In this paper, aluminium alloy of grade ADC-12 was considered as a base metal and chromium carbide (Cr3C2) particles were reinforced through friction stir process. A detailed analysis of mechanical property and metallurgical characterization studies were performed to evaluate the surface composite. Remarkable changes were observed in the developed composite due to the mechanical force produced by the stir tool with an increase in hardness. The metallurgical investigation infers that the presence of silica in ADC-12 alloys has undergone mechanical fracture and long needle structure changed to reduced size. On the other hand, at higher tool rotational speed, the uniform distribution of hard particles was confirmed through SEM micrographs. Thus the modified surface composite has produced good mechanical property with high metallurgical qualities.

The paper analyses the as-cast state structure of chromium cast iron designed for operation under harsh impact-abrasive conditions. In the process of chromium iron castings manufacture, very strong influence on the structure of this material have the parameters of the technological process. Among others, adding to the Fe-Cr-C alloy the alloying elements like tungsten and titanium leads to the formation of additional carbides in the structure of this cast iron, which may favourably affect the casting properties, including the resistance to abrasive wear.

In this work, sorption of chromium on granular ferric hydroxide (GFH) has been investigated using batch and column techniques. The adsorption behavior of Cr on GFH, depending on pH, contact lime and sorbent amount were studied. The equilibrium adsorption capacity of GFH for Cr was measured and cxtrapo latcd using Freundlich isotherms. Metal ions bounded lo the GFH could be recovered by alkaline solution, and the GFH can be recycled. The sorption capacity of GFH was 25.0 mg/g. The ion exchange of chromium on GFH follows pseudo-first-order kinetics. The intraparticlc diffusion of chromium on GFH presents the limiting rate. The results indicated practical value of this method for industry and also provide strong evidence to support the proposed thesis about the adsorption mechanism.

The results of research on stereological parameters of carbides in modified hypoeutectic chromium cast iron were shown in the paper. The

effect of distance the casting heat centre of casting to the carbide phase morphology was examined. The samples for metallographic

examination were taken from various locations of the model casting prepared in a special tester. This model casting was designed to

simulate the solidification of heavy castings. Using the proposed methodology the relation of the distance from the model mould and the

size, perimeter, length, width and the shape factor of carbides was examined. During the analysis, the values of stereological parameters of

carbides changed on various sections of the model casting.