some toughness and ease of processing. They can also display desirable magnetic, superconducting and chemical properties, due to their strong internal order and mixed (metallic and covalent/ionic) bonding, respectively. Intermetallics have given rise to various novel materials developments. Some examples include alnico and the hydrogen storage materials in nickel metal hydride batteries. Ni3Al, which is the hardening phase in the familiar nickel-base super alloys, and the various titanium aluminides have also attracted interest for turbine blade applications, while the latter is also used in very small quantities for grain refinement of titanium alloys. Silicides, inter-metallic involving silicon, are utilized as barrier and contact layers in microelectronics. Examples Magnetic materials e.g. alnico, sendust, Permendur, FeCo, Terfenol-D Superconductors e.g. A15 phases, niobium-tin Hydrogen storage e.g. AB5 compounds (nickel metal hydride batteries) Shape memory alloys e.g. Cu-Al-Ni (alloys of Cu3Al and nickel), Nitinol (NiTi) Coating materials e.g. NiAl High-temperature structural materials e.g. nickel aluminide, Ni3Al Dental amalgams, which are alloys of intermetallics Ag3Sn and Cu3Sn Gate contact/ barrier layer for microelectronics e.g. TiSi2 Laves phases (AB2), e.g., MgCu2, MgZn2 and MgNi2. The formation of intermetallics can cause problems. For example, intermetallics of gold and aluminium can be a significant cause of wire bond failures in semiconductor devices and other microelectronics devices. The management of intermetallics is a major issue in the reliability of solder joints between electronic components. Intermetallic particles Intermetallic particles often form during solidification of metallic alloys, and can be used as a dispersion strengthening mechanism. History Examples of intermetallics through history include: Roman yellow brass, CuZn Chinese high tin bronze, Cu31Sn8 Type metal, SbSn Chinese white copper, CuNi German type metal is described as breaking like glass, not bending, softer than copper but more fusible than lead. The chemical formula does not agree with the one above; however, the properties match with an intermetallic compound or an alloy of one. See also Complex metallic alloys Kirkendall effect Maraging steel Metallurgy Solid solution References Gerhard Sauthoff: Intermetallics, Wiley-VCH, Weinheim 1995, 165 pages Intermetallics, Gerhard Sauthoff, Ullmann's Encyclopedia of Industrial Chemistry, Wiley Interscience. (Subscription required) External links Intermetallics, scientific journal Intermetallic Creation and Growth – an article on the Wire Bond Website of the NASA Goddard Space Flight Center. Intermetallics project (IMPRESS Intermetallics project at the European Space Agency) Video of an AB5 intermetallic compound solidifying/freezing