CERAMIC SCIENCE & ENGINEERING
Year:2017 | Volume:5 | Issue:4 |Papers Count:7

In this study, domestic and foreign kaolin and ballclay were selected for thermal activation and structural order studies. The calcination temperature 700°C for 3 hrs was selested. Kaolin conversion to metakaolin was investigated using; differential thermal analysis, theramal gravimetric (DTA/TG), x-ray diffraction( XRD) and fourier transorm infrared spectroscopy (FTIR). The degree of kaolinite dehydroxylation in kaolins and ballclays were also investigated using TGA analysis. The highest and lowest degree of hydroxylation after calcination was 90 and 60% Respectively under  the same calcination conditions. Based on DTA and FTIR results, the highest order was observed in foreign kaolin and the lowest order was seen in the domestic ballcaly.but order indexes related to XRD, was shown different results with above analysis.

One way to environmental protection and avoid raw materials waste is using bone china scraps in body composition. In this paper, the influence of bone china scraps addition on sintering behavior of hard porcelain body has been investigated. For this purpose, hard porcelain bodies produced with 0, 5.6, 10.7, 15.2 wt% bone china scraps and mixed in Jar mill and fired at temperatures 1340oC and 1250°C in kiln and their properties such as mechanical strength, bulk density, thermal expansion coefficient were investigated. The microstructure of fired specimens was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that increasing of Bone china scraps, increase Mulite and decrease Quartz crystals in fired body. Also, addition of this waste cause to rising of Anorthite phase in fired body at 1250oC. The further results show, an increase in bone china scraps (up to 5.6 wt%) increase fired mechanical strength tow times in fired body at 1340°C and an increase of 15.2% bone china scraps increased mechanical strength of fired body in 1250oC for 4 times. Bulk density increasing in fired body in 1250oC, reducing bulk density and thermal expansion coefficient in fired body at 1340°C are the other result of addition of these scraps.

In this study, corrosion behavior of nanostructured multilayer coatings of Ti/TiN applied on the 7075 aluminum substrate was evaluated by EIS method. Ti/TiN nano scale multilayer coatings were deposited on surface of samples by high-vacuum magnetron sputtering process, then structure and morphology of the coating were analyzed by using GIXRD, FESEM and AFM, afterwards, the corrosion behavior of coating was investigated by Nyquist and Bode phase curves after1, 12, 24, 48, 60 and 72 hours of immersion in 3.5% NaCl solution. Results show, the applying of nanostructured multilayer coating and interrupting columnar structure of TiN by the Ti as an intermediate layer causes to increase the impedance and corrosion resistance of Al7075 about 43 times compare with bare of Al7075, which proving that this coating is so effective for enhancing of corrosion behavior of Al7075.

In this paper, the effect of sodium aluminate concentration on the corrosion behavior of coatings formed on the surface of 6061 Al alloy by plasma electrolytic oxidation is studied. This process applied by DC current mode with current density of 15 A/cm2 in two different concentration of sodium aluminate (6 and 8 g L-1). The corrosion behavior of coatings evaluated by potentiodynamic polarization test in 3.5 wt. % NaCl solution. The microstructure of coatings are investigated by scanning electron microscopy (SEM) images. X-ray diffraction (XRD) pattern confirmed the formation of ceramic compounds in coating. According to the results, increasing of sodium aluminate concentration caused to improvement of surface quality, decreasing of pores size and increasing of corrosion resistance of coatings. According to the potentiodynamic polarization test, the coating formed by 8 g L-1 sodium aluminate concentration presented 31 times lower corrosion current density compared to the aluminum substrate that shows improvement in corrosion resistance of substrate.

Titanium dioxide thin films with a thickness of 280 nm were deposited using pulsed DC magnetron reactive sputtering,on glass substrates. In order to deposit a Ti source in an Ar+O2 gas mixture was used with a substrate of temperature 2500c.The X-ray diffraction (XRD) showed anatase phases and Topographical surface using atomic force microscopy (AFM) is studied. Then RF plasma system was changed and treatment effect of N2 + O2 mixture plasma on the reduction concentration of methylene blue dye in the presence of TiO2 thin films evaluated. Finally, the color removal rate (R%) and also degradation reaction rate constant (k) is calculated.characterized.

In this study, CuInS2 nanoparticles have been synthesized via one-pot facile thermolysis route and the decomposition temperature of CuCl and InCl3 complexes were investigated. The stabled colloidal CuInS2 compound has been prepared by solving CuCl and In2(SO4)3 as cationic elements, thiourea (SC(NH2)2) as sulfur source and PVP as surfactant in the nontoxic and cost effective solvent of Diethylene glycol ((CH2CH2OH)2O) and ethylene diamine(C2H8N2) . The samples were characterized by X-ray diffraction for structural evauation, Fourier transform infrared (FTIR) for revealing the formed complexes and capping agents and absorbance spectrophotometer (UV-VIS) for detecting optical properties. The results revealed that the In2(SO4)3 was decomposed when the temperature was more than 210oC and  CuInS2 compounds with polytypism crystalline structure (chalcopyrite and wurtzite) was formed. Furthermore, increasing the temperature from 120 °C to 240 °C, facilitates formation of the chalcopyrite crystalline structure rather than the wurtzite structure.

In the present paper, ZrB2-SiC was developed by pressureless sintering method and SiC powder at nano and micro-sized scale was used as reinforcement phase. AlN was added to this composite from 2.5 to 15 vol.% as sintering aid. In order to produce composite samples, the primary powders were milled and blended in planetary ball mill apparatus with rotational speed of 200rpm and then processed using uniaxial press (70oC and 70MPa), cold isostatic press (200MPa), Pyrolysis (1000oC) and sintering (2150oC). The values of relative density and porosity of samples were measured to evaluate the effect of presence of micro-sized SiC and SiC nano particles simultaneously on the pressureless sintering behavior of ZrB2-SiC. In order to compare the microstructure and mechanical properties of samples Scanning Electron microscopy (SEM), equipped with EDS spectroscopy, XRD analysis, hardness and toughness tests were used. The results show that as the volume percentage of nano SiC decreases to 15 vol.% and AlN increases to 7.5 vol.%  the hardness, toughness, relative density and shrinkage initially increase and then decrease.