Refractory Carbides

The present stage of technological development makes new and ever more complex demands on materials that have to work under conditions of high temperature and pressure, in high vacuum, and in corrosive media. In consequence special importance is now at­ tached to the refractory compounds of transition metals of groups IV to VI with such nonmetals as boron, carbon, silicon, and nitro­ gen. These compounds possess high melting points, great hard­ ness, and high refractory and corrosion-resisting properties. The most widely used and important compounds of this type from a technological point of view are the carbides, which are already fairly widely used in various fields of technology. The present collection of papers contains the results of re­ cent investigations into methods of producing high-purity carbides and also components made of the carbides and their alloys. Great attention has been paid to the study of a wide range of properties of the carbides and of alloys based on them, viz., the electro-and thermophysical, thermodynamic, mechanical, and chemical prop­ erties, and also to the utilization of the carbides as wear-and abrasion-resistant materials. In contrast to many previous publications dealing with carbides, the results presented in this collection relate to the properties of carbides having a definite phase composition, corresponding to a higher degree of purity 0 In some of the contributions the physical and chemical properties of the carbides are interpreted in terms of certain solid-state models and concepts concerning the types of chemical bonding in these compounds.

Contenu

Some Problems in the Theory of the Properties of Carbides.- I. Methods of Producing Carbides and Carbide-Base Alloys.- Methods of Producing Pure Carbides.- Production Technology and Some Properties of the Pyrolytic Carbides of Zirconium and Titanium.- Investigation of the Production Conditions and Some Properties of Metalloceramic Materials Based on Titanium Carbide Bonded with Alloy Steel.- Investigation of a Method of Obtaining Niobium Carbide Powder and Coatings from the Vapor Phase.- The Production and Some Properties of Carbohydrides of Titanium, Vanadium, and Niobium.- New Methods of Comminuting Powders of Refractory-Metal Carbides.- II. Methods of Producing Components of Carbides and Alloys Based on Them.- Fundamental Aspects of the Compaction of Carbides.- Producing High-Porosity Materials from Transition-Metal Carbides.- The Effect of the Conditions of Producing Zirconium Carbide Powder on the Properties of Sintered Specimens.- Porosity-Free Polycrystalline Silicon Carbide and Its Application in High-Temperature Technology.- III. Refractory-Carbide Coatings.- The Vacuum Carbidization of Transition Metals of Groups IV and V.- Some Problems in the Thermodynamics and Kinetics of the Formation of Carbide Coatings on Graphite from the Vapor Phase.- Investigation of the Effect of Boron Additions on the Carburization of Silicon.- A Study of the Soldering of Graphite Materials with the Formation of a Carbide Layer.- IV. Phase Diagrams of Systems Containing Carbon.- The Phase Diagram of the System Titanium-Molybdenum-Carbon.- Study of the Phase Equilibria in the System Tantalum-Vanadium-Carbon in the Range 0-33 at.% C.- The NbC-Re Polythermal Section in the Niobium-Rhenium-Carbon System.- V. Physical Properties of Carbides.- An X-Ray Spectral Study of Some Compounds of Niobium and Carbon.- The State of the Carbon Atom in Transition-Metal Carbides.- The Energy Structure of Titanium Carbide.- Soft X-Ray Spectra of Vanadium Carbides in the Homogeneity Range.- The Effect of Neutron Irradiation on the Structure of Titanium and Chromium Carbides.- Some Physical Properties of Pyrolytic Boron Carbide.- Emissive Power and Specific Electrical Resistivity of Zirconium and Niobium Carbides at High Temperatures.- Variation in the Lattice Parameters and Static Distortions in the Homogeneity Range of Transition-Metal Monocarbides.- Electron-Fractographic Study of the Fractures in Zirconium Carbide after Tensile Testing in the Range 20-2000°C.- Physical Properties of Carbides of Rare-Earth Metals.- Regularities in the Variation of the Electrophysical Properties of Solid-Solution Alloys of Some Carbides of Transition Metals of Groups IV and V.- Thermal Coefficient of the Electrical Resistivity of Carbides and Their Solid Solutions.- A Study of Some Physical Properties of Alloys of the System TaC-WC.- Thermal Expansion of Solid Soltuions in the Systems ZrC-NbC and HfC-TaC.- Study of the Galvanomagnetic and Electrical Properties of TiC-TiO, TiN-TiO, TiC-TiN, and ZrC-ZrN Alloys.- The Influence of Production Conditions on Some Physical Properties of Tungsten Carbide and of a Complex Carbide Based on It.- A Study of Recrystallization Processes in Refractory Compounds.- VI. Thermodynamic Properties of Carbides.- The Thermodynamic Properties of Tantalum Carbide in the Homogeneity Range.- A Study of the Dependence of Some Thermodynamic Properties of Niobium and Zirconium Carbides on Temperature and Composition.- Temperature Dependence of the Congruently Evaporated Compositions of the Zirconium Monocarbide Phase and Their Evaporation Rate.- Mass-Spectrometric Study of the Evaporation of Zirconium Carbide at High Temperatures.- Thermodynamic Properties of Titanium Carbide of Variable Composition at High Temperatures.- Thermodynamic Properties of the Higher Manganese Carbide.- Enthalpy and Specific Heat of Silicon Carbide at High-Temperatures.- VII. Mechanical and Abrasive Properties of Carbides.- Investigation of the Hot Hardness of Cast Zirconium Carbide.- The Microhardness of Transition-Metal Carbides.- Some Aspects of the Abrasive Wear of Transition-Metal Carbides.- Hard-Facing Alloys Based on Refractory Compounds.- New Polishing Materials Consisting of Quasimetallic Compounds.- Antiabrasion Material Resistant to Erosive and Aggressive Media.- Reduction of the Erosive Wear of Refractory Compounds in Plasma Streams by Means of Thermochemical Protection.- Indentors for Measuring the Hardness of Materials at High Temperatures.- A Study of the External Friction of Refractory Carbides at High Temperatures in Vacuo.- VIII. Chemical and Refractory Properties of Carbides.- The Chemical Bond in Carbides of the Rare-Earth Metals.- A Study of the Reaction of Zirconium Dioxide with the Carbides of Group VI Metals.- The Reaction of Refractory Carbides with Molten Steels and Cast Irons.- A Study of the Corrosion of Nonmetallic Materials in Molten Borax.- The Reaction of Highly Refractory Oxides, Refractory Carbides, and Boron Carbonitride with Molybdenum and Tungsten under the Operating Conditions in High-Temperature Electric Furnaces.