Low-temperature sintering and prolonged holding time on the densification and properties of zirconia ceramic

C.H. Ting,S. Ramesh,C.Y. Tan,N.I. Zainal Abidin,W.D. Teng,I. Urriés,L.T. Bang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.8

In the present work, the effect of low temperature sintering, focusing on varying the sintering holding times on the mechanicalproperties, microstructure and low temperature degradation behavior of undoped and MnO2-doped Y-TZP ceramics wereinvestigated. Green samples were sintered at temperatures ranging from 1100 to 1250 oC at varying holding times rangingfrom 12 min. to 480 min. The sintered bodies were characterized in terms of bulk density, Vickers hardness, fracturetoughness, phase stability and grain size. The results indicated that the relative density of above 95%, Vickers hardness of 14GPa and fracture toughness of 5 MPam1/2 were obtained when sintered at lower sintering temperature (below 1250 oC) andlonger sintering times for MnO2-doped Y-TZP samples. Grain growth was marginal and the average grain size of all samplesranged between 0.14 and 0.28 µm. The results indicated that the grain growth kinetics was influenced mainly by the sinteringtemperature and not by the sintering holding time. The addition of MnO2 was found to be beneficial in enhancing densificationand mechanical properties of Y-TZP particularly at low sintering temperature of 1100 oC and low holding time of 12 min. Thelow-temperature degradation experiment conducted in superheated steam indicated that all the samples did not transformedto the monoclinic symmetry, attributed mainly to the lower grain size sintered at relatively low sintering temperatures

저온소결을 통한 초고용량 MLCC 개발

손성범,김효섭,송순모,김영태,허강헌 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.2

It is necessary to minimize the thickness of Ni inner electrode layer and to improve the coverage of inner electrode, for the purpose of developing the ultra high-capacity multi layered ceramic capacitor (MLCC). Thus, low temperature sintering of dielectric BaTiO₃ ceramic should be precedently investigated. In this work, the relationship between dielectric properties of MLCC and batch condition such as mixing and milling methods was investigated in the BaTiO₃(BT)-Dy-Mg-Ba system with borosilicate glass as a sintering agent. In addition, several chip properties of MLCC manufactured by low temperature sintering were compared with conventionally manufactured MLCC. It was found that low temperature sintered MLCC showed better DC-bias property and lower aging rate. It was also confirmed that the thickness of Ni inner electrode layer became thinner and the coverage of inner electrode was improved through low temperature sintering. It is necessary to minimize the thickness of Ni inner electrode layer and to improve the coverage of inner electrode, for the purpose of developing the ultra high-capacity multi layered ceramic capacitor (MLCC). Thus, low temperature sintering of dielectric BaTiO₃ ceramic should be precedently investigated. In this work, the relationship between dielectric properties of MLCC and batch condition such as mixing and milling methods was investigated in the BaTiO₃(BT)-Dy-Mg-Ba system with borosilicate glass as a sintering agent. In addition, several chip properties of MLCC manufactured by low temperature sintering were compared with conventionally manufactured MLCC. It was found that low temperature sintered MLCC showed better DC-bias property and lower aging rate. It was also confirmed that the thickness of Ni inner electrode layer became thinner and the coverage of inner electrode was improved through low temperature sintering.

