scholarly journals Research and Development of Novel Refractory of MgO Doped with ZrO2 Nanoparticles for Copper Slag Resistance

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2277
Author(s):  
Cristian Gómez-Rodríguez ◽  
Yanet Antonio-Zárate ◽  
Josept Revuelta-Acosta ◽  
Luis Felipe Verdeja ◽  
Daniel Fernández-González ◽  
...  
Keyword(s):  
Grain Growth ◽  
Copper Slag ◽  
Ceramic Composites ◽  
Zro2 Nanoparticles ◽  
Corrosion Mechanism ◽  
Sintering Process ◽  
Slag Resistance ◽  
Powder Mixtures ◽  
Chemical Attack ◽  
Diffusion Of Vacancies

This study investigates the corrosion mechanism on 100 wt.% MgO and 95 wt.% MgO with 5 wt.% nano-ZrO2 ceramic composites. First, MgO powder and powder mixtures (MgO + nano ZrO2) were uniaxially and isostatically pressed; then, they were sintered at 1650 °C. Corrosion by copper slag was studied in sintered samples. Physical properties, microstructure, and penetration of the slag in the refractory were studied. Results reveal that ZrO2 nanoparticles enhanced the samples’ densification, promoting grain growth due to diffusion of vacancies during the sintering process. Additionally, magnesia bricks were severely corroded, if compared with those doped with nano-ZrO2, mainly due to the dissolution of MgO grains during the chemical attack by copper slag.

scholarly journals Study of the corrosion resistance on nano-ZrO2 doped MgO ceramic composites by copper slag.

2020 ◽  
Author(s):  
L.V. García-Quiñonez ◽  
L.F. Verdeja ◽  
D. Fernández-González ◽  
E. Castro-Soto ◽  
G.A. Castillo-Rodríguez ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Grain Growth ◽  
Copper Slag ◽  
Ceramic Composites ◽  
Corrosion Mechanism ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Chemical Attack ◽  
Diffusion Of Vacancies

Abstract This study investigated the corrosion mechanism on 100 wt. % MgO and 95 wt. % MgO with 5 wt. % nano-ZrO2 ceramic composites. First, MgO powder and powder mixtures (MgO + nano ZrO2) were uniaxially and isostatically pressed and, then, they were sintered at 1650 °C. Corrosion by copper slag was studied with sintered samples. Physical properties, microstructure and penetration of the slag in the refractory were studied. Results reveal that ZrO2 nanoparticles enhanced the densification of the samples, promoting grain growth due to diffusion of vacancies during sintering process. Additionally, magnesia bricks were severely corroded, if compared with those doped with nano-ZrO2, due to the dissolution of MgO grains during the chemical attack by copper slag.

Effect of Boron and Carbon Addition on the Phase Transformations during High-Energy Ball Milling and Subsequent Sintering of Si3N4+B and Si3N4+C Powder Mixtures

2016 ◽  
Vol 869 ◽  
pp. 58-63
Author(s):  
Luiz Otávio Vicentin Maruya ◽  
Bruna Rage Baldone Lara ◽  
Belmira Benedita de Lima ◽  
Vanessa Motta Chad ◽  
Gilberto Carvalho Coelho ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Ceramic Composites ◽  
Nitrogen Atmosphere ◽  
Carbon Addition ◽  
Powder Mixtures ◽  
X Ray ◽  
Milled Powders

This study reports on effect of boron and carbon addition on the phase transformations during ball milling and subsequent sintering of Si3N4+B and Si3N4+C powder mixtures. Ball milling at room temperature was conducted using stainless steel vials (225 mL) and balls (19mm diameter), 300 rpm and a bal-to-powder weight ratio of 10:1. The as-milled powders were uniaxially compacted in order to obtain cylinder samples with 10 mm diameter, which were subsequently sintered under nitrogen atmosphere at 1500°C for 1h. Characterization of the as-milled powders and sintered samples was performed by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Only peaks of Si3N4 were identified in X-ray diffractograms of as-milled Si3N4+B and Si3N4+C powders, suggesting that metastable structures were found during milling. After sintering at 1500°C for 1h, the Si3N4+BN and Si3N4+SiC ceramic composites were formed from the mechanically alloyed Si3N4+B and Si3N4+C powders.

scholarly journals Pressureless sinterability study of ZrB2–SiC composites containing hexagonal BN and phenolic resin additives

