University of California

The United States of America As Represented by the United States

John J Petrovic

Richard E Honnell

Frank D Gac

David H Carter

Robert P Rodriguez

W Scott Gibbs

Zuhair A Munir

Kenneth J McClellan

Ivar E Reimanis

Joseph N Woolman

Alloys of transition metal suicides that contain one or more alloying elements are fabricated by a two-stage process involving mechanical activation as the first stage and densification and field-activated reaction as the second stage. Mechanical activation, preferably performed by high-energy planetary milling, results in the incorporation of atoms of the alloying element(s) into the crystal lattice of the transition metal, while the densification and field-activated reaction, preferably performed by spark plasma sintering, result in the formation of the alloyed transition metal silicide. Among the many advantages of the process are its ability to accommodate materials that are incompatible in other alloying methods.

Microalloying of transition metal silicides by mechanical activation and field-activated reaction

Molybdenum disilicide/&bgr;&prime;-Si,Al,O,N,, wherein z&equals;a number from greater than 0 to about 5, composites are made by use of in situ reactions among &agr;-silicon nitride, molybdenum disilicide, and aluminum. Molybdenum disilicide within a molybdenum disilicide/&bgr;&prime;-Si,Al,O,N,eutectoid matrix is the resulting microstructure when the invention method is employed.

Molybdenum disilicide composites

Process for making graded porosity ceramics. A process for making graded porosity ceramics is described which includes the steps of placing a chosen amount of ceramic powder into a mold, compacting the ceramic powder into a green body, applying at least one sintering aid precursor to at least one chosen surface of the green body, allowing the at least one sintering aid precursor to penetrate the at least one surface within a chosen volume of the green body, heating the green body, whereby the sintering precursor generates a sintering aid, and hot pressing and sintering the heated body at a temperature whereby the green body is transformed into the sintered ceramic object.

Process for making ceramic bodies having a graded porosity

Compositions consisting essentially of molybdenum disilicide, silicon carbide, and a zirconium oxide component. The silicon carbide used in the compositions is in whisker or powder form. The zirconium oxide component is pure zirconia or partially stabilized zirconia or fully stabilized zirconia.

Molybdenum disilicide composites reinforced with zirconia and silicon

Compositions of matter consisting of matrix materials having silicon carbide dispersed throughout them and methods of making the compositions. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms.

Molybdenum disilicide alloy matrix composite

Compositions of matter comprised of silicon nitride and molybdenum disilicide and methods of making the compositions, where the molybdenum disilicide is present in amounts ranging from about 5 to about 50 vol. %.

Silicon nitride reinforced with molybdenum disilicide

Compositions of matter comprised of molybdenum disilicide and zirconium oxide in one of three forms: pure, partially stabilized, or fully stabilized and methods of making the compositions. The stabilized zirconia is crystallographically stabilized by mixing it with yttrium oxide, calcium oxide, cerium oxide, or magnesium oxide and it may be partially stabilized or fully stabilized depending on the amount of stabilizing agent in the mixture.

Zirconia-molybdenum disilicide composites

A composition consisting of an intermetallic compound, molybdenum disilicide, which is reinforced with VS silicon carbide whiskers dispersed throughout it and a method of making the reinforced composition. Use of the reinforcing material increases fracture toughness at low temperatures and strength at high temperatures, as compared to pure molybdenum disilicide.

Molybdenum disilicide matrix composite

Compositions of matter consisting of matrix matrials having silicon carbide dispersed throughout them and methods of making the compositions. A matrix material is an alloy of an intermetallic compound, molybdenum disilicide, and at least one secondary component which is a refractory silicide. The silicon carbide dispersant may be in the form of VLS whiskers, VS whiskers, or submicron powder or a mixture of these forms.

Growing community of inventors

Los Alamos, NM, United States of America

John J Petrovic