Hypersonic Plasma Particle Deposition
Jami Hafiz, advisor:

Nanostructured materials consist of grains in the nanometer size regime, and have generated considerable interest due to their remarkable mechanical, electrical, optical and magnetic properties. We have developed a one-step method of producing and depositing nanoparticles using a DC thermal plasma reactor called hypersonic plasma particle deposition (HPPD). In the HPPD process, vapor-phase reactants are injected into a thermal plasma, which is then expanded to low pressure through a cooled nozzle. Nanoparticles are nucleated from supersaturated vapor resulting from rapid cooling in the nozzle and accelerated in the hypersonic jet. The high-speed particles are then deposited by inertial impaction to form films and micropatterns. We are currently researching synthesis of nanostructured coatings comprised of the elements B, C, N, Si, Ti, as substances composed of these elements essentially constitute all of the hardest known materials.

In addition to film synthesis, a major focus of the project is film characterization. Several techniques have been employed to investigate nanoparticles prior to deposition as well as films constructed from these nanoparticles. A sampling probe interfaced to a scanning mobility particle sizer (SMPS) is used for in-situ measurements of particle size distributions. Structural and chemical characterizations are performed using various characterization tools such as X-ray diffraction, Rutherford backscattering, X-ray photoelectron spectroscopy, and scanning electron microscopy. Film cross sections are characterized using a focused ion beam (FIB) milling technique. Characterization of mechanical properties is being carried out using nanoindentation techniques.