Abstract: Disclosed is a hermetic bond for a joint including a first layer of silicon carbide; a second layer of silicon carbide; and a bonding layer positioned between the first layer and the second layer, wherein the bonding layer includes an iridium layer, a first reaction zone positioned between the iridium foil layer and the first layer, and a second reaction zone positioned between the iridium foil layer and the second layer, wherein the first reaction zone and the second reaction zone include iridium silicides.

Abstract: Disclosed is a hermetic bond for a joint including a first layer of silicon carbide; a second layer of silicon carbide; and a bonding layer positioned between the first layer and the second layer, wherein the bonding layer includes an iridium layer, a first reaction zone positioned between the iridium foil layer and the first layer, and a second reaction zone positioned between the iridium foil layer and the second layer, wherein the first reaction zone and the second reaction zone include iridium silicides.

Abstract: An exemplary method of bonding of silicon carbide and objects having a hermetic silicon carbide-iridium-silicon carbide bond. The method includes the steps of inserting an iridium foil between two SiC layers; heating the iridium foil and SiC layers at a temperature of 1500 C in a vacuum of <10?5 ton; applying a pressure between 1 ksi and 7 ksi to the iridium foil and SiC layers; maintaining the temperature and pressure for 6-10 hours; and forming a hermetic seal having a leak rate <3×10?9 cm3/sec between the iridium foil and the two SiC layers. The SiC-iridium bonds lack cracks and are hermetic.

Abstract: An exemplary method of bonding of silicon carbide and objects having a hermetic silicon carbide-iridium-silicon carbide bond. The method includes the steps of inserting an iridium foil between two SiC layers; heating the iridium foil and SiC layers at a temperature of 1500° C. in a vacuum of <10-5 torr; applying a pressure between 1 ksi and 7 ksi to the iridium foil and SiC layers; maintaining the temperature and pressure for 6-10 hours; and forming a hermetic seal having a leak rate <3×10-9 cm3/sec between the iridium foil and the two SiC layers. The SiC-iridium bonds lack cracks and are hermetic.

Abstract: A ductile alloy is provided comprising molybdenum, chromium and aluminum, wherein the alloy has a ductile to brittle transition temperature of about 300 C after radiation exposure. The invention also provides a method for producing a ductile alloy, the method comprising purifying a base metal defining a lattice; and combining the base metal with chromium and aluminum, whereas the weight percent of chromium is sufficient to provide solute sites within the lattice for point defect annihilation.

Abstract: A method for producing monolithic Zirconium Carbide (ZrC) is described. The method includes raising a pressure applied to a ZrC powder until a final pressure of greater than 40 MPa is reached; and raising a temperature of the ZrC powder until a final temperature of less than 2200° C. is reached.

Abstract: A ductile alloy is provided comprising molybdenum, chromium and aluminum, wherein the alloy has a ductile to brittle transition temperature of about 300 C after radiation exposure. The invention also provides a method for producing a ductile alloy, the method comprising purifying a base metal defining a lattice; and combining the base metal with chromium and aluminum, whereas the weight percent of chromium is sufficient to provide solute sites within the lattice for point defect annihilation.

Abstract: A method for producing monolithic Zirconium Carbide (ZrC) is described. The method includes raising a pressure applied to a ZrC powder until a final pressure of greater than 40 MPa is reached; and raising a temperature of the ZrC powder until a final temperature of less than 2200° C. is reached.

Abstract: A method for diffusion bonding ceramic layers such as boron carbide, zirconium carbide, or silicon carbide uses a defocused laser beam to heat and to join ceramics with the use of a thin metal foil insert. The metal foil preferably is rhenium, molybdenum or titanium. The rapid, intense heating of the ceramic/metal/ceramic sandwiches using the defocused laser beam results in diffusive conversion of the refractory metal foil into the ceramic and in turn creates a strong bond therein.