The Sintering Behaviour of Fe-Mn-C Powder System, Correlation between Thermodynamics and Sintering Process, Mn Distribution and Microstructure

2007 ◽  
pp. 761-764 ◽  
Author(s):  
Eduard Hryha ◽  
Eva Dudrova
Keyword(s):  
Sintering Process ◽  
Powder System ◽  
Sintering Behaviour

The Sintering Behaviour of Fe-Mn-C Powder System, Correlation between Thermodynamics and Sintering Process, Mn Distribution and Microstructure

2007 ◽  
Vol 534-536 ◽  
pp. 761-764 ◽  
Author(s):  
Eduard Hryha ◽  
Eva Dudrová
Keyword(s):  
Cross Section ◽  
Dew Point ◽  
Gas Mixture ◽  
Porous Iron ◽  
Sintering Process ◽  
Iron Matrix ◽  
Powder System ◽  
Temperature Ranges ◽  
Mn Content ◽  
Sintering Behaviour

To study of the sintering behaviour of the Fe-0.8Mn-0.5C powder system the cylindrical specimens with a density of ~7.0 g/cc were sintered in container at the temperature of 11200C for 30 min in a gas mixture of 7%H2/93%N2 with the inlet dew point of -600C. The composition (CO/CO2- content) and the dew point of the flowing and “container micro-climate” atmospheres during the whole sintering cycle were monitored. It was shown, that carbothermical reduction and formation esp. CO/CO2 occurs in two different temperature ranges. Three peaks of dew point profile also can be distinguished during sintering cycle. Following sintering the changes of ferromanganese particles, Mn-content distribution and microstructures around the Mn-source were micro-analytical evaluated at cross-section of specimens using the SEM with EDX microanalyses. The results showed that manganese travels through porous iron matrix up to ~60 μm. The type of local microstructure constituents is determined by the local Mn- and C contents.

scholarly journals Sintering Behaviour of Al-Cu-Mg-Si Blends

2007 ◽  
Vol 534-536 ◽  
pp. 597-600 ◽  
Author(s):  
C. Lucien Falticeanu ◽  
I.T.H. Chang ◽  
J.S. Kim ◽  
R. Cook
Keyword(s):  
Alloy Powder ◽  
Effect Of Temperature ◽  
Microstructural Development ◽  
Al Alloy ◽  
Sintering Process ◽  
Scanning Calorimetry ◽  
Increasing Demand ◽  
Sintering Behaviour ◽  
Evolution Of Microstructure ◽  
Initial Starting

The increasing demand for automotive industries to reduce the weight of the vehicles has led to a growing usage of Al alloy powder metallurgy (P/M) parts such as camshaft bearing caps, shock absorber pistons and brake calipers [1,2]. In order to control the sintered microstructure and mechanical properties of the aluminium alloy powder metallurgical (P/M) parts, it is essential to establish a fundamental understanding of the microstructural development during the sintering process. Current research at Birmingham University is focussed on the investigation of the sintering behaviour of Al-Cu-Mg-Si powder blends using a combination of Scanning Electron Microscopy, Energy Dispersive Microanaylsis (SEM) and Differential Scanning Calorimetry (DSC). This paper presents a detailed study of the effect of temperature and initial starting materials on the evolution of microstructure during the sintering of Al-Cu-Mg-Si blends for PM.

scholarly journals Effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CaAl12O19 composite refractories

2021 ◽  
Vol 15 (1) ◽  
pp. 11-18
Author(s):  
Yaochen Si ◽  
Miao Xia ◽  
Hongxia Li ◽  
Honggang Sun ◽  
Ang Guo ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Coal Slurry ◽  
Refractory Materials ◽  
Sintering Process ◽  
Active Oxidation ◽  
Passive Oxidation ◽  
Different Temperatures ◽  
Sintering Behaviour

In order to develop chrome-free refractory materials applicable in coal slurry gasification, SiC-CaAl12O19 (SiC-CA6) composite refractories were developed and prepared by using SiC aggregates and CA6 powders as main raw materials. The sintering behaviour of the composites was investigated. After firing at different temperatures under CO atmosphere, the effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CA6 composite refractorieswere investigated. SiC-CA6 composites could not be sintered when firing temperature was lower than 1500?C. SiC had a passive oxidation and the oxidation components were able to react with CA6 to form CaAl2Si2O8. The CaAl2Si2O8 melted into liquid when sintering temperature was in the range of 1500-1600?C, which promoted the sintering process of the SiC-CA6 composites. At temperatures above 1600 ?C, an active oxidation of SiC occurred. Simultaneously, SiC could also reacted with the SiO2(s,l) to form SiO, leading to the precipitation of Al2O3 and CaO in the liquid to generate plate-like CA6. Above this temperature, the sintering of the SiC-CA6 composite refractories was affected by the growth of CA6 and oxidation of SiC. This work demonstrates that the optimal sintering temperature for the SiC-CA6 composite refractories was 1600?C.

scholarly journals Study on Sintering of Artificially Oxidized Steel Compacts

2019 ◽  
Vol 19 (1) ◽  
pp. 12-22
Author(s):  
C. Gierl-Mayer ◽  
T. Stepan ◽  
J. Sun ◽  
H. Danninger
Keyword(s):  
Thermal Analysis ◽  
Iron Oxides ◽  
Steel Powder ◽  
Microstructural Development ◽  
Sintering Process ◽  
Low Oxygen ◽  
Iron And Steel ◽  
Reducing Conditions ◽  
Different Temperatures ◽  
Sintering Behaviour

