Freeze Casting is a Facile Method to Create Solid Solution Alloy Foams: Cu–Ni Alloy Foams via Freeze Casting

Abstract

Porous metals have attracted great attention for their functional and structural applications; however, they often possess limited applicability in their pure form for the areas requiring decent strength and corrosion resistance. In this study, pure copper (Cu), pure nickel (Ni), and Cu-Ni alloy foams with five different compositions are successfully fabricated using freeze casting, resulting in open-pore structures with varied porosity (from 55% to 75%). Their varied morphologies and crystal sizes are compared, and the lattice parameters and crystal sizes are calculated. The corrosion resistance of the synthesized Cu-Ni alloy foams is superior to those of the pure Cu and Ni foams. The weight loss rate of the Cu 7 Ni 3 alloy foam is six times and five times slower than those of the pure Ni and pure Cu foams in a sulfuric corrosive environment, respectively. The yield strength of Cu 7 Ni 3 alloy foam (53 AE 2% porosity) is 72 AE 2 MPa and its yield strength when normalized by the Gibson-Ashby model is the largest with a value of up to 852 AE 3 MPa. The elastic modulus and hardness values are varied in the range of 73.4-152.4 GPa and 1.6-4.7 GPa, respectively, depending on the composition of the alloy foam.

Highly Dispersed and Stable Hydrotalcite-Derived NiCu/MgAlO Alloy Catalyst for Efficient Amination of Cyclohexanol to Cyclohexylamine in the Vapor Phase

“…The diffraction peaks for Cu/MgAlO at 43.3, 50.4, and 74.1° can be assigned to (1 1 1), (2 0 0), and (2 2 0) of metallic Cu, respectively. However, for the NiCu/MgAlO catalyst, there are three diffraction peaks at 44.1, 51.5, and 75.0°, which are different from the characteristic peaks of monometallic Cu and Ni catalysts, suggesting that NiCu 0.33 alloy is successfully fabricated. − To further verify the form of NiCu 0.33 alloy, the extended X-ray absorption fine structure (EXAFS) characterization was carried out, as shown in Figure B. Obviously, the EXAFS spectra of the Ni–Cu alloy in NiCu/MgAlO were different from those of Ni and Cu foils.…”

Manufacturing of Open-Cell Aluminium Foams: Comparing the Sponge Replication Technique and Its Combination with the Freezing Method

“…Sublimation of the frozen solvent produces a porous structure. Initially, sublimation freezing was used to make highly porous ceramics, but recently this method has also been applied to metal suspensions such as titanium [ 7 , 8 ], Ti-Al alloy [ 9 ], iron [ 10 , 11 , 12 ], copper [ 13 , 14 , 15 , 16 ], nickel foams [ 17 , 18 , 19 ] and Cu-Ni [ 17 ].…”