Effect of Copper Oxide on the Sintering of Alumina Ceramics

2008 ◽  
Vol 47-50 ◽  
pp. 801-804 ◽  
Author(s):  
Ramesh Singh ◽  
K.L. Aw ◽  
C.H. Ting ◽  
Chou Yong Tan ◽  
Iis Sopyan ◽  
...  
Keyword(s):  
Grain Size ◽  
Copper Oxide ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Alumina Ceramics ◽  
Maximum Hardness ◽  
Air Atmosphere ◽  
Al2o3 Phase ◽  
Α Al2o3 ◽  
Effect Of Copper

The effect of adding small amounts of copper oxide (CuO) on the sintering and mechanical properties of alumina ceramic was studied. Samples were prepared and fired in air atmosphere at temperatures ranging from 1400oC to 1600oC. Sintered samples were characterized to determine phase present, bulk density, hardness and grain size. The results indicated that all the doped samples could be sintered to high density > 3.85 Mgm−3 when compared to the undoped alumina. According to the XRD analysis, the α-Al2O3 phase was not disrupted by the dopant addition. Although the hardness of the CuO-doped material was higher when sintered below 1550°C, the maximum hardness of 21 GPa was measured for the undoped ceramics when sintered at 1600°C. The lower hardness of the doped samples could be attributed to the increased in grain size with increasing sintering temperature.

Effects of Adding Form of Additives on the Structure and Properties of High-Purity Alumina Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1130-1132
Author(s):  
Qiang Ren ◽  
Xiu Lan Wu ◽  
Xuan Meng He
Keyword(s):  
High Purity ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Normal Pressure ◽  
The Body ◽  
Raw Material ◽  
Sintering Process ◽  
Alumina Ceramics ◽  
Dry Pressing ◽  
Α Al2o3

High-purity alumina ceramics was prepared using high-purity α-Al2O3 powder as raw material, nitrates or oxides of magnesium, chromium and copper as additives by a wet ball milling with a later dry pressing forming and normal pressure sintering process. The influence of additives on the sintering temperature, microstructure and bending strength of the prepared alumina ceramics was studies. The results showed that the additive doped with nitrate can be dispersed uniformly in the body with molecule scale, and the oxides obtained by decomposing of nitrates have the higher reactivity. Thus, the nitrate additives have better capacity than oxide additives in reducing the sintering temperature and inhibiting the abnormal grain growth, and the alumina ceramics prepared by adding of nitrate additives have higher density and bending strength.

Low-Temperature Sintering of 3Y-TZP/Glass Composites as All-Ceramic Dental Materials

2007 ◽  
Vol 336-338 ◽  
pp. 1593-1595
Author(s):  
Zheng Qiu Sun ◽  
Hong Yan Miao ◽  
Guo Qiang Tan ◽  
Ao Xia
Keyword(s):  
Grain Size ◽  
Sintering Temperature ◽  
Dental Materials ◽  
Xrd Analysis ◽  
Cold Isostatic Pressing ◽  
Liquid Phase Sintering ◽  
Glass Composites ◽  
All Ceramic ◽  
Mean Grain Size ◽  
The Mean

3Y-TZP ceramics were fabricated with the addition of 10wt% MgO-Al2O3-SiO2 glass additive by cold-isostatic pressing and afterwards liquid-phase sintering at 1200-1400°C for 2 h. The densities of samples sintered at 1300°C for 2 h reaches 99.1%, but further increase of sintering temperature results in the decrease of densities. XRD analysis showed that the cordierite crystals and a small amount of amorphous phase were presented at the grain junctions, and SEM observation indicated that the mean grain size of ZrO2 with round-shape ranged from 200 to 300 nm, which was below the critical transformation size, and the increase in sintering temperature was accompanied with an increase in the mean grain size. The strength and toughness of samples were kept in the range of 396-528 MPa, 4.4-5.8 MPa·m1/2 respectively, which could meet the need of clinical applications of all-ceramic dental materials.

Effect of Sintering Temperature on Properties of Multiferroic BaFe12O19/MgFe2O4/BaTiO3 Composites

2016 ◽  
Vol 846 ◽  
pp. 410-415
Author(s):  
M.F.A. Zolkepli ◽  
Rozidawati Awang ◽  
Zalita Zainuddin
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Tetragonal Batio

In this paper, the structural, magnetic and electrical properties of multiferroic BaFe12O19/MgFe2O4/BaTiO3 composites have been studied. BaFe12O19/MgFe2O4/BaTiO3 composites were synthesized by using the conventional solid state reaction technique and sintered at different temperatures. XRD analysis confirmed the existence of hexagonal BaFe12O19, cubic spinel MgFe2O4 and tetragonal BaTiO3 for ferrites and ferroelectric phases, respectively. The suitable sintering temperature for preparing BaFe12O19/MgFe2O4/BaTiO3 composites is between 1000 °C and 1050 °C. SEM analysis showed that as a whole the grain size increases and the pores is reduced with sintering temperature; thus the sample became denser. The coercive field and saturation magnetization decreases when sintering temperature is increased. Resistance of the samples decrease from 103 kW to 19 kW while the capacitance increases from 0.8 nF to 4.0 nF with sintering temperature.

