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Surface Properties Modification of Zirconia Toughened Alumina by Using Titania Additives
Abdullah Al Mahmood,
Abdul Gafur,
Emdadul Hoque
Issue:
Volume 2, Issue 1, March 2017
Pages:
1-5
Received:
17 December 2016
Accepted:
3 January 2017
Published:
19 January 2017
DOI:
10.11648/j.css.20170201.11
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Abstract: Aluminium oxide (Al2O3) were mixed with multicomponent such as Zirconia (ZrO2) and Titania (TiO2). The aim of this thesis was to investigate the effect of TiO2 addition to Zirconia Toughened Alumina (ZTA). The physical, mechanical and microstructural behavior was characterized in this research. The percentage of Alumina was 83-85% and Zirconia used a fixed percentage of 15% for all samples where the percentages of Titania were used 0-1.5%. Each composition was weighted, mixed in pot mill with alcohol medium, heated, again mixed with polyvinyl alcohol binder and pressed using hydraulic press under 160 MPa into 10 mm pellets. The pellets were pre-sintered at 600°C for 2 hours and then sintered at 1450°C under pressureless condition. Bulk density, porosity and other properties of the samples were measured using standard procedure. Vickers hardness and fracture toughness of the sintered samples were measured using the Vickers indentation method. Phase analysis and microstructural analysis were carried out by XDR and SEM. By comparing ZTA ceramics with and without addition of MgO and TiO2 the results found an increasing of fracture toughness and hardness of the materials. The XRD patterns of ZTA samples containing 15 wt% of ZrO2, 0.5-1.5 wt% TiO2 and sintered at 1450°C for 2 hours indicated that α-Al2O3, t -ZrO2, and TiO2 are the crystalline phases present in the composite samples. The microstructures show highly homogeneous microstructures without agglomerates, pores or abnormally grown alumina grains with less porosity when compared to only Zirconia Toughened Alumina. The approach adopted in the present study may provide an alternative to design Al2O3-ZrO2-TiO2 composites with improved mechanical properties.
Abstract: Aluminium oxide (Al2O3) were mixed with multicomponent such as Zirconia (ZrO2) and Titania (TiO2). The aim of this thesis was to investigate the effect of TiO2 addition to Zirconia Toughened Alumina (ZTA). The physical, mechanical and microstructural behavior was characterized in this research. The percentage of Alumina was 83-85% and Zirconia used...
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Surface Chemical Studies on Silicon Carbide Suspensions in the Presence of Poly (Ethylene Glycol) and Chitosan
Saravanan Loganathan,
Subramanian Sankaran
Issue:
Volume 2, Issue 1, March 2017
Pages:
6-20
Received:
5 November 2016
Accepted:
30 December 2016
Published:
23 January 2017
DOI:
10.11648/j.css.20170201.12
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Abstract: The changes in the surface chemical properties of SiC suspensions consequent to the addition of polyethylene glycol (PEG) and chitosan, both individually and in the presence of each other were studied. The adsorption densities of PEG and chitosan for SiCwere found to be higher at pH 2-3 and 7-7.5 respectively. The adsorption behaviour in the combined presence of PEG and chitosan was akin to those observed for the individual systems. The isoelectric point (i.e.p.) of SiC was found to be located at pH 3. The addition of chitosan shifted the i.e.p. towards more alkaline pH values, in proportion with the concentration of chitosan added, with a concomitant change in the zeta potentials to less electronegative or more electropositive values. On the contrary, only a marginal change in the electrokineticbehaviour of SiC suspension was found after PEG addition. The favourable pH regimes were established to be 2-6 and 9-11, for the enhanced stability of SiC suspension with the optimum dosage of chitosan. The electrokinetic and dispersion characteristics of the SiC-chitosan system were only slightly altered by the addition of PEG. FTIR spectral investigations provided evidence in support of the proposed hydrogen bonding forces of interaction between SiC and PEG or chitosan.
Abstract: The changes in the surface chemical properties of SiC suspensions consequent to the addition of polyethylene glycol (PEG) and chitosan, both individually and in the presence of each other were studied. The adsorption densities of PEG and chitosan for SiCwere found to be higher at pH 2-3 and 7-7.5 respectively. The adsorption behaviour in the combin...
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Synthesis and Characterization of Smart Antibacterial Towels Based on Layered Silicates
Issue:
Volume 2, Issue 1, March 2017
Pages:
21-25
Received:
17 December 2016
Accepted:
4 January 2017
Published:
27 January 2017
DOI:
10.11648/j.css.20170201.13
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Abstract: New smart coating for towels was developed. Montmorillonite (MT) as clay layers was decorated with silver nanoparticles (AgNPs) of an average size of 32 nm. Developed MT-AgNPs composite were dispersed in commercial binder producing good dispersion coating system. Then the formed coating was coated on two different towels. The mass loadings of montmorillonite in the coating layer were varied and their effect was studied. Antibacterial properties of the untreated and treated towels were evaluated and the effect of coating layer on mechanical properties was investigated. The bacterial inhibition was significantly improved for developed towels achieved inhibition zone of 17 mm compared to zero mm for untreated ones. Also, the mechanical properties were improved.
