Electrodeposition

The Materials Science of Coatings and Substrates

by

Jack W. Dini

Reviewed by George A. DiBari

Originally Published in:

PLATING AND SURFACE FINISHING

Journal of the American Electroplaters and Surface Finishers Society

May 1993

As indicated by the subtitle, this book is not about electrodeposition processes. It is about materials science and the relations among structure, composition, processing properties and performance in materials systems. The authors purpose is to relate materials science and electrodeposition, and that purpose is accomplished. In 11 clearly written chapters, the author provides examples of how structure and composition influence the properties and performance of electrodeposited and physically vapor deposited coatings.

Chapter one is on hydrogen embrittlement, which is an unusual beginning for a book on electrodeposition. The explanation for the unusual beginning is related to the organization of the book. In addition to the substrate, three zones are considered: (1) The interface between the substrate and the coating; (2) the coating itself; and (3) the interface between the coating and the environment. Because the author considers the substrate first, hydrogen embrittlement is a logical place to start. The section on the interface-related properties includes chapters on adhesion and diffusion. The characteristics of the coating itself are discussed in five chapters, properties, structure, additives, porosity and stress. The interface between the coating and its environment is covered in two chapters; corrosion and wear. The order could easily have been reversed, but a practical electroplater knows that the process begins with serious consideration of the substrate. The organization makes this book cohesive and a real pleasure to read.

Although the relations between materials science and electrodeposited coatings are probed throughout the book they become crystal clear in Chapter 6, "Structure." The discussion of the influence of texture on formability, corrosion, paint adhesion, contact resistance, wear resistance, porosity and other properties is one of the best examples of the authors purpose. In the same chapter, the author discusses fractals, a concept that lends itself to computer modeling of coating characteristics, and his enthusiasm for this relatively new tool is apparent in his writing.

The chapter on additives has a good summary on chromatography and electro-analytical techniques for studying additives with emphasis on new methods that promise to improve additive control. The chapter on porosity defines a pore (something that is still the subject of debate in some circles), and reviews many methods of detecting pores.

The chapter on stress includes a brief discussion of holographic interferometry and other methods for measuring stress. The chapter on corrosion also emphasizes the materials science approach and includes a brief discussion of the corrosion characteristics of decorative nickel-chromium coatings. The chapter on adhesion is comprehensive.

Sprinkled throughout the book are tables summarizing useful information. The tables include electrolytes for electrographic testing, preparation of substrates for coating, analytical techniques best suited for specific process, etc. There are also many good photographs and useful charts.

Each chapter includes an extensive list of references for further study. The author assumes a certain degree of prior knowledge of electrodeposition and metallurgy from the reader. One who is not familiar with these disciplines may need to refer to the technical literature referenced. However, the book is so well written that anyone with some knowledge of coating technology will profit from reading it.

The author is well known to most of the readers of Plating and Surface Finishing. He is a former member of the Board of Directors and a Past President of AESF. He has received many honors, including the AESF Scientific Achievement Award and the Research Award of the Electrodeposition Division of the Electrochemical Society. He has a reputation as a good speaker who is always logical arid understandable. Those same qualities are reflected in his book.

There are many enlightening features in this book. Crystal structure, texture, diffusion in solid solutions, polarization, polarography, phase transformations and other topics are shown to have real practical significance in electrodeposition. The ultimate goal of materials science is to learn to tailor the properties of coatings to specific applications. The author proves the goal is achievable. Its a good book.

Cost: AESF members, $70; nonmembers, $85. Include $5 for shipping (in the US) or $25 outside the US. Order by credit card from AESF Publications Sales: 1-800/334-2052.