scholarly journals SINTERING BEHAVIOUR OF MAGNESIUM OXIDE OBTAINED FROM SEAWATER DOPED WITH NANO-TiO2

2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Jelena Jakić ◽  
Miroslav Labor ◽  
Vanja Martinac ◽  
Martina Perić
Keyword(s):  
Positive Impact ◽  
Microstructural Properties ◽  
Secondary Phases ◽  
Nano Tio2 ◽  
Homogeneous Microstructure ◽  
Optimal Amount ◽  
Eds Analysis ◽  
Tio2 Addition ◽  
Sintering Behaviour ◽  
Boundary Surfaces

In order to improve the properties of sintered MgO (80 % precipitation) obtained from seawater, an investigation was carried out with (0, 1, 2) w/% of nano-TiO2 and micro-TiO2 additions during sintering at a temperature of 1500 °C (1 h and 2 h). The effects of the TiO2 addition on its microstructural properties, density, porosity and chemical composition after sintering were observed. The SEM/EDS analysis confirmed the formation of a homogeneous microstructure composed mainly of periclase grains and well-distributed secondary phases. CaTiO3 and MgTiO4 are predominantly located at the inter- and intra-periclase grain boundary surfaces during cooling. The microstructure of the MgO samples with the addition of nano-TiO2 become more compact, having a positive impact on the porosity and density of the samples. The addition of 1 w/% of nTiO2 represents the optimal amount for the improvement of the properties of the MgO samples (80 % precipitation) obtained from seawater.

Tribological Behaviour of Alumina Ceramics with Nano TiO2 as a sintering aid in Non-Conformal Contact

2021 ◽  
pp. 1-21
Author(s):  
Partha Haldar ◽  
Tapas Kumar Bhattacharya ◽  
Nipu Modak
Keyword(s):  
Mechanical Properties ◽  
Secondary Phase ◽  
Alumina Ceramics ◽  
Alumina Matrix ◽  
Tribological Behaviour ◽  
Nano Tio2 ◽  
Sintering Aid ◽  
Tio2 Addition ◽  
Sintering Behaviour ◽  
Hexagonal Columnar

Abstract The study emphasized the sintering behaviour and tribo-mechanical properties of alumina ceramics by nano TiO2 addition as a sintering aid. With increase in sintering temperature, the bulk density of alumina has increased gradually and optimized at 1600°C. The optimizing effect of densification at 1600°C is 98.25% by the addition of 1 wt.% nano TiO2. The maximum solid solubility of titania in alumina grains was at 1600°C, causes optimisation of densification by 1 wt. % addition. The excess addition of TiO2 formed low dense Al2TiO5, appear as a secondary phase at grain boundaries and does not significantly improved densification. Fracture toughness increases and coefficient of friction decreases with the addition of nano TiO2 in alumina matrix. The 1wt.% nano TiO2 addition improved hardness to 8.82% and reduces specific wear rate to 45.56%. The 1wt.% nano TiO2 addition greatly influenced the microstructure of sintered Al2O3. The morphology was sharply changed from hexagonal columnar shape to order sub round orientation which also directly impact the tribo-mechanical properties of sintered alumina. The 1wt.% addition substantially decreases wear track depth as observed by 3D surface profilometer. Microscopic observation of the worn-out surface showed that wearing is majorly caused by plastic deformation and abrasion.

Sintering of Silicon Carbide Ceramics with Additives Based on the (Y2O3-Al2O3-SiO2) System

2006 ◽  
Vol 45 ◽  
pp. 1739-1744 ◽  
Author(s):  
J. Marchi ◽  
José Carlos Bressiani ◽  
Ana Helena A. Bressiani
Keyword(s):  
Silicon Carbide ◽  
Molar Ratio ◽  
Sintering Behavior ◽  
Thermal Treatments ◽  
Secondary Phases ◽  
Tem Analysis ◽  
Sem And Tem ◽  
Carbide Ceramics ◽  
Sintering Behaviour ◽  
Silicon Carbide Ceramics

The sintering behavior of silicon carbide using alumina, silica and yttria as additives was investigated. Powders containing 90 vol. % SiC and 10 vol. % additives (keeping 1Y2O3:1Al2O3 molar ratio) were sintered at 1950°C/1h, in a dilatometer or a graphite resistance furnace. Thermal treatments were also done from 1500°C/1h up to 1800°C/1h, in order to evaluate the formation of transient crystalline secondary phases. The sintered samples were characterized through XRD, SEM and TEM analysis. The results showed that sintering behaviour is clearly related to the additive composition investigated, as demonstrated by linear shrinkages and linear shrinkages rate curves. Temperatures of particle rearrangment, solution-reprecipitation of SiC grains, as well as secondary crystalline phase(s) formation and dissolution could be revealed after dilatometric analysis. These temperatures are in good agreement with XRD results. Microstructural observations through SEM and TEM analysis are also related to the sintering behaviour.

