Nano-Composite W-2% ThO2 Electrode Material Preparation Process of Swaging

Prepared by swaging nanocomposite W-2% ThO2 electrode material of this test tungsten alloy plant in Taebaek, the specific process is as follows:

(1) Mixing: The After dispersing, mixing a good first composite powder sieved through a 100 mesh sieve manually three times and allowed to stand 30min. In sifted before adding binder, adhesive formulations as follows: ethanol + glycerol (volume ratio of 1: (1.5-2)). The proportion of binder added: Every 1000g sifted powder was added 3mL binder.

(2) Compression: W powder particle size of 0.6μm, very fine-grained, leading to increased friction, resulting in the actual sample pressure is still small. After the suppression of the larger specimens resilience, resulting in greater stress. Also causing uneven density inside the sample, the surface density, the center is less dense, prone to early stratification and micro-cracks, sintering is easy to burst. If the binder added more, since the surface density, gas difficult to discharge, it could easily lead to burst. If the mixed powder is uneven, the compacts are likely to cause an early break. Considering these factors, the pressing process point is: bonding agent added in moderation; powder mixed carefully controlled process to ensure uniform mixing powder; increase the pressure; increased dwell time. Specific process parameters: each billet quality powder 580g (normal 640g), pressure 70T (50T normal production pressure), a pressure of about 60MPa, dwell time 5min.

(3) Pre-Sintering: In the protection of hydrogen, at a temperature of 1150-1200 ℃ sintering 1h, aims to improve the density and strength of the green body in order to facilitate the subsequent sintering electrically heated melt down. Pre-sintered body size is about 400mm x 12mm X 12mm.

(4) Vertical melt sintering: current heating current is 90% of the fusing current, the temperature does not exceed 3000 ℃, time of l0min.

(5) The Swaging: the vertical melt sintered billet at a temperature of 1350-1450 ℃ swaging.

(6) Drawing: caustic deburring and oil after drawing wire.

(7) Straightening Polished.


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