Milling 조건에 따른 BaTiO₃의 저온 소결성 및 전기적 특성 변화

홍민희,손성범,김영태,허강헌 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.2

It is necessary to minimize the mismatch of sintering shrinkage between dielectric ceramic and Ni inner electrode layers for the purpose of developing the ultra high-capacity multi layered ceramic condenser(MLCC). Thus, low temperature sintering of dielectric BaTiO₃ ceramic should be precedently investigated. In this work, the influence of the milling condition on sintering behavior and electrical properties of BaTiO₃ ceramics was investigated in the BaTiO₃(BT)-Mg-Dy-Mn-Ba system with borosilicate glass as a sintering agent. As milling time increased, specific surface area(SSA) of the powder increased linearly, while both sinterability and dielectric property were found to be drastically decreased with an increasing SSA. It was also revealed that the sinterability of the excessively milled BaTiO₃ ceramics could be recovered by increasing Ba content, rather than increasing glass addition. These results suggest that the sintering behavior of BaTiO₃ ceramics under the high SSA was more strongly dependent on the transient liquid phase caused by Ba addition, than the liquid phase from additional glass. It is necessary to minimize the mismatch of sintering shrinkage between dielectric ceramic and Ni inner electrode layers for the purpose of developing the ultra high-capacity multi layered ceramic condenser(MLCC). Thus, low temperature sintering of dielectric BaTiO₃ ceramic should be precedently investigated. In this work, the influence of the milling condition on sintering behavior and electrical properties of BaTiO₃ ceramics was investigated in the BaTiO₃(BT)-Mg-Dy-Mn-Ba system with borosilicate glass as a sintering agent. As milling time increased, specific surface area(SSA) of the powder increased linearly, while both sinterability and dielectric property were found to be drastically decreased with an increasing SSA. It was also revealed that the sinterability of the excessively milled BaTiO₃ ceramics could be recovered by increasing Ba content, rather than increasing glass addition. These results suggest that the sintering behavior of BaTiO₃ ceramics under the high SSA was more strongly dependent on the transient liquid phase caused by Ba addition, than the liquid phase from additional glass.

저온 소결 처리된 SnO2 전자전달층을 가진 페로브스카이트 태양전지의 물성

김호준,이용욱,오영준,김광배,송오성 대한금속·재료학회 2022 대한금속·재료학회지 Vol.60 No.7

This study investigated the photovoltaic properties and microstructure of perovskite solar cells (PSCs) with an ITO/SnO2/perovskite/HTL/Au electrode configuration, developed with varying sintering temperatures (100~200°C). The goal was to use SnO2 ink as the electron transport layer (ETL) by lowtemperature sintering. TGA-DTA analysis was conducted to determine the optimum sintering temperature of the SnO2 ink and the photovoltaic properties were examined by solar simulator analysis. To analyze the microstructure, a 3D profiler, optical microscope, and scanning electron microscopy (SEM) were used. The TGA-DTA analysis results show that SnO2 ink was effectively sintered at the low temperature of 80°C and above. As for the photovoltaic(PV) properties, the PV efficiency was approximately 15% at 120~150°C, and increased to a maximum of 17.16% at 180°C, and then fell to 12% at 200°C. The RMS value, a representation of surface roughness, of the SnO2 layer according to sintering temperature incrementally decreased, reached its lowest at 180°C, before finally increasing. The microstructure analysis showed that the perovskite layer formed on the SnO2 at a sintering temperature of 180°C had a relatively greater grain size of 402 nm and a thickness of 432 nm, thereby improving the PSC’s PV properties. These results suggest it is possible to implement a PCS with SnO2 ETL by low temperature sintering process.

CuO를 첨가한 (Ba0.5,Sr0.5)TiO3 세라믹의 소결온도와 전기적 특성의 연구

윤석우,이규탁,강이구,고중혁 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.6

The influence of CuO addition on what of the (Ba,Sr)TiO3 ceramics was studied. The sintering temperature of (Ba,Sr)TiO3 ceramics was lowered by the addition of CuO additives. The 1 - 5 wt% CuO were selected and employed as the sintering aids. Low-Temperature Co-fired Ceramic technologies are popular technologies used in the manufacture of microwave devices. In this study, crystalline and electrical properties of CuO doped (Ba,Sr)TiO3 ceramics were investigated to determine the low temperature sintering properties. The addition of CuO to (Ba,Sr)TiO3 lowered the sintering temperature from 1350℃ to 1150℃. The dependence of the sintering temperature shrinkage rate and mechanism of CuO doped (Ba,Sr)TiO3 ceramics are investigated and discussed. Also, the crystalline structure of CuO - doped (Ba,Sr)TiO3 ceramics is discussed by the X-ray diffraction (XRD) method.

