Solution Precursor Plasma Spraying of Bismuth Titanate by Means of Inductively-Coupled Thermal Plasma

Lead-free piezoelectric materials are nowadays drawing considerable attention as lead titanium zirconium oxide (PZT) is considered “as a substance of very high concern” by the European Chemicals Agency because of its toxicity. An interesting PZT replacement material for high temperature capable ultrasonic transducers is bismuth titanate (Bi₄Ti₃O₁₂), which could be used for pipe thickness and corrosion monitoring in the oil & gas and nuclear industries. In this study, solution precursor plasma spraying (SPPS) is used to deposit Bi₄Ti₃O₁₂ coatings onto stainless steel substrates by means of inductively-coupled thermal plasma. The crystal structure and the morphology of the deposited coatings is studied as a function of the SPPS operating parameters such as plasma gases, electrical power, chamber pressure and spraying distance. SPPS of piezoelectric materials is an interesting one step process alternative to the time consuming layered-based chemical spray pyrolysis/calcination of sol-gel precursors.