The viscosity properties of zinc‐rich coatings from sodium silicate solution modified with aluminium chloride

Abstract

PurposeThe purpose of this paper is to measure the apparent and complex viscosities of the zinc‐rich coatings derived from sodium silicate solution modified with aluminium chloride (AlCl3), and then theoretically analyse the relation between viscosity behaviour and physiochemical mechanisms.Design/methodology/approachAccording to the different dosages of AlCl3, five coatings were prepared. The apparent viscosities as functions of shear rate, time and temperature, complex viscosity with variations of temperature and heating rate of these coatings were measured using an AR500 rheometer.FindingsResults showed that the zinc‐rich coatings possessed the typical shear thinning behaviour and the apparent viscosity increased with time until solidification. Complex results showed that the complex viscosity depended strongly on heating rate. Both apparent and complex viscosities initially decreased to minimum and then started to increase, while temperature was ramped from 0 to 70°C.Originality/valueIt is believed that there is no published literature about the apparent and complex viscosities of the zinc‐rich coatings from sodium silicate solution modified with AlCl3. This paper presents the first attempt to obtain the rheological data of these zinc‐rich coatings.