No abstract

No abstract

PurposeTo study the effect of feldspars as inorganic filler on the mechanical and dielectric properties of epoxy coatings.Design/methodology/approachCoating systems used were of either filler‐free epoxy resin (as reference), or epoxy resin filled with feldspars powder at four different levels by weight. Mechanical properties of the coatings were evaluated via damping hardness and abrasion and impact resistance measurements. Electrochemical impedance spectroscopy measurements were used for the evaluation of the dielectric properties while visual observations of the test panels after salt‐spray test were also made.FindingsThe addition of 15 per cent w/w feldspars resulted in a formulation giving the most positive results, e.g. improvement of the coating's mechanical characteristics and dielectric behaviour similar to that of filler‐free epoxy coatings. Practically comparable to this behaviour was that possessed by coatings with 30 per cent w/w feldspars, while further increase of the feldspars content resulted either in a reduction in the extent of the enhancement of the mechanical behaviour or even in a worsening of both mechanical and dielectric characteristics.Originality/valueFeldspars are the most abundant group of minerals in the earth's crust; it is an inorganic, environmentally friendly material, which exhibits high Mohs hardness. The effects of feldspars in improving the mechanical characteristics of organic coatings, while not causing any reduction in the anticorrosive performance of the polymeric matrix was found through the study.

No abstract

Concrete surface coatings, either organic or inorganic, have long been used for the protection of reinforced concrete. The aim of the present work was to compare, in the presence of chloride ions, the performance of an acrylic emulsion and an inorganic coating, when the latter is or is not combined with an inorganic corrosion inhibitor. The behaviour of the inorganic coating was examined, as its use is increasing due to environmental reasons and it can be applied on concrete surfaces for the rehabilitation of old structures. Strain gauge (SG) technique, half‐cell potential measurements, mass loss and carbonation depth measurements, as well as chloride diffusion rate, revealed that the acrylic emulsion provides better protection for reinforcing steel in concrete than the inorganic coating. However, the combination of the inorganic coating with the corrosion inhibitor provides a higher level of protection against steel bar corrosion.