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• Vehicular soot as protective coating for cement based composites is demonstrated. • Soot coating protects concrete from corrosion, acid rain and sewage like atmospheres. • Mechanism of enhanced acid resistance property of coated mortars is explained. This study explores the use of vehicular soot, an otherwise waste product, for protecting cement based composites against corrosion and degradation due to acid rain and sewage like atmospheres. Cement mortar cubes (volume 70.7 × 70.7 × 70.7 mm3) were coated with colloidal vehicular soot dispersed in ethanol medium using a simple drop casting technique. The coated cement mortar specimens were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The protective role of soot coating against acid rain and sewage atmospheres were assessed by crack propagation and water absorption tests. Specimens, previously subjected to stress until minor cracks become visible, were employed to study crack-propagation as a function of time. The reasoning for the observed variation between the coated and the reference sample are discussed. The mechanism of enhanced acid resistance property of coated mortars is explained based on the hydrophobic and water absorptive behavior of soot. Present study presents a novel and economical technique for corrosion protection of cement based composites. [ABSTRACT FROM AUTHOR]

CaZrO 3 ceramic pigment exhibits high chemical, thermal and structural stability. However, its application as a host for various luminophores/activators has not been clearly explored. In the present investigation, CaZrO 3 doped with Eu 3+ , as a potential orange-red phosphor has been demonstrated. Ca 1-x ZrO 3 :Eu x (x = 0.01–0.09) nanophosphor is prepared here through a low temperature, one pot solution combustion synthesis approach using glycine as the fuel. X-ray diffraction results show that all the samples are stabilized in orthorhombic crystal structure without any impurity phases. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution TEM are carried out to determine the microstructure of the phosphor. The particles are found to be significantly agglomerated and in the nano-regime (∼40 nm). The observed excitation spectrum suggests that Ca 1-x EuZrO 3 can be efficiently excited using ultra-violet (UV), near-UV and UV blue (UVB), making it immediately relevant for current solid state lighting technologies. In fact with every ∼1 at% doping increase, the primary excitation line intensity increases by a factor of ∼1.5; this provides a simple parameter to enhance the UV excitability of the phosphor. The color coordinates are deduced using the Commission International De Eclairage (CIE) co-ordinates (x, y = 0.58, 0.40). The critical distance of energy transfer in this system is determined to be ∼10.7 Å, making multipole-multipole interactions as the plausible reason for concentration quenching beyond 7 mol.% Eu doping. The luminescence behaviour of the material is evaluated using Judd-Offelt (JO) intensity parameters. Judd-Ofelt (JO) intensity parameters (Ω 2 and Ω 4 ) are calculated for the sample Ca 1-x ZrO 3 :Eu x (x = 0.01–0.09), in order to understand the local structure around the activator. Irrespective of the concentration of Eu 3+ , Ω 2 is found to be greater than Ω 4 , indicating asymmetric environment around the activator. Furthermore, with increase in Eu 3+ , Ω 2 increases suggesting an increase in covalency of Eu-O bonds with significant effect of host crystal field on Eu 3+ . [ABSTRACT FROM AUTHOR]