Abstract
Diamond films were synthesized on a Mo substrate using combustion flame. Most diamond films delaminated, during the cooling process. In our previous work it has been shown that a three stepwise combustion flame method was possible to prevent a delamination. But it was not perfect. In this study, effect of a distance of the flame inner cone from the substrate (the inner cone distance) of each step of the three stepwise method and substrate surface profiles after scratching treatment were remarked as most important factor to prevent the delamination. In order to improve the bonding strength, the inner cone distance of each step of the three stepwise method and surface profile were changed. The first step of the three stepwise method was set to the distance d=1.0mm, the second step was set to the distance d=2.0mm and the third step was set to the distance d=3.0mm, respectively, with each the scratching treatment of #180, 400, 800 and 1500 on the substrate surface. The results showed that the change of the distance of the three stepwise method was effective much in the delamination prevention. Especially, no delamination was observed at the scratching treatment of #400 and no abnormal growth of diamond crystal was also observed by the changing distances. The result of SEM observation and XRD analysis showed that high quality diamond crystal at the synthesized film for the scratching treatment of #400 was obtained by the changing distances. It was concluded that high delamination resistance diamond film could be realized by changing the distances.
