Crack Formation during Electrodeposition and Post-deposition Aging of Thin Film Coatings - 2nd Quarterly Report
Second Quarterly Report - AESF Research Project #R-118. This new NASF-AESF Foundation research project report covers the second quarter of project work (April-June 2016).
Prof. Stanko R. Brankovic*
University of Houston
Houston, Texas, USA
Editor’s Note: This NASF-AESF Foundation research project report covers the second quarter of project work (April-June 2016) on this new AESF Foundation Research project at the University of Houston. A printable PDF version is available by clicking HERE.
Stanko R. Brankovic, PI, Electrical and Computer Engineering and Chemical and Biomolecular Engineering, University of Houston,
Kamyar Ahmadi, PhD Student, Material Science Program, University of Houston,
Nikhil Chaudhuri, PhD Student, Material Science Program, University of Houston.
The objective of this work is to study the fundamental and practical aspects of crack formation in electrodeposited thin films. The aim is to identify and quantify the key parameters of the electrodeposition process affecting the crack formation in thin films. This study should enable development of an effective strategy generally applicable in practice whenever an electrodeposition process for crack free films is demanded.
The activities performed in the second quarter were focused on initial studies of electrodeposition of chromium thin films of arbitrary thickness on polycrystalline copper substrates from Cr+3-containing electrolytes. The main focus of the experimental work was the EXDBA 1411 Bath with pH=5 (see http://short.pfonline.com/NASF16Nov2 for description).
Current efficiency measurements
The initial work focused on accurate determination of the current efficiency for the EXDBA 1411 bath chemistry as a function of deposition current density at room temperature. The work performed involved deposition of chromium films with significant thickness (one hour deposition time), and precise measurements of the weight gain due to the formation of the chromium film. This mass was compared to the mass gain calculated from the deposition charge measurements during galvanostatic deposition. The ratio between the measured and calculated mass, assuming 100% current efficiency, is presented in the data in Fig. 1.