The gas industry not only offers the most effective gas for all thermal spray processes, it also provides a variety of supply concepts and hardware with which maximum profitability can be achieved. The operator of the thermal spray equipment is responsible for ensuring that sufficient gas quantities are available at all times, comparable to the logistics involved in spray material management. Linde is now offering a fully automatic gas supply concept, including everything from consultancy and installation, through to the types of gases which can be used. The customer can therefore choose to manage his stocks himself as before, or to have the gas delivered and the bundles replaced by the supplier. With a minimum of time and effort, this electronic aid enables a reliable and fail-safe gas supply

MoSi 2 -TiB 2 coatings were applied on Ti6Al4V substrates by means of low pressure plasma spraying with and without a surface pre-treatment with plasma-transferred-arc. The coatings were characterized by optical and scanning electron microscopy, X-ray diffraction analysis and hardness measurements. No difference in the microstructure between the coatings was detectable. The microstructure shows the typical lamellar structure of thermal spray coatings with a good embedding of the titanium borides in the matrix. At the interface between matrix and some borides a reaction zone is visible. In comparison to the feedstock powder, the phase composition of the coatings has change, because a great amount of the tetragonal MoSi 2 phase transformed into the hexagonal high temperature modification. The content of titanium diboride is lower in the coating. Coatings on substrates with a pre-treatment show a good adhesion to the substrate, while the adhesion of the coatings on the pre-treated substrates is poor.

The atomization of molten materials using hot gases has advantages in comparison to the conventional gas atomization techniques. Some of these advantages favour the hot gas technology for the powder production for thermal spraying. Firstly, a considerably higher output of fine powder, in particular within the important particle size range between 5 and 30 µm, is a result of hot (inert) gas atomization. The reasons are the strongly increased gas exit velocity and the higher overall temperatures inside the interaction zone of the gas and the melt droplets. The enhanced shear forces acting on the molten liquid and the prolonged liquid state of the atomized particles lead to a more efficient atomization. Secondly, the extended time regime for liquid droplets facilitates the atomization of highly viscous melts, such as oxide melts, and results in more spherical particle shapes with good flowability. Thirdly, oxide or nitride powders can be generated directly from the molten metal by the usage of hot reactive gases or gas components for atomization. This paper describes the special features of a 25 bar hot gas atomization technique with pre-heated gases up to 1200°C and discusses its potentials for the generation of powders in view of their suitability in thermal spray applications.

The Goal of this research project is the development of a thermal spray technique for production of layers with high SiC content. Due to its physicochemical characteristics, silicon carbide (SiC) is a material which is particularly well suited as a component of wear-protection layers [1]. In thermal spray, however, silicon carbide can not be processed easily, since it disintegrates and sublimates into the gaseous phase at the prevailing high process temperatures under atmospheric conditions. In this project, SiC-phases of the spray layers are to be in-situ synthesized from silicon and carbon-containing substances during the spray process. Silicon containing solids are to be brought into reaction with carbon-containing solids, liquids and gases. For economic reasons, this technique is aimed at using low-priced basic materials to be processed by flame- and plasma spraying techniques with only slight modifications to existing atmospheric spraying equipment; thus the said SiC coatings might become an alternative to assigned hard material coatings. In this first step the technologic-mechanical potential and thus the feasibility and usability of a yet to develop coating system by different synthesis routes should be evaluated.

With the incoming of HVOF, the coating properties and application extent of WC-Co type have been greatly improved, in the recent years, we found that the characteristics of WC-Co powder has some influence on its coating properties prepared by HVOF. In this paper, study has been prepared on powders made from aboard and Beijing General Research Institute of Mining & Metallurgy properties such as fluidity, aspect, profile of coating SEM and carbon content, also phase structure and properties analysis of HVOF coating has been made. Finally, influence of powder preparing technology and HVOF technology parameters of different powders for coating properties have been described.

One of the largest successes of modern medicine is the total hip replacement. Presently this procedure has one of the highest success rate among surgical interventions, only second to the appendix removal procedure. However the lifetime of the prosthesis itself is still limited to 10 to 20 years, which means that for numerous patients replacement of the procedure will become mandatory. This replacement finds its origin in aseptic loosening of the prosthesis mainly caused by the formation of wear particles at articular joints and by the difference in stiffness between the bone and the metallic prosthesis leading phenomena called stress shielding. To overcome this problem, new designs of more biomimetic prostheses, with stiffness similar to that of cortical bone, are being studied. Among the latter, a novel design based on polymer composite materials of total hip replacement prosthesis is under development. One of the key characteristics of this biomimetic prosthesis is its hydroxyapatite coating, which permits Osseo integration (integration into the bone). Thermally sprayed hydroxyapatite coatings are already used successfully for metallic implants, but plasma sprayed hydroxyapatite coatings have yet to be developed for polymer composites due to quite challenging heat management and adhesion concerns. This paper describes and discusses the optimization of the plasma sprayed technique and the formation of the adequate underlayer enabling the plasma spray on highly heat sensitive substrate. Adhesion, shear and fatigue results are presented. Abstract only; no full-text paper available.