The Effect of Sintering Temperature on the Sintered Mg/3wt.%Zn-Bioglass (45S5) Composites

2015 ◽  
Vol 819 ◽  
pp. 325-330
Author(s):  
Noorazimah Ab Llah ◽  
Shamsul Baharin Jamaludin ◽  
Zuraidawani Che Daud
Keyword(s):  
Grain Size ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Good Combination ◽  
Crystalline Compound ◽  
X Ray Diffraction ◽  
Bioactive Materials ◽  
Xrd Pattern ◽  
X Ray ◽  
Optical Micrograph

Magnesium and bioglass are a good combination to create biocompatible and bioactive materials. Magnesium-bioglass composites can be manufactured by casting or sintering. This work was aimed to manufacture the composite Mg-3wt.%Zn filled with 5, 10, 15, 20, 25 and 30wt.% bioglass (45S5) by powder metallurgy. Two sintering temperatures of 450 °C and 550 °C were used to sinter the samples. The sintered samples were characterized using optical micrograph and X-Ray diffraction (XRD). Optical micrograph shows that increasing of bioglass content lead to smaller grain size. XRD analysis shows no new crystalline compound detected on XRD pattern for Mg-3wt%Zn sintered at 450 °C ad 550 °C.

Accelerated sintering of SiC Nanopowder with Stacking Disorder-Order Transformation

2005 ◽  
Vol 903 ◽  
Author(s):  
Kenshiro Shirai ◽  
Takeshi A Yamamoto ◽  
Manshi Ohyanagi ◽  
Zuhair A Munir
Keyword(s):  
Grain Size ◽  
Sintered Material ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
The Other ◽  
Disordered Structure ◽  
Other Hand ◽  
Stacking Disorder

AbstractConsolidation of SiC nanopowder with stacking disordered structure was accelerated by milling with the AlN as the additive. SiC powders without the additive was sintered at 1900°C to a density of 99%. The grain size of the sintered material was approximately 500 nm. On the other hand, with AlN as additive, the sintering temperature to reach a density of 98% was reduced to 1700°C by the addition of 1.0 mol% AlN. The grain size of this material was less than 100 nm. The effect of AlN addition on SiC sintering with disorder-order transformation was evaluated by shrinkage profile, XRD analysis, and TEM observation.

scholarly journals Oxidation Behavior of Non-Modified and Rhodium- or Palladium-Modified Aluminide Coatings Deposited on CMSX-4 Superalloy

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 613 ◽  
Author(s):  
Maryana Zagula-Yavorska
Keyword(s):  
Oxide Layer ◽  
Oxidation Behavior ◽  
Intermetallic Phase ◽  
Phase Region ◽  
Air Atmosphere ◽  
Aluminide Coatings ◽  
Ni3al Phase ◽  
Al2o3 Phase ◽  
Α Al2o3 ◽  
Palladium Content

Rhodium-modified as well as palladium-modified and non-modified aluminide coatings on CMSX-4 Ni-based superalloy were oxidized in air atmosphere at 1100 °C. Uncoated substrate of CMSX-4 superalloy was also oxidized. The microstructure of coatings before oxidation consists of two layers: an additive and an interdiffusion one. The NiAl intermetallic phase was found in the microstructure of non-modified coatings, while the (Ni,Rh)Al intermetallic phase was observed in the microstructure of rhodium-modified aluminide coatings before oxidation. The (Ni,Pd)Al phase of palladium-modified aluminide coatings in the additive layer was observed before oxidation. The microstructure of the oxidized non-modified coatings consists of the γ’-Ni3Al phase. The oxide layer (10 μm thick) consists of the NiAl2O4 phase and porous Ni-rich oxide. The oxide layers (5 μm thick) formed on the surface of rhodium or palladium-modified coatings consist of the α-Al2O3 phase and the top layer of the NiAl2O4 phase. Al-depleted (30 at. %) β-NiAl grains besides the γ’-Ni3Al phase were found in the rhodium-modified coating, while only the γ’-Ni3Al phase region was revealed in the palladium-modified coating, Rhodium-modified coatings with small rhodium content (0.5 μm rhodium layer thick) can be an alternative for palladium-modified ones with bigger palladium content (3 μm thick palladium layer).

