Flexure strength of a silicon nitride at 20, 1200 and 1300 C : Effects of a 0.4% H(2)S + 0.75% H(2)O + H(2) bal. environment
In order to evaluate the corrosion induced mechanical strength degradation of hot-pressed silicon nitride in a simulated coal gasification environment, flexure tests have been carried out on the material in the as-received condition and also after exposure to the corrosive environment. For the unexposed as-received material, flexure strength results at 20 C (in air), and at 1200 and 1300 C (in nitrogen) are presented. For the corroded material, flexure strength data have been obtained only at 20 C. Studies are complemented by surface roughness measurements and by microstructural and fractographic analyses. Exposure tests to measure the weight change per unit surface area as a function of time at 1300 C are also reported for different surface to volume ratios. Further investigations are to continue but, based on present results, it seems that the slight reduction in the mechanical strength of silicon nitride after exposure is due to the decrease in specimen dimensions (by an amount equal to the thickness of the corroded outer surface layer).
Bibliographic Reference: Paper presented: Materiais 91, Lisboa (PT), Nov. 6-8, 1991
Availability: Available from (1) as Paper PT 36504 ORA
Record Number: 199111608 / Last updated on: 1994-12-02
Original language: pt
Available languages: pt