Barium, strontium or lead ferrite is produced in the usual manner by mixing together barium, strontium or lead carbonate and ferric oxide, calcining this to form the barium, strontium or lead ferrite and grinding the ferrite in slurry form in a mill to a particle size of about 1 micron average diameter. According to the invention, the barium, strontium or lead ferrite slurry before, during or after grinding in the mill has added thereto a reagent, which converts any barium, strontium or lead hyd...

Ferrite having a uniform degree of oxidation is produced at a higher rate of ferrite forming reaction by pelletizing a mixture of iron oxide and ferromanganese powders and calcining the mixture at a temperature of 900.degree. C. or higher. Zinc oxide, magnesium oxide and/or nickel oxide may be further added to the mixture, as required.

A solid material useful for producing hexagonal ferrites comprises a homogeneous mixture of the cations of the composition (I) and one or more anions comprising one or more thermally decomposable anions.

Metallic ferrites are prepared by forming a solution of metallic sulfate a ferrous sulfate. A mixed sulfate is formed when the solvent in the solution is evaporated. Heat transforms the mixed sulfate into the corresponding ferrite.

A method for sintering Mn--Zn ferrite green compacts is provided which includes a first heating step of raising the temperature from room temperature to 600.degree. C. within a period from 30 minutes to 5 hours, a second heating step of raising the temperature from 600.degree. C. to the sintering temperature and holding the sintering temperature until the start of cooling within a period shorter than 10 hours, and a cooling step of lowering the temperature to 150.degree. C. within a period longe...

Platelike alkaline-earth ferrites and lead ferrites for memory cores are produced from impure initial substances by decomposing the initial substances with a molten, basic alkali compound, and the precursor separated off after dissolution in water is annealed for 0.5 to 6 hours at 600.degree. to 950.degree. C.

The present invention provides a method for metallizing a ceramic surface comprising a ferrite through a surface reduction treatment. A ceramic surface comprising a ferrite is heated. At least a portion of the ferrite is contacted with a gaseous reducing agent to create a metallic region by removing oxygen from the ferrite. The surface is cooled and, optionally, post-treated to enhance adhesion of the metallic region. Typical gaseous reducing agents are hydrogen, forming gas, and ammonia while t...

Miniature-sized, manganese-zinc ferrites of 5000, and higher, permeabilities with relative core loss factors of 10 .times. 10.sup.-.sup.6, and lower, at 100 KHz are produced from high purity manganese, zinc and iron oxides which are milled to micron sizes, spray-dried to form spherical shapes, and sphere sizes selected for compaction. The compacted parts are plunged directly into a high temperature (1200.degree. to 1450.degree.) sintering environment. Sintering is carried out in atmospheric air ...

The improvement in the process for recovering zinc from ferrites which includes treating electrolytic zinc plants residues with a sulfuric acid solution to dissolve the zinc and metals, a solution resulting which contains sulphates of zinc and the other dissolved metals. The undissolved residue is separated in a certain manner from the solution. The solids-free solution is neutralized in a second step with calcine or another neutralizing agent containing zinc until a certain acidity is reached s...

A process for producing a ferrite magnetic material of the cubic, hexagonal magnetoplumbite or garnet type comprises mixing with ferric oxide derived from a process involving iron or steel making or working, an activator capable of reacting with the ferric oxide to impart to it the required magnetic characteristics, sintering the mixture at a temperature effective to produce the reaction, and grinding the sintered material to the required particle size.