저온 소결 조제에 따른 PMN-PZ-PT 후막 세라믹 특성

정명원,전대우,김진호,이영진,Jung, Myungwon,Jeon, Dae-Woo,Kim, Jin-Ho,Lee, Youngjin 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.8

Convectional PZT based piezoelectric ceramics have to sinter at high temperature about $1,200^{\circ}C$ for their suitable electrical properties. However, some issues: low temperature sintering piezoelectric ceramic composition and reliable internal electrode, have recently attracted a great deal of interest as a highly efficient multi-layered piezoelectric ceramics. In order to optimize low temperature sintering conditions of thick-film PMN-PZ-PT ceramic, it was investigated sintering and piezoelectric properties according to the change of $LiBiO_2$ contents. Thus, the superior piezoelectric properties were found at the pallet type PMN-PZ-PT optimized with low sintering processing at $925^{\circ}C$ including 7 wt% $LiBiO_2$ sintering aid. Consequentially, we successfully manufactured thick-film PMN-PZ-PT ceramics, which had superior piezoelectric and dielectric properties, with 5 wt% of $LiBiO_2$ sintering aid at temperature of $900^{\circ}C$.

Nd-Fe-B permanent magnets fabricated by low temperature sintering process

Kim, J.W.,Kim, S.H.,Song, S.Y.,Kim, Y.D. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.551 No.-

Fabrication of 13Nd-2Dy-6B-bal. Fe (at.%) sintered magnets by low temperature sintering was demonstrated, focusing on grain size control. A magnet with a density higher than 99% was successfully obtained by sintering a Nd-Fe-B powder compact at 970<SUP>o</SUP>C for 20h. The average grain size of the magnet was 5.5μm, which was similar to that of the initial powder size (5μm). Compared with a conventionally sintered specimen (1070<SUP>o</SUP>C/4h), the coercivity of the magnet increased from 1672kA/m to 1823kA/m upon low temperature sintering. Consequently, the low temperature sintering process enabled us to suppress grain growth and to distribute the grains more uniformly, which resulted in improved magnetic properties, in particular improved intrinsic coercivity. The grain-size reduction through the low temperature sintering was explained by analyzing microstructures in relation to sintering behavior.

소결온도와 B₂O₃첨가량에 따른 Mn첨가 PMN-PZT의 유전 및 압전특성의 변화

신효순,Shin Hyo-Soon 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.9

우수한 압전 특성을 나타내는 것으로 알려진 Mn 첨가 PMN-PZT의 저온소결 첨가제가 실험되었다. 저온소결 첨가제로는 B$_2$O$_3$가 사용되었고 소결온도와 B$_2$O$_3$ 첨가량의 변화가 소결성과 유전 및 압전특성의 변화에 미치는 영향을 조사하였다. B$_2$O$_3$ 첨가량과 소결온도를 변화시킨 결과 B$_2$O$_3$ 첨가량 2wt% 이하 100$0^{\circ}C$이하 조건에서 소결밀도가 증가하여 B$_2$O$_3$가 저온소결재로 작용하였다. 그러나 10$50^{\circ}C$ 이상에서는 주조성인 PMN-PZT보다 낮은 소결밀도를 나타내었다. B$_2$O$_3$ 첨가에 따른 유전상수($\varepsilon$$_{33}$ $^{T}$ )의 변화를 확인할 결과 B$_2$O$_3$ 2wt% 100$0^{\circ}C$ 조건에서 1000의 유전율을 나타내었다. B$_2$O$_3$ 첨가량이 전기-기계 결합계수(k$_{p}$ )와 압전상수(d$_{33}$ )에 큰 저하를 가져오지 않는 B$_2$O$_3$ 첨가 한계는 2wt% 이하로 나타났다. 이때, k$_{p}$ 는 약 50%, d$_{33}$ 는 약 300(${\times}$$10^{-12}$ C/N) 정도의 값을 얻을 수 있었다. B$_2$O$_3$ 첨가는 기계적 품질계수(Q$_{m}$ )의 증가를 가져왔으며 0.5wt% B$_2$O$_3$ 첨가 110$0^{\circ}C$ 소결 조건에서 1700의 품질계수를 나타내었다. 유전손실은 B$_2$O$_3$ 첨가에 따라 큰 변화 없이 0.5% 이하의 값으로 나타났다. The additive of low temperature sintering in Mn-doped PMN-PZT known as high piezoelectric materials was studied in this experiment. B$_2$O$_3$ was used for the additive of low temperature sintering. The effects of sintering temperature in dielectric, and piezoelectric properties were investigated with the amounts of B$_2$O$_3$. Sintered density was increased in comparison with no addition and under 2wt% B$_2$O$_3$ and lower sintering temperature than 100$0^{\circ}C$. Therefore, in the low sintering temperature, the densification was improved by the addition of the B$_2$O$_3$. However, the sintering density was lower than that of the main composition in the case of the sintered at over 10$50^{\circ}C$. Dielectric constant with the addition of B$_2$O$_3$ was evaluated. The dielectric constant was 1000 2 wt% of B$_2$O$_3$ and sintered at 100$0^{\circ}C$. Under 2wt% of B$_2$O$_3$, the electromechanical coupling factor and the piezoelectric constant were not so much decreased. The electromechanical coupling factor and the piezoelectric constant were 50% and 300(${\times}$10$^{-12}$ C/N) respectively. The mechanical quality factor was increased with B$_2$O$_3$. The mechanical quality factor was 1700 at 0.5wt% B$_2$O$_3$ and sintered at 110$0^{\circ}C$. Dielectric loss was less than 0.5% regardless of the amount of B$_2$O$_3$.

