Abstract

A new approach of combined electroless nickel plating (ENP) and spark plasma sintering (SPS) was used to determine the feasibility of fracture toughness improvement of ZrO2. Nano-grained yttria stabilized zirconia (YSZ) particles of 100nm average diameter were coated with about 1-5 nm of nickel coating by ENP. To reduce nano particle agglomeration throughout the ENP process; vigorous agitation with an ultrasonic horn was used. The coated powder was characterized using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Transmission electron microscopy (TEM) to study the microstructure and coating characteristics. The coating was identified to be predominantly nickel and of 1 to 5 nm thickness. The plated powder was dried and consolidated by Spark plasma sintering (SPS) with sintering times significantly lower than used in conventional sintering processes. The solid compact was evaluated for mechanical properties. Hardness values were obtained from Vickers micro hardness indentations; fracture toughness was calculated by indentation-crack-length measurement and three-point bend test of notched samples; flexural strength was measured by 3-point bend tests. The measured hardness is comparable to the results found in the literatures. The coated and uncoated zirconia show significantly higher average fracture toughness compare to existing values.

Committee Chair

Dr. Shankar Sastry

Committee Members

Dr. Shankar Sastry Dr. Srikanth Singamaneni Dr. Peng Bai

Comments

Permanent URL: https://doi.org/7936/2amq-wx38

Degree

Master of Science (MS)

Author's Department

Mechanical Engineering & Materials Science

Author's School

McKelvey School of Engineering

Document Type

Thesis

Date of Award

Winter 12-18-2018

Language

English (en)

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