Wear Mechanisms of Mcraiy Abradable Plasma-Sprayed Coatings

1998 ◽  
Author(s):  
S. Li ◽  
C. Langlade-Bomba ◽  
D. Treheux ◽  
F. Crabos ◽  
P. Monge-Cadet
Keyword(s):  
Wear Mechanisms ◽  
Gas Turbines ◽  
Coating Microstructure ◽  
Blade Tip ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Abradable Coatings ◽  
Engine Components ◽  
New Generation ◽  
Sprayed Coatings

Abstract Reduction of operating clearance between the HP turbine and the shroud in the new generation of gas turbines is one way often used by engine manufacturers to improve efficiency. This implies developing a blade tip coating/shroud coating system to minimize the degradation (particularly blades wear) during eventual rubbing. In this study, the chosen systems are: - VPS NiCoCrAIYTa as HP blade tip coating, - Plasma-sprayed MCrAIY coatings deposited under various atmosphere as abradable coatings. In order to understand the wear mechanisms of these systems tribological tests (block on ring and fretting) were performed to study the influence of the coating microstructure on the wear mechanisms. The results were compared and correlated to those of rub tests performed with real engine components.

A Review of Clearance Control Wear Mechanisms for Low Temperature Aluminium Silicon Alloys

1998 ◽  
Author(s):  
F. Ghasripoor ◽  
R.K. Schmid ◽  
M.R. Dorfman ◽  
L. Russo
Keyword(s):  
Wear Mechanisms ◽  
Gas Turbines ◽  
Hexagonal Boron Nitride ◽  
Silicon Alloys ◽  
The Matrix ◽  
Abradable Coatings ◽  
Silicon Based ◽  
Wear Maps ◽  
Clearance Control ◽  
Sprayed Coatings

Abstract Aluminium silicon alloys have shown favourable properties when used as the matrix for abradable coatings in low pressure compressors of gas turbines [1 and 2]. This paper aims to describe the wear mechanisms found in aluminium silicon based abradables. To this end three thermally sprayed coatings are investigated. Aluminium silicon polyester, aluminium silicon-graphite and the most recently developed, aluminium silicon-hexagonal boron nitride (hBN) examined here are amongst a few of these materials. To be able to design materials to functi?n in as wide a parameter range as possible, a test ng simulating engine mechanisms is required. Tests were conducted using titanium blades at velocities ranging from 250 - 450 m/s, temperatures of ambient to 450°C and controlled incursion rate of 5, 50 and 500 µm/s. The data obtained from these tests is best interpreted in the form of wear maps which characterise the seal performance and therefore are of use to engine and material designers.

scholarly journals A Comparison between CoNiCrAlY Bond Coat and Zirconia Plasma Sprayed Coatings on Creep Tests

2008 ◽  
Vol 591-593 ◽  
pp. 30-35
Author(s):  
Danieli A.P. Reis ◽  
Carlos de Moura Neto ◽  
Antônio Augusto Couto ◽  
Cosme Roberto Moreira Silva ◽  
Francisco Piorino Neto ◽  
...  
Keyword(s):  
Bond Coat ◽  
Ceramic Coating ◽  
Constant Load ◽  
Creep Tests ◽  
Engineering Ceramic ◽  
Wide Range ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Engine Components ◽  
Sprayed Coatings

Thermomechanical and electrical properties of zirconia-based ceramics have led to a wide range of advanced and engineering ceramic applications like solid electrolyte in oxygen sensors, fuel cells and furnace elements and its low thermal conductivity has allowed its use for thermal barrier coatings for aerospace engine components. A comparison between CoNiCrAlY bond coat and zirconia plasma sprayed coatings on creep tests of the Ti-6Al-4V alloy was studied. The material used was commercial Ti-6Al-4V alloy. Yttria (8 wt.%) stabilized zirconia (YSZ) with a CoNiCrAlY bond coat was atmospherically plasma sprayed on Ti-6Al-4V substrates by Sulzer Metco Type 9 MB. Constant load creep tests were conducted on a standard creep machine in air on coated samples, at stress levels of 520 MPa at 500°C to evaluate the oxidation protection on creep of the Ti-6Al-4V alloy. Results indicate that the creep resistance of the ceramic coating was greater than metallic coating.

