Tampere University of Technology

TUTCRIS Research Portal

Characterization of Powder-Precursor HVOF-Sprayed Al2O3-YSZ/ZrO2 Coatings

Research output: Contribution to journalArticleScientificpeer-review

Details

Original languageEnglish
Pages (from-to)98-107
JournalJournal of Thermal Spray Technology
Volume28
Issue number1-2
Early online date2018
DOIs
Publication statusPublished - Jan 2019
Publication typeA1 Journal article-refereed

Abstract

Thermal spraying using liquid feedstock can produce coatings with very fine microstructures either by utilizing submicron particles in the form of a suspension or through in situ synthesis leading, for example, to improved tribological properties. The focus of this work was to obtain a bimodal microstructure by using simultaneous hybrid powder-precursor HVOF spraying, where nanoscale features from liquid feedstock could be combined with the robustness and efficiency of spraying with powder feedstock. The nanostructure was achieved from YSZ and ZrO2 solution-precursors, and a conventional Al2O3 spray powder was responsible for the structural features in the micron scale. The microstructures of the coatings revealed some clusters of unmelted nanosized YSZ/ZrO2 embedded in a lamellar matrix of Al2O3. The phase compositions consisted of γ- and α-Al2O3 and cubic, tetragonal and monoclinic ZrO2. Additionally, some alloying of the constituents was found. The mechanical strength of the coatings was not optimal due to the excessive amount of the nanostructured YSZ/ZrO2 addition. An amount of 10 vol.% or 7 wt.% 8YSZ was estimated to result in a more desired mixing of constituents that would lead to an optimized coating architecture.

Keywords

  • AlO-ZrO, ceramic matrix composite, coating, HVOF, hybrid, solution-precursor spraying

Publication forum classification

Field of science, Statistics Finland

Downloads statistics

No data available