Effect of processing on toughness index of diamond grains during vacuum brazing

To reduce the thermal damage when brazing diamond, four solutions are proposed and tested according to the thermal damage mechanism of diamonds.SEM observation and toughness index test are used to analyze those solutions.Resultsshow that reducing oxygen content in the stove has limited effect on improving toughness index (TI) values of diamond, while reducing content of catalyst and coating diamond with Ti-Ni composite layers would increase TI, compared with that of the original process, by more than 15% and 20% separately.It is found that Cu-based solder causes the smallest thermal damage to diamond, whose toughness index remains 91.5% of the original state.