Structure and thermal stability of ceria films supported on YSZ(100) and α-Al2O3(0001)

Innovation in material science progresses the usage of Al2O3/SiC based nanocomposites in gas turbine engine components, the harp-shaped structure of hypersonic rocket engine cutting tools for Ni, Al alloys, and clutch plate for two-wheelers. Thermal stability is one of the significant properties of gas turbine and rocket engine materials. Future engines may have to operate at very high temperature that may require high thermally stable material. In this research, an attempt is made to enhance the thermal stability of the Al2O3/SiC based nanocomposite by reinforcing 5-20 Vol. % nano Titanium Boride. Fabrication of α-Al2O3/SiC with 5-20 Vol. % n-TiB2 was carried out through pressureless sintering at 1600˚C followed by cold compaction. The fabrication process was carried out at a controlled Ar atmosphere. Thermal stability of the sintered samples was analyzed by NETZSCH STA 449F3 thermogravimetric analyzer with a heating rate of 10˚C/min and compared with Al2O3/SiC. The composite α-Al2O3/SiC/(5-20 Vol. %) n-TiB2 showed good thermal stability up to 1488˚C with 6% less mass change than Al2O3/SiC. The addition of n-TiB2 enhanced the collaboration between the atoms and postponed the decomposition temperature. The microstructure of the 20 vol % n-TiB2 added α-Al2O3/SiC was captured by 20 kV JSM-5600J Scanning Electron Microscopy and confirmed the presence of n-TiB2. Also, the presence of Ti, Si, Al, O, and B in the nanocomposite was confirmed by energy dispersive analysis of X-beams (EDS).

Download Full-text

The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Download Full-text

Microstructure studies of tungsten silicide schottky contacts on Gaas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126445 ◽

1987 ◽

Vol 45 ◽

pp. 328-329

Author(s):

Yih-Cheng Shih ◽

E. L. Wilkie

Keyword(s):

Thermal Stability ◽

Field Effect Transistors ◽

Schottky Contact ◽

Schottky Contacts ◽

Excellent Thermal Stability ◽

Barrier Heights ◽

Gaas Substrates ◽

Film Adhesion ◽

Threshold Voltages ◽

Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

Download Full-text