Study on Wear Mechanism of an AlSi–Hexagonal Boron Nitride Abradable Seal Coating

To improve gas turbine performance, it is essential to decrease back flow gases in the high-temperature combustion region of turbo machine by reducing the shroud/rotor gap. An abradable seal coating will function effectively. Therefore, it is significant to identify and characterize the main wear mechanisms occurring on turbo machinery seals. A high temperature and speed test rig has been developed by BGRIMM for testing the AlSi–hBN abradable seal coating and Ti-6Al-4V dummy blade. Impact velocities between 150 and 300m·s-1 and incursion rates between 5.0 and 480 μm·s-1 have been applied. It was found that incursion rate has a greater impact on the wear mechanism of the AlSi–hBN coating, with tests at low incursion rate showing a obvious grooving and little micro-rupture, whereas tests at high incursion rate showing significant cutting and adhesion. The present work also shown that tests at low incursion rate related to a higher IDR, which means that blade suffered a serious wear. The investigation together with SEM and XRD analysis on the coating revealed both wear and adhesion occurred at the end of the test.

Download Full-text

Progress on Facilities and Methodology to Evaluate Abradable Seal Coatings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.1992 ◽

2013 ◽

Vol 690-693 ◽

pp. 1992-1998

Author(s):

Qiu Yuan Lu ◽

Jie Shen ◽

Yue Guang Yu ◽

Xian Jing Ren ◽

Hai Jun Xuan ◽

...

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Working Conditions ◽

Analytical Methods ◽

Turbine Performance ◽

Detection Technology ◽

Experimental Parameters ◽

Temperature Combustion ◽

Combustion Region ◽

High Temperature Combustion

To improve gas turbine performance, it is essential to decrease back flow gases in the high-temperature combustion region of the turbo machine by reducing the shroud/rotor gap. An abradable seal coating will function effectively. The present work described an advanced detection technology and test rigs to study abradability of the seal coatings. Several early used analytical methods were also reviewed in the work as comparison,like NASAPWA and Sulzer Innotec, have developed abradable test rigs and specified different experimental parameters by simulating the determined working conditions. Thence, suggestions to further develop evaluation methods for seal coatings were proposed and discussed.

Download Full-text

Ti2AlN Prepared by Self-Propagating High-Temperature Combustion Method Using TiN as Additive

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.710.37 ◽

2013 ◽

Vol 710 ◽

pp. 37-40

Author(s):

Jia Jin Tian ◽

Li Li Zhang ◽

Xiong Wei Bi ◽

Gui Yang Liu ◽

Zhi Mei Ding

Keyword(s):

High Temperature ◽

Raw Materials ◽

Synthesis Method ◽

Combustion Method ◽

Xrd Analysis ◽

X Ray Diffraction ◽

High Temperature Synthesis ◽

Temperature Combustion ◽

Micro Morphology ◽

High Temperature Combustion

Ti2AlN ceramic have been prepared by self-propagating high-temperature synthesis method using Ti, Al and TiN mixture as raw materials under different N2 pressures. X-ray diffraction (XRD) and scanning electron microscope (SEM) have been used to determine the phase composition and micro morphology of the products. XRD analysis indicates that the main phase of the products is layered ternary compound Ti2AlN, but there are TiN and AlTi3 impurities in the products. With increasing N2 pressure, the relative content of TiN and AlTi3 decreases. SEM imagines exhibits that the grains of the products become larger with increasing N2 pressures.

Download Full-text