Hypoeutectic alloys of the Au-Co system were studied for use in dental castings. Microhardnese and tensile data were determined for annealed and aged alloys of compositions from 0.5 to 10 at. yo Co in Au. Maxima for this alloy of HK 119, elongation 23% in 10 mm, yield st,rengt,h of 185 MN/m2 (0.20/, oRset) and tensile strength of 257 MX/m2 occurred following aging a t 350Β°C for 15 min. The system is cousidered promising for use as a dental casting gold alloy.
Modern dental casting alloys contain gold in quantities sufficient to prevent gross corrosion while in service, and yet they are alloyed xith sizeable amounts of non-precious metals in order to enhance their mechanical properties and reduce cost. This arrangement has resulted in a wide variety of casting gold alloys with excellent characteristics, which have been tailored to specific situations. At present, these alloys must contain minimum amounts of non-corrosive gold and platinum group metals in order to be certified by the American Dental Association according to Specification No. 5.' These minima are established because no reliable tests for tarnish or corrosion resistance in the oral cavity are available. Experience has shown