A composite construction 1 is obtained by coating the outer periphery of a
core material 2 with a shell layer 3. The core material 2 is composed of
a first sintered body that is obtained by bonding, with a binder metal, a
first hard particle composed of one or more of carbides, nitrides and
carbonitrides of metals of Groups 4a, 5a and 6a of the Periodic Table, or
a first ceramics obtained by bonding, with a sintering additive, a first
ceramic particle composed of at least one of oxides, carbides, nitrides
and carbonitrides selected from the group consisting of metals of Groups
4a, 5a and 6a of the Periodic Table, Al, Si and Zn. The shell layer 3 is
composed of a second hard sintered body or second ceramics having a
different composition from the first hard sintered body. The ratio of the
residual free carbon amount C.sub.in in the core material 2 to the
residual free carbon amount C.sub.out in the shell layer 3,
C.sub.in/C.sub.out, is 0.5 to 2. This prevents shrinkage during the time
of sintering and also prevents the strength of the composite construction
from lowering due to poor sintering.