|
| Abstract No.: |
|
| Title: |
Role of HVOF spray NiCr coatings to control high temperature oxidation of boiler steels
|
|
| Authors: |
Harpreet Singh Saheet* / BBSB Engineering College, FATEHGARH SAHIB, INDIA
Gagandeep Kaushal / RIMT-Institute of Engineering and Technology, INDIA
Satya Prakash/ Indian Institute of Technology, INDIA
|
|
| Abstract: |
A study was carried out to determine the role of HVOF-spray NiCr coatings to enhance high temperature oxidation resistance of T22 and 347H boiler steels. NiCr coatings were deposited on the boiler steels by HVOF process. Subsequently high temperature oxidation behavior of the coated as well as uncoated steels was investigated by laboratory tests in the air at an elevated temperature of 900ºC under cyclic conditions. Each oxidation cycle consisted of 1 hour heating in silicon carbide tube furnace followed by 20 minute cooling in ambient air. Thermogravimetric data was taken after each cycle for a total exposure of 50 hours to establish oxidation kinetics. The specimens were physical examined also after each cycle to notice any macrographic physical changes, spallation tendency of their oxide scales etc. The oxide products were characterized using X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). It was observed that the oxidation rate was low in coated substrates as compared to their uncoated counterparts. The NiCr coating was found to be useful in protecting the substrate steels against high temperature oxidation.
|
|