Abstract: The successful fabrication of alloy foam (or porous alloy) is very rare, despite their potentially better properties and wider applicability than pure metallic foams. The processing of three-dimensional copper-nickel alloy foams is achieved through a strategic solid-solution alloying method based on oxide powder reduction or sintering processes, or both. Solid-solution alloy foams with five different compositions are successfully created, resulting in open-pore structures with varied porosity. The corrosion resistance of the synthesized copper-nickel alloy foams is superior to those of the pure copper and nickel foams.

Abstract: A sodium-chloride-space-holder process with two-step heat treatment is used to create an open-porous metal foam (e.g., titanium foam) with a high porosity of about 70 to 90 percent for use in load-bearing applications. A mechanically reliable titanium foam is manufactured using a space-holder method containing two-step heat treatment where a sodium chloride powder is first sieved for desired pore size range, mixed with titanium powder, and compacted under pressure at high temperature. An additional heat treatment is applied to further strengthen the chemical bonding between the titanium particles after the removal of sodium chloride in water to create pores. This process uses a pneumatic pressing machine in combination with a furnace under an argon gas to simultaneously apply both the pressure and temperature. The resulting titanium foam is chemically well bonded and has enhanced durability for proper used in structural applications.

Abstract: A metal-foam structure is used to shield or reduce harmful electromagnetic waves that are generated by electronic devices. A metal-foam material has regulated pores and is incorporated in an electronic device. The metal foam structure shields, prevents, or reduces harmful electromagnetic waves generated by the electronic device from reaching the human body or interfering with a sensitive electronic component. This metal foam is a relatively lightweight material having regulated microscale pore structure. The pores in the metal foam can also form directionality relative to the direction of incoming electromagnetic waves for more effective reflection or absorption of electromagnetic waves. The metal foam can also be used as both an electromagnetic-shielding and a heat-dissipating component for electronics including popular consumer electronics such as mobile phones, notebooks, and high-power desktop computers.

Abstract: A capacitor and supercapacitor design are based on metal-foam electrodes. An electrolytic capacitor has a metal foam dielectric (e.g., aluminum oxide, titanium oxide, iron oxide, or others). An electric double-layer supercapacitor has an electrode with metal foam (e.g., copper, nickel, titanium, iron, steel alloy, or aluminum) filled with activated carbon, or graphene, or metal foam with activated carbon foam, or any combination of these to enhance the electrical conductivity and thus the power and capacity of the cell. A pseudocapacitor device has an electrode with metal foam (e.g., iron, cobalt, nickel, copper, titanium, aluminum, magnesium, tin, manganese, and stainless steel, and their alloy foams) coated with an oxide- or hydroxide-based material containing highly active zones. The pseudocapacitor metal-foam electrode can also be filled with activated carbon in the form of a slurry to further enhance its capacity.

Abstract: A gas sensing device is manufactured with three dimensionally connected metal oxide foam structure of large surface area and elongated channel pores within the three-dimensional porous structure for gas sensing applications, thereby increasing the surface area of the sensing layer and expediting sensitivity and sensor response. A gas sensor device includes the fabricated metal-oxide-foam sensing material attached via silver paste to platinum electrodes and ruthenium heater that are printed on low temperature co-fired ceramic substrate. This device will provide improved gas sensing performance with improved sensitivity and response time. Gas sensors including the metal oxide foam sensing material exhibit higher sensitivity to toxic gases such as ethanol and carbon monoxide due to the large surface area achieved from the porous three-dimensional structure providing increased chemical reaction sites and the larger porous channels allowing gases to easily pass, shortening the gas diffusion reaction path.

Abstract: A facile method is based on a pack-cementation process using large-area copper foil instead of copper powder. By controlling a pack-cementation time and an amount of alloying element (e.g., aluminum), a hierarchical microporous or nanoporous copper can be created. When coated with tin active material, the hierarchical microporous or nanoporous copper can be used as an advanced lithium-ion battery anode. A coin-cell test exhibited a four-fold higher areal capacity (e.g., 7.4 milliamp-hours per square centimeter without any performance degradation up to 20 cycles) as compared to a traditional graphite anode.

Abstract: The successful fabrication of alloy foam (or porous alloy) is very rare, despite their potentially better properties and wider applicability than pure metallic foams. The processing of three-dimensional copper-nickel alloy foams is achieved through a strategic solid-solution alloying method based on oxide powder reduction or sintering processes, or both. Solid-solution alloy foams with five different compositions are successfully created, resulting in open-pore structures with varied porosity. The corrosion resistance of the synthesized copper-nickel alloy foams is superior to those of the pure copper and nickel foams.