Process‐Controlled Plasma‐Sprayed Yttria‐Stabilized Zirconia Coatings: New Insights from Ultrasmall‐Angle X‐ray Scattering

Abstract

A multicomponent microstructure model is applied in ultrasmall‐angle X‐ray scattering studies of two groups of plasma‐sprayed yttria‐stabilized zirconia thermal barrier coatings (TBCs). One group was sprayed from a single powder feedstock using controlled processing conditions. The other group included three different feedstock morphologies (obtained from different manufacturing methods), each with a similar particle size distribution and sprayed under the same average controlled processing conditions. The microstructure is quantitatively related to the feedstock morphology and processing conditions. Relationships are explored among these microstructures and the coating properties (e.g., thermal conductivity, elastic modulus). The degree of microstructural anisotropy is demonstrated to be pore‐size dependent, being more pronounced for larger pores, and more sensitive to feedstock morphology (powder processing) than to spray processing. The microstructure analysis indicates two broad distributions of interlamellar pores, which combined, account for 70%–80% of the pore volume. The total porosity is found to increase with decreasing particle temperature or velocity. For all coatings, a negative linear relationship exists between thermal conductivity and total porosity. Comparison of the new analysis is made with earlier small‐angle neutron scattering results, and implications are considered for a more general application of this metrology in TBC microstructure design.

Protein Localization in Silica Nanospheres Derived via Biomimetic Mineralization

“…By using the MaxEnt method a histogram is obtained which corresponds to the maximum configurational entropy compatible with the data. This approach has been successfully applied to determine the size distribution in a wide range of different materials 41–45…”

Synthesis of Monoclinic and Cubic ZrO2 Nanoparticles from Zircon

“…1 In addition, there is a high level of interest in zirconia nanocoatings have because of high-performance applications, such as wearresistant insulating coatings, sensors and thermal barrier coatings. 21,22 It is suitable for powder phosphorization and is used to produce proton-conductive zirconium phosphate particles. Phosphorized zirconium oxide nanoparticles are used for the preparation of composite polymer membranes.…”

“…27 Pure ZrO 2 has three stable crystal forms, namely P21/c monoclinic (m), P42/nmc tetragonal (t) and Fm3 m cubic fluorite (c) at different temperatures. 22 An orthorhombic polymorph is also possible, 28 but only occurs at room temperature in pure zirconia under metastable conditions due to constraint. 29 Zirconia has a monoclinic phase at room temperature and it transforms into tetragonal and cubic phase at 11701 and 23701C, respectively.…”

A highly strain and damage‐tolerant thermal barrier coating fabricated by electro‐sprayed zirconia hollow spheres

“…Researchers have been devoted to stiffness modification of APS TBCs by controlling the coating porosity. These work focused on the plasma spraying parameters, feedstock materials (e.g., morphology and size distribution) . The bimodal structured in top coats have been developed previously to enhance the TBCs durability, using nano‐structured YSZ powder prepared by spray drying.…”

“…These work focused on the plasma spraying parameters, [13][14][15][16][17][18][19][20] feedstock materials (e.g., morphology and size distribution). [21][22][23][24] The bimodal structured in top coats have been developed previously to enhance the TBCs durability, using nano-structured YSZ powder prepared by spray drying [25][26][27][28] .…”