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Effect of electrochemical cycling of LaNi₅ powder composite material on hydrogen diffusivity at pressures of 0.08÷30 bar

DYMEK M.

BALA H.

Department of Chemistry, Faculty of Materials Processing, Engineering and Applied Physics,

Czestochowa University of Technology, Czestochowa

On the basis of galvanostatic charge/discharge curves plotted in E – logt coordinate system we present a precise graphical way to determine atomic hydrogen charge and discharge times for powder (particle diameter 20÷50 μm) LaNi5 composite electrode working in deaerated 6M KOH solution. At experimental conditions (│i_c│= i_a = 0.5C) we calculate effective hydrogen diffusion coefficients in the electrode material, based on Crank’s diffusion model, and present them as a function of cycling. The diagnostic experiments included galvanostatic tests with simultaneous changes of external pressure of Ar-gas in the reaction chamber. The effective diffusion coefficients of atomic hydrogen increase for initial cycles as a result of material surface development and increase of its porosity. Starting with N =

15, further cycling gives rise to decrease of hydrogen diffusivity, evidently as a consequence of electrode material corrosion and hydrogen diffusion inhibition by oxide phases. Pressure of inert gas (Ar) in the range of 0.08÷30 bar has rather imperceptible effect on hydrogen diffusivity.

Keywords: LaNi₅ compound, electrochemical hydrogenation, hydrogen diffusivity, external pressure

2013

Vol.. 56, nr 1

s. 3-6

Ref.18

Evaluation of the self-repairability of epoxy-cement composite

ŁUKOWSKI P.

ADAMCZEWSKI G.

Warsaw University of Technology, Faculty of Civil Engineering,

Department of Building Materials Engineering

The paper deals with the issue of the self-repairability of epoxy-cement building composites. The methods of obtaining such material have been presented, including the modification of a cement composite using an epoxy resin without a hardener. The methodology of testing the self-repairability of the building composite has been described. Selected results of investigations have also been presented.

Keywords: cement, epoxy resin, epoxy-cement composite, self-repair

2013

Vol.. 56, nr 1

s. 7-9

Ref .9

Ochrona przed korozją w praktyce

Anti-corrosion protection and repair of concrete structures of waste and water treatment plants in the framework of structure management strategy according to the European Standards from the series PN-EN 1504

CZARNECKI L.

ŁUKOWSKI P.

Politechnika Warszawska

JASICZAK J.

Politechnika Poznańska

Repairs of the concrete structures are complex and difficult technical task. The overall approach is necessary for establishing the scientific basis of repairing. The series of ten European Standards EN 1504 dealing with the products and systems for repair and protection of the concrete structures has been developed by the European Committee for Standardization. The series is an attempt of the formal expression of the problem with respect to up-to-date status of the knowledge and technology. The standards also give some new inspirations in the range of the concrete repairing and

protection. However, that topic is still dynamically developed and under discussion not only in Europe. The symptoms and causes of the concrete structures’ failures have been briefly presented in the paper as well as the structure and provisions of the European Standards on repairs and protection of concrete. As the illustration, an example of using of the Standards for repairing the water treatment plant objects has been presented. Also, the attention has been paid to the connections of the Standards from 1504 series with PN-EN 206 and Eurocode 2.

Keywords: concrete, structure, material, repairing works, standardization, protection

2013

Vol.. 56, nr 1

s. 13-18

Ref . 7

Ochrona przed korozją w praktyce

Study of algae on residential building facades. Part 1

KSIĄŻEK M.

Politechnika Wrocławska, Instytut Budownictwa

The current state of residential building facade insulation applied by means of the light-wet method has been evaluated. Based on a series of inspections and technical assessments, design and workmanship errors, which have a decisive influence on the biological corrosion of facades, the basic material properties and functional properties of the buildings, have been presented.

Keywords: algae, biological corrosion, residential building facades, design and workmanship errors, thermal insulation of buildings

Vol.. 56, nr 1

s. 19-22

Ref .14

Ochrona przed korozją w praktyce

Corrosion perils and protection methods deployed on the communication infrastructure – requirements of the Warsaw Direction of Urban Roads Confronted with proposed designs and their realizations

CHRZANOWSKI R.

Zarząd Dróg Miejskich m.st. Warszawy

Warsaw Direction of Urban Roads investor’s requirements on the new, renewable anticorrosion protections of steel and concrete engineering communication infrastructure is presented. Constant need for close cooperation between investor, designers and contractor at every stage of design and realization is underlined.

Keywords: corrosion, corrosion protection, maintenance works

2013

Vol.. 56, nr 1

s. 23-24

Ref.-