Abstract:
Monel K-500 is a nickel-based alloy broadly
used in several industries such as power generation, aerospace, marine and chemical processing for manufacturing
several critical components. During hydraulic applications,
the alloy is subjected to different degradation phenomena
such as cavitation erosion, slurry erosion and corrosion.
The current study assesses the potential of using two
HVOF-sprayed nickel-based cermet coatings: WC-10Ni5Cr and WC-18Hastelloy C to control the slurry erosion of
Monel K-500. The coatings were subjected to slurry erosion tests for 90 min at normal (90) and oblique (30)
impingement angles. It was observed that these coatings
significantly reduced the erosive wear in Monel alloy. WC10Ni-5Cr coating, having relatively better microhardness
and fracture toughness has shown minimum erosion losses.
At normal impact, WC-10Ni-5Cr coating and WC18Hastelloy C coating reduced the erosion rate of Monel
by 2.3 and 1.6 times, respectively. At oblique impact, WC10Ni-5Cr coating and WC-18Hastelloy C coating reduced
the erosion rate of Monel by 4.75 and 2.4 times, respectively. In-depth study of the erosion mechanism for the
investigated materials was conducted using scanning
electron microscopy. Ploughing and micro-cutting were the
primary erosion mechanisms in Monel alloy, whereas
coating spallation and crater formation were the primary
erosion mechanisms in the coatings.