2021 ◽  
Vol 1 (2) ◽  
pp. 99-104
Author(s):  
Iman FarahBakhsh ◽  
Riccarda Antiochia ◽  
Ho Won Jang
Keyword(s):  
Phenolic Resin ◽  
Vacuum Furnace ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Cold Pressing ◽  
X Ray ◽  
Sic Ceramics ◽  
Sic Composites ◽  
By Products

This research is dedicated to the role of different amounts of hexagonal BN (hBN: 0, 1.5, 3, and 4.5 wt%) on the pressureless sinterability of ZrB2–25 vol% SiC ceramics. Phenolic resin (5 wt%) with a carbon yield of ~40 % was incorporated as a binder to the powder mixtures and after initial cold pressing, the final sintering process was performed at 1900 °C for 100 min in a vacuum furnace. The as-sintered specimens were characterized by X-ray diffractometry, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results disclosed that the incorporation of 1.5 wt% hBN could increase the relative density to ~92%, while the sample with zero hBN content just reached ~81% of full densification. Appropriate hBN content not only facilitated the particle rearrangement during the cold pressing, but also removed the harmful oxide impurities during the final sintering. Nevertheless, the addition of higher amounts of hBN remarkably lessened the densification because of more delamination of the non-reacted hBN flakes and release and entrapment of more gaseous by-products induced by the reacted hBN phases.

Preparation and Characterization of Alumina based TiNn and SiCn Composites

2002 ◽  
Vol 740 ◽  
Author(s):  
Mats Carlsson ◽  
Mats Johnsson ◽  
Annika Pohl
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Growth ◽  
Ceramic Composites ◽  
Processing Route ◽  
Nano Structure ◽  
Plasma Sintering ◽  
Water Based ◽  
Spark Plasma

ABSTRACTCeramic composites containing 2 and 5vol. % of nanosized commercially available TiN and SiC particles in alumina were prepared via a water based slurry processing route followed by spark plasma sintering (SPS) at 75 MPa in the temperature range 1200–1600°C. Some of the samples could be fully densified by use of SPS already after five minutes at 1200°C and 75 MPa. The aim was to control the alumina grain growth and thus obtain different nano-structure types. The microstructures have been correlated to some mechanical properties; e.g. hardness and fracture toughness.

Elongated Grain Growth Mechanism of Alumina Ceramics with Additives

2010 ◽  
Vol 105-106 ◽  
pp. 844-847
Author(s):  
Yong Chang Zhu ◽  
Shou Fan Rong ◽  
Ji Wei Guo ◽  
Jun Gang Li
Keyword(s):  
Grain Growth ◽  
Growth Mechanism ◽  
Second Phase ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Alumina Ceramics ◽  
Effect Of Additives ◽  
Sintering Properties ◽  
Columnar Grain

The elongated grain evolution of alumina ceramics doping with Al2O3-CaO-SiO2(CAS), Nb2O5, and 3Y-TZP was studied under pressureless sintering. From in-situ growth elongated grain cooperating with second phase to toughen the alumina ceramics, microstructure and sintering properties were firstly studied systematically. The effect of additives on the alumina ceramics with columnar grain were analyzed by means of TEM, SEM, XRD, etc. Basing on the analyzed sintering process by the principle of dynamics, the elongated grain growth mechanism was further studied.

Simulation of the Effect of Sintering Temperature on Microstructure Evolution in Nanocomposite Ceramic Tool Materials

2013 ◽  
Vol 770 ◽  
pp. 194-197
Author(s):  
Hong Mei Cheng ◽  
Chuan Zhen Huang ◽  
Xiu Ye Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Sintering Temperature ◽  
Sintering Process ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Mean Grain Size ◽  
Higher Temperature ◽  
The Mean ◽  
Simulation Results

A Monte Carlo Potts model coupled with sintering temperature for the sintering process of nanocomposite ceramic tool materials is proposed, the relation between grain growth and sintering temperature is presented. The grain growth process at different sintering temperature is investigated in this model, and the effect of sintering temperature on microstructure evolution is discussed, it is found that the mean grain size increases with the increase of sintering temperature during simulation, and nanoparticles are easier to enter into matrix grains to form intragranular-type microstructure at higher temperature. The simulation results are in accordance with the experimental observations.