AbstractSintering of Cr-prealloyed PM steels requires atmospheres with good quality – low oxygen potential – to achieve satisfactory sintering results. But during heating even the best atmospheres may be oxidizing, the system turns to reducing conditions only at high temperatures, which can be monitored by thermal analysis. During the dewaxing process, oxidizing conditions are favourable for effective dewaxing without sooting and blistering. However, this may result in some oxygen pickup during heating, and then the final properties of the produced parts may be strongly influenced by this intermediate oxidation. This study demonstrates the behaviour of artificially oxidized steels (Fe-C and Fe3Cr-0.5Mo-C) during the sintering process by stepwise sintering. Iron and steel powder were slightly oxidized and then pressed and sintered at different temperatures. In parallel, as a second approach, pressed samples were oxidized and then sintered. Density, hardness and impact energy were measured and dilatometry/MS was used for online monitoring of the sintering process. The starting oxygen content of 0.20 to 0.30 wt% is high enough to change the sintering behaviour of the materials, but still leads to rather good properties. Thermal analysis showed that most of the oxygen picked up was present as iron oxides on the surface which were reduced by hydrogen at rather low temperatures, confirming that these were iron oxides, which also holds for the Cr-prealloyed variant. The biggest influence on the final performance was exerted by the final carbon content and the microstructural development of the material.

Dilatometry Coupled with Mass Spectrometry as Instrument for Process Control in Sintering of Powder Metallurgy Steels

2016 ◽  
Vol 835 ◽  
pp. 106-115 ◽  
Author(s):  
Christian Gierl-Mayer ◽  
Herbert Danninger
Keyword(s):  
Mass Spectrometry ◽  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Process Control ◽  
Analytical Data ◽  
Sintering Process ◽  
Sintering Atmosphere ◽  
Surface Oxides ◽  
The Press ◽  
Sintering Behaviour

The production of ferrous powder metallurgical parts by the press-and-sinter route becomes more and more attractive. Today, parts are produced for loading requirements that until now only could be fulfilled by conventional produced steel components. The high mechanical properties that must be attained require the use of alloying elements so far not common in powder metallurgy because of their high affinity for oxygen. The sintering of chromium containing steels is a challenge for the whole production process, because the reduction of the surface oxides is critical for successful sintering.Dilatometry can be a useful instrument to control the sintering behaviour of the materials, especially the combination with mass spectrometry allows analysing the very complex sintering process and simultaneously monitoring the solid-gas reactions. This work shows that the sintering atmosphere plays a major role in the entire process. Degassing and deoxidation processes during sintering are demonstrated for different alloying systems (Fe, Fe-C, Fe-Mo-C, Fe-Cr-Mo-C). Dilatometry coupled with MS is shown to be a very good instrument for process control of the sintering process. The generated analytical data can be related to the mechanical properties of the sintered steels if the size of the specimen is large enough.

scholarly journals Low-temperature sintering of sodium beta alumina ceramics using nanosized SnO2 sintering aid

2020 ◽  
Vol 14 (1) ◽  
pp. 56-62
Author(s):  
Moghadam Ahmadi ◽  
Mohammad Paydar
Keyword(s):  
Alumina Powder ◽  
Sintering Process ◽  
Alumina Ceramics ◽  
Solid State Method ◽  
Sintering Aid ◽  
Mechanical And Electrical Properties ◽  
Sodium Beta Alumina ◽  
Al2o3 Phase ◽  
Sintering Behaviour ◽  
Beta Alumina

Sodium beta alumina ceramics (Na1.67Al10.67Li0.33O17) is used in sodium sulphur batteries as solid electrolyte. In the present work, sodium beta alumina powder has been synthesized by the solid state method using Al2O3, Na2CO3 and Li2CO3 as the starting materials. The effect of nanosized SnO2 additive on sintering behaviour, microstructure, mechanical and electrical properties of sodium beta alumina ceramics has been investigated. The results indicated that the addition of 1mol% of nanosized SnO2 particles, determined as the optimal amount, can decrease the sintering temperature of sodium beta alumina ceramics for about 100?C, and lead to the excellent densification and proper microstructure, as well. Improvement in sintering behaviour of beta alumina ceramics in the presence of nanosized SnO2 additive is apparently due to the formation of a liquid phase during the sintering process and lower sodium loss. The results also proved that by SnO2 addition, ionic conductivity at 300?C, fracture strength and Weibull modulus of the sintered samples are improved by 66%, 58%, and 45%, respectively. These improvements could be attributed to the higher amount of ???-Al2O3 phase, higher density and more uniform microstructure.

scholarly journals Nanocrystalline Hydroxyapatite Ceramics Prepared by Hydrolysis in Polyol Medium, Microstructure and Mechanical Properties after Spark Plasma Sintering

2013 ◽  
Vol 6 (3) ◽  
pp. 1085-1092 ◽  
Author(s):  
Abderrahmen Mechay ◽  
Noureddine Jouini ◽  
Fréderic Schoenstein
Keyword(s):  
Spark Plasma Sintering ◽  
Sintering Process ◽  
New Approach ◽  
Plasma Sintering ◽  
Hydroxyapatite Ceramics ◽  
Nanocrystalline Hydroxyapatite ◽  
Different Temperatures ◽  
Polyol Medium ◽  
Spark Plasma ◽  
Sintering Behaviour

This Letter describes a new approach for the synthesis of hydroxyapatite (HA) nanoparticles by polyol process has been successfully conducted by spark plasma sintering process, resulting in a dense hydroxyapatite compacts. Besides, the sintering behaviour of hydroxyapatite powders at different temperatures ranging from 800°C to 950°C at 50 MPa was studied. The microstructure, Vickers microhardness, fracture toughness and density are described. The suitable sintering condition under the pressure of 50 MPa is 900°C for 5 min. A maximum value of the density was reached at around 900°C, and then decreased with further increase in the temperature due to the decomposition of hydroxyapatite into β-tricalcium phosphates.

Sign in / Sign up

Export Citation Format

Share Document