Highly concentrated aqueous suspension containing fine SiC particles

Highly concentrated aqueous SiC slurry containing fine SiC powder: A new approach for ultra‐dense green body

“…28,29 PEG has one of the simplest structures among the non-ionized water-soluble polymers. 19 The results indicated that the optimum conditions for 64 vol% oxidized fine SiC slurry was pH 8 with 0.8 wt% PEG. Using a proper amount of PEG during slurry preparation process, a green body with more rigid surface and no surface exfoliation can be achieved after drying.…”

“…The lowest viscosity achieved at 0.8 wt% PEG was 166.7 mPa s. This result was better than that of our former result without oxidation treatment (202.4 mPa s using 62 vol% slurry). 19 The results indicated that the optimum conditions for 64 vol% oxidized fine SiC slurry was pH 8 with 0.8 wt% PEG. Subsequently, using the optimum condition, aqueous fine SiC slurry with 66 vol% solid loading could be prepared with the viscosity of 1147 mPa s at pH 9.…”

“…18 In our former report, aqueous SiC slurry with high solid loading up to 62 vol% was prepared using the fine SiC powder without oxidation. 19 The optimum condition for the dispersion of as-fabricated fine SiC powder was pH 9 with 0.4 wt% polyethylene glycol (PEG) dispersant.…”

Improved thermal stability of SiCf/SiC ceramic matrix composites fabricated by PIP process

“…A slurry with 30 vol.% solid loading made of the SiC powder, deionized water and 0.5 wt.% of polyethylene glycol (PEG) dispersant (molecular weight: 2000, Alfa Aesar, UK, based on the weight of SiC powder and DI water) was prepared by mechanical stirring and ultrasonication with a probe sonicator (VCX750, Sonics and Materials, CT, USA) for 30 min. The pH of the slurry was adjusted to 9 by adding 1 M NaOH solution [6].…”

“…However, during the repeated PIP cycles, SiC f /SiC CMC was frequently exposed to the environmental atmosphere. The humidity and oxygen in the air may easily react with ultra-fine SiC fillers and SiC-based liquid precursors, which may induce the formation of oxides on the SiC filler surface or in the PDC matrix and thereby decreasing the thermal stability and mechanical property of the CMC [6,7]. As a consequence, the decrease of oxygen impurity content in the CMC by suppressing air contamination during PIP process and the In the present investigation, tubular SiC f /SiC CMCs were fabricated by PIP process with the optimization of pyrolysis atmosphere and the pre-treatment of SiC filler.…”