Tanner Guerra – DMSE FPOP 2014

UCSB Summer Internship:

Thermal Barrier Coatings Tanner Guerra

Tanner Guerra – DMSE FPOP 2014

Where I worked

University of California, Santa Barbara

Tanner Guerra – DMSE FPOP 2014

Where I worked

•  Top 3 Graduate Materials Dept. •  Home •  California

Why?

Tanner Guerra – DMSE FPOP 2014

Who I worked with

•  Interned for 3rd year grad student Stefan Heinze

•  We were under the Levi Group, consisting of a few post-docs, and around 10 grad students and their interns

•  Group Leader, Carlos Levi, a Professor of Materials and Mechanical Engineering at UCSB

•  Industry Partner

Tanner Guerra – DMSE FPOP 2014

What is a Thermal Barrier Coating (TBC)?

What do you think?

•  Metal or Ceramic? •  Applications •  Importance •  Material

Properties

Tanner Guerra – DMSE FPOP 2014

TBCs

•  Ceramics! …basically •  Applications: Hot portions of Cars and Airplanes,

such as a turbine or engine. •  Importance: Protects elements that you want to

keep cool relative to the environment •  Material Properties…

•  Historically 7YSZ

Tanner Guerra – DMSE FPOP 2014

What is 7YSZ?

•  7 mol% Yttria Stabilized Zirconia Yttria = YO1.5 Zirconia = ZrO2

•  One of the First TBCs used •  Still used today

•  Correct mol % discovered through experiments empirically

Tanner Guerra – DMSE FPOP 2014

TBC Application

Tanner Guerra – DMSE FPOP 2014

CERAMIC BASICALLY…

Tanner Guerra – DMSE FPOP 2014

Tanner Guerra – DMSE FPOP 2014

Tanner Guerra – DMSE FPOP 2014

Layer Function

Tanner Guerra – DMSE FPOP 2014

Important Material Properties

•  Low Thermal Conductivity •  Strain Tolerance

•  Toughness •  Phase Stability

•  Compatibility with other layers

•  Resistance to calcium–magnesium–alumino-silicates (CMAS)

Tanner Guerra – DMSE FPOP 2014

What the Group Does

•  Examine, investigate, and characterize new TBCs (we didn’t “make” new TBCs)

•  Conduct research on CMAS resistance, phase stability, and toughness

•  Confer with industry partner about different theories and problems

Tanner Guerra – DMSE FPOP 2014

What I do

•  Concerned with learning and helping understand the new TBCs.

•  Sample Prep, a lot of it

•  Use Powder XRD (X-Ray Diffractometer) and Raman Spectroscopy machines in order to help determine the microstructural phase of the material

•  Determine how to test for toughness in the material

Tanner Guerra – DMSE FPOP 2014

Phases

•  What are the microstructural phases? - I am concerned with three simple forms.

- Monoclinic, Tetragonal, and Cubic

Monday, August 20, 2007 Can change this on the Master Slide 16

Tanner Guerra – DMSE FPOP 2014

Bad vs. Good

•  In terms of what we wanted, Tetragonal was good, cubic was ok, and monoclinic was bad.

•  Cubic – (in our case) too brittle, but still very hard (not nearly perfect)

•  Monoclinic – causes deleterious effects because the material often starts in a different phase. This is due to a change in volume, causing cracking and breaking of the material.

Wednesday, August 20, 2014 Yolo 17

Tanner Guerra – DMSE FPOP 2014

Phase Stability

Monday, August 20, 2007 Can change this on the Master Slide 18

c: cubic t: tetragonal m: monoclinic

Tanner Guerra – DMSE FPOP 2014

Ternary Phase Diagram

Wednesday, August 20, 2014 Yolo 19

-  Keep in mind this is at one temperature.

-  Zirconia (Base), Yttria, Ytterbia, Tantala

Tanner Guerra – DMSE FPOP 2014

Sample Prep (Phase Stability)

•  Simple. •  Study powder on XRD and Raman machines

•  To test phase stability, put in furnace at different temperatures for 100 hours or 400 hours and compare results to the original powder.

Monday, August 20, 2007 Can change this on the Master Slide 20

(XRD) (Raman)

Tanner Guerra – DMSE FPOP 2014

Sample Prep. (Toughness [3-point bend])

•  Most ceramics start as a powder •  Press powders with high pressure into pill form

•  Sinter these pills, like what Jose did. - put in at and temp ramped to ~1700*C and

then cooled after sitting for a day at temp. •  Slow speed saw into toughness test bars •  Surface Grind sample to get extremely smooth

finish •  Then cut a chevron notch into each bar

Monday, August 20, 2007 Can change this on the Master Slide 21

Tanner Guerra – DMSE FPOP 2014

Data

•  Well, we are still waiting on results… December?

Monday, August 20, 2007 Can change this on the Master Slide 22

Tanner Guerra – DMSE FPOP 2014

Thank you!

•  Thanks for listening, hope you enjoyed learning about my internship and high-performance ceramic coatings.

Wednesday, August 20, 2014 Yolo 23