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N. Radek and N. Konstanty

The main objective of the present work was to determine the influence of laser treatment on microstructure, microhardness, roughness, bonding strength, corrosion resistance and tribological properties of wear resistant coatings produced on C45 carbon steel by the electro-spark deposition (ESD) process. Consumable WC-Co-Al2O3 electrodes were prepared by the powder metallurgy route and transferred to the substrate surface using the EIL-8A apparatus. The cermet layers were subsequently melted by means of the BLS 720 Nd:YAG laser. The coating characterisation studies showed marked improvements in the bonding between the steel substrate and the cermet coating, and in corrosion resistance at the expense of higher surface roughness and minor drop in the Vickers microhardness.

Open access

J. Pietraszek, A. Szczotok and N. Radek

Abstract

The primary objective was to test a usefulness of the specific fixed-effect model for the analysis of quantitative relationships gathered from the image analysis of the material microstructures. The dataset was obtained from the investigation of turbine blades made from superalloy IN713C. The analysis based on the general linear model resulted in informative plots revealing mutual relationships between secondary dendrite arm spacing and the mean plane section area of carbides in the material. Directions for further research also were obtained.

Open access

N. Radek, J. Konstanty and M. Scendo

The main objective of the present work was to determine the influence of laser treatment on microstructure, X-ray diffraction, microhardness, surface geometric structure and roughness, corrosion resistance and tribological properties of coatings deposited on C45 carbon steel by the electro-spark deposition (ESD) process. The studies were conducted using WC-Cu electrodes produced by the powder metallurgy route. The tests show that the laser-treated electro-spark deposited WC-Cu coatings are characterized by higher corrosion resistance, surface roughness and seizure resistance which come at the expense of lower microhardness. The laser treatment process causes the homogenization of the chemical composition, structure refinement and healing of microcracks and pores of the electro-spark deposited coatings. Laser treated ESD coatings can be applied in sliding friction pairs and as protective coatings.

Open access

A. Szczotok, J. Pietraszek and N. Radek

Abstract

The study describes the influence of a surface modification in cored, thin-walled castings of blades from IN-713C nickel superalloy on γ' phase precipitates. The blades were produced by using the investment casting process in the laboratory conditions as parts for a low-pressure turbine rotor. The microstructural observations of the γ' phase precipitates on the cross sections of the blades were performed. The observations were followed by quantitative metallography evaluation, and finally, a comparison of the precipitates between one blade with the conventionally applied ceramic core and one with the core covered layer contained a surface modifier (5% of CoAl2O4) was made.

Open access

M. Scendo, N. Radek, J. Konstanty and K. Staszewska

Abstract

Sliding wear properties and corrosion resistance in Ringer’s solution of uncoated and diamond-like carbon (DLC) coated X46Cr13 steel was tested. The Raman spectra showed that the DLC film was successfully coated by plasma assisted CVD method onto the steel surface. The wear test, carried out using a ball-on disk tribometer, revealed that the DLC coating show better resistance to sliding wear and lower friction coefficient against a 100Cr6 steel ball than five times softer X46Cr13 steel. The oxidation kinetic parameters were determined by means of both the gravimetric and electrochemical method. It was found that the DLC coating markedly decreased the rate of corrosion of the X46Cr13 steel, irrespective of the corrosion mechanism involved.

Open access

Birendra P. Singh, Om N. Bhargava, Radek Mikuláš, Subhay K. Prasad, Garry Singla and Ramanpreet Kaur

Abstract

An assemblage of trace fossils comprising Asteriacites stelliformis, A. quinquefolius, Biformites insolitus, Helminthoidichnites? isp., Lingulichnus isp., Lockeia siliquaria, Palaeophycus tubularis, Planolites isp., Protovirgularia isp. A, Protovirgularia isp. B, Protovirgularia isp. C, Psammichnites isp., Rusophycus isp., and Treptichnus isp. from the Po Formation (Visean-Serpukhovian) exposed along the base of Ganmachidam Hill near the village of Chichong, Spiti Valley in the Himalaya, is described. Storm beds (tempestites) are highly bioturbated. Sedimentary structures such as hummocky cross-stratification (HCS), low-angle planar and trough cross beds, and shallow, slightly asymmetrical gutter casts are observed. The overall trace fossil assemblage indicates the presence of upper shoreface to lower shoreface Cruziana ichnofacies of an open shelf.