Effects of plasma nitriding interlayer on adhesion and tribological behaviors of AlTiSiN coating

Purpose This study aims to the service life of TA15 alloy by solving the problem of the binding force between the matrix and AlTiSiN coating. The effect of a plasma nitriding (PN) interlayer on the magnetron-sputtered AlTiSiN coating was also investigated in detail. Design/methodology/approach The double-glow plasma alloying (DGPA) and magnetron sputtering (MS) techniques were combined as a new approach to realize a bilayer on TA15 consisting of an AlTiSiN layer with a PN interlayer. A TiN interlayer was formed via co-diffusion during the PN conducted at 1050°C for 3 h. Findings The PN interlayer can effectively improve the adhesion between coating and matrix; the PN/AlTiSiN coating presented excellent adhesion (80.1 N) and anti-wear property with a nano-hardness of 18.62 GPa. The resulting three-dimensional wear-track morphology exhibited a shallow depth and a narrow width. Originality/value The novel combination of the DGPA and MS technologies, using an infiltration layer rather than a coating one as the intermediate layer, can effectively enhance the adhesion between AlTiSiN coating and TA15 matrix. Meanwhile, the gradient layer can effectively improve both surface bearing and wear resistance.

Practical and Economical Effects of the Use of Screen Meshes for Steel Nitriding Processes with Glow Plasma

The dynamically developing energy sector forces technologists to create new materials that meet the increasingly higher mechanical, chemical, and electrical requirements. The paper relates to the method of reducing the energy consumption of the plasma nitriding process of austenitic steels. The method proposed by the authors involves the modification of nitriding technology in glow plasma. It consists of introducing perforated screens between the anode and nitrided surface made of a material with a composition similar to the processed material and the use of an HF power supply with controlled mean current generating negative voltage peaks of about 1000 V. Nitriding is carried out in a nitrogen-hydrogen atmosphere. The processed material has a negative potential in relation to the surrounding plasma and strongly negative in relation to the vacuum chamber jacket. The actual treatment is preceded by ionic cleaning of the surface of the detail and heating it to the temperature that activates the diffusion processes. The authors analyse the dynamic distribution of electric fields generated at the surface of the nitrided material with different configurations of the cathode-sample-screen system, trying to find the correlation of treatment parameters with the parameters of the nitrided layer. A significant influence of the screening meshes on the depth of the obtained diffusion layers containing nitrogen was found. The oscilloscopic measurements of the plasma in the boundary layer allowed for the observation of voltage peaks, probably leading to an increase in the peak kinetic energy of nitrogen ions and their easier penetration into the material. The work is of a cognitive nature and is probably one of the first to look for relationships between the dynamic electrical parameters of plasma and the efficiency of nitriding.

Effects of a Plasma Water and Biostimulant on Lawn Functional Value

The research was conducted between 2014 and 2016 at the Agricultural Experimental Station of the University of Environmental and Life Sciences in Wrocław. In the experiment, Poa pratensis and Lolium perenne in pure stand and in mixtures were used as Factor A. Two substances that stimulate grass growth and development constituted Factor B. The first was a biostimulant produced from brown algae (Phaeophyceae), containing various essential chemical compounds including amino acids, vitamins, alginic acid, microelements, and other unexplored biologically active components. The other was water treated with low-pressure glow plasma (LPGP). The seeds were sown in well-mixed light, alluvial loamy sand soil. During three growing seasons, a 9-point scale was used to evaluate grass density, leaf fineness, susceptibility to disease, and lawn overwintering. The lawns were mown every 14 days at a height of 4 cm. The substances with a stimulating effect significantly affected lawn grass features, including turf density and overwintering. Additionally, the biostimulant and plasma water reduced the incidence of fungal diseases. Better transport of water in plants after its low-pressure glow plasma treatment may be due to the effect of its declustered structure, its higher oxygen concentration, and its better solubility of the biostimulant.