Synthesis of nano WC/Co for tools and dies
- Materials Modification Inc., Fairfax, VA (United States)
Materials for cutting tools and dies must have high hardness, high toughness, and high wear/erosion resistance. Tungsten carbide (WC) has been well known for its exceptional hardness and wear/erosion resistance. However, its low toughness causes brittle fracture. Addition of ductile metals, such as cobalt, can improve its toughness. To obtain the optimum results, WC has to be evenly distributed in a continuous cobalt matrix, which has been a technical challenge at high WC contents (94--97wt%). It is also well established that toughness of ceramic materials can be increased remarkably, without sacrificing hardness, by reducing the grain size. Significant improvement of microhardness has been observed in nano-sized composites over micron-sized materials. In the current investigation, nano-sized WC particles, synthesized by carburizing tungstic acid powders, are first coated with Co compound individually and uniformly by a solution precipitation process. The coated WC powders are then processed in H{sub 2} to obtain individually Co coated nano particles, which are subsequently consolidated by various techniques emphasizing short ({approximately} minutes) exposure times at high temperature. This paper will present some of their experiences and will also highlight some of the basic problems associated with synthesis and consolidation of nano particles.
- OSTI ID:
- 237712
- Report Number(s):
- CONF-9510290--; ISBN 1-878954-58-X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BULK DENSITY
CARBONATES
COBALT
COBALT NITRATES
COMPOSITE MATERIALS
FABRICATION
GUANIDINES
HOT PRESSING
HYDROGEN
METHANE
MICROHARDNESS
MICROSTRUCTURE
MORPHOLOGY
PARTICLE SIZE
POWDERS
REDUCTION
SCANNING ELECTRON MICROSCOPY
SINTERING
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
TUNGSTEN CARBIDES
TUNGSTEN OXIDES