In this study, microstructural, Daimler-Benz adhesion and tribological
properties of boro-tempered ductile cast iron were investigated.
The following conclusions can be drawn from the results.
For all boro-tempering conditions the boride layers consisted of
major Fe2B and minor FeB phases. Boro-tempering conditions
(boriding time and tempering temperature) affected the boride
layer. Low boriding time and high tempering temperature decreased
amount of FeB phase. Thickness of boride layer increased
with the increase in boriding time. The layer thicknesses of borotempered
samples were 26 ± 2, 52 ± 5 and 58 ± 5 lm for boriding
time of 1, 3, and 5 h, respectively.
Boride layers on the ductile iron surface had saw tooth morphology
and layer/matrix interfaces were rather smooth. Underneath
the boride layers, ductile irons had different matrix
structures with acicular lower ausferrite at 250 C, acicular upper
ausferrite at 300 C, upper ausferrite at 350 C and rude upper ausferrite
matrix structure at 400 C depending on tempering temperature.
While the hardness of boride layer varied between 694 and