Process for joining molded silicon nitride parts

Abstract From the Canadian patent

For joining shaped bodies of silicon nitride together silicon nitride surfaces to be joined are first polished and then put into an apparatus for applying sputtered layers where they are first cleaned by ion bombardment in argon followed, immediately by sputtering with silicon in a nitrogen atmosphere such that a layer is deposited having a nitrogen content exceeding the Si3N4 stoichiometric ratio. This readily provides a layer of the composition Si3N5.5. A complementary nitrogen deficient layer is also provided in the joint before hot pressing,either in the form of a silicon layer that goes between the nitrogen-rich silicon nitride layers or in the form of a nitrogen-deficient silicon …