الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 130 |  |  |
| | | from | 130 | | |
Abstract
Nickel was used as a metal binder for tantalum niobium carbide (Ta, Nb) C cermets. Different Ni content was added to the (Ta, Nb) C powders by two different methods namely, mixing and electroless nickel coating (NEP). The chemical compositions of the powdered composites were adjusted to be 5, 10, 15, 20, 25 and 30 by weight of Ni powder. The produced composite powders were cold compacted at 400 MPa and sintered under vacuum at 1450 oC for 90 min. X-Ray Diffraction, SEM and EDAX analysis are used to study the microstructure. Physical and mechanical properties were studied. The density of the produced (Ta, Nb) C/Ni sintered materials was measured by the Archimedes method. The results revealed that the coated sintered materials have homogeneous microstructure and exhibit higher relative density than mixed samples. It is observed that saturation magnetization; electrical conductivity, and thermal expansion of mixed and coated samples increase by increasing the nickel content. Thermal expansion of coated samples is lower than those of mixed samples. However, mixed samples exhibit higher physical properties than coated samples. The results of the mechanical properties show that the coated samples have higher hardness and low specific wear rate than that of the mixed samples.