Atmospheric-pressure plasma-assisted powder jet deposition for thick hydroxyapatite film formation -Effect of atmospheric-pressure plasma jet

Powder jet deposition (PJD) is a spray coating method and can perform under an environment of atmospheric pressure and room temperature. The deposition environment is advantageous for clinical use and the PJD process has been tried to apply to dental treatment by using fine particles of hydroxyapatite. However, its deposition rate is significantly low compared with other heating and/or vacuum processes. We, therefore, applied an atmospheric-pressure plasma jet (APPJ) to the PJD process to increase its deposition rate without changing the environment. The experimental results illustrate that the APPJ assistance provided the effect of increasing the deposition rate on the PJD process, while the effect of the APPJ irradiation time was saturated within 15 s. Additionally, the interval of the APPJ irradiation and the PJD process also had a significant effect on the deposition rate, i.e., the shorter the interval was, the larger the deposition rate got. These results are in accord with our assumption of the effect of the APPJ irradiation on increasing the PJD rate.