Thermal decomposition of ethylpentaborane in gas phase

The thermal decomposition of ethylpentaborane at temperatures of 185 degrees to 244 degrees C is approximately a 1.5-order reaction. The products of the decomposition were hydrogen, methane, a nonvolatile boron hydride, and traces of decaborane. Measurements of the rate of decomposition of pentaborane showed that ethylpentaborane has a greater rate of decomposition than pentaborane

Measurement of uniform flame movement in carbon monoxide - air mixtures containing either added D2O or H2O

Relative velocities of the flame in a carbon monoxide - air mixture containing either added heavy water or light water were measured in a glass tube. Throughout the range of carbon monoxide - air composition, the flame containing added light water had a faster speed than the flame containing heavy water

Effect of water on carbon monoxide-oxygen flame velocity

The flame velocities were measured of 20 percent oxygen and 80 percent carbon monoxide mixtures containing either light water or heavy water. The flame velocity increased from 34.5 centimeters per second with no added water to about 104 centimeters per second for a 1.8 percent addition of light water and to 84 centimeters per second for an equal addition of heavy water. The addition of heavy water caused greater increases in flame velocity with equilibrium hydrogen-atom concentration than would be predicted by the Tanford and Pease square-root relation. The ratio of the flame velocity of a mixture containing light water to that of a mixture containing heavy water was found to be 1.4. This value is the same as the ratio of the reaction rate of hydrogen to that of deuterium and oxygen. A ratio of reaction rates of 1.4 would also be required for the square-root law to give the observed ratio of flame-velocity changes

Explosion and combustion properties of alkylsilanes I : temperature-composition limits of explosion for methyl-,dimethyl-,trimethyl-,tetramethyl-,and vinylsilane at atmospheric pressure

The explosion limits of five alkylsilanes were determined as a function of temperature and composition at a pressure of 1 atmosphere. Over a fuel concentration range of 2 to 10 percent, the lowest temperatures (zero C) below which explosion did not occur for the five fuels studied were: tetramethylsilane (CHsub3)sub4Si, 450 degrees; trimethlysilane (CHsub3)sub3SiH, 310 degrees;dimethylsilane (CHsub3)sub2SiHsub2, 220 degrees; methylsilane CHsub3SiHsub3, 130 degrees; and vinylsilane Hsub2C=CH-SiHsub3, 90 degrees. Explosion limits for hydrocarbons analogous to these silanes fall in a temperature range of 500 degrees to 600 degrees C. Since the explosion temperatures of the alkylsilanes are lower than those of the hydrocarbons and since they decrease as hydrogen atoms are substituted for methyl groups, it was concluded that the Si-H bond is more readily susceptible to oxidation than the C-H bond

Thermomechanical behavior of plasma-sprayed ZrO2-Y2O3 coatings influenced by plasticity, creep and oxidation

Thermocycling of ceramic-coated turbomachine components produces high thermomechanical stresses that are mitigated by plasticity and creep but aggravated by oxidation, with residual stresses exacerbated by all three. These residual stresses, coupled with the thermocyclic loading, lead to high compressive stresses that cause the coating to spall. A ceramic-coated gas path seal is modeled with consideration given to creep, plasticity, and oxidation. The resulting stresses and possible failure modes are discussed