Fe—Ni alloy metal foil having excellent heat resilience and method for manufacturing same
An aspect of the present invention provides an Fe—Ni alloy metal foil having excellent heat resilience, where the Fe—Ni alloy metal foil is prepared by an electroforming (EF) method and has a thickness of 100 μm or less (except O μm), wherein the Fe—Ni alloy metal foil comprises, by wt %, Ni: 34-46 %, a remainder of Fe and inevitable impurities, and wherein the Fe—Ni metal foil has a degree of heat resilience in an amount of 30 ppm or less.
1. An Fe—Ni alloy metal foil having excellent heat resilience, manufactured using an EF method and having a thickness of 100 μm or less (excluding 0 μm), the Fe—Ni alloy metal foil comprising, by wt %, Ni: 34% to 46%, Fe as a residual component of the Fe—Ni alloy metal foil, and inevitable impurities,
wherein microstructure of the Fe—Ni alloy metal foil has a face-centered cubic (FCC) and body-centered cubic (BCC) structure, and an area percentage of BCC is in a range of 5% to 20%,
wherein the Fe—Ni alloy metal foil has a heat resilience rate expressed using Formula 1, below, of 30 ppm or lower,
Heat resilience rate=( L−L 0)/ L 0, [Formula 1]
where L0 is a length of a metal foil before heat treatment (at a surface temperature of 30° C.), and L is a length of a metal foil after heat treatment and refers to the length of the metal foil when a surface temperature of an alloy having a surface temperature of 30° C. is increased to 300° C. at a rate of 5° C./min, maintained at a surface temperature of 300° C. for 5 minutes, and decreased to 30° C. at a rate of 5° C./min.
2. The Fe—Ni alloy metal foil having excellent heat resilience of claim 1 , wherein an average grain size of the Fe—Ni alloy metal foil is less than or equal to 100 nm (excluding 0 nm).
3. The Fe—Ni alloy metal foil having excellent heat resilience of claim 1 , wherein tensile strength of the Fe—Ni alloy metal foil is higher than or equal to 800 MPa.