Effect of a titanium nitride interlayer on the densification, properties and microstructure of cermets based on alumina and nickel — Part 2: Microstructures
SEM microstructural analyses in conjunction with EDX and TEM microstructural analyses have been conducted with cermets based on nickel and alumina, the latter as such and with a chemical-vapour-deposited titanium nitride layer. It has been proved that there is excellent bonding at both the Al2O3/TiN and the TiN/Ni interface, whereas Al2O3 and Ni do not adhere to each other. This is the reason for the observation that the mechanical properties as well as the densification of cermets consisting of Al2O3 and Ni are enhanced by applying a TiN interlayer between the ceramic phase and the metallic phase.
Effect of a titanium nitride interlayer on the densification, properties and microstructure of cermets based on alumina and nickel — Part 1: Densification and properties
In order to manufacture cermets based on Al2O3 and Ni, Al2O3 particles were first coated with TiN by CVD and then mixed with pure Ni powder. The cermets were produced from the mixed powders by powder metallurgy processes. The relative density and the mechanical properties of the cermets are improved due to the presence of the TiN interlayer. The contribution of this interlayer to the mechanical properties of the cermets produced by hot-pressing is superior to that by pressureless sintering.
Alumina: Processing, Properties, and Applications
1 Introduction.- 1.1 Scope of the Book.- 1.2 General Remarks on the Use and the Behavior of Ceramic Materials.- 1.3 The History of Alumina.- 1.4 Preceding Summarizing Literature on Alumina.- 2 Physical Properties.- 2.1 Structure.- 2.2 Thermal Properties.- 2.3 Diffusion.- 2.3.1 General Remarks on Diffusion Phenomena in Ceramics.- 2.3.2 Intrinsic Diffusion and Disorder Mechanism.- 2.3.3 Extrinsic Diffusion.- 2.3.4 Problems in Determining the Diffusion Coefficient.- 2.3.5 Diffusion Data.- 2.4 Electrical Conductivity.- 2.5 Sintering and Grain Growth.- 2.5.1 Fundamental Sintering Mechanisms in Al2O3.- 2.5.2 Intermediate and Final-Stage Sintering.- 2.5.3 Influence of Additives.- 2.5.4 Effect of MgO.- 2.5.5 Influence of Atmospheres.- 2.5.6 Grain Growth.- 2.6 Hot Pressing.- 2.7 Segregation.- 3 Mechanical Properties.- 3.1 Elastic Properties.- 3.2 Fracture Strength.- 3.2.1 The Strength of Ceramics.- 3.2.2 Fracture Energy.- 3.2.3 Types of Flaws.- 3.2.4 Strength Data.- 3.2.5 Strength-Grain Size Relationships.- 3.3 Time-Dependent Strength and Subcritical Crack Growth.- 3.3.1 The Model of Time-Dependent Strength.- 3.3.2 Subcritical Crack Growth Data.- 3.3.3 Fatigue Data.- 3.3.4 Mechanisms of Slow Crack Growth in Alumina.- 3.4 Thermal and Mechanical Shock Resistance.- 3.4.1 Thermal Shock Properties.- 3.4.2 Mechanical Shock Properties.- 3.4.3 Crack Healing.- 3.5 Plastic Deformation.- 3.5.1 Slip.- 3.5.2 Twinning.- 3.5.3 Hardness.- 3.5.4 Abrasive Wear.- 3.6 Creep.- 3.6.1 Basic Creep Mechanisms.- 3.6.2 Creep of Pure and MgO-Doped Alumina.- 3.6.3 Effect of Other Dopants.- 3.6.4 High Temperature Failure Mechanisms.- 3.7 Strengthening Mechanisms.- 3.7.1 Second Phase Dispersions.- 3.7.2 Compressive Surface Stresses.- 3.7.3 Transformation Thoughening.- 4 Fabrication.- 4.1 Preparation of Powders.- 4.2 Forming.- 4.2.1 Dry Pressing.- 4.2.2 Hydrostatic Molding.- 4.2.3 Extrusion.- 4.2.4 Injection Molding.- 4.2.5 Hot Pressing.- 4.3 Sintering.- 4.4 Hard Machining.- 4.5 Quality Control.- 4.6 Manufacturing Tolerances.- 4.7 Principles of Design.- 5 Applications.- 5.1 Electronic Applications.- 5.1.1 Metal-to-Ceramic Bonding.- 5.1.2 Spark-Plug Insulators.- 5.1.3 Components and Housings for Electron Tubes.- 5.1.4 Discharge Lamps.- 5.1.5 Microelectronics.- 5.2 Mechanical Engineering Applications.- 5.2.1 Thread Guides for Textile Machines.- 5.2.2 Wire Drawing Step Cones.- 5.2.3 Paper Machine Covers.- 5.2.4 Bearings.- 5.2.5 Cutting Tools.- 5.3 Medical Applications.- 5.3.1 Artificial Joints.- 5.3.2 Dental Implants.- 5.3.3 Maxillary Reconstructions.- 5.4 Armor Applications.- 5.5 Other Applications.- References.