Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 1 September 1 1991 November 31 1991 written by and published by . This book was released on 1991 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this program is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 5 September 1 1992 December 1 1992 written by and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Calcia-stabilized cubic zirconia was mixed with soda, then fired at 840-1100 C. SiC was also reacted with alkali-containing atmosphere at 1000 C.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 3 December 1 April 1 1995 written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1992 with total page 1128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 4 June 1 1992 August 31 1992 written by and published by . This book was released on 1992 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this research is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 3 March 1 1992 May 31 1992 written by and published by . This book was released on 1992 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this research is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions as a function of temperature and time.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 10 December 1 1993 March 1 1994 written by and published by . This book was released on 1994 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alkali corrosion kinetics of mullite were studied in a constant partial pressure of sodium nitrate. Reaction layer thickness appears to be linearly related to reaction time; linear reaction rate constants are 9 [mu]m/h at 1000°C and 25 [mu]m/h at 1050°C. XRD after reaction revealed sodium aluminate and carnegieite, with a suggestion of a solid solution of the sodium aluminate and carnegieite phases. SEM reveals a large number of microcracks in the reaction layer.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 6 December 1 1992 February 28 1993 written by and published by . This book was released on 1992 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The high temperature alkali corrosion kinetics of SiC have been systematically investigated from 950 to 1100°C at 0.63 vol % alkali vapor concentration. The corrosion rate in the presence of alkaliis approximately 104 to 105 times faster than the oxidation rate of SiC in air. The activation energy associated with the alkali corrosion is 406 kJ/mol, indicating a highly temperature-dependent reaction rate. The rate-controlling step of the overall reaction is likely to be the dissolution of silica in the sodium silicate liquid, based on the oxygen diffusivity data.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 11 March 1 1994 June 1 1994 written by and published by . This book was released on 1994 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature alkali corrosion has been to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. The objective of this research is to systematically evaluate the alkali corrosion resistance of the most commonly used structural ceramics including silicon carbide, silicon nitride, cordierite, mullite, alumina, aluminum titanate, zirconia, and fireclay glass. The study consists of identification of the alkali reaction products (phase equilibria) and the kinetics of the alkali reactions.

Download or read book Broadening the Uses of Research written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993-09 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Quarterly Progress Report No 7 March 1 1993 June 1 1993 written by and published by . This book was released on 1993 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion kinetics of SiC were investigated from 950 to 1100C at 0.63 vol% alkali vapor concentration. Corrosion rate in alkali is 104 to 105 times faster than oxidation rate of SiC in air. Activation energy of the alkali corrosion is 406 kj/mol, indicating a high sensitivity to temperature changes. Overall reaction appears to be controlled by the oxidation of SiC. The alkali corrosion kinetics of Si3N4 from 950 to 1050°C were also examined in the same atmosphere (0.63 vol% alkali vapors). Reaction thickness of Si3N4 appears to vary linearly with reaction time from 950 to 1050C, suggesting that the alkali corrosion process is controlled by the oxidation of Si3N4. At 1050°C, the alkali-enhanced oxidation of Si3N4 is approximately 107 times faster than the oxidation of Si3N4 in dry oxygen. Compared to SiC corroded in the same alkali atmosphere, Si3N4 seems to be less alkali-resistant than SiC. Phase relations of the Na2O-Al2TiO5 vertical section from 5--40 wt% Na2O and 840-1100C were studied. Phase analysis indicates that this section is not a true binary system. A tentative phase diagram for the Na2O-Al2O3-TiO2 system was constructed.

Download or read book High Temperature Alkali Corrosion of Ceramics in Coal Gas Eighth Quarterly Progress Report June 1 1993 September 1 1993 written by and published by . This book was released on 1993 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gaseous alkali corrosion kinetics of Si3N4 were investigated from 950 to 1100°C in an atmosphere containing 0.98 vol % sodium nitrate vapors. Linear reaction rates from 950 to 1100°C indicate that the alkali reaction Of Si3N4 is interface-controlled with an activation energy of 199 kJ/mol. Rate controlling step of overall reaction appears to be the oxidation of Si3N4 to SiO2. An alkali reaction mechanism, involving a complex dissolution-oxidation process, was proposed. The difference between oxidation of Si3N4 in air and reaction of Si3N4 in presence of alkali is dissolution process of SiO2 in sodium silicate liquid. Gaseous alkali corrosion kinetics of alumina were also investigated at 1100 and 1150°C. The reaction thickness is linearly related to the reaction time, suggesting an interface-controlled reaction mechanism. The reaction rate constants are 0.24 [mu]m/h and 0.45 [mu]m/h at 1100 and 1150°C. The alumina grains seemed to be preferentially attacked along certain crystallographic directions. Subsolidus phase relations in the Na2O-Al2O3-TiO2 system were also studied. Phase analysis indicates that the Na2O-Al2TiO5 section is not a true binary system. A revised phase diagram was constructed.

Download or read book Engineered Materials Abstracts written by and published by . This book was released on 1992-07 with total page 942 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fossil Energy Update written by and published by . This book was released on 1977 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Temperature Alkali Corrosion of Dense SiC and Si3N4 Coated with CMZP and Mg DOPED Al2TiO5 in Coal Gas Quarterly Progress Report No 6 October 1 1995 December 31 1995 written by and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature alkali corrosion has been known to cause premature failure of ceramic components used in advanced high temperature coal combustion systems such as coal gasification and clean-up, coal fired gas turbines, and high efficiency heat engines. Non-oxide ceramics, such as SiC and Si3N4, are applied in HITAF systems for their well-known and desirable high temperature thermal and mechanical properties. However, these materials are prone to rapid corrosion under some types of high temperature coal combustion conditions. The objective of this research is to apply CMZP and Mg- Al2TiO5 as coatings to SiC to improve corrosion resistance under coal combustion atmospheres as well as to improve high temperature mechanical properties. The research will not only develop and characterize CMZP and Mg-Al2TiO5 coatings but will also strive to expand the existing knowledge of the mechanism of coal combustion corrosion of SiC in the temperature range of 1000- 4000°C.