[en] Schemes of classification for different groups of ''materials'', ''non-metallic inorganic materials'' and ''ceramic materials'' are introduced. The position of groups with a borderline or transitional character, such as cermets, glass ceramics, compound materials, metallic hard materials and hard metals is also discussed. For ceramic materials, two classification principles regarded as being of equal value are proposed, one from the point of view of specific materials and the other according to the application. The usability of the description frequently used at present for modern technical ceramic materials, such as ''engineering ceramics'' and ''high performance ceramics'' is explained. (orig.)

No abstract available

[en] Environmentally conscious hard turning and technology has placed more importance on the machining process. In this research, the possibility of environmentally conscious hard turning of cemented carbides was studied. The effects of cutting methods of dry and wet (vegetable oil mist, and mineral oil) and work material on cutting resistance and wear characteristics of cutting tools were experimentally investigated. The turning and micro-cutting process in SEM was carried out by using four kinds of tungsten carbides with the PCD cutting tools. Specifically, an emphasis was put on the effect of WC and Co additives in four kinds of cemented carbides on machinability and tool wear characteristics. The tool wear width and the cutting resistances were measured, and the worn flank was observed

[en] In the paper several aspects of the wear mechanisms of coated hardmetals, ceramics and super-hard materials (CBN) in machining cast iron are discussed, with particular attention being given to high-speed machining of different cast iron grades. The influence of machining parameters, microstructure, composition and mechanical and chemical properties of the cutting tool and the work-piece material on wear are considered. (author)

[en] The horizontal sinter-HIP equipment with great charge capacity and high performance, developed and manufactured by Central Iron and Steel Research Institute(CISRI), is mainly used for sintering and condensation of hard metals. This equipment is characterized by large hot zone, high heating speed, good temperature uniformity and fast cooling system. The equipment can provide uniform hot zone with temperature difference less than 6 ^oC at 1500-1600 ^oC and 6-10 MPa by controlling temperature, pressure and circulation of gas precisely. Using large scale horizontal sinter-HIP equipment to produce hard matals have many advantages such as stable quality, high efficiency of production, high rate of finished products and low production cost, so this equipment is a good choice for manufacturer of hard metals. (author)

[en] A type of novel plastification agent for plasticizing powder extrusion molding of cemented carbides has been developed. By optimizing their formulation and fabrication method, the novel plastification agent, with excellent properties and uniform distribution characters, were manufactured. The thermal debinding mechanism has been studied, the extruding rheological characteristics and debinding behaviors have been investigated. Using the newly developed plastification agent, the cemented carbides extrusion rods, with diameter up to 25 mm, have been manufactured. (author)

[en] Diamond films were deposited on the cemented carbide WC-15 % Co substrates by a hot-filament chemical vapor deposition reactor. The substrate surfaces were chemically pretreated with the two-step etching method, using first Murakami reagent for 1-3 min, and afterwards an HNO₃: HCl=1:1 solution for 10-40 min. It is indicated that the Co content of the substrate surfaces could be reduced from 15 % to 0.81-6.04 % within the etching depth of 5-10 μm, and the surface roughness of the substrates was increased up to Ra=1.0 μm, the substrates hardness was decreased from 89.0 HRA to 83.0 HRA alter the two-step etching. It is observed that the morphologies of the diamond films on the WC-15 % Co substrates emerge in various shapes. The indentation testing shows that the good adhesion between diamond film and the substrate after HF CVD deposition could be obtained. (author)

[en] After an attempt to classify the basic constituents of cermets in function of their resistivity and microhardness, the history of ceramic-metal composites is reviewed. The two main methods of production, sintering and impregnation, are examined from the point of view of the problems posed and solutions required to obtain optimum mechanical properties (resistance to creep and thermal shock...). A summary table of the chief cermets and their applications is proposed with precise details in some particular cases

[en] An improved method for preparing a cermet comprises preparing a compact having about 85 to 95 percent theoretical density from a mixture of metal and metal oxide powders from a system containing a eutectic composition, and inductively heating the compact in a radiofrequency field to cause the formation of an internal molten zone. The metal oxide particles in the powder mixture are effectively sized relative to the metal particles to permit direct inductive heating of the compact by radiofrequency from room temperature. Surface melting is prevented by external cooling or by effectively sizing the particles in the powder mixture

No abstract available