PNN-PZT 세라믹스의 저온 소결 및 전기적 특성 평가

이명우,김성진,윤만순,류성림,권순용,Lee, Myung-Woo,Kim, Sung-Jin,Yoon, Man-Soon,Ryu, Sung-Lim,Kweon, Soon-Yong 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.12

To fabricate a multi-layered piezoelectrics/electrodes structure, the piezoelectrics should be sintered at the temperature lower than $950^{\circ}C$ to use the silver electrode, which is cheaper than the electrodes containing noble metals such as Pd and Pt. Therefore, in this study, we modified the composition of $Pb(Zr,Ti)O_3$-based material as $(Pb_{0.98}Cd_{0.02})(Ni_{1/3}Nb_{2/3})_{0.25}Zr_{0.35}Ti_{0.4}O_3$ to lower the sintering temperature and to improve the piezoelectric properties. Small amount of $MnCO_3$, $SiO_2$, and $Pb_3O_4$ were also added to lower the sintering temperature of the ceramic. The prepared raw powders were mixed by using a ball mill for 24 hours. And then the mixed powders were calcinated for 2 hours at $800^{\circ}C$. The calcinated powders were again crushed with the ball mill for 72 hours. The final powders were pressed for making the shape of ${\emptyset}15\;mm$ disk. The disk-type samples were sintered at temperature range of $850{\sim}950^{\circ}C$. The crystal phases of the sintered specimens were perovskite structure without secondary phases. All of the measured electrical properties such as electromechanical coupling coefficients ($k_p$), mechanical quality factors ($Q_m$), and piezoelectric charge constants ($d_{33}$) were decreased with decreasing the sintering temperatures. The electrical properties measured at the sample sintered at $950^{\circ}C$ were 54% of $k_p$, 503 of $Q_m$, and 390 pC/N of $d_{33}$, respectively. These properties were considered to be fairly good for the application of multi-layered piezoelectric generators or actuators.

Low-temperature sintering behaviors in a titanium oxide–copper oxide system through two-step heat treatment

Woo Jae-Yong,Oh Kyung-Sik,Chung Tai-Joo,Lee Hyuk-Jae,백용균 한국세라믹학회 2021 한국세라믹학회지 Vol.58 No.2

The low-temperature sinterability of TiO 2 –CuO systems was examined through a two-step sintering process. The first-step heat treatment was carried out at 900 °C for either 5 min or 1 h. The subsequent second-step sintering by reheating after cooling proceeded at 800 °C for various times. Micron-sized (2 μm) powders as received were used as the starting materials. In the present system, the densification behaviors through grain-boundary diffusion were similar to those in nanocrystalline ceramics at low temperatures. The diff erence in temperature sensitivity for densification or grain growth was thus exploited to enhance densification and hinder grain growth. As a result, enhanced densification without notable grain growth was achieved after second-step sintering, as opposed to conventional sintering at 800 °C. This implies that the grain-boundary diffusion contributing to densification was more active than the grain-boundary migration at 800 °C. In this regard, the current results show a trait of activated sintering as well.