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The rhodium incorporated aluminide coating was produced by the rhodium electroplating (0.5 μm thick layer) followed by the chemical vapor deposition process on the Inconel 713 superalloy. This coating is composed of the β-NiAl phase. A part of nickel atoms was replaced by rhodium atoms in the β-NiAl phase. The plain, rhodium and platinum incorporated aluminide coatings were oxidized at 1100 ºC under the atmospheric pressure. The oxidation kinetics of the rhodium and platinum incorporated aluminide coatings were similar, but different than oxidation kinetic of the plain coating. The α-Al2O3 was the main product both in rhodium and platinum modified coatings after 360 h of oxidation. Moreover, the γ-Ni3Al phase, besides the β-NiAl phase, was identified. The presence of 4 at. % rhodium in the coating provided similar oxidation resistance as the presence of 10-20 at. % platinum. Both rhodium and platinum incorporated aluminide coatings produced by the chemical vapor deposition process offer good oxidation protection of the Inconel 713 superalloy. [ABSTRACT FROM AUTHOR]

Copper-nickel sulfide ores are one of the main sources of platinum. One of the ways to extract precious metals from such ores involves melting of a concentrate in electric ore smelting furnaces, where the melt is divided into matte and slag. Platinum is generally concentrated in matte; however, some of it remains in the slag, thus leading to metal losses. In order to reduce platinum losses, the forms of platinum in these phases should be studied. It was found that during the melting of this ore, iron, nickel, and copper are reduced. The mineral composition of matte was studied. Platinum in matte is present in the form of intermetallics with Fe and Ni. The PtFe intermetallic is a dispersed needle formation with a length of 20 to 500 µm and a thickness of up to 10 µm. The size effect is revealed: the content of platinum in the PtFe intermetallic decreases with decreasing the thickness of needle formations. The decreases in the content of platinum in dispersed needle formations can be explained by an increase in the thermodynamic activity and changing properties of the dispersed substance and a corresponding increase in solubility. It was found that matte drops, together with their associated platinumcontaining particles of no more than 5-7 µm in size, were carried into the slag by gas bubbles using flotation. The conditions for the rise of a matte drop, together with a bubble in the slag, consist in the fact that the adhesive force of the drop with the bubble and the buoyancy force acting on the bubble must be greater than the gravity of the drop. [ABSTRACT FROM AUTHOR]