Affiliation:
1. JSS Academy of Technical Education
2. Visvesvaraya Technological University
Abstract
<div class="section abstract"><div class="htmlview paragraph">High-temperature corrosion is a crucial issue in power plant components such as
boilers and superheaters when they operate in high-temperature aggressive
environments leading to early component failure. As a result, surface
modification is critical to protect parts against various types of degradations
and increase operational performance at the lowest possible cost. The present
study deals with Metco 42C and cenosphere-based composite coating on ASME A387
Grade 22 boiler steel material. The coating compositions were prepared by weight
fraction of 5% and 10% cenosphere with Metco 42C and coated on T22 boiler tube
material by plasma spray technique. To check the performance a high-temperature
cyclic oxidation study at 600°C for 20 cycles in a molten salt environment of
sodium sulfate (40%Na<sub>2</sub>SO<sub>4</sub>) and vanadium pentoxide
(60%V<sub>2</sub>O<sub>5</sub>) was carried out and simultaneously corrosion
kinetics was evaluated after each cycle. Neutral salt spray (NSS) and cyclic
corrosion tests were carried out at defined temperature and humidity cycles in a
salt mist environment to understand the relative corrosion resistance of coated
and uncoated substrates. The characterization techniques such as scanning
electron microscope (SEM) and X-ray diffraction (XRD) were utilized to check the
morphology of tested samples. The bond strength, porosity, and hardness tests
were done independently to characterize the coating. The results of the
high-temperature oxidation test showed protective oxide layers formation on
coated samples, improving high-temperature oxidation resistance. Additionally,
the neutral salt spray and cyclic corrosion test results of coated substrate
showed higher relative corrosion resistance as compared to uncoated
substrate.</div></div>