Oriented strontium ferrites which yield superior ceramic permanent magnets are produced by the four-step process of A. preparing small particles of agglomerated less than 0.1 micron grains of ferric oxide and strontium oxide, B. maintaining the particles of agglomerated oxides at temperatures of from about 800.degree. C to 1100.degree. C for up to about 24 hours to cause the oxides to react (ferritize) and form less than 0.5 micron diameter crystallites of strontium ferrite, C. sintering the cry...

Desirable properties of manganese zinc ferrites are obtained without the need for controlling or changing the oxygen partial pressure during the sintering and cooling steps by adding a small amount of germanium or gallium to the ferrite and using an atmosphere, such as air, during the sintering and cooling steps, that has at least 1 percent oxygen by volume.

A ferrite material based on nickel, copper and zinc has the following formula: in which: A material of this kind has the advantage of showing reduced losses.

A glass having a composition which would result by mixing from 20 to 80 weight percent of glass A with 80 to 20 weight percent of glass B and melting the mixture to form a homogeneous glass: said glass having a coefficient of thermal contraction from 15.degree. C. below the annealing point to room temperature of from 106 to 115.times.10.sup.-7 /.degree.C.

A pearlescent pigment which is a ferrite-coated iron oxide-coated platy substrate in which the ferrite is substantially free of crystallites is obtained by adding metal ions to a slurry of hydrous iron compound and platy particles and then co-calcining in the metal and iron.

A ferrite for magnetostrictrive vibrators is produced by the simple process of press forming a preformed structure formed from starting powder of magnetite or a mixture of magnetite and ferric oxide, said powder having an average particle size d (.mu.) of from 0.02 to 5.0 .mu., sintering this structure in an atmosphere wherein the partial pressure of oxygen is from 10.sup.-1 to 10.sup.-11 atmosphere at a temperature of from 1,000.degree. to 1,350.degree. C. and which will meet the requirement: a...

Methods of preparing ferrite powders for use in microwave elements such as isolators, circulators, phase shifters and transmission line elements. In one method separate precipitations of metal dicarboxylate salts such as oxalates or malonates are mixed with a ferrous dicarboxylate. This is followed by mixing and calcining of the precipitated dicarboxylates to form the ferrite powder. In another method metal acetates in a solution of concentrated acetic acidare mixed with iron powder to form a so...

Ferrite powder of consistent good quality and homogeneity is obtained by using nitric acid to form solutions of the nitrate of each of the metals involved, mixing the solutions in the requisite proportions, and decomposing the mixture by spray deposition on the hot surface of an agitated bed of granular material identical with the decomposition product while avoiding any accumulation of liquid, and then calcining the obtained oxide mixture to obtain ferrite powder with a desired proportion of re...

Microwave ferrites with narrow resonance linewidths, good temperature performance, low losses, low costs, and rectangular hysteresis loops are made from a lithium-titanium ferrite containing a small amount of zinc. In addition, small amounts of copper or manganese can be present in the ferrites.

A spherical resonator device includes a resonant sphere around which transducers for electrical coupling are metallized layers on a flat surface shaped to provide exposure of a sphere to a quasi constant field. In particular, the pattern comprises a transmission line of non-constant width in the region proximate to the sphere where a taper is provided which increases in width with distance from the sphere.