Accelerating densification in Kovar alloy powders prepared by water–gas combined atomization

Abstract

The utilization of ultrafine, near-spherical Kovar alloy powders is promising for applications such as injection molding and additive manufacturing. This study successfully produced these powders using the newly developed water–gas combined atomization technique. Subsequently, the morphology and surface structure of the as-prepared powders were investigated by using scanning electron microscopy, transmission electron microscopy and electron probe microanalysis. Our findings revealed that the water–gas combined atomization yields a high powder output. In addition, an inhomogeneous layer of Fe₂O₃ oxide film was observed on the powder surfaces. Kovar alloys sintered with the as-produced powders exhibit higher relative density than those produced with gas atomization powders. This increased density results from the nonuniformity of the oxide film, promoting sintering neck formation and accelerating densification. The insights from this research contribute to the design of Kovar alloy and offer valuable guidance for refining production processes to enhance powder quality and performance.