Current Trends in Boriding

This book presents the most important thermochemical and physical techniques of boriding. The formation and characterization of different boride layers or boride coatings are compared in this book. The author analyzes the technological aspects of boriding processes, presenting the advantages and disadvantages of each method. The effect of the boriding techniques on the microstructure of borided materials are also indicated. The mechanism of formation of active boron atoms or ions and the phenomena during re-melting of alloying material together with the substrate are described. Special attention is devoted to powder-pack boriding, electrochemical boriding in borax, gas boriding, plasma gas or paste boriding and laser or plasma surface alloying with boron, acknowledged as the most important current methods in boriding. The thermodynamics of gas boriding is also analyzed.

Auteur
Michal Kulka is Associate Professor and Head of Division of Metal Science and Surface Engineering at the Institute of Materials Science and Engineering, Faculty of Mechanical Engineering and Management at Poznan University of Technology, Poland. His specialties are: gas boriding, growth kinetics of boride layers, borocarburizing, laser surface alloying with boron, plasma paste boriding, gas carburizing, gas nitriding, laser modification of diffusion layers (borided, carburized and nitrided layers), low-cycle fatigue, wear, mechanical and nanomechanical properties of the diffusion layers.

Contenu

1. Introduction.....1

References...3

2. Classification of boriding techniques..5

References...8

3. Borided materials....9

References13

4. Trends in thermochemical techniques of boriding...17 4.1 Boriding in solid media.17

4.1.1 Powder-pack boriding.17

4.1.2 Paste boriding..31 4.2 Boriding in liquid media...36

4.2.1 Boriding in chloride, fluoride or carbonate salt baths using

reducers with boron37

4.2.2 Boriding in molten borate baths using reducers with boron...42

4.2.3 Boriding in molten borate baths using reducers without boron..46

4.2.4 Electrochemical boriding in molten salt baths....50

4.2.5 Boriding in fluidized bed61

4.3 Gas boriding..67

4.3.1 Gas boriding with the use of boron halides67

4.3.2 Gas boriding with the use of boranes and other boron sources..82

4.3.3 Thermodynamics of gas boriding with the use of boron

trichloride as a boron source...86

References94

5. Trends in physical techniques of boriding.105

5.1 Boriding under glow-discharge conditions.105

5.1.1 Plasma gas boriding..105

5.1.2 Plasma paste boriding...117

5.1.3 Plasma electrolytic boriding.123

5.1.4 Spark plasma sintering boriding...135

5.1.5 Double glow plasma surface alloying with boron. ..139

5.2 Boron ion implantation...141

5.2.1 Beam line boron ion implantation142

5.2.2 Plasma immersion boron ion implantation...152

5.3 High energy techniques of boriding157 <p...