Superplastic Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite at Low Temperature

2007 ◽  
Vol 551-552 ◽  
pp. 487-490 ◽  
Author(s):  
Jun Ting Luo ◽  
Qing Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Sintered Body ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size

The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering (LPS) method. XRD analysis shows sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is only 1550°C. Rod-shaped grains aligned along the perpendicular direction of pressure and the mechanical properties increase about 10% after the materials were forged.

Superplasticity and Sinter-Forging of Fine-Grained Si3N4-Si2N2O Composite

2005 ◽  
Vol 475-479 ◽  
pp. 2987-2990 ◽  
Author(s):  
Jun Ting Luo ◽  
Kai Feng Zhang ◽  
Guo Feng Wang ◽  
Wen Bo Han
Keyword(s):  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Liquid Phase Sintering ◽  
Sintered Body ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Cavitation Failure

The Si3N4- Si2N2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering(LPS) method in this article. XRD analysis shows that the sintered body consists of β-Si3N4 and Si2N2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The superplastic deep-drawing forming can be proceed at a low temperature of 1550°C with a forming velocity of 0.2mm/min. There are only a few small sintered defects before forming, but there are a lot of cavity groups after forming. Cavitation failure occurs by nucleation, growth and interlinkage of cavities. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is 1550°C.

Dense Manganese Doped Biphasic Calcium Phosphate for Load Bearing Bone Implants

2010 ◽  
Vol 93-94 ◽  
pp. 393-396 ◽  
Author(s):  
Iis Sopyan ◽  
Natasha Ahmad Nawawi ◽  
Qasim Hussain Shah
Keyword(s):  
Calcium Phosphate ◽  
Biphasic Calcium Phosphate ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Maximum Hardness ◽  
Mn Doping ◽  
Manganese Doping ◽  
Air Atmosphere ◽  
Tcp Phases ◽  
Mn Doped

Dense pure biphasic calcium phosphate (BCP) and Mn-doped BCP ceramics were fabricated via uniaxial pressing using the sol-gel derived powders. The compacted discs were sintered in air atmosphere with temperatures ranging from 1000 °C to 1400 °C. All powders have been proved to show HA and β-TCP phases only. Manganese doping improves the densification in the BCP structure as the relative density increased with Mn doping and also sintering temperature. Considerable grain growth has been observed at 1300 °C for Mn-doped BCP samples compared to the pure BCP. 15 mol% Mn showed the maximum hardness value of 6.66 GPa at 1400 °C compared to pure BCP of only 2.89 GPa. Similarly, the Mn-doped BCP has superior fracture toughness where it attained maximum values of 1.05 MPam1/2 at 1400 °C compared to 0.72 MPam1/2 at 1300 °C of pure BCP. In a nutshell, Mn doping has successfully brought improvement in the mechanical properties of the BCP.

Sintering Behavior of Microstructured γ-Alumina with Nanosized γ-Alumina Additive

2006 ◽  
Vol 317-318 ◽  
pp. 7-10 ◽  
Author(s):  
S.W. Oh ◽  
Hiroyuki Muto ◽  
K. Muramoto ◽  
Wataru Minami ◽  
Hee Joon Kim
Keyword(s):  
Phase Transformation ◽  
Relative Density ◽  
Sintering Temperature ◽  
Holding Time ◽  
Sintering Behavior ◽  
Alumina Ceramics ◽  
Nanosized Powders ◽  
Low Sintering Temperature ◽  
Α Al2o3 ◽  
Average Size

In order to fabricate an alumina ceramics with high density at low sintering temperature, nanosized γ–Al2O3 powders with average size of 9.7 nm were added to microsized γ–Al2O3 powders with 2 #m and they were well mixed. Its sintering behavior was studied in the temperature range of 1000oC to 1300oC and in holding time from 1 hour to 10 hours. Compacted samples with a different mixed ratio of nanosized and microsized Al2O3 powders (N/M ratio) were prepared and pressured at 1 GPa in a uniaxial direction. The phase transformation from γ–Al2O3 to α–Al2O3 takes place at 1100oC for 1hour sintering in all compacted samples. This rate is increased with increasing N/M ratio. The relative density varied from 70% to 95% depending on temperature and N/M ratio. With increasing sintering temperature from 1000oC to 1300oC, it was changed from 70% to 93%. Especially, the relative density was enhanced about 9% higher than that of only microsized sample by only 10 wt% addition of nanosized powders.

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