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Despite the higher phase fraction of Cr3C2 produced by the three-component precursor system , SEM imaging of the sample microstructures and fracture analysis indicated that increased bonding occurred in Cr3C2 produced by conversion of Cr/Cr2O3 .
 phase fraction, precursor, SEM, imaging, sample, microstructures, fracture, bonding
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 phase fraction, precursor, SEM, imaging, sample, microstructures, fracture, bonding