The as-cast microstructures of the standard 
935 sterling silver alloy (93.5Ag-6.5Cu) prepared 
by investment and metal mould casting are given in 
Figure 4. Both microstructures consist of cored Ag-
rich (
α
-phase) dendrites with small amounts of 
interdendritic eutectic 
constituent. The faster 
cooling rate during solidification of the sample cast 
in the metal mould has given a much finer grain 
size and dendrite arm spacing than the investment 
cast sample resulting in the higher observed 
hardness of the metal mould sample. Almost no 
macropores appeared in the as-cast microstructure 
of the standard sterling (no Zn or Si addition) 
prepared by investment casting, while macropores 
in size of 10 
μ
m are normally appeared in the 
metal mould cast sample.