In this study, Mo coatings were fabricated on cast-iron substrate using a plasma-spray technique for diesel engine motors. In
order to undergo cyclic heating because of piston element in combustion chamber, thermal behaviour of these coatings were
scrutinized through a thermal cycling machine. These Mo coatings were tested at temperature range of 47–600
8
C for periods of
303 s under thermal cycling conditions. The effects of thermal cycling on the properties of the samples were characterized by
using an optical microscope, image analyzer, SEM, X-ray diffraction
(
XRD
)
, thermogravimetric analysis
(
TGA
)
, differential
scanning calorimetry
(
DSC
)
and microhardness tester. Microstructural observations showed that the coatings possessed lamellae
structure with boundaries. XRD, TGA and DSC results revealed that Mo coatings transformed to MoO and MoO during the
3
thermal cycling process. It was found that an increase in porosity and residual thermal stresses after thermal cycling influenced
the hardness results of the samples considerably. It was also observed to be a delimination between coating and substrate after
thermal cycling