Potentiometric determination of molybdate ions
YOUSEFF G. I.
SHEHATA M. F.
EL HOSARY A.
National Research Center,
Physical Chemistry Dept., Dokki, Cairo, Egypte
Molybdates are one of the recently developed corrosion inhibitors for cooling systems. This paper presents a simple and accurate method for molybdate analysis in these systems, based on the potentiometric titration of molybdate with lead acetate, using molybdenum, lead and molybdenum-containing alloys as indicator electrodes. At the equivalent point, a rapid jump of the potential of the indicator electrode relative to the reference calomel electrode takes place indicating complete precipitation of the present molybdate in the form of lead molybdate. The results show a linear relationship between volumes of molybdate and the consumed acetate with equimolar concentrations. Bimetallic electrodes have been also used in following the titration reaction, with no need to apply a reference electrode. The method is applicable in the presence of the constituents of cooling water and the corrosion products of the main materials used in the construction of cooling systems. It is also applicable in LiBr containing cooling systems.
Keywords: molybdate corrosion inhibitors, potentiometric titration, indicator electrodes, LiBr
GIL A.
AGH, Akademia Górniczo-Hutnicza,
Wydział Inżynierii Materiałowej i Ceramiki, Kraków
KUC A.
Politechnika Krakowska,
Wydział Inżynierii i Technologii Chemicznej, Kraków
The paper presents the results of two stages of oxidation with the use of 18O oxygen isotope as well as marker experiments and microscopy observations of the scale on titanium in the edge area. These investigations indicate that the rutile layer which remains in direct contact with the metal grows via the predominant outward diffusion of titanium atoms, while the TiO2 lamellar scale formed on titanium after a longer time has macrodefects, which are inward diffusion paths for molecular oxygen.
Keywords: titanium, oxidation mechanism, lamellar scale
Science in corrosion fighting
ZUBIELEWICZ M.
Instytut Inżynierii Materiałów Polimerowych i Barwników
Oddział Farb i Tworzyw w Gliwicach
Review of scientific projects related to corrosion and corrosion protection, that were granted financing in years 2005-2011, are discussed in regard of using their results in practice. Projects have been divided into a few subject fields: corrosion and corrosion testing, microbiological corrosion, corrosion of steel in concrete, corrosion in power engineering, corrosion in agriculture, surface treatment – preparation of surface layers for corrosion protection, metallic coatings – hot-dip coatings, thermal spraying coatings, organic coatings – test methods, intumescent coatings and based on conductive polymers, new paints and binders, conversion coatings, composite and sol-gel coatings, cathodic protection, corrosion inhibitors and standardization. The main criterion of granting projects is their scientific value, however, many realized projects have also practical significance and their results may be applied in different industrial branches.
Keywords: scientific projects; corrosion and corrosion protection; metal, organic and inorganic coatings; corrosion inhibitors; cathodic protection; testing; standardization
Ochrona przed korozją w praktyce: Optimization of costs of corrosion protection in the steel construction industry by upgrading it
BRANDT A.
Agencja Anticorr Sp. z o.o., Gdańsk
A constant upgrading of equipment applied for cleaning and painting is observed in the steel construction industry. It is mainly driven by the reduction of the costs together with the increasing requirements of environmental protection and the quality of the coatings. The main upgrades are observed among supporting facilities with the equipment for construction cleaning with the use of metal abrasives and painting rooms that allow the proper coating while maintaining the safety and environmental protection requirements.
Keywords: equipment, cleaning, painting