# Microstructural Characteristics of Graded Ni-Fe Coatings Fabricated Through DED-L

## TL;DR

The study finds that bidirectional scanning with 90° layer rotation produces the best quality graded Ni-Fe coatings with fewer pores.

## Contribution

A systematic evaluation of scanning speed and deposition strategy for optimizing DED-L fabricated graded metal coatings.

## Key findings

- Bidirectional samples show fewer pores than monodirectional samples.
- Higher scanning speed reduces porosity in bidirectional scanning with 90° rotation.
- Bidirectional deposition with 90° rotation yields the best coating quality.

## Abstract

What are the main findings?
Bidirectional samples show fewer pores than samples with monodirectional movement.Increasing the scanning speed leads to lower porosity (bidirectional scanning mode with 90° layer rotation).Bidirectional deposition with 90° layer rotation exhibits best quality

Bidirectional samples show fewer pores than samples with monodirectional movement.

Increasing the scanning speed leads to lower porosity (bidirectional scanning mode with 90° layer rotation).

Bidirectional deposition with 90° layer rotation exhibits best quality

What are the implications of the main findings?
Systematic study of scanning speed and deposition strategy.Practical guidance for process improvement of graded metal coatings; properties under evaluation.Functionally graded Ni-Fe coatings fabricated by DED-L with tailored microstructures.

Systematic study of scanning speed and deposition strategy.

Practical guidance for process improvement of graded metal coatings; properties under evaluation.

Functionally graded Ni-Fe coatings fabricated by DED-L with tailored microstructures.

Directed Energy Deposition-Laser (DED-L) enables high-performance coatings through melting and successive powder deposition. Its compositional flexibility suits functionally graded layers that enhance corrosion and wear resistance. This study aimed to improve parameters for producing dense, defect-free, graded Ni- and Fe-based coatings by varying the scanning speed and deposition strategy (monodirectional versus bidirectional, with/without layer rotation), while keeping the power and hatch distance constant. Laser and electron microscopy were used to link parameters to porosity and uniformity. Optimal settings minimized pores, improved interlayer bonding and preserved geometry; inadequate parameters yielded porous, irregular deposits. A bidirectional path with 90° rotation appeared best. Ongoing research activities are needed to assess its properties.