11/17/2003

Brazing Cast Iron

"Process for forming unusually strong joints between metals and ceramics
by brazing at temperatures that do no exceed 750 degree C. 


Abstract
This invention is a process for joining metals to ceramics to form very
strong bonds using low brazing temperature, i.e., less than 750.degree.
C., and particularly for joining nodular cast iron to partially
stabilized zirconia. The process provides that the ceramic be coated
with an active metal, such as titanium, that can form an intermetallic
with a low melting point brazing alloy such as 60Ag-30Cu-10Sn. The
nodular cast iron is coated with a noncarbon containing metal, such as
copper, to prevent carbon in the nodular cast iron from dissolving in
the brazing alloy. These coated surfaces can be brazed together with the
brazing alloy between at less than 750.degree. C. to form a very strong
joint. An even stronger bond can be formed if a transition piece is used
between the metal and ceramic. It is preferred for the transition piece
to have a coefficient of thermal compatible with the coefficient of
thermal expansion of the ceramic, such as titanium. "

US Patent 4,621,761

Nobody - especially those that like to coat metal with ceramics - would
have an interest - right?