In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using

cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain

refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed.

In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion

test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the

melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was

founded at degassing and as-received condition (3.9x10-3 mm/year). However, additive elements do not show the effect which degassing

process shows.

Ni625/WC composite coatings added with different amounts of Y ₂O ₃were prepared on the surface of 304 stainless steels by laser cladding. This study focused on the microstructure characteristics, microhardness, and corrosion performances of Ni625/WC composite coatings. The results showed that Y ₂O ₃ can effectively improve the corrosion resistance of the composite coatings. The microstructure from the bottom to the surface of composite coatings consists of plane crystal, cellular crystal, columnar crystal and equiaxed crystal. The Y ₂O ₃content of optimum composite coating was 1.0%. Its microhardness was three times that of matrix material. In addition, the corrosion current density of the composite coating was only 2% of Ni625/WC coating, which was attributed to the good properties of Y ₂O ₃ and appropriate Y ₂O ₃ refined microstructure.

Cast stainless steel of the Cr-Ni duplex type is used, among others, for the cast parts of pumps and valves handling various chemically

aggressive media. Therefore, the main problem discussed in this article is the problem of abrasion wear resistance in a mixture of SiC and

water and resistance to electrochemical corrosion in a 3% NaCl- H2O solution of selected cast steel grades, i.e. typical duplex cast steel,

high silicon and manganese duplex cast steel, and Cr-Ni austenitic cast steel (type AISI 316L). The study shows that the best abrasion

wear resistance comparable to Ni-Hart cast iron was obtained in the cast duplex steel, where Ni was partially replaced with Mn and N.

This cast steel was also characterized by the highest hardness and matrix microhardness among all the tested cast steel grades. The best

resistance to electrochemical corrosion in 3% NaCl- H2O solution showed the cast duplex steel with high content of Cr, Mo and N. The

addition of Ni plays rather insignificant role in the improvement of corrosion resistance of the materials tested.

TiNi alloys have excellent shape memory properties and corrosion resistance as well as high biocompatibility. This study investigated the effects of copper addition on the phase transitions and electrochemical corrosion behaviors of Ti50Ni50-xCux alloys. TiNi, Ti50Ni47Cu3, Ti50Ni44Cu6, and Ti50Ni41Cu9 alloys were prepared using vacuum arc remelting followed by 4 h homogenization at 950°C. Differential scanning calorimetry and X-ray diffraction analyses were conducted. The corrosion behaviors of the alloys were evaluated using potentiodynamic polarization test in Hank’s balanced salt solution at a temperature of 36.5 ± 1°C. The TiNi alloy showed phase transitions from the cubic B2 phase to the monoclinic B19’ phase when the alloy was thermally cycled. The addition of copper to the TiNi alloy played a major role in stabilizing the orthorhombic B19 phases during the phase transitions of Ti50Ni50-xCux alloys. The shifts in the corrosion potential toward the positive zone and the low corrosion current density were affected by the amount of Cu added. The corrosion resistance of the TiNi alloy increased with increasing copper content.