In this proposed doctoral work, we intend to continue the research already initiated relating the effect of thermal barrier coating on the Ti-6Al-4V. These studies considered a ceramic coating with high levels of porosity, cracks and inclusions. The objective of this project is to develop a process for depositing a multilayer of CoNiCrAlY + ZrO2 in Ti-6Al-4V alloy using a plasma torch, aiming to improve coating microstructure to optimize the mechanical properties of the alloy. The parameters thermal conductivity, modulus of elasticity (strain tolerance), growth rate, thickness, crystalline structure, porosity, surface roughness, cohesion and adhesion will be used to evaluate the coating produced. The development of the deposition process is going to be done in the Laboratory of Plasmas and Processes (LPP) of the ITA with a thermal plasma torch. Process parameters such as plasma density, Mach, power, gas flow, gas enthalpy, gas used, the powder injection angle, distance from the spray trajectory and speed of the positioning system of the sample and the characteristics of the powder used will be studied to optimize the coating. After applied the coating on the Ti-6Al-4V, creep tests at temperatures of 500 to 600ºC will be conducted, initially in the form of constant load, and the stress range will be determined via the hot tensile tests. Complete studies in order to develop a process for depositing a multilayer substrate ZrO2 + CoNiCrAlY alloy Ti-6Al-4V, using a plasma torch are scarce. A set of curves will be obtained and experimental parameters relating primary, secondary and tertiary creep stages as a function of applied stress and temperatures. Microstructural characterization via scanning electron and transmission microscopy, as well as atomic force microscopy are valuable tools for the characterization of the coating obtained by plasma deposition process and the operating creep mechanisms (TEM).
News published in Agência FAPESP Newsletter about the scholarship: