Sisson, Richard D.
UCT Coatings, Inc
The goal of this project was to determine the microhardness values of electroless Ni-B coating during isothermal heat treatments and gain an understanding of the phase transformations that occur. The test matrix ranged from 200?C to 1000?C for various times. Hardness testing was used to determine the amount of time necessary to obtain peak microhardness values. X-ray diffraction determined the ratio of Ni to NiB in each sample. Optical microscopy and SEM analysis helped study the microstructure and failure of samples. EDS analysis helped to determine composition and diffusion. Results show that peak hardness occurs between 550?C and 650?C after 2 hour heat treatments; iron diffuses into the coating which may have caused failure at 850?C; and the concentration of NiB decreases at the surface with increasing time and temperature.
Worcester Polytechnic Institute
Major Qualifying Project
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