Polycrystalline ferroelectric fiber

An inorganic, polycrystalline, ferroelectric fiber with a diameter of from about 1 micron to 1 millimeter, a porosity of less than about 40 percent, a density of at least about 60 percent of the theoretical density, and a carbonaceous material content of from about 0 to about 5 percent, wherein:

• (a) said fiber consists essentially of grains of which substantially 100 percent are from about 0.01 to about 5.0 microns in size, provided that the ratio of the size of the largest grain in said fiber to the size of the smallest grain in said fiber is no greater than about 10;
• (b) at least about 95 weight percent of said fiber consists of crystals of a formula selected from the group consisting of ABO.sub.3, (A.sub.y A'.sub.z [A".sub.w ].sub.x)(B.sub.2 B'.sub.8)O.sub.30, A.sub.a B.sub.b O.sub.c, and mixtures thereof, wherein:
• 1. A, A', and A" are each atoms selected from the group consisting of lithium, sodium, potassium, lanthanum, gadolinium, calcium, strontium, barium, lead, bismuth, yttrium, cerium, praseodymium, neodymium, samarium, europium, terbium, dysprosium, holmium, and cadmium atoms, and mixtures thereof, provided that A" differs from both A and A';
• 2. x is from 0 to 1;
• 3. w, y, and z are each positive numbers, wherein w is from 0 to 4, y is from 0 to 5, and z is from 0 to 5;
• 4. a is from 2 to 9, b is from 1 to 8, and c is from 6 to 27;
• and
• 5. B and B' are each atoms selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, magnesium, tantalum, tungsten, molybdenum, tin, manganese, antimony, chromium, nickel, iron, zinc, scandium, silicon, germanium, tellurium, aluminum, and cobalt atoms, and mixtures thereof.