Flexural and impact properties of flax fibre reinforced epoxy composite with nano TiO2 addition

2018 ◽  
Vol 5 (11) ◽  
pp. 24862-24870 ◽  
Author(s):  
Vishnu Prasad ◽  
M.A. Joseph ◽  
K. Sekar ◽  
Mubarak Ali
Keyword(s):  
Epoxy Composite ◽  
Flax Fibre ◽  
Nano Tio2 ◽  
Impact Properties ◽  
Tio2 Addition

Efficacy of HfN as sintering aid in the manufacture of ultrahigh-temperature metal diborides-matrix ceramics

2004 ◽  
Vol 19 (12) ◽  
pp. 3576-3585 ◽  
Author(s):  
Frédéric Monteverde ◽  
Alida Bellosi
Keyword(s):  
Hot Pressing ◽  
Applied Pressure ◽  
Thermomechanical Properties ◽  
Full Density ◽  
Secondary Phases ◽  
Homogeneous Microstructure ◽  
Sintering Aid ◽  
Metal Diborides ◽  
Ultrahigh Temperature ◽  
Average Size

HfB2 and (ZrB2 + HfB2)-based ceramics containing 19.5 vol% SiC particulate were developed from commercially available powders by hot-pressing. With the assistance of 3 vol% HfN as sintering aid, after hot-pressing at 1900 °C and 50 MPa of applied pressure, full density in both the composites was successfully achieved. The materials revealed a homogeneous microstructure, characterized by faceted diboride grains(2 μm average size) and SiC particles regularly dispersed. Limited levels of secondary phases were found. The thermomechanical properties of the composites were promising: about 22 GPa microhardness and 500 GPa Young’s modulus for both. The HfB2–SiC composite showed values of strength of 650 ± 50 and 465 ± 40 MPa at 25 and 1500 °C, respectively. Likewise, the (ZrB2–HfB2)–SiC composite exhibited values of strength of 765 ± 20 and 250 ± 45 MPa at 25 and 1500 °C, respectively. The excellent response at high temperature in air was attributed to the refractoriness of the phases constituting the composites and to the resistance to oxidation enhanced by the presence of the SiC particulate.

scholarly journals An Important Factor Affecting the UV Aging Resistance of PBO Fiber Foped with Nano-TiO2: The Number of Amorphous Regions

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 869
Author(s):  
Jiping Liu ◽  
Xiaobo Liu ◽  
Dong Wang ◽  
Hu Wang
Keyword(s):  
Thermal Decomposition ◽  
Wet Spinning ◽  
Nano Tio2 ◽  
Uv Aging ◽  
Tio2 Particles ◽  
Aging Resistance ◽  
Pbo Fiber ◽  
Tio2 Addition ◽  
Resistance Performance ◽  
Derivative Thermogravimetry

Modified nano-TiO2 was prepared by using triethanolamine and tetraisopropyl di (dioctylphosphate) titanate, respectively. Then the poly(p-phenylene benzobisoxazole) (PBO) fibers doped with different additions of modified nano-TiO2 particles were prepared by preparing PBO polymer solution and dry-jet wet spinning technique. Thermogravimetric and derivative thermogravimetry results showed that the addition of nano-TiO2 could improve the crystallinity and maximum thermal decomposition rate temperature of PBO fibers. Tensile strength results showed that nano-TiO2 addition did not affect the tensile properties of PBO fibers before ultraviolet (UV) aging began, and nano-TiO2 with addition values lower than 3% could improve the UV aging resistance performance of PBO fibers, while the aging resistance would be seriously reduced if values were over 5%. The size and quantity of the amorphous regions have a more important influence on the aging resistance of PBO fibers.

An Assessment on Mechanical and Microstructural Properties of Friction Stir Welded 316 L Austenitic Stainless Steel

2015 ◽  
Vol 787 ◽  
pp. 381-385 ◽  
Author(s):  
S. Shashi Kumar ◽  
N. Murugan ◽  
K.K. Ramachandran
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Microstructural Analysis ◽  
Stir Zone ◽  
Microstructural Properties ◽  
Secondary Phases ◽  
Percentage Elongation ◽  
Friction Stir ◽  
Tool Tilt Angle ◽  
Mechanical And Microstructural Properties

The aim of the present study is to investigate on mechanical and microstructural properties of Friction Stir Welded 316 L austenitic stainless steel. Defect free weld were produced at a tool rotational speed (N) of 600 rpm, transverse speed (V) of 45 mm/min, axial force (F) of 11 kN and tool tilt angle (T) of 1.50.Mechanical properties such as Ultimate Tensile strength (UTS), Percentage Elongation (PE), Impact Strength (IS) were evaluated on the welded specimen. Further,micro hardness and microstructural analysis were carried out the transverse direction to the welded specimen. No significance of HAZ in the welded joint with observation of sigma phase precipitation revealed by Groesbeck and Modified Mukrami reagent. Further,FESEM with Electron Dispersive Spectroscopy (EDS) were obtained at the stir zone to ensure constituent of alloying elements present and ensuring no secondary phases found in the stir zone.

Sign in / Sign up

Export Citation Format

Share Document