Effect of Steam Velocity on the Hydrothermal Oxidation/Volatilization of Silicon Nitride
The hydrothermal oxidation behavior of silicon nitride was studied as a function of vapor velocity in the range of 1–35 cm/s, at atmospheric pressure and ∼100% H2O, using a custom-designed hydrothermal apparatus. At lower velocities, silicon nitride showed a marginal weight gain during early exposure times followed by a linear weight loss at longer exposure times. At higher velocities only linear weight loss was seen. The linear weight loss rates were determined from the weight change studies and they showed a square root dependence on velocity at higher flow rates. At the low flow rates a threshold velocity of ∼1 cm/s was observed for volatilization to initiate. The weight loss rates obtained in the apparatus at the higher steam velocities were comparable to those obtained in high pressure burner rigs, proving its viability as a good laboratory scale screening method for potential gas turbine materials.
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Document Type: Research Article
Affiliations: Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, 80309-0427
Publication date: 2006-04-01