This paper describes the applications of the new type high productive high velocity arc spray system, at the same time makes a comparison with the effects of the atomized particles sprayed separately by the high-velocity and general arc spraying gun, analyzing the effects of the original velocity of the particles to the coating structures and comparing the difference of the surface roughness, the porosity and the bond strength of the coatings. Some new applications examples of the latest three years on the high productive high velocity arc spray system are presented in this paper.

HVOF sprayed Cr 3 C 2 -NiCr cermet coating was investigated to improve the erosion resisting performance of the coal burning boiler tube exposed by fly ash erosion. SUS 310S stainless steel substrate was used to examine the effect of surface treatments. HVOF coating was compared with the calorizing treatment. Coating microstructure, mechanical properties such as hardness and sand blast erosion resistances, and high temperature oxidation resistance were examined. Erosion resisting performance and durability of the HVOF sprayed Cr 3 C 2 -NiCr cermet coating were superior to those obtained from the calorizing surface treatment.

The paper will describe a collaboration of the DoD Propulsion Environmental Working Group (PEWG), Oklahoma City Air Logistics Center (OC-ALC), Pratt & Whitney and Engelhard Corporation to qualify and transition High Velocity Oxy Fuel (HVOF) thermal spray of tungsten carbide coatings to replace electrolytic chrome plating for the repair of Pratt and Whitney (PWA) engines at the OC-ALC. This depot is the primary location for engine repair for the US Air Force. The paper details the engineering effort to qualify the HVOF tungsten carbide coating on PWA TF33 engine components as an precursor to qualifying the coatings for other military PWA engines. The paper also provides details of the transition of HVOF thermal spray technology into a new state-of-the-art production facility at the OC-ALC depot. The paper highlights a notably successful industry and government partnership to rapidly transition a world-class thermal spray capability into OC-ALC. The PEWG is a special management group that works with US military propulsion managers to educate/apprises government and industry collaborations of mature advanced pollutant free technologies and then facilitate the transition to full-scale production. Pratt and Whitney is the original equipment manufacturer of the TF33 engine and supplies other gas turbine engines to the Air Force and other military services. Engelhard Corporation is a surface and science company that develops technologies to improve customers’ products and processes. A Fortune 500 company, Engelhard is a world-leading provider of technologies for environmental, process, appearance, performance application and engineering solutions. Engelhard led the technology transition effort under contract to the PEWG. [This effort, as will be described in the paper, encompasses process engineering, coating qualification, spray parameter definition, tooling concepts, accelerated mission engine test support, inspection techniques, and production bed-down at the OCALC depot.]

The use of modern thermal spraying techniques for filler metal application may offer new solutions for brazing complex metal components without fluxing agents, when the spraying processes are fitted to the requirements of the following brazing process. The necessary coating parameters always depend on the kind of base material, the geometry of the joint, the used filler metal, and the chosen heating process for brazing (heating in vacuum or protective atmosphere furnaces, inductive or flame heating etc.). Copper and nickel based alloys are typical filler metals for brazing complex components made of stainless steel (heat exchanger, fuel pipe systems, exhaust systems, catalytic devices etc.). Using these examples, the results of brazing experiments and technical aspects of thermally sprayed braze coatings compared with conventional filler metal application techniques are discussed.

The use of diamond-impregnated tools for the machining of any type of building material or natural stone is an established technology. Sintering and brazing are the key manufacturing technologies. The restricted flexibility of the geometry variation, the absence of the repair possibilities of damaged tool surfaces as well as difficulties in controlling the materials interfaces are some drawbacks. Therefore, manufacturing diamond tools through new technology concepts are required not only to avoid these restrictions mentioned but also to enhance the tools properties. In particular, thermal spraying technologies can act as a potential problem solver due to their special technological properties. Especially the new high-speed technologies such as the detonation-gun and high velocity oxygen fuel thermal spraying are promising approaches. Through these technologies, it is possible to control the kinetic energies of the diamond particles as well as their temperature during coating. In this report, a novel manufacturing technology of the diamond-impregnated tools based on these high-speed thermal spraying technologies will be reported. The layer properties will be evaluated with respect to the diamond quality after coating and with respect to the properties of the diamond composite coatings. Diamond spraying efficiency, diamond distribution in the layer as well as diamond-metal binder-interaction are analysed.