Abstract: New smart coating for towels was developed. Montmorillonite (MT) as clay layers was decorated with silver nanoparticles (AgNPs) of an average size of 32 nm. Developed MT-AgNPs composite were dispersed in commercial binder producing good dispersion coating system. Then the formed coating was coated on two different towels. The mass loadings of montm...
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Surface Characterization of Plasma Immersion Nitrogen Ion Implanted Austenitic Stainless Steel
Pandurangan Saravanan,
Vngaranahalli Srinivasan Raja
Issue:
Volume 2, Issue 1, March 2017
Pages:
26-36
Received:
29 November 2016
Accepted:
3 January 2017
Published:
31 January 2017
DOI:
10.11648/j.css.20170201.14
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Abstract: Plasma immersion ion implantation (PIII) of nitrogen has been performed on three austenitic stainless steels namely, Type 304L SS, MnSS-1 (16%Cr-6%Mn-4Ni) and MnSS-2 (16%Cr-9%Mn) with at three different temperatures namely, 250, 380 and 500°C for 3 h. The GXRD studies shows that mixed iron nitride phases were formed along with expanded austenitic, when sample implanted at 250°C and 380°C. These nitrides are with different stoichiometry along the thickness and their formation is less favorable in nickel free Mn alloy at lower implantation temperature and timing (250°C for 3 h). On higher implantation condition (500°C, 6 h), Ni promotes the ′ formation and Mn suppress the ′ formation. Microhardness measurements revealed a significant increase in hardness after PIII treatment for all the alloys under investigation, but it is more effective in Ni free Mn containing SS.
Abstract: Plasma immersion ion implantation (PIII) of nitrogen has been performed on three austenitic stainless steels namely, Type 304L SS, MnSS-1 (16%Cr-6%Mn-4Ni) and MnSS-2 (16%Cr-9%Mn) with at three different temperatures namely, 250, 380 and 500°C for 3 h. The GXRD studies shows that mixed iron nitride phases were formed along with expanded austenitic, ...
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Catalytic Ignition and Extinction of Very Fuel-Lean Hydrogen-Air Mixtures on Platinum Surfaces
Issue:
Volume 2, Issue 1, March 2017
Pages:
37-42
Received:
6 January 2017
Accepted:
16 January 2017
Published:
9 February 2017
DOI:
10.11648/j.css.20170201.15
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Abstract: Surface ignition and extinction of very fuel-lean hydrogen-air mixtures on platinum surfaces were modeled using a detailed surface kinetic mechanism and transport phenomena. A stagnation-point flow geometry was employed to study the effect of heat flux, flow velocity, and composition on the surface ignition and extinction. The temperature and concentration on platinum surfaces as well as the coverage of surface species were also explored to evaluate the role of gas-phase chemistry. It was shown that the platinum surface can be poisoned by different adsorbates, and the dynamic process of surface ignition and extinction is associated with a phase transition from one poisoning species to another. For certain temperatures, multiple poisoned states of the surface coexist. Comparisons of simulations with experiments were carried out, and the results revealed that the self-inhibition of hydrogen surface ignition is caused by poisoning of platinum by atomic hydrogen.
Abstract: Surface ignition and extinction of very fuel-lean hydrogen-air mixtures on platinum surfaces were modeled using a detailed surface kinetic mechanism and transport phenomena. A stagnation-point flow geometry was employed to study the effect of heat flux, flow velocity, and composition on the surface ignition and extinction. The temperature and conce...
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Radiation Effect on Layered Crystals of GaS and GaS <Yb>
R. S. Madatov,
N. N. Gadzhieva,
A. I. Nadjafov,
N. I. Huseynov,
F. G. Asadov,
A. A. Abdurrahimov,
D. J. Askerov
Issue:
Volume 2, Issue 1, March 2017
Pages:
43-46
Received:
29 December 2016
Accepted:
13 January 2017
Published:
13 February 2017
DOI:
10.11648/j.css.20170201.16
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Abstract: It has been conducted the analysis of IR-absorption spectra of layered single crystals of GaS and GaS <Yb>, irradiated by gamma-quanta with subsequent annealing. It has been found that, a part of impurity atoms, introduced during the growth of crystals, as well as point defects, formed by irradiation, are located in the interlayer space, that indicates the decrease in the intensity and extension of the half-width bands 188 and 184 cm-1 in the IR spectra. During the annealing (T = 150°C, t = 150 min.) of irradiated samples there occurs an increase of intensity and a decrease of the half-width of these bands, which is caused by partial annealing of radiation defects and the transition of a part of impurity atoms from the interlayer area in the layer.
Abstract: It has been conducted the analysis of IR-absorption spectra of layered single crystals of GaS and GaS <Yb>, irradiated by gamma-quanta with subsequent annealing. It has been found that, a part of impurity atoms, introduced during the growth of crystals, as well as point defects, formed by irradiation, are located in the interlayer space, that...
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