Abstract:
The nanoindentation fracture of multilayer hard coatings, such as
TiN,TiN/Ti(C,N)/TiC,TiN/Ti(C,N)/TiC/Ti(C,N)/TiC and TiN/Ti(C,N)/TiC/Ti(C,N)/TiC/Ti(C,N)/TiC
coatings, deposited on cemented carbide using a CVD technique are
studied. It is found that these coatings have high hardness. Based
on the analysis of the energy release in cracking, the fracture
toughness of these coatings are calculated. The observations
clearly establish a step occurs in the force-displacement curves
at the onset of coating fracture and a straight line segment in
the load-penetration depth squared curves to identify the
interfacial failure of coatings. The hardness, fracture toughness
and anti-wearability of these coatings are clearly compared. The
results show that with the layers increasing, the fracture
toughness and anti-wearability are getting larger.
Key words: Mechanical
properties CVD Multilayer coatings Nanoindentation
Manuscript received on
August 30, 1999; revised manuscript December 8, 1999
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