Evaluation of electrochemical properties of steel sheets for automotive applications

Galvanizing as a process of zinc coating of base material is still the most widely used technology applied in surface treatment of materials which are supposed to meet the requirement of high corrosion resistance in various environments. This article presents the results of research aimed at determining the corrosive properties of galvanized sheets in selected environments – distilled water, NaCl and SARS solution, using electrochemical potentiodynamic test

The influence of heat treatnemnt on the abrasive wear resistnace of a construction and a tool steel

The paper deals about the influence of heat and chemical-heat treatment of construction steel 100Cr6 and alloy steel X210Cr12, which were treated according to their corresponding norms. The steel X210Cr12 was also treated in an unconventional way. The influence of the material structures and hardness on the abrasion wear resistance was studied. The influence of nitridation was considered in a way how to increase the abrasion wear resistance and how the heat treatment affects the hardness and the quality of the nitrided layer. The nitridation with diffusion annealing of the tested materials caused a decrease and also an increase of the materials wear resistances

Resistance of surface layers to selected tribodegradation factors

Contribution presents the results of research focused on resistance of surface layers to selected tribodegradation factors. Research is focused on the renovation of dies for hot work. Newly created renovation layers made with new types of filler materials are compared with conventionally used renovation materials. X37CrMoV5-1 was chosen as the die base material, which was hardened and tempered to a working hardness of 500 ± 15HV. The experiments are carried out practical measurements of mechanical properties of cladding. The quality of cladding was evaluated in tribological conditions of adhesion wear (ČSN EN 1071-13) and abrasive wear (STN 01 5084)

The change in the morphology of the blasted surface after phosphating and cataphoretic coating

The paper focuses on the quality of coatings applied by cataphoretic deposition and cataphoretic deposition technology with a phosphate layer. The quality of the coatings was evaluated by determining the roughness of the coatings, the morphology of the coatings, spectral analyses were performed detecting the presence of individual elements in the coatings. There was analysed also defect – uncoated spot

Magnetic Properties of Sintered Fe₅₀Co₅₀ Powder Cores

We investigated coercivity, total losses and complex permeability of sintered Fe-Co powder cores to detect magnetization processes performing in ac magnetic field. The Fe-Co solid solution alloy powders with 50:50 wt% ratio were prepared by 1, 15, and 20 h alloyed mixture of pure chemical elements in planetary ball mill. The resulting powder was subsequently sintered into a disk form. The compaction was performed at a pressure of 800 MPa for 5 min at temperatures of 400°C, 500°C and 600°C in vacuum oxidation protective atmosphere, with pressure of 5×10¯³ Pa. The best magnetic properties exhibit sample prepared from 1 h alloyed powder, compacted at 600°C