conformal to the powder’s surface. Aluminum oxide coatings on the nylon powders did not show a significant change in the flow properties of the powder, given the already low cohesivity of nylon. In contrast, the highly cohesive melamine powders exhibited significant improvements in flowability after being coated with a layer as thin as 20 nm, due to a reduction in inter-particle cohesivity. The basic flowability decreased from 199 to 185 mJ and the specific energy increased from 4.95 to 6.39 mJ/g.

某些有机增材制造原料可能具有内聚力，并易于在悬浮液中附聚，这可能会导致配制载有固体的流体方面面临许多挑战，就像许多增材制造过程中使用的那些一样。通过沉积与原料粉末表面保形的第二材料的超薄层，原子层沉积（ALD）可用于独特地改变表面，从而在不改变粉末材料性能的情况下凝聚粉末材料。散装物料。本文展示了在温度敏感材料上的低温（<115°C）氧化铝的ALD：首先在聚酰亚胺薄膜平板上，然后在三聚氰胺和尼龙有机粉末原料上，以改善其粉末流变性。该工艺产生的无定形氧化铝-氢氧化铝涂层既均匀又与粉末表面保形。考虑到尼龙的内聚力已经很低，尼龙粉末上的氧化铝涂层在粉末的流动性能上没有显示出明显的变化。相反，由于颗粒间内聚力的降低，高内聚力的三聚氰胺粉末在被涂覆至薄至20nm的层之后显示出流动性的显着改善。基本流动性从199 mJ / g降低到185 mJ，比能从4.95 mJ / g增加。由于颗粒间内聚力的降低，高内聚力的三聚氰胺粉末在涂覆了20 nm的薄层后，其流动性有了显着改善。基本流动性从199 mJ / g降低到185 mJ，比能从4.95 mJ / g增加。由于颗粒间内聚力的降低，高内聚力的三聚氰胺粉末在涂覆了20 nm的薄层后，其流动性有了显着改善。基本流动性从199 mJ / g降低到185 mJ，比能从4.95 mJ / g增加。