Work

Ultrafast CO 2 Laser Sintering of Nonwetting Alumina–Iron Ceramic–Metal Composites

Year: 2026

Type: article

Abstract: ABSTRACT Alumina–iron composites are attractive for structural and functional applications but are difficult to consolidate because molten Fe poorly wets Al 2 O 3 , promoting capillary‐driven segregation during conventional liquid‐phase sintering. Here, we show that ultrafast nonequilibrium CO 2 laser sintering enables rapid consolidation of this unstable system while limiting liquid‐phase redistribution. Al 2 O 3 –Fe slurries containing 20–50 vol% Fe were tape‐cast and processed under argon using single‐pass laser scanning. The results indicate that Al 2 O 3 remains predominantly solid and densifies by diffusion, while Fe transiently melts and undergoes limited viscous flow. Rapid heating and cooling restrict droplet coalescence, producing a consolidated Al 2 O 3 matrix with a fine, dispersed metallic phase. Increasing scan speed refines the Fe features, consistent with a shorter time available for liquid‐phase redistribution. Quantitative two‐dimensional analysis of the BSE micrographs further supports the scan‐speed‐dependent refinement of the Fe‐rich phase. SEM, TEM, XRD, and STEM‐EDS reveal discrete Al 2 O 3 –Fe interfaces without a continuous reaction layer, while localized FeAl 2 O 4 spinel forms at Al 2 O 3 grain boundaries. This work supports ultrafast laser sintering as a route for consolidating nonwetting ceramic–metal systems.

Source: Journal of the American Ceramic Society

DOI: 10.1111/jace.71135