The Ni-based single crystal superalloy has an excellent performance derive for high temperature fatigue strength. So, the expansion of application has been expected mainly in advanced gas turbine parts. However, it is known that the γ′ microstructure changes inside the material by plastic strain processing and heat-treatment. As a result, the fatigue strength was remarkably reduced. The new phenomenon was found that the B containing alloy coatings formed by thermal spraying restore high temperature fatigue strength of the weakened single crystal superalloy. We introduce the improvement effect of high temperature fatigue strength achieved by means of spraying the B containing alloy to CMSX-4 Ni base alloy substrate produced alterated layer.

Spark-plasma sintering (SPS) was adopted in this study as a rapid post-spray treatment for yttria stabilized zirconia (YSZ) electrolytes prepared through the direct current (dc) plasma spray process. The lamellar microstructure in the as-sprayed samples was found to significantly reduced the ionic conductivity of the YSZ electrolytes. However, the ionic conductivity (at 1053 °C) increased sharply from 0.065 S/cm for the as-sprayed electrolyte to 0.122 S/cm for electrolyte post-spray treated through SPS at 1400°C for 3 minutes. These phenomena were attributed to the microstructure transformation from lamellar structure of the as-sprayed samples to equi-axial type granular structure of the post-spray samples treated by SPS. Correspondingly, porosity reduced from ~ 10.72 % in as-sprayed coating to ~ 1.38% in the SPS sample treated at 1400°C for 3 min. Majority of the pores in the SPS sample were also found to have contracted to a narrow size range 0.03 – 1 µm. AC impedance spectroscopy demonstrated the effect of the microstructure modification between samples treated in the SPS at temperature 1200, 1300 and 1400°C for 3 minutes with the concomitant reduction of the resistivity, which is consistent with the microstructure changes of the YSZ electrolyte from lamellar structure to granular structure. Overall, the results show that spark-plasma-sintering (SPS) is an effective and rapid post-spray treatment to improve the relative density and electrical properties of plasma sprayed YSZ electrolytes.

Nose and wing leading edges for future generations space vehicles will withstand very high temperature in an oxidizing environment. UHTC (Ultra High Temperature Ceramics) materials are very promising candidate materials for such applications. An innovative, proprietary methodology was developed to produce, by plasma spraying deposition, a ceramic composite containing SiC particles (25 wt %) dispersed in a ZrB 2 matrix. With such a technique both coatings and self standing parts were fabricated. In the present paper, the results of mechanical characterisations, carried out on self standing samples, are presented. Tensile and bending properties were determined by mechanical tests on as sprayed samples and on samples exposed at high temperature (2173 K) in oxidising conditions. Experimental results clearly evidenced the possibility to use the plasma spraying technology and suggest that the so fabricated ZrB 2 -SiC material is suitable to be adopted as protective coating.

The author carried out in 2003 a multiclient survey and research covering thermal spraying industry in China. This work mainly focus on the productive level and scale of thermal spraying equipment and materials, application and coating job shop, R&D in universities and institutes as well as the develop trends of thermal spraying industry in China. This presentation intends to provide general pictures on thermal spraying industry in China, by offering data and analysis, forecasts the future of thermal spraying in China.

New composite materials thermally spray powder is developed in order to protect the surface of boiler tube while long period more than up to this time. This powder is so constitute that original sermet is organized from several bolides and inter metallic compounds (patent pending applied for). For the reliable electric power supply, the steam generating boiler is important facility still today. And in boiler operation, one of the most significant problems is the prevention of boiler tube failure. The main destructive processes that ravage boiler tubes are corrosion and erosion. During the last several years, thermally sprayed coating has been applied to the surfaces of boiler tubes. Accordingly, this paper reports on the effects of this developed powder’s coating as compared with these conventional coatings on the prevention of these hot abrasion are tested in laboratory.

