Hafnium is a good absorber of neutrons and is used to make control rods for nuclear reactors (Control rod for nuclear reactors (1989)) .
Hafnium has been successfully alloyed with several metals including iron (Amorphous Alloy Containing Iron Group Element And Hafnium (1982)), titanium (Hafnium containing high temperature alloy (1990)), and niobium (Improvements in or relating to niobium base alloys containing hafnium (1967)).
Hafnium oxide is used as an electrical insulator in microchips (Integrated Electronic Circuit Including A Thin Film Portion Based On Hafnium Oxide (2010)), while hafnium containing catalysts have been used in polymerisation reactions (Hafnium metallocene catalyst for the polymerization of olefins (1988)).
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All patent information has been obtained from Espacenet (European Patent Office).