Influence of fuel ashes on corrosion of surface coatings cladded by CMT method

The aim of the present research was to investigate the influence of different biomasses and sewage sludge ash (at 650°C for 1000 h and 2000 h, respectively) on the surface of weld cladded (Cold Metal Transfer technique, CMT) stainless steels 309 and 310. The biomass ashes were rich in K₂O, CaO, SiO₂, whereas sewage sludge ash in P₂O₅, CaO, Fe₂O₃, and SiO₂. Characterization of the stainless steel cross-section and surface after the corrosion process inducted by the presence of ash were carried out by scanning electron microscopy (SEM) with EDAX analysis. Phase analysis of corrosion products was made by X-ray diffraction (XRD). Chromium, nickel, and iron oxides were the main oxides which occurred after the corrosion test. It has been proved that biomass ashes have the corrosive properties (because of their chemical composition) and are more aggressive than the sewage sludge ash for that kind of materials.     

Effect of Low-Friction Composite Polymer Coatings Fabricated by Electrophoretic Deposition and Heat Treatment on the Ti-6Al-4V Titanium Alloy’s Tribological Properties

Metallurgical and Materials Transactions A - In this work, polytetrafluoroethylene/polyetheretherketone (PTFE/PEEK 708) coatings were fabricated by electrophoretic deposition (EPD) and heat...     

Microstructure and Selected Properties of Advanced Biomedical n-HA/ZnS/Sulfonated PEEK Coatings Fabricated on Zirconium Alloy by Duplex Treatment

In this work, sulfonated polyetheretherketone (S-PEEK)-based coatings, nanocrystalline ZnS and hydroxyapatite (n-HA) particles were developed on Zr-2.5Nb zirconium alloy substrates by electrophoretic deposition (EPD) combined with subsequent heat treatment. The properties of suspensions and deposition kinetics were studied. Cationic chitosan polyelectrolyte ensured the stabilization of the suspension and allowed for the co-deposition of all coating components on the cathode. The heating of the coated samples at a temperature of 450 °C and slow cooling resulted in sulfonation of the PEEK and the formation of dense coatings. The coatings were characterized by high roughness, hardness, modulus of elasticity and adhesion strength. The coatings revealed mild hydrophilicity, improved the electrochemical corrosion resistance of the alloy and induced the formation of hydroxyapatite with a cauliflower-like morphology on its surface during the Kokubo test. This work explored the great development potential of advanced sulfonated PEEK-based coatings, incorporating antibacterial and bioactive components by EPD combined with heat treatment to stimulate the surface properties of zirconium alloy for prospective dental and orthopedic applications. The antibacterial and osteoconductive properties of the obtained coatings should be further investigated.     

Microstructure and electrical properties of RuO2-CeO2 composite thin films

RuO₂-CeO₂ composite thin films are deposited on various Si substrates by a radiofrequency magnetron sputtering technique. Compacted polycrystalline pellets of the nanostructured CeO₂-RuO₂ composite system are used as standard samples for comparative electrical analyses. All films and composite samples are analyzed by X-ray diffraction and transmission electron microscopy. Electrical measurements of radiofrequency sputtering of thin films are performed as a function of the RuO₂ fraction and of the temperature (between 25 and 400 °C). A nonlinear variation in the electrical conductivity of the RuO₂-CeO₂ composite thin films as a function of the RuO₂ volume fraction (Φ) is observed and discussed. It is interpreted in terms of a power law (in (Φ − Φc)^m ), where m and Φc are parameters characteristic of the distribution of the conducting phase in a composite medium.     

Development of Microstructure and Properties of Multicomponent MoS2/HA/PEEK Coatings on a Titanium Alloy Via Electrophoretic Deposition and Heat Treatment

Metallurgical and Materials Transactions A - In this study, molybdenum disulfide nanosheets, bioactive hydroxyapatite particles of two types in various amounts, and PEEK 704 microparticles were...     

Microstructure and Properties of Electrodeposited nc-TiO2/Ni–Fe and Ni–Fe Coatings

Metals and Materials International - In this study, nc-TiO2/Ni–Fe composite coatings, and Ni–Fe alloys as equivalents to their matrices, were obtained from citrate-sulphate baths in the...