They rejected oxides of aluminium (which is abundant) and lanthanum (which isn't) and eventually lighted upon hafnium.
Over the summer prices for cerium (used in glass), lanthanum (petrol refining), yttrium (displays) and a bunch of other –iums have zoomed upward (see chart) as China, which accounts for almost all of the world's production, squeezes supply.
Alternatives based on oxides of hafnium and lanthanum are being tried, but the industry is not keen about moving to a less-familiar material.Another way to cut current leakage is to move the transistor up out of the plane of the chip's surface.
The substances in question include a bunch of rare-earth metals and a few other elements which used a pinch here, a pinch there enhance the way many industrial materials function.It is not as though the rare-earth elements—scandium, yttrium and lanthanum plus the 14 so-called lanthanides are all that rare.
The results of these investigations, however, were extremely perplexing, and confusion persisted until 1939 when Otto Hahn and Fritz Strassmann in Germany, following a clue provided by Irène Joliot-Curie and Pavle Savić in France (1938), proved definitely that the so-called transuranic elements were in fact radioisotopes of barium, lanthanum, and other elements in the middle of the periodic table.
Lanthanum chromite (LaCr2O4) is a small polaron conductor; substituting alkaline-earth ions (e.g., calcium, or Ca2+) for La3+ results in an equal proportion of Cr3+ being converted to Cr4+.
Hydrogen is absorbed at high temperatures by many transition metals (scandium, 21, through copper, 29; yttrium, 39, through silver, 47; hafnium, 72, through gold, 79); and metals of the actinoid (actinium, 89, through lawrencium, 103) and lanthanoid series (lanthanum, 57, through lutetium, 71) to form hard, alloy-like hydrides.
The elemental metal is prepared by the metallothermic reduction of its oxide, Yb2O3, with lanthanum metal, followed by a vacuum distillation to further purify the metal.
Misch metal, alloy consisting of about 50 percent cerium, 25 percent lanthanum, 15 percent neodymium, and 10 percent other rare-earth metals and iron.
