All of the following statements about cast cobalt
alloys are true EXCEPT:
(A) They have a modulus of elasticity twice that of gold alloys. (B) They are more rigid than gold alloys. (C) They have higher ductility than gold alloys. (D) They have a lower proportional limit than gold alloys.
(C) Gold is the most ductile and malleable metal. This property enables manufacturers to beat it into thin foils. Silver is second. Among other metals platinum ranks third in ductility and copper ranks third in malleability.
Mannapalli 3 ed page no 16