Preface

Tungsten carbide (WC) was first extracted from steel and properly identified around mid 19th century. It has attracted great interest to both engineers and academics for the sake of its excellent properties such as hard and wear-resistance, high melting point and chemically inert. Although it has been known for over one hundred years, recently tungsten carbide has been applied in numerous important industries including aerospace, oil and gas, automotive, semiconductor and marine, which also has a promising future. Cemented tungsten carbide, often simply called carbide, and also called cemented carbide and hard-metal, is a metal matrix composites (MMCs) where tungsten carbide particles are the aggregate and metallic cobalt serves as the matrix. It has excellent physicochemical properties, particularly enables to resist high temperatures and is extremely hard, which bring out wide application in the industry for cutting and mining tools, moulds and dies, and wear parts.

This book aims to provide fundamental and practical information of tungsten carbide from powder processing to machining technologies for industry to explore more potential applications. Chapter 1 introduces the self-propagating high-temperature synthesis (SHS) method to produce nanosized tungsten carbide powder. Chapter 2 explores the kinetic mechanism for spark plasma sintering (SPS) of tungsten carbide nanosized powder to produce cemented carbide. Chapters 3 and 4 are dedicated to production of metal/ceramic matrix composites with enhanced mechanical properties using tungsten carbide particle as a reinforcement phase. Chapter 5 is dedicated to the machinability investigation of cemented tungsten carbide, which could expand their application areas by making components using novel machining technologies. The last chapter presents an ultrasonic vibration shoe centerless grinding technology for tungsten carbide component manufacturing.

The book can serve as an informative reference for academics, researchers, engineers and professional that are related to tungsten carbide processing and applications.

The editor would like to thank InTech for this opportunity and their enthusiastic and professional support. Finally, I sincerely thank all the authors for their contributions to this book.

> **Dr. Kui Liu** Singapore Institute of Manufacturing Technology, Singapore

**Chapter 1** 

© 2012 Ignatieva et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

**Self-Propagating High-Temperature Synthesis** 

Transition metal carbides, particularly tungsten carbide, are rather attractive due to their physical and mechanical properties [**1**]. They are characterized by the high melting point, unusual hardness, low friction coefficient, chemical inertness, oxidation resistance, and excellent electric conductivity. Nowadays, highly dispersed tungsten carbide powders appear to be very important for production of wear-resistant parts, cutters,

It is well known, that fine-grained alloys demonstrate better mechanical properties in comparison with coarser alloys of the same composition under the same terms [2-4]. Use of ultrafine or nanosized powders is one of the most efficient ways to produce new materials

That is why nowadays the production technologies of nanopowders play the leading role

There are several phases of tungsten carbide; the most important ones are WC and W2C [5]. Though W2C is unstable at T=1300°C, in most cases the mixture of WC and W2C is observed in the synthesis products. Precipitation of the single phase of WC is only possible in the

There are different ways to obtain tungsten carbide powders, and each process changes the

Tungsten carbide powders are obtained by direct carbonization of tungsten powder. This process implies production of pure highly dispersed powder of metal tungsten within the first stage. The initial material in this case is very pure WO3, tungsten acid or ammonium

and reproduction in any medium, provided the original work is properly cited.

**of Ultrafine Tungsten Carbide Powders** 

I. Borovinskaya, T. Ignatieva and V. Vershinnikov

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/51303

**1. Introduction** 

non-iron alloys, etc.

tungstate [7-9].

with required properties.

among the widely used directions.

characteristics of the forming product.

narrow area of the technological parameters [6].
