Close-Coupled Gas Atomization

Nozzle Geometry

Fluid dynamics within the delivery tip dictate droplet breakup efficiency through annular or discrete jet configurations. Liquid metal emerges from a ceramic orifice directly into the convergence zone of supersonic gas expansion. Momentum transfer from the expanding gas shears the liquid film before surface tension pulls the fragments into spheres.

Orifice erosion alters the liquid stream diameter during extended casting runs. Wear-resistant zirconia components maintain dimensional stability under prolonged thermal exposure. Proper standoff distance between the liquid tip and the gas impingement point prevents freeze-off defects.

Thermal radiation from the melt pool alters local gas viscosity and changes the resultant droplet trajectory.

Gas Dynamics

High-pressure nitrogen or argon delivery determines the kinetic energy available for primary atomization events. Delivery pressure regulation controls shockwave formation at the convergent-divergent nozzle exit plane. Expansion efficiency relies on maintaining sonic velocities across the annular gap.

Gas consumption scales directly with the targeted median particle size reduction. Purity levels of the atomizing medium prevent surface oxidation of reactive alloys during flight. Kinetic losses through turbulence reduce the overall energy transfer efficiency to the liquid metal.

Gas preheating reduces thermal shock at startup and stabilizes the steady-state spray cone angle.

Powder Morphology

Solidification kinetics during flight dictate microstructural refinement and cooling rates within individual particles. Rapid quenching suppresses dendritic segregation in high-alloy systems. Spherical geometry permits high tap densities required for powder bed fusion applications.

Satellite formation occurs when fine droplets collide with partially solidified larger particles during descent. Hollow particles form when gas is trapped inside shrinking shells during solidification. Sieve analysis classifies the cooled powder batch into specific size fractions for commercial delivery.

Apparent density measurements verify batch consistency before the material ships to end users.