The Effect of Fe/Al Ratio and Substrate Hardness on Microstructure and Deposition Behavior of Cold-Sprayed Fe/Al Coatings

Abstract

Fe/Al composite coatings with compositions of Fe-25 wt.% Al, Fe-50 wt.% Al and Fe-75 wt.% Al were deposited on pure Al and P91 steel plates by a cold spray, respectively. The microstructure of the cross-section of the fabricated coatings was characterized by SEM and EDX. The bonding strength between the coatings and substrates was measured and analyzed. The effects of the Fe/Al ratios and substrate hardness on the deposition behavior were investigated. It was interesting to find fragmented zones in all fabricated coatings, which were composed of large integrated Al particles and small fragmented Al particles. Meanwhile, the fraction of fragmented zones varied with the fraction of the actual Fe/Al ratio. An Fe/Al ratio of 50/50 appeared to be an optimized ratio for the higher bonding strength of coatings. The in situ hammer effect caused by larger and harder Fe particles played an important role in the cold spray process. The substrate with the higher hardness strengthened the in situ hammer effect and further improved the bonding strength.

Tribological Behavior of Ti-Coated Diamond/Copper Composite Coating Fabricated via Supersonic Laser Deposition

“…The substrate hardness of the composite was 93 HV 0.1 . Clearly, the microhardness of all the laser-irradiated samples was harder than that of the cold sprayed copper due to the hammer effect of the diamond and the softening effect of laser irradiation [29]. In addition, although the diamond content in the composites enhanced with the increase of laser power, the hardness increased first and then decreased.…”

Comparison of Cold-Sprayed Coatings of Copper-Based Composite Deposited on AZ31B Magnesium Alloy and 6061 T6 Aluminum Alloy Substrates

“…Based on the above-mentioned points, the CS technique has received special attention as a promising candidate for a surface modification method of various materials as it generates a minimal heat-affected zone in both the as-deposited material and substrate [ 5 ]. Copper (Cu) [ 6 ], Cu-based alloys [ 7 , 8 ], Al [ 9 ], Al-based alloys [ 10 , 11 ], Ni [ 12 ], Ni-based alloys [ 13 , 14 ], Ti-based alloys [ 15 , 16 ], Fe-based alloys [ 8 , 17 ], Sn [ 18 ], high or medium entropy alloys [ 19 , 20 ], and metal-based composites such as Cu-Al 2 O 3 [ 21 ], Al-SiC [ 22 ], Al-TiB 2 [ 23 ], Al-Al 2 O 3 [ 24 ], Ni-WC [ 25 ], etc., in the form of coatings or parts, have been successfully actualized by CS technology so far.…”