The aim of this work is to discuss the effect of different amounts of NaF in electrolyte on structure, corrosion resistance and wear behaviour of the prepared ceramic coatings on Ti6Al4V alloy by plasma electrolytic oxidation (PEO) technique. PEO process was carried out under constant current of 2 A, frequency of 1 kHz, anodic duty cycle of 45% and cathodic duty cycle of 25% using a pulse bipolar power supply. TiO 2 based coatings were prepared from three aluminate base electrolytes containing various amount of NaF (0.75, 1.5 and 2.25 g L 21 ). Phase composition, surface morphology and thickness of the resultant coatings were examined by means of X-ray diffraction and field emission scanning electron microscopy. Results indicated that solution composition and process time have a great effect on thickness and surface porosity of the coatings. Corrosion resistance and wear properties of the coatings were in a good accordance with structural properties.
The proper metallic charge ratio for Electeric Arc Furnaces (EAFs) has significant effects on the quality of the produced steel and performance of the furnace. Identification of this ratio based on inaccurate trial and error decision making gives rise to many defects. The aim of the study is to specify the best mixture of charge materials with respect to the operational parameters such as energy and material consumption and etc In this regard, the FHTOPSIS model has been utilized in fuzzy environment for pinpointing the alternatives for an EAF in a steel making company in Iran in order to reduce the erroneous decision. Consequently, the Analytical Hierarchical Process (AHP) has been applied to determine the relative importance of the criteria. Then the rank of most common metallic charges has been achieved by using the fuzzy TOPSIS. The result and its comparison with real word data revealed that the charge with 20% of DRI and 80% of scrap is the proper mix as EAF metallic charge.
Nomenclature
CECarbon Equivalent MD Metallization degree A Pairwise comparison matrix CR Consistency ratio CI Consistency index RI Random index l max Largest eigenvalue P ij Entry of the matrix A norm a ij Entry in the ith row and the jth column of A E j Entropy value of j th alternatives m Number of alternatives k Constant coefficient d j Deviation degree of j th criteria w j Criteria weight vector D Decision matrix x ij Entry in the ith row and the jth column of D r ij Normalized decision matrix R Normalized dimension-less fuzzy matrix RECEIVED
Experimental investigation of the isothermal and nonisothermal reduction of low silica hematite pellets in H2/CO mixture between 600 and 1234°C shows that the reduction rate in H2 rich gas mixture for nonisothermal condition is lower than for isothermal case at comparable temperatures. On the basis of the two period reduction model, some of the physical and chemical characteristics of pellets and reducing gas is calculated. Because of the advantage shown for isothermal reduction, a new technique for direct reduction of pellets is suggested.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.