Effects of CuO on the Preparation, Microstructure and Dielectric Response of CaCu3Ti4O12

2008 ◽  
Vol 368-372 ◽  
pp. 121-122
Author(s):  
Jian Fang Qiao ◽  
Dan Dan Qin ◽  
Li Guan ◽  
Hai Long Wang ◽  
Rui Zhang
Keyword(s):  
Solid State ◽  
Grain Growth ◽  
Barrier Layer ◽  
Solid State Reaction ◽  
Dielectric Response ◽  
Second Step ◽  
Sintering Process ◽  
Ceramic Capacitor ◽  
Inhomogeneous Microstructure ◽  
Maximum Permittivity

CaCu3Ti4O12 (CCTO) barrier layer ceramic capacitor was prepared by a two-step sintering process. The CCTO powders were pre-synthesized at 900oC by solid-state reaction and the effects of the amount of CuO on the formation of the CCTO powders were investigated. The CCTO ceramics were prepared by the second-step sintering. It was found that the abnormal grain growth and inhomogeneous microstructure are controlled by the amount of excessive CuO. The optimized CuO content in the composites is ~14 wt%. The maximum permittivity is 115,000 (1 kHz, 210oC).

The Dimensional Change in the Sintering of a Plain Iron Powder and High-Alloyed Iron Powder Mixtures

2006 ◽  
Vol 530-531 ◽  
pp. 747-752
Author(s):  
Maurício David Martins das Neves ◽  
Nelson Karsokas Filho ◽  
Daniel Rodrigues ◽  
Lucio Salgado ◽  
Francisco Ambrozio Filho
Keyword(s):  
Iron Powder ◽  
Composite Powder ◽  
Dimensional Change ◽  
Atomic Motion ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Dilatometric Analysis ◽  
Heating And Cooling ◽  
Wide Range ◽  
High Alloyed Steel

In plain iron powder or powder mixtures sintering process, it is very important to control the dimensional change. In the sintering associated events, such as lubricant removal, atomic motion and phase transformation could change dimensions over a wide range. Dilatometric analysis has shown that most contributions in the dimensional change in the sintering of iron powder mixtures were due to the combination of several effects occurring in all stages of the processing, including the heating and cooling stages. The present paper has the objective of studying the dimensional behavior and to determine the transformation temperature of a composite powder mixture of a plain iron powder with various additions of high-alloyed steel, carbon, nickel and lubricant powders, during sintering by dilatometric analysis.

Two-Steps Sintering of Alumina-Zirconia Ceramics

2010 ◽  
Vol 660-661 ◽  
pp. 819-825
Author(s):  
Milena K. Manosso ◽  
Elíria Maria Jesus Agnolon Pallone ◽  
Adilson Luiz Chinelatto ◽  
Adriana Scoton Antonio Chinelatto
Keyword(s):  
Grain Size ◽  
Ball Milling ◽  
Grain Growth ◽  
Sintering Process ◽  
Ceramic Powders ◽  
Zirconia Ceramics ◽  
Linear Rate ◽  
Commercial Alumina ◽  
Mean Grain Size ◽  
Cold Pressed

Sintering in two-steps has been applied with success for densification of nanometric ceramic powders without grain growth. Another mechanism that alters the sintering process is the presence of rigid inclusions in the ceramic. In this work it was studied the effect of two-steps sintering and the presence of zirconia inclusions (5% in volume) in the microstructure of a commercial alumina. For this, the powders of alumina and zirconia were desaglomerated in a ball milling and uniaxially pressed at 80 MPa to form cylindrical compacts and isostatically cold pressed at 200 MPa. Temperatures of the steps were chosen starting from the curves of linear rate shrinkage in function of the temperature. The samples were characterized for apparent density, scanning electronic microscopic and mean grain size. The results showed that two-steps sintering and the zirconia inclusions were efficient to control the densification and grain size of alumina.

Practical Evolutions and Computer Simulation of Pores in BaTiO3 Ceramics during Sintering Process

2008 ◽  
Vol 368-372 ◽  
pp. 1585-1587 ◽  
Author(s):  
L.M. Li ◽  
Guo Li Ji ◽  
Y.P. Yang ◽  
Zhao Xian Xiong
Keyword(s):  
Computer Simulation ◽  
Free Energy ◽  
Grain Growth ◽  
Pore Shape ◽  
Sintering Process ◽  
Ceramic System ◽  
Ceramic Microstructure ◽  
Compact Body ◽  
Shape And Size ◽  
Good Agreement

Practical evolutions of pores in BaTiO3 ceramics during sintering are studied, including the preparation of practical BaTiO3 ceramics and observation of ceramic microstructure by SEM. The reduction of porosity and thus dense process results from the change of the free energy in the ceramic system, which is altered by the disappearing of the interface between solid and pore. The sintering process are monitored, including sintering neck growth, pore shape and size changing, grain growth and compact body contracting. Theoretical formulae during the sintering process are applied for the computer simulation. The experimental results of BaTiO3 ceramics are in good agreement with that of simulation.

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