Which material serves as the binder in cemented carbides___________________?
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Answer: A. cobalt
Explanation
Cemented carbides require a tough metallic matrix to hold brittle carbide particles securely together. Cobalt serves as the standard binder material because it wets tungsten carbide grains exceptionally well. This metallic binder imparts necessary impact toughness to otherwise brittle carbide cutting tool inserts. Cemented tungsten carbide tools are manufactured using powder metallurgy and liquid-phase sintering. The hard carbide phase provides extreme wear resistance, while the cobalt binder provides toughness. Adjusting the cobalt binder percentage allows tool designers to balance toughness and wear resistance.
Machining operations across aerospace and automotive industries rely on cobalt-bonded tungsten carbide inserts. Mining drill bits and rock excavation tools utilize tough cobalt-carbide composites to resist severe impacts. Powder metallurgy manufacturing requires precise control of sintering temperatures to bond the cobalt properly. Nickel is occasionally used in specialized corrosion-resistant cermets, but cobalt is the primary standard binder. Vanadium forms hard carbides within steel but does not serve as the primary binder for cemented carbides. Iron lacks the optimal wetting characteristics and toughness combination needed for heavy-duty carbide binding.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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