New Arc Wire Approvals for Aircraft Power Plant Overhaul

2000 ◽  
Author(s):  
E.R. Sampson ◽  
P. Sahoo
Keyword(s):  
Aircraft Engine ◽  
Historical Background ◽  
Spray Process ◽  
Arc Spray ◽  
Auxiliary Power ◽  
Auxiliary Power Units ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Engine Components ◽  
Aircraft Overhaul

Abstract Arc spray systems are increasingly used in the overhaul of aircraft engine components and auxiliary power units. The increasing use of arc spray over plasma for metallic coatings has created a demand for new wire approvals. The chemistry is already established as a powder and it is a matter of conversion to a wire and the arc spray process. The increasing popularity of the arc spray process is due to its superior bond strength and microstructure that exceed those of plasma. In one case, there is a two and one-half percent porosity requirement for the arc spray and up to 15% is allowed for plasma. This density approaches HVOF quality requirements. This paper will discuss some historical background of the process, what is approved and then move on to the new materials that are submitted for approval. Microstructures and bond strengths will be presented and some information about a proprietary method to solve a coating problem in the aircraft overhaul industry of long standing. The paper will also discuss new advances in arc spray systems and materials, which makes these systems amenable to replacing plasma sprayed coatings.

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.

An Alternative Thermal Spray Process to Plasma Spray in the Aircraft and Stationary Gas Turbine Industry

1994 ◽  
Author(s):  
Menno P. Zwetsloot ◽  
Elliott R. Sampson
Keyword(s):  
Thermal Spray ◽  
Plasma Spray ◽  
Nickel Aluminum ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Arc Spray ◽  
Spray System ◽  
Technological Advances ◽  
Attachment Device ◽  
Plasma Sprayed

Technological advances in arc spray have produced an arc spray system that competes very favorably with other thermal spray processes. In the past arc spray was thought of as a process for very large parts that need thick buildups. However, an attachment device has been developed which focuses the pattern and accelerates the particles and is known as the Arc Jet system. The advantages of this device were discussed by Zwetloot, Sampson and Thorpe (1993), Reference 4. This attachment device coupled with the introduction of metal cored wires that provide the same chemistries as plasma sprayed powders, provides application engineers with a viable economic alternative to existing spray methods. A comparative evaluation of a standard production plasma spray system was conducted with the arc spray process utilizing the device mentioned above. This evaluation was conducted by an airline company on four major parts coated with nickel aluminum and results show that, for those applications, the arc spray process demonstrated significant benefit. It is expected that other applications may benefit from the use of the arc spray process as well.

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.

Comparison of Plasma-Sprayed Coatings Produced in Argon or Nitrogen Atmosphere

1997 ◽  
Author(s):  
M. Leylavergne ◽  
A. Vardelle ◽  
B. Dussoubs ◽  
N. Goubot
Keyword(s):  
Plasma Spraying ◽  
Nitrogen Atmosphere ◽  
Cryogenic Cooling ◽  
Ambient Atmosphere ◽  
Air Plasma ◽  
Spray Process ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
Thick Coatings ◽  
Sprayed Coatings

Abstract When spraying is conducted in the ambient atmosphere, the entrainment of air cools down the plasma jet and affects its expansion. It may also cause the oxidation or the chemical decomposition of the sprayed materials. Inert Plasma Spraying (IPS), generally conducted in argon atmospheres, prevents these phenomena. However, the main drawbacks of IPS in comparison with air plasma spraying are the capital and apparating costs. To reduce the latter by 25 to 30%, nitrogen atmospheres may be used as a substitute for the conventional argon atmosphere. This paper presents a study in which titanium carbide and niobium powders were sprayed in argon and nitrogen atmospheres. Cryogenic cooling of the substrate was used during the spray process. This helps to maintain a low temperature in the chamber, produces thick coatings and allows the use of substrate materials that are sensitive to heat. The adhesion, roughness and microstructure of the coatings produced in both atmospheres are compared as well as their nitrogen content.

Solid Particle Erosion Behaviour of Plasma Sprayed Coatings on a Fe-Based Superalloy

2005 ◽  
Author(s):  
S. B. Mishra ◽  
S. Prakash ◽  
K. Chandra
Keyword(s):  
Plasma Spray ◽  
Impact Angle ◽  
Silica Sand ◽  
Spray Process ◽  
Air Jet ◽  
Microhardness And Microstructure ◽  
Plasma Sprayed Coatings ◽  
Plasma Sprayed ◽  
The Impact ◽  
Sprayed Coatings

In the present investigation plasma sprayed metallic coatings of NiCrAlY and Ni-20Cr were deposited on a Fe-based Superalloy (32Ni-21Cr-1.5Mn-1Si-0.3Ti-0.3Al-0.1C and Balance Fe) by shrouded plasma spray process. NiCrAlY was used as bond coat in both the cases. Erosion studies were conducted on uncoated as well as plasma spray coated superalloy specimens using an air-jet erosion test rig at a velocity of 40m/s and impingement angles of 30° and 90°. Silica sand particles of size ranging between 150 and 212 μm were used as erodent. The coatings have been characterised for porosity, microhardness and microstructure. Erosion behaviours of the superalloy and plasma spray coatings are discussed. Of the two plasma sprayed coatings, the NiCrAlY coating gave the lowest erosion rate regardless of the impact angle.

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

Impacts assessment and trade-offs of fuel cell-based auxiliary power units

2005 ◽  
Vol 139 (1-2) ◽  
pp. 205-213 ◽  
Author(s):  
Francesco Baratto ◽  
Urmila M. Diwekar ◽  
Davide Manca
Keyword(s):  
Fuel Cell ◽  
Auxiliary Power ◽  
Trade Offs ◽  
Auxiliary Power Units
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