scholarly journals Advances in Abradable Coatings for Gas Turbines

1994 ◽  
Author(s):  
R. Schmid ◽  
A. R. Nicoll
Keyword(s):  
Gas Turbines ◽  
Environmental Changes ◽  
Labyrinth Seal ◽  
Operating Conditions ◽  
Mechanism Analysis ◽  
Coating Materials ◽  
Turbine Engine ◽  
Plasma Sprayed ◽  
Abradable Coatings ◽  
Sprayed Coatings

Gas turbine engine development continues to accelerate, creating more demanding requirements for abradable seal coatings. These coatings are necessary to provide very small clearances between the rotating and stationary parts in order to minimize gap losses and so Increase efficiency. The relatively few abradable coating materials developed over the last 20 years still perform well in many blade tip seal and labyrinth seal applications. However, rising operating temperatures, corrosion and other environmental changes, longer overhaul times and even better tip clearances are dictating the design of new coating materials which requires a strong scientific approach. For example, ways are being Investigated to replace Nickel-Graphite and other flame sprayed coatings being used between 450 and 700°C respectively because of steady state/corrosion/oxidation/erosion and wear problems respectively. New plasma and HVOF sprayed coatings have been developed using a systematic approach based on material response to operating conditions, minimizing trial and error. The major steps in the programme were: 1. Selection of constituent materials able to withstand service temperatures up to 325 (AISI-Polyester or Polyimide), 450 (AISI base), 700 (MCrAlY base) and 1100°C (ceramic base) respectively. 2. Powder particle manufacture and coating deposition to guarantee highly reproducible coatings. 3. Coating optimization based on wear tests carried out using a fully instrumented abradability test rig and wear mechanism analysis. 4. An investigation of blade tipping systems for high temperature applications. This paper discusses the results of plasma sprayed coatings developed for use at 450 and 700°C.

Influence of the Torch to Substrate Velocity and Resulting Temperature on the Residual Stresses in Alumina Plasma Sprayed Coatings

1997 ◽  
Author(s):  
A.C. Leger ◽  
A. Grimaud ◽  
P. Fauchais ◽  
G. Delluc
Keyword(s):  
Residual Stresses ◽  
Displacement Sensor ◽  
Columnar Growth ◽  
Coating Microstructure ◽  
Plasma Sprayed Coatings ◽  
Stress Formation ◽  
Flat Beam ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Abstract A system, developed in the laboratory, allows to record in situ the deformation of a flat beam with a displacement sensor and so to analyse stress formation during spraying and upon cooling with fixed or rotating substrates. The beam is fixed onto a pair of knife edges by springs. The knife edges are disposed on a water-cooled rotating cylindrical substrate holder and the beam substrate (2 x 15 x 100 mm3) is parallel to the holder axis. The torch is moved back and forth parallel to the holder axis and the beam temperature is recorded by a thermocouple spot welded to it and also by an IR pyrometer. The influence of beam temperature for a given torch/substrate velocity on the residual stresses is studied for alumina and zirconia coatings. With fixed substrates a sharp increase of the residual stresses related to coating microstructure exists for a transition temperature around 600°C. It seems to correspond to a columnar growth throughout the layered splats. The effect of the torch to substrate velocity and so the pass thickness is studied too.

CHARACTERIZATION OF AS-SPRAYED AND LASER-TREATED ZIRCONIA-BASED PLASMA SPRAYED COATINGS

1990 ◽  
Vol 51 (C5) ◽  
pp. C5-393-C5-402
Author(s):  
A. FERRIERE ◽  
G. FLAMANT ◽  
J.-F. ROBERT ◽  
P. PEKSHEV ◽  
I. SMUROV ◽  
...  
Keyword(s):  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings

Investigation of agricultural tools with plasma-sprayed coatings

1990 ◽  
Vol 23 (5) ◽  
pp. 297-300 ◽  
Author(s):  
R.L. Kushwaha ◽  
L. Chi ◽  
C. Roy
Keyword(s):  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Sprayed Coatings
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