scholarly journals High Temperature Thermo-Mechanical Properties of Praseodymium Doped Ceria Thin Films Measured Two Ways

2022 ◽  
Author(s):  
Yuxi Ma ◽  
Quan Zhou ◽  
Jason D. Nicholas
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
High Temperature ◽  
Temperature Dependence ◽  
Internal Stress ◽  
Expansion Coefficient ◽  
Mechanical Stability ◽  
Doped Ceria ◽  
Stress Strain ◽  
Chemical Expansion

The temperature dependence of a Mixed Ionic Electronic Conducting (MIEC) material’s thermo-chemical expansion coefficient, biaxial modulus, and/or Young’s modulus are crucial in determining the internal stress, strain, and/or mechanical stability...

Temperature dependence of the mechanical properties of tetrahedrally coordinated amorphous carbon thin films

2005 ◽  
Vol 87 (16) ◽  
pp. 161915 ◽  
Author(s):  
David A. Czaplewski ◽  
J. P. Sullivan ◽  
T. A. Friedmann ◽  
J. R. Wendt
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Temperature Dependence ◽  
Amorphous Carbon ◽  
Carbon Thin Films

scholarly journals Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hendrik Wulfmeier ◽  
Dhyan Kohlmann ◽  
Thomas Defferriere ◽  
Carsten Steiner ◽  
Ralf Moos ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Film Thickness ◽  
Solid Solutions ◽  
Low Voltage ◽  
Excitation Frequency ◽  
Dimensional Change ◽  
Potential Core ◽  
Chemical Expansion

Abstract The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.

Thin Film Stoichiometry Determination by High Temperature Microbalance Technique

2002 ◽  
Vol 756 ◽  
Author(s):  
H. Fritze ◽  
H. Seh ◽  
O. Schneider ◽  
H. L. Tuller ◽  
G. Borchardt
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
High Temperature ◽  
Electrical Impedance ◽  
Ceramic Materials ◽  
Small Mass ◽  
Transport Processes ◽  
Electrical Impedance Spectroscopy ◽  
Mechanical Stiffness ◽  
Resonance Behavior

ABSTRACTThe in-situ determination of small mass changes of thin films became feasible with the availability of high temperature stable microbalances. With this technique, changes of the mechanical properties of thin films deposited on piezoelectric resonators are investigated at temperatures above 500 °C by monitoring the resonance behavior of the resonators. The results are valuable for fundamental understanding of the ionic and electronic transport processes in ceramic materials and for applications such as high temperature gas sensors.This work correlates the electrical and the mechanical properties of TiO2-x at different oxygen partial pressures. TiO2-x films are deposited onto high temperature resonators by laser ablation and characterized by the high temperature microbalance technique as well as electrical impedance spectroscopy at 600 °C.The oxygen partial pressure dependent resonance behavior cannot be attributed solely to mass changes of the TiO2-x film. Changes of the film's mechanical stiffness have to be taken into consideration to explain the resonance behavior. The simultaneous electrical impedance measurements indicate a n-type conduction behavior of the TiO2-x films.

Investigation of the influence of the vanadium content on the high temperature tribo-mechanical properties of DC magnetron sputtered AlCrVN thin films

2017 ◽  
Vol 328 ◽  
pp. 172-181 ◽  
Author(s):  
Wolfgang Tillmann ◽  
David Kokalj ◽  
Dominic Stangier ◽  
Michael Paulus ◽  
Christian Sternemann ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
High Temperature ◽  
Vanadium Content

Measurement of Thin Film Mechanical Properties by Microbeam Bending

1999 ◽  
Vol 563 ◽  
Author(s):  
J. Florando ◽  
H. Fujimoto ◽  
Q. Ma ◽  
O. Kraft ◽  
R. Schwaiger ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Metal Film ◽  
Constitutive Law ◽  
Stress Strain ◽  
Strain Behavior ◽  
Testing Method ◽  
Beam Geometry ◽  
Simple Numerical Model

AbstractAn improved microbeam bending technique has been developed for the study of mechanical properties of thin films on substrates. This testing method utilizes a triangular beam geometry and improved micromachining techniques compared to previously used methods. The technique permits the stress-strain law for a metal film on a substrate to be determined. Single crystal Si beams and bi-layer Si/Al beams of lengths 25–100 pgm have been fabricated and tested. The beams are deflected with a nanoindenter, which accurately imposes a load on the beam and measures the corresponding displacement. For the bi-layer beams, a simple numerical model utilizing a Ramburg-Osgood constitutive law the film has been developed to determine the stress-strain behavior of the Al film.

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