Plasma deposition technologies are applied as an alternative approach to conventionally used sintering techniques for the fabrication of the entire cell assembly of solid oxide fuel cells (SOFC). Based on advanced processes with both DC and RF plasma DLR Stuttgart has developed a concept of a planar SOFC with consecutive deposition of all layers of a thin-film cell onto a metallic substrate support. The current state of the development of this “spray concept” which focuses on the application of SOFC as auxiliary power units (APU) for electric power supply in vehicles and aircrafts is summarized in this paper.

Ultra-fine hydroxyapatite (HA) powders were produced with radio frequency (RF) suspension plasma spraying (SPS). This novel technique utilizes the inherent properties of the RF plasma enabling axial feeding of the suspension into the plasma producing spherical ultra-fine HA powders. These powders were examined by XRD and Rietveld analysis using the Rietquan 2.3 Quantitative Analysis software package. The aim of the analysis was to determine the various amounts of decomposed phases and amorphous content after SPS of HA. Results showed that the amount of decomposed phases rose up to a plate power of 15 kW there after decreasing at higher plate powers. The amorphous phase however kept increasing with plate power reaching about 35 wt.% in the powders sprayed at 21 kW. These trends have led to the belief that the phase content and hence, the characteristics of the powders are controlled mainly by the competitive processes of decomposition and melting and evaporation within the plasma. The morphology of the powders was also observed through TEM and changes in molecular structure were investigated by FTIR. DSC was carried out to observe the crystallisation of amorphous calcium phosphate into HA.

Plasma spraying at low pressure conditions (LPPS) is a well established thermal spray process with a broad variety of important applications in different industrial segments. The operating conditions for LPPS processes can vary in a wide range from only a few mbar up to typically 200 mbar which imposes different characteristics of the corresponding spray conditions and resulting coating properties. Thermal spray processes have been approved being suitable for integrated fabrication of various layers for SOFC components. Depending on the process conditions, different layers used as functional coatings of SOFC components such as dense electrolyte layers as well as porous electrodes can be realized using the LPPS technology. Due to the flexibility of these processes, an optimized performance of the application on different target materials and geometries is possible with an increased technological and economical benefit compared to conventional thermal spray techniques. This paper presents an overview on the general potential and spray conditions of the LPPS process and its application for the deposition of various functional layers such as electrolyte and electrodes for SOFC components.

In this paper the point of view for the industrial coating manufacturing is presented. The perspective for industrial manufacturing of thermal spray coatings and facts that effect on the processibility of coatings in real life is often requested but seldom published. The perspective is from Pikoteknik Oy, which has a wide and long-term experience in the improvement and repair of machine parts in-situ, containing measurements, machining, coating and balancing of rolls and cylinders. Pikoteknik Oy is able to perform maintenance of paper cylinders on-site including pretreatments, thermal spraying and balancing quickly and skillfully. Due to their versatile state-of-the-art equipment, they are able to work flexibly on-site. To be able to operate on-site there are special demands for equipment, personnel and scheduling. The quality of the final product is in the hands of operator. Destructive testing is not possible to carry out and large amount of variables, such as moisture and positioning of equipment's exist. Grinding and grit blasting must carry out without dust formation due to the surrounding bearings and sensors. Large amount of experience and special knowledge is needed to be able to produce high quality coatings over paper cylinders.

A NAS battery cell is comprised of a sodium negative electrode and a sulfur positive electrode separated by a solid electrolyte made of beta-alumina, housed within a cylindrical aluminum container. The container is exposed highly corrosive materials, but have to be designed to deliver 4500 charge/ discharge cycles over a 15-year operating life. Studies have shown that a plasma sprayed Fe-75Cr alloy coating provides an effective protection layer. The major challenge to implementing this technology was the development of methods to apply plasma spray coatings in high volume mass production of the cells. This paper describes the development of high speed plasma spray guns optimized for volume manufacturing conditions, and the quality and reliability of NAS cells using this technology demonstrated over a period of nine years in laboratory tests. In April 2002 TEPCO and NGK decided to launch commercial production of NAS batteries. By April 2003, NGK started operation of a new NAS battery manufacturing facility and plasma sprayed aluminum cell containers are now being produced at a rate of over 1300 per day.

