This work investigates the biofunctionality and corrosion resistance of titanium (Ti) and Ti/bioglass composite coatings. Commercially pure Ti (CP-Ti) and 45S5 bioglass powders were deposited on CP-Ti plates by air plasma spraying and the coating samples were placed in Hanks’ balanced salt solution for simulated body fluid (SBF) testing. After four weeks of immersion, the coatings were examined by SEM imaging and EDS and XRD analysis. EDS analysis showed that the Ca content on the Ti/bioglass coatings increased from 4 to 16 wt%, while no increase in Ca was observed on the Ti coatings. Hydroxyapatite formation was found on both coatings, although the relative intensity of HA on the XRD spectrum was higher for the Ti/bioglass composite layers. Weight measurements before and after immersion showed that the CP-Ti samples experienced a mass gain and that the Ti/bioglass samples underwent a mass loss likely due to the dissolution of calcium and phosphate.

Many ceramic materials are microstructurally stable at high temperatures, but exhibit poor mechanical properties under load. In this study, a Ni-base superalloy wire mesh is used as a reinforcement to strengthen a 6.15 mm thick layer of plasma-sprayed YSZ. The flexural performance of the ceramic matrix composite (CMC), as determined by a three-point bend test, exceeds that of monolithic YSZ in terms of peak load and displacement before fracture. Heat treatment of the CMC further increases the load at the onset of crack initiation due to enhanced bonding between the constituent materials.

In thermal barrier coating (TBC) systems, a continuous alumina layer developed at the ceramic topcoat/bond coat interface helps to protect the metallic bond coat from further oxidation and improve the durability of the TBC system under service conditions. However, other oxides such as spinel and nickel oxide, formed in the oxidizing environment, are believed to be detrimental to TBC durability during service at high temperatures. It was shown that in an air-plasma-sprayed (APS) TBC system, post-spraying heat treatments in low-pressure oxygen environments could suppress the formation of the detrimental oxides by promoting the formation of an alumina layer at the ceramic topcoat/bond coat interface, leading to an improved TBC durability. This work presents the influence of post-spraying heat treatments in low-pressure oxygen environments on the oxidation behaviour and durability of a thermally sprayed TBC system with high-velocity oxy-fuel (HVOF)-produced Co-32Ni-21Cr-8Al-0.5Y (wt.%) bond coat. Oxidation behaviour of the TBCs is evaluated by examining their microstructural evolution, growth kinetics of the thermally grown oxide (TGO) layers, as well as crack propagation during low frequency thermal cycling at 1050°C. The relationship between the TGO growth and crack propagation will also be discussed.

Affordable and reliable solid oxide fuel cells (SOFCs) are being widely sought as the next-generation answer to the power needs of many applications throughout the world. Maintaining stable hermetic sealing is critical for SOFC stacks to achieve high efficiency and longevity. The authors have introduced a novel multi-layered composite seal, consisting of thin layers of oxidation resistant alloys, plasma sprayed ceramic, and hermetic filler materials. The seal structure will be directly fabricated onto the surfaces of mating adherends using low-cost manufacturing methods such as atmospheric plasma spray (APS). During stack assembly, sealing can be achieved through a simple heat/pressure-assisted curing process. As an important part of the layered composite seal, a plasma sprayed porous alumina-YSZ (yttria-stabilized zirconia) ceramic coating on Fe-Cr based interconnect material has been developed. The ceramic coating was made from low-cost commercially available powders and deposited by atmospheric plasma spray (APS) method. The coating composition and fabrication procedure were optimized for high mechanical robustness, low electric conductivity. Experimental results based on coated “button” samples have demonstrated good bond strength between the plasma-sprayed ceramic layers and interconnect substrates, excellent thermal shock resistance, good electrical insulation properties, and low permeability. Initial testing result of a composite seal formed with a glass filler has shown a low gas leak rate and good thermo-cycling resistance.

The balanced flow type condenser is one of important part used in the air-conditioner of automobile. The manufacture needs the surface of aluminum multi-void to be coated with zinc. One of economical and efficient process is the automatic wire arc spray, in which the maintain of temperature and the in-process speed can make key effects on the quality of coatings. The relation between substrate temperature and the composition, structure and corrosion resistance of the coating of aluminum multi-void are mainly discussed to confirm the best in-process speed of aluminum multi-void, the maintain of temperature and the parameters of arc spraying. Abstract only; no full-text paper available.

In this paper describes the design of the arc spray gun with secondary atomization, which using the mixture of propane and air as the main gas and the compressed air as the gas for secondary atomization. The test shows that in the high velocity airflow produced by the combustion of propane – air mixture, the atomized particle size is less than 20 micron. In the second- combustion thermal airflow, the high temperature area of the arc beam is obviously lengthened at the same time the combustion gas environment restrains the oxidation of the spraying materials. Because the speeds of particles are improved greatly, the coatings obtained are denser. Through practical application it shows that this system can obtain stable deposition efficiency, high bond strength, and low roughness and greatly reduce the cost of machining. Abstract only; no full-text paper available.

Research and selection the performance requirements for the coating, at the same time obtain the WC-Co powders with high efficient spray rate and low cost, through research on the relation between the WC-Co powders sprayed by the HVOF in different morphology and in different manufacturing process and the spraying parameters and structures of coatings. Abstract only; no full-text paper available.

This paper provides a summary of conventional thermal spray powder feeders, examines the influence of carrier gas flow, powder tube diameter, powder tube type, and gas flow path on the feed precision and continuity of pressure-type powder feeders, and discusses the cause of pulsation associated with the injection of super fine ceramic powders.

This paper discusses the basic design and operating characteristics of a precision heavy-duty thermal spray turntable. The system incorporates eccentricity and speed control and accommodates working pieces up to 100 mm in diameter and 2000 mm in height weighing as much as 1500 kg. Site tests, as reported in the paper, indicate that the turntable also meets dust and heat tolerance requirements.

Plasma transferred arc (PTA) welding is widely used in the petroleum and chemical industry to deposit nickel and cobalt-based materials on key parts for the purpose of surface modification. As test results show, the process improves corrosion, wear, and high-temperature resistance, prolonging the service life of components and equipment and reducing production costs.