Preparation of Ni–Cr alloy foam by vacuum evaporation deposition from pure nickel foam

In order to get a filter with oxidation resistance at high temperature, Ni–Cr alloy foam was prepared by vacuum evaporation deposition chromium on pure nickel foam. The effects of evaporation temperature and evaporation time on the Cr content, microstructure, compressive property and oxidation performance of the Ni–Cr alloy foams were investigated. The Ni–Cr alloy foam has a filament diameter of approximately 60–130 μm and a pore size of 200–330 μm, respectively. The results showed that increasing evaporation temperature and extending evaporation time can significantly increase Cr deposition and improve the uniformity of element distribution. The Ni–Cr alloy foam prepared by evaporation at 1100 ℃ for 1 h has a Cr content about 22.9 wt%, and its compressive strength reached 5.5 MPa at a strain of 0.35 while no fracture occurred. The Ni–Cr alloy foam has oxidation rates of 71.6, 79.2 and 171.0 mg/(m 2 ·h) at 600 °C, 700 °C and 800 °C, respectively, showing a good oxidation resistance. Therefore, vacuum evaporation deposition can realize alloying of pure nickel foam with chromium to get Ni–Cr alloy foam, with the characteristics of simple process, controllable composition and good properties.