Studies on Various Functional Properties of Titania Thin Film Developed on Glazed Ceramic Wall Tiles

Abstract

A sol-gel based TiO 2 thin film was applied on glazed wall tiles for studying its various functional properties. Thin film was deposited by spin coating on the substrate and subjected to curing at different temperatures such as 600°C, 650, 700°C, 750°C and 800°C with 10 minutes soaking. The gel powder was characterized by FTIR, DTA/TG and XRD. Microstructure of thin film was analyzed by FESEM and EDX. Surface properties of the coatings such as gloss, colour difference, stain resistance, mineral hardness and wettability were extensively studied. The antibacterial activity of the surface of coated substrate against E. coli was also examined. The durability of the coated substrate in comparison to the uncoated was tested against alkali in accordance with ISO: 10545 (Part 13):1995 standard. FESEM images showed that thin films are dense and homogeneous. Coated substrates after firing results in lustre with high gloss, which increased from 330 to 420 GU as the curing temperature increases compared to that of uncoated one (72 GU). Coated substrate cured at 800°C shows higher mineral hardness (5 Mohs’) compared to uncoated one (4 Mohs’) and films cured at all temperatures showed stain resistance. The experimental results showed that the resistance towards alkali attack increase with increase in curing temperature and alkali resistance of sample cured at 800 °C was found to be superior compared to uncoated substrate. Contact angle of water on coated surface of substrates decreased with increase in temperature. Bacterial reduction percentages of the coated surface was 97% for sample cured at 700°C and it decreased from 97% to 87% as the curing temperature increased to 800 °C when treated with E. coli bacteria.

Effect of Curing Temperature on Surface Characteristics of TiO2-Fe2O3Multi Oxide Thin Film Deposited over Glazed Ceramic Wall Tiles

“…The decrease in hardness of coated substrate cured at 600 o C could be attributed to factors such as poor density of the film as evident from FESEM results, lower rutile phase formation and lack of proper adhesion of film due to non-softening of the glaze. Our earlier studies 13 showed that pure TiO 2 film had poor adhesion at 600 o C and it showed a jump from 2 to 5 Mohs only with increase in curing temperature from 600 o to 800 o C. This further supports the fact that the enhancement in hardness from 3 to 6 Mohs of TiO 2 -Fe 2 O 3 thin film coated sample is due to combined effect of factors such as softening temperature, fluxing action of iron oxides, highly dense and crystalline thin film with rutile as major phase and iron based oxides as minor phase. Downloaded by [Monash University Library] at 07:47 26 November 2014…”

“…[11][12][13] However, scanty literature is available with regard to the effect of these coatings on glazed ceramic surface properties such as gloss, stain resistance, hardness, etc; 6, 13, 14 these properties are also equally important in addition to the functional properties reported earlier. 11,12 In our previous work, 13 the effects of sol-gel based TiO 2 thin film on various surface properties of glazed wall tile such as gloss, colour difference, antibacterial property and chemical resistance were reported which indicated that TiO 2 thin film did not adhere on the surface after curing at 600 o -650 o C and exhibited adherence only in the curing temperature range of 700 o -800 o C even though tile exhibited superior functional properties compared to uncoated substrate. In order to increase its adhesion and to improve functional properties, Fe 2 O 3 was opted to incorporate into the TiO 2 system due to its various properties such as high refractive index, fluxing property, anti-bacterial property and colour imparting property.…”