Conventional Fe-C-Si alloy cast iron shows good properties at low temperature but at high temperature its properties decrease very sharply. So, to protect this behaviour of cast iron, Si was replaced by Al, since both elements have similar graphitizing effect. In the present study, two types of cast iron, Fe-C-Si and Fe-C-Al, were cast in cold set resin bonded sand mould. After casting, the microstructures were studied using standard metallographic techniques. The wear tests were conducted using “CSM High Temperature Tribometer” following pin-on-disk method at 25 °C, 100 °C, 200 °C and 300 °C. The worn tracks were characterized using optical profilometer, SEM etc.. The results show that abrasive type wear was observed in both types of cast iron and always the Fe-C-Al cast has low wear rate compared to Fe-C-Si. However, after at 100 °C temperature, the wear resistance of Fe-C-Si cast iron starts to decrease whereas at lower temperature, it remains almost unchanged. The wear rates for Fe-C-Si alloy cast iron are 12.42, 16.51, 46.75 and 98.87x10-5mm 3 /N/m whereas the wear rates for Fe-C-Al cast iron are 3.32, 4.23, 4.40 and 8.15x10-5mm 3 /N/m at 25 °C, 100 °C, 200 °C and 300 °C, respectively.

A Fe48Cr15Mo14C15B6Y2 alloy with high glass forming ability (GFA) was selected to prepare amorphous metallic coatings by atmospheric plasma spraying (APS) process. The as-deposited coatings present a dense layered structure and low porosity. Microstructural studies show that some nanocrystals and a fraction of yttrium oxides formed during spraying process, which induced the amorphous fraction of the coatings decreasing to 69% compared with fully amorphous alloy ribbons of the same component. High thermal stability employs the amorphous coatings to work below 910K temperature without crystallization. Corrosion behavior of the amorphous coating was investigated by electrochemical measurement. The results show that the coatings exhibit extremely wide passive region and low passive current density in 3.5% NaCl and 1mol/L HCl solutions, which illustrate their superior ability to resist localized corrosion. Moreover, the corrosion behavior of the amorphous coatings in 1mol/L H 2 SO 4 solution is similar to their performance in chlorine ions contained conditions, which manifests their flexible and extensive ability to withstand aggressive environments.

Recently much research work has been undertaken worldwide to develop iron base materials which can be used for thermal spraying of anti-wear coatings. Besides economical ideas reasons exist like health- and environmental aspects for the usability of iron base materials instead of Ni- or Co containing carbide coatings. Until now, however, iron base materials showed a worse life time under abrasive wear compared with conventional carbide coatings like WC/ CO or NiCr-CrC. This article presents the research work on new iron base materials for wear protection purposes. Thereby, the focus is set on high carbon containing iron-chromium base alloys which solidify under the formation of primary carbides. The material development included the study of different additional alloying elements. The relation of different chemical compositions and their typical microstructure to the wear behaviour is presented in this paper, too. To follow an integral way for the evaluation of the wear behaviour both powders and cored-wires could be produced. Therefore the wear tests considered coatings produced via HVOF, PTA and arc-spraying.

Combined damage of cavitation and abrasion is one of the serious problems that affect lifetime and performance on hydraulic machineries and its components. Thermal spraying as a surface hardening and protection technology is required to protect hydraulic components, such as water turbine and radial flow pump, in general. Detonation sprayed coating with high abrasion resistance is one of the promising solutions as the protective coating against combined damage of cavitation and abrasion under solid-liquid double phase liquid conditions. In this study, NiCr-Cr 3 C 2 and WC12Co coatings on the No.45 steel substrate surface have been formed by detonation spraying with the same technological parameter and their properties such as microstructure and microhardness have been studied. The cavitation and abrasion behavior of coatings and the substrate has been investigated using a self-manufactured rotating disk system. The resistance properties of cavitation erosion and abrasion have been illustrated and analyzed with the substrate by the cumulative mass loss curves. The results indicate that, the resistance properties of cavitation erosion and abrasion of NiCr-Cr 3 C 2 coating are the best.

Thermally sprayed cermet coatings are widely used in pulp and paper industry and also in other applications of such corrosive conditions where chlorine is present. In these conditions corrosion resistance and wear resistance of the coatings are the most important characteristics. Corrosion resistance can be improved by sealing the corrosion sensitive base material surface under the coating from chlorine containing environment. Test materials in this work were thermally sprayed WC-10Co4Cr, Cr 3 C 2 -25NiCr and Sanicro 28 coatings prepared using HVAF and arc spray techniques. The degradation of the coatings and base material surface was characterized using micro hardness tests, optical and scanning electron microscopy, and also by conventional weight loss measurements. Wear resistance of the coatings was evaluated using modified rubber-wheel abrasion tests. In this work ASTM G48 corrosion testing standard was utilized in corrosion testing of these corrosion resistant thermally sprayed coatings. In demanding chlorine containing corrosion conditions it is essential to understand where the corrosion is concentrating in the structure. In the studied corrosion conditions Sanicro 28 and Cr 3 C 2 -25NiCr coatings were heavily corroded inside the coating material. Corrosion resistant Cr 3 C 2 -25NiCr cermet coating was corroded also between the coating and the base material and the adhesion between the base and the coating was lost in some of the specimens after one day exposure. Unexpectedly HVAF sprayed WC-10Co4Cr coating was giving the best performance of the coatings tested in this work.