Aluminum coatings minimum 1.8 mm thick are applied to water-cooled proton beam collimators used in the manufacture of medical isotopes on the TRIUMF TR30 cyclotrons in Vancouver, British Columbia, Canada. The sprayed surface of the collimators is made from silver. These collimators are used to trim the proton beam so that only a designated area on the isotope production target is irradiated with protons. Aluminum is used because its activation products at the energies used have short half-lives, thus minimizing the amount of collateral radioactivity produced. The aluminum is sprayed using an Axial III plasma spray torch. In service, the collimators are subject to high heat fluxes due to the proton beam. Service life, heat transfer and application data are provided in this paper.

Industry faces the continual challenges of operating in less space and accelerating line speed in order to increase productivity, improve quality, and reduce cost. These challenges are particularly evident in the film and papermaking markets. To maintain competitive products in the market place, it is essential to incorporate rollers that are; lightweight, high stiffness, and compact. To satisfy these requirements, rolls made of carbon fiber reinforced plastics (hereinafter referred to CFRP) have proven effective and have come into wide use in many industrial fields. CFRP rolls are the structural materials that were developed mainly to improve the Young's modulus of rolls. Guiding and transfer rollers frequently require surface features such as non-adhesion and wear resistance. The typical surface treatments to CFRP currently employed are; painting, plating, and rubber lining or the like, but these treatments have their limits in the manufacturing process and effectiveness. Consequently, we have developed the technology to provide rolls with the desired surface by spraying various metals, ceramics, or cermets, directly on CFRP substrate. These sprayed rolls have been intensely monitored in actual operations to insure high speed capability and longevity. In this presentation, we will talk about the rotary bending fatigue test of CFRP rolls on which the carbide cermet was plasma-sprayed and the quality stability of the roll with the two-layer composites that was confirmed based on the test results.

Samaria doped ceria (SDC), used as a solid oxide fuel cell (SOFC) electrolyte, was deposited by Solution Plasma Spray (SolPS) process. An aqueous solution of mixed nitrates was axially injected into the Radio Frequency (RF) inductively coupled plasma through an atomization probe. The atomic ratio of the SDC components in solution was (Ce 0.85 Sm 0.15 )O 1.925 . In order to control the initial spray droplet diameter, Malvern RTsizer atomization tests were performed. In-flight particle temperature and velocity were analyzed by DPV 2000. Coatings thickness and morphology were measured and observed by scanning electron microscopy, the substrate porosity being determined through gas permeability measurements. Results indicate that the coating's porosity and density strongly depend on the plasma spraying parameters. Gap size of the injection probe, atomization gas flow rate and the probe position have no significant effects on the coating’s porosity under the spraying conditions applied in this study

For many years coatings have been successfully applied to aerospace engine components to improve life and performance. The key success areas have been in thermal barrier coatings, clearance control, oxidation/hot corrosion and wear coatings. Today, design engineers in the industrial gas turbine sector have leveraged the “aerospace” technology into the power generation industry. This paper gives a general overview of key coatings used in the compressor and turbine sections. Design requirements will be reviewed and compared between aerospace and power generation coatings. Application process improvement areas will also be discussed as a method of reducing component cost. Therefore, the total solution will be more reproducible, cost effective coatings that add value. This will result in engineered components that operate at higher temperatures and/or last for longer periods of time.

In the paper, a newly composite TiB 2 /Al 2 O 3 coating prepared by High Velocity Electric Wire Arc Spraying and cored wire with ceramic powders composed of refractory Al 2 O 3 and TiB 2 filling inside was introduced. The microstructure and composition of the TiB 2 /Al 2 O 3 coating were investigated by metallgraphic microscope, scanning electron microscope and X-rayed diffraction, Bonding strength and hardness and mechanics properties were tested. The experimental results show the TiB 2 /Al 2 O 3 composite coating possessed high hardness and higher bonding strength with substrate and excellent comprehensive mechanical properties. It can be used for improving shoot-proof properties in the surface of arms.