PMC

Formation mechanisms of different types of spatter during L-PBF: (a) morphology of spherical spatter (Type-I spatter); (b) morphology of coarse spherical morphology (Type-II spatter); (c) morphology of irregular spatter (Type-III spatter). (Reprinted with permission from Ref. []. Copyright 2016 Elsevier B.V.).

Classification and suppression of spatter under high gravitational acceleration: ① solid spatter; ② metallic ejected spatter; ③ powder agglomeration spatter; ④ entrainment melting spatter; and ⑤ defect induced spatter. (Reprinted with permission from Ref. []. Copyright 2021 Elsevier B.V.).

Field photographs of the three different spatter types described in this study: primary (a–d); late-stage (e,f) and secondary (g,h). (a) A spatter rampart that formed on the northern side of the 1969 Mauna Ulu eruptive fissure; (b) agglutinated rampart interior with many clasts showing post depositional flow; (c) primary spatter located on top of a tree mould south of the eruptive fissure; (d) interior of tree mould spatter mound, where clasts are less welded compared to those in the northern rampart deposits; (e) green/blue vent proximal late-stage spatter forming a thin deposit on top of the drain-back lava; (f) typical late-stage spatter clasts showing a wide range of fluidal shapes; (g) a secondary spatter mound formed over a ground crack to the south and (h) a close up view of a secondary spatter mound. Scales (marked in white if unclear) measure 16 cm for all images except in a, g and h where the scale is 1.2 m.

A comparison of condensate deposited on the surface of spatters: (a) spatter particle without condensate, (b) spatter particle with a condensate of approximately 5–10 μm thickness, (c) spatter particle with a condensate thickness of approximately 40 μm, (d) multiple layers of condensate and spatter, and (e) high-magnification inset from (d).