zirconium hydride powder is a dark gray to black metallic powder used in many applications including as a moderator in nuclear reactors, and in the fabrication of metal foams. zirconium hydride powder is also used in the production of zirconium and zirconium alloy products using powder metallurgy processes. The powder is manufactured by a hydride dehydride process where massive zirconium obtained by Kroll reduction is rendered brittle by hydrogenation and then crushed and ground to the required particle size. The resulting hydride is then heated to form a molten state that can be sintered under hot vacuum conditions to yield a ductile metal product.
Zirconium hydride is a highly reactive material with a high vapor pressure and a low melting point. It is able to bond with almost all other elements. It is very important in preparing zirconium alloys for nuclear power applications as it allows the use of relatively low temperatures to achieve good strength and ductility. Unlike other refractory metals, zirconium hydride is very stable in air, and has excellent corrosion resistance. It is also the only refractory metal to have good ductility in the molten state, even at very high temperatures.
The ductility of zirconium alloys is dependent upon the microstructural orientation of the hydride network that forms within them. In order to ensure that the network has the proper orientation to maintain high ductility, it is necessary to control the growth direction of the precipitate plates that form in the a-zirconium matrix. Precipitate plate orientation in the a-zirconium structure is controlled by the distribution of tensile stress in the component and the geometry of the hydride interfaces that form with other constituents such as the carbides.