Silicon carbon rod, silicon molybdenum rod production process

Carbon rod (silicon carbon rod) production process

Raw material preparation: high-purity silicon carbide powder is acid-washed and alkaline-washed to remove impurities, mixed with phenolic resin binder and a small amount of additives to make a plastic blank.

Molding: straight rods are extruded, and complex special-shaped parts are isostatically pressed (100-200MPa high pressure compaction) to obtain a blank of a set shape.

Drying: 60-150℃ step-by-step drying to remove moisture and volatiles to prevent sintering cracking.

Sintering: 1600-2200℃ sintering in an inert atmosphere, silicon carbide particles are combined through solid phase diffusion to form a dense structure.

Electrode treatment: metal slurry is sprayed on both ends and baked to form a conductive layer, and the size is corrected by grinding to complete the finished product.

Molybdenum rod production process

Molybdenum powder preparation: ammonium molybdate is calcined to generate molybdenum trioxide, and then hydrogen is two-stage reduced (500-1100℃) to obtain high-purity molybdenum powder (purity ≥99.95%).​
Molding: Molybdenum powder is loaded into the mold and pressed into a green billet by cold isostatic pressing (150-200MPa). ​
Sintering: High temperature sintering at 1800-2200℃ under hydrogen protection, molybdenum powder particles are fused, and the density reaches more than 98% of the theoretical value. ​
Processing and heat treatment: 1200-1400℃ hot rolling or forging to reduce diameter and improve strength; 1000-1200℃ hydrogen annealing to eliminate stress. ​
Finishing: Fine grinding of the outer circle to control tolerance (±0.02mm), cutting to a fixed length to ensure that the surface roughness meets the standard. ​
Both require strict control of raw material purity, and rely on protective atmosphere to prevent oxidation during production. Carbon rods focus on sintering process to control conductivity, while molybdenum rods are key to reducing powder and hot processing to ensure strength. In the end, both need to pass density and resistivity tests to ensure quality.