Y-TZP/Ce-TZP 구조세라믹스의 제조 및 특성연구

이종현,이윤복,김영우,오기동,박흥채 한국세라믹학회 1996 한국세라믹학회지 Vol.33 No.10

Y-TZP/Ce-TZP ceramics having relative sintered densities of>95% average grain sizes of 0.36$\mu\textrm{m}$ microhar-dness of 1150 kg/mm2 fracture strength of 390-830 MPa and toughness of 6.4-10.2 MPa$.$mm1/2 were prepared by conventional sintering of 3 mol% Y2O3-ZrO2 and 12 mol% CeO2-ZrO2 powders at 1400 and 1500$^{\circ}C$ The average grain sizes of Y-TZP/Ce-TZP ceramics were mainly governed by those of Ce-TZP. White increasing Ce-TZP content toughness increased while microhardness and fracture strength decreased. With comparing microhardness and toughness fracture strength was more sensitive on not only grain size but also other factors such as microstructural and compositional variations. The densification of Y-TZP/Ce-TZP cermaics was not greatly affected by composition and soaking time at temperature over 1400$^{\circ}C$ With increasing CE-TZP content the stability of t-ZrO2 decreased under thermal aging in air whereas increased in hydrothermal atmosphere and aqueous solution.

Y2O3와 CeO2의 첨가에 따른 Y-TZP계 세라믹스의 기계적 특성

강종봉 ( Jong Bong Kang ),정승화 ( Seung Hwa Jung ),문종수 ( Jong Soo Mun ),정기욱 ( Ki Uk Jung ) 경남대학교 신소재연구소 2009 신소재연구 Vol.21 No.-

Y-TZP계 세라믹스의 특성 및 기계적 물성을 향상시키기 위한 대표적인 첨가제로는 SiO2, TiO2, Fe2O3, Al2O3 등을 들 수 있으며, 이러한 첨가제들의 종류와 양은 Y-TZP계 세라믹스의 기계적 물성에 있어서 제조 공정 조정 변수와 더불어 중요한 역할을 한다. 본 실험에서는 Y2O3와 CeO2의 첨가가 Y-TZP세라믹스에 미치는 영향을 확인하기 위하여, 지르코니아에 안정화제인 Y2O3를 2.4~3.4 mol% 첨가하여 혼합 밀링 하였으며, CeO2의 첨가로 인한 3.2Y-TZP의 소결체에 미치는 영향에 대하여 연구하였다. 그 결과 Y2O3가 3.2 mol% 첨가된 3.2Y 시편은 1400℃에서 6.08 g/cm3의 겉보기 밀도와 1390.4 Hv의 높은 경도 값을 나타내었으며, 1300℃에서부터 정방정상으로의 상전이가 이루어졌다. 하지만 1500℃ 온도구간에서 다시 단사정상이 잔존해있음을 관찰하였다. Y2O3가 3.2 mol% 첨가된 3.2Y 시편에 CeO2를 0.l wt% 첨가 시 1350℃에서 가장 높은 1404.4 Hv의 경도와, 6.08 g/cm3의 겉보기 밀도 값을 가졌지만 1500℃에서 단사정상이 잔존해있음을 관찰하였으며, 미세구조 관찰 시 CeO2의 첨가량이 증가할수록 큰 결정립들이 관찰되었고, 이러한 결정립들이 정방정상의 임계크기 이상으로 성장하였기 때문에 단사정상이 잔존해 있는 것으로 사료되어진다. Zirconia ceramics is the excellent mechanical properties of the organic phase-moss. Because zirconia ceramics trans from tetragonal to monoclinic. This is used structural materials. The Y-TZP of ceramics are the most widely used. Typically, 3Y-TZP powder made coprecipitation is the high cost of manufacturing and highly sintering temperature than 1450℃. In this study, Powder mixed and milled of the Y2O3 and ZrO2 oxides will decrease costs. It is purpose to lowering sintering temperature and increasing mechanical properties by added Al2O3 and CeO2. 3.2Y-TZP added 0.25 wt% of Al2O3 got 99.4% of theoretical density value by 1350℃ sintered. 32Y-TZP added 0.25 wt% Al2O3 and 0.1 wt% CeO2 got the best hardness (1412.1 Hv) by 1400℃ sintered.

Effect of Conditioning Methods on the Shear Bond Strength of Veneering composite on Zirconia Ceramic

남현석,송광엽,안승근,박주미 대한턱관절교합학회 2010 구강회복응용과학지 Vol.26 No.3

The purpose of this study is to know whether Yttrium-stabilized-tetragonal -zirconia-polycrystal(Y-TZP ceramic) gets enough shear bond strength for clinical uses by applying veneering composite resin through surface treatment on it and finally to compare it with the case of applying veneering porcelain. LavaTM zirconia frameworks(3M ESPE, Seefeld, Germany) were prepared. Group P was manufactured with LavaTM Ceram(3M ESPE, Seefeld, Germany) in cylindrical shape which has 4mm diameter, 5mm height. Group ZSR disposed sandblasting and applied silane, bonding agent and after that indirect composite resin was applied. Group ZRR got tribochemical coating by RocatecTM system(3M ESPE. Seefeld, Germany) and treated silane. Finally Group ZPR took the same treatment and applied LavaTM Ceram in the size of 0.3-0.5mm height. After burning out, sandblasting, HF and silane was applied. And then, indirect composite resin was applied. 1000 cycle thermocycling was performed in 5-55℃ and shear bond strength was measured. There were no significant differences between combining veneering porcelain to Y-TZP ceramic group and combining veneering resin to Y-TZP ceramic group in the aspect of shear bond strength (p>.05).

저온열화에 따른 치과용 지르코니아의 전자현미경 관찰 연구

이정환,주규지,안재석,Lee, Jung-Hwan,Joo, Kyu-Ji,Ahn, Jae-Seok 대한치과기공학회 2011 대한치과기공학회지 Vol.33 No.1

Purpose: Thy yttria tetragonal zirconia polycrystalline(Y-TZP) is a good structural ceramic for dental restoration. But it have a problem that delamination of veneering ceramic from the Y-TZP core materials. The problem generally occur at the interface, thus this study was conducted to evaluate the interface of Y-TZP using scanning electron microscopy(SEM). Methods: To investigate this aspect, high-resolution SEM observations were made of polished and etched (HF content gel) cross-sections of the interface area. Dry and moist veneering porcelain powders were built up on the zirconia base. Results: The extent of this surface faceting is dependent upon the moisture content of the porcelain powder and the firing temperature. More moisture and higher final heating temperature accelerates the observed faceting of the Y-TZP grains at the interface to the veneering ceramic. Conclusion: These changes of the Y-TZP grains indicate that destabilization of the tetragonal phase of zirconia occurs at the interface during veneering with ceramic. It may result in a reduction of the stability of the zirconia and interface.

3Y-TZP/WC 복합체의 소결 방식에 따른 특성비교

남민수,최재형,남산,김성원 한국분말재료학회 2022 한국분말재료학회지 (KPMI) Vol.29 No.5

3Y-TZP ceramics obtained by doping 3 mol.% of Y2O3 to ZrO2 to stabilize the phase transition are widely used in the engineering ceramic industry due to their excellent mechanical properties such as high strength, fracture toughness, and wear resistance. An additional increase in mechanical properties is possible by manufacturing a composite in which a high-hardness material such as oxide or carbide is added to the 3Y-TZP matrix. In this study, composite powder was prepared by dispersing a designated percentage of WC in the 3Y-TZP matrix, and the results were compared after manufacturing the composite using the different processes of spark plasma sintering and HP. The difference between the densification behavior and porosity with the process mechanism was investigated. The correlation between the process conditions and phase formation was examined based on the crystalline phase formation behavior. Changes to the microstructure according to the process conditions were compared using field-emission scanning electron microscopy. The toughness-strengthening mechanism of the composite with densification and phase formation was also investigated.

알루미나 분산이 지르코니아 복합체의 미세구조와 파괴인성에 미치는 영향

김민정,이종국,이은구 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.2

고 인성의 Y-TZP 세라믹스에 0.5$\mu\textrm{m}$, 1$\mu\textrm{m}$, 3$\mu\textrm{m}$ 알루미나를 20 vol% 분산시킨 후 입자크기에 따른 미세구조와 파괴인성 변화를 관찰하였다. 알루미나 분산 지르코니아 세라믹스는 98% 이상의 높은 밀도를 나타내었으며, 알루미나 입자가 균질하게 분산된 치말한 미세구조를 나타내었다. 알루미나를 분산시킨 시편에서는 순수 지르코니아에 비하면 파괴인성이 증가하였고, 분산시킨 알루미나 입자크기가 증가함에 따라 파괴인성이 증가하였다. 파괴인성은 분산된 알루미나 입자크기가 3$\mu\textrm{m}$일 때 3Y-TZP는 8.6 MPa.m$^{1}$2/에서 12.5 MPa.m$^{1}$2/로, 2Y-TZP는 13.5 MPa.m$^{1}$2/에서 18.9 MPa.m$^{1}$2/로 각각 증가하였는데, 이는 파괴시 알루미나 입자에 의한 균열편향 효과로 인하여 균열길이가 증가하기 때문이었다.

수소분위기에서 소결한 Y-TZP 세라믹스의 미세구조 및 등온 상전이 거동

이종국,이현규 조선대학교 생산기술연구소 1993 生産技術硏究 Vol.15 No.2

2Y-TZP and 3Y-TZP ceramics were prepared by sintering at 1,450℃ in hydrogen atmosphere for a time of 0.5 to 20h. Specimens surfaces show the black color due to the reduction of Zr^(4+) to Zr^(3+) during sintering. In case of specimen sintered for 20h, a large grain and loosening microstructure was developed on the surface during sintering and therefore the monoclinic phase of 45~80% was existed on surface. The tetragonal phase of 2Y-TZP ceramics was isothermally transformed to monoclinic in rapid during aging at 250℃ and its behaviour was independent on the grain size. But in case of 3Y-TZP ceramics, its behaviour was greatly dependent of grain size on the specimensurface. Isothermally transformed specimens were contained the many cracks formed by volume expansion on transformation.

Effect of cement type on the color attributes of a zirconia ceramic

Farhad Tabatabaian,Maliheh Habib Khodaei,Mahshid Namdari,Minoo Mahshid 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.6

PURPOSE This in vitro study evaluated the effects of four different cements on the color attributes of a zirconia ceramic. MATERIALS AND METHODS 40 zirconia ceramic disk specimens (0.5 mm thickness, 10 mm diameter, 0.1 mm cement space) were fabricated by a computer-aided design and computer-aided manufacturing system. The specimens were divided into 4 groups of 10 specimens and cemented to composite substrates using four different cements including: Glass Ionomer, Panavia F2.0, Zinc Phosphate, and TempBond. The L*, a*, and b* color attributes of the specimens were measured before and after cementation by a spectrophotometer. Additionally, ΔE values were measured to determine color changes for the groups and then compared with the perceptional threshold of ΔE = 3.3. Repeated Measures ANOVA, Tukey Post Hoc, Bonferroni, One-way ANOVA, and One-sample t-test tests were used to analyze the data. All tests were carried out at the 0.05 level of significance. RESULTS Statistically significant differences were detected in the ΔE values for Zinc Phosphate (P<.0001) and TempBond (P<.0001) groups. However, there were no statistically significant differences in this respect for Glass Ionomer (P=.99) and Panavia F2.0 (P=1) groups. The means and standard deviations of the ΔE values for Glass Ionomer, Panavia F2.0, Zinc Phosphate, and Tempbond groups were 2.11±0.66, 0.94±0.39, 5.77±0.83, and 7.50±1.16 Unit, respectively. CONCLUSION Within the limitations of this study, it was concluded that Zinc Phosphate and Tempbond cements affected the color attributes of the tested zirconia ceramic beyond the perceptional threshold. However, Glass Ionomer and Panavia F2.0 cements created acceptable color changes.

Effect of the amount of thickness reduction on color and translucency of dental monolithic zirconia ceramic

Hee-Kyung Kim,Sung-Hun Kim,Jai-Bong Lee,Jung-Suk Han,In-Sