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Open access

P. Wilkołek, M. Szczepanik, M. Gołyński, Ł. Adamek, A. Pomorska, M. Maj-Martyniuk and W. Sitkowski

The evaluation of selected parameters of cellular nonspecific immunity in normal and allergic horses

The main aim of this study was to compare selected nonspecific immunity parameters in 14 allergic and 12 healthy horses. Each animal was assessed according to the following parameters: in vitro functional capacity of phagocytic cells using the nitro blue tetrazolium chloride reduction test, both spontaneous (NBT) and zymozan stimulated (NBTs), and ingestion capacity of phagocytic cells using a phagocytic index test (IF) and percentage of phagocytosing neutrophils activity (%KF). Differences were demonstrated between the group of allergic horses, especially with severe allergy symptoms, and healthy horses in NBTs values, with higher values in healthy horses. The values of the phagocytic index were significantly higher in horses with allergy.

Open access

J. Wieczorek, B. Oleksiak, J. Mizera, K. Kulikowski and P. Maj

The paper presents results of a study on the quality of coatings deposited on surfaces of AZ31 magnesium alloy products. In order to obtain protective coatings (corrosion and erosive wear protection), the methods of anodising (specimens A, B and C) and, for comparison, electroless plating (specimen D) were applied. The assessment of coating quality was based on the scratch test results. The results were used for determination of critical loads resulting in coating rupture. The best result was obtained for the specimen B (sulphuric acid anodising in combination with sealing): the critical load was 7.5 N. The smallest value (5.5 N) was observed for the specimen D, i.e. the coating produced using the electroless plating method. Moreover, erosion resistance of the coatings was assessed. In this case, a depth of the wear trace due to an erodent agent (SiC powder) effects was investigated. The results are comparable to those obtained in the scratch test. The poorest erosion resistance is demonstrated by the coating D and the best resistance is observed for the coating B.

Open access

P. Maj, B. Adamczyk-Cieslak, M. Slesik, J. Mizera, T. Pieja, J. Sieniawski, T. Gancarczyk and S. Dudek

Abstract

Inconel 718 is a precipitation hardenable nickel-iron based superalloy. It has exceptionally high strength and ductility compared to other metallic materials. This is due to intense precipitation of the γ’ and γ” strengthening phases in the temperature range 650-850°C. The main purpose of the authors was to analyze the aging process in Inconel 718 obtained in accordance with AMS 5596, and its effect on the mechanical properties. Tensile and hardness tests were used to evaluate the mechanical properties, in the initial aging process and after reheating, as a function of temperature and time respectively in the ranges 650°-900°C and 5-480 min. In addition, to link the mechanical properties with the microstructure transmission microscopy observations were carried out in selected specimens. As a result, factors influencing the microstructure changes at various stages of strengthening were observed. The authors found that the γ’’ phase nucleates mostly homogenously in the temperature range 650-750°C, causing the greatest increase in strength. On the other hand, the γ’ and δ phases are formed heterogeneously at 850°C or after longer annealing in 800°C, which may weaken the material.