Suppression of carbon dust agglomeration and volatile molecular formation in C–H–N reactive molecular system

Chemical erosion of carbon materials and dust formation in low-temperature and neutral particle-dominated plasmas were investigated using high-pressure inductively coupled plasmas. Experiments were performed with Ar/H2/N2 mixture plasma irradiation to graphite targets. The addition of just a few percent of nitrogen gas to hydrogen led to significant suppression of carbon dust formation on the graphite target. From optical emission spectroscopy, CN band spectra were observed strongly in Ar/H2/N2 plasmas with a decrease of CH and C2 band emission intensity. These results showed that CN bond formation, which caused chemical erosion of carbon by producing volatile CN, HCN, and C2N2 particles, might have been a key suppression mechanism of the carbon particle aggregation.