1 - Introduction to alumina ceramics

Abstract

This 16 chapter/180,000 word book is a comprehensive overview of alumina ceramics, defined as dense Al2O3 ceramics in the purity range 85%–100%. Alumina powder technology (e.g., abrasives), low purity alumina ceramics (below 85% pure), porous alumina ceramics, and alumina-matrix ceramic composites are beyond the scope of the book. The fledgling alumina ceramics industry began in the 1950s. It is 35 years since the last book dedicated to alumina ceramics was published, at which time the alumina ceramics industry was still quite rudimentary, with a primary focus on refractories and electrical insulators. Thus this book represents a major update on alumina ceramics. In 2018, the two most commercially significant applications for alumina are: (1) alumina feedthroughs in bionic implants, a $25 Billion industry (pacemaker, bionic ear, bionic eye, deep brain stimulator, and 10 other bionic implant types); (2) alumina electrical substrates in the semiconductor and microelectronics industry—SOI substrates are a $50 Billion industry, the thick-film alumina microelectronics industry is comparable in scale. Alumina bearings have revolutionized the hip replacement industry, reaching global dominance in 2015, and now capturing 55% of the global market of 1.3 million hip replacements a year. Alumina lightweight body armor, first trialed in 1965, has changed the world. Ceramic body armor has been deployed on a massive global scale since 1996, for the first time in history military/security personnel of all ranks are protected against the munitions of the day, an extraordinary humanitarian and egalitarian advancement. Alumina wear-resistant ceramics dominate the global $500 Billion mining industry, uniquely combining low cost with extreme wear resistance, and they are also important in textile manufacturing, papermaking, food processing, pumps, seals, and general engineering, and many other industries. Alumina continues to play an important role in the $50 Billion refractories industry, and has many other important applications such as dental technology, tissue scaffolds, oxygen sensors, architectural ceramics, aerospace ceramics, and machining tools. This book begins with a look at alumina refining (bauxite and the Bayer process), and then an overview of alumina processing, structure, and properties. It then comprehensively overviews all the applications for alumina ceramics discussed above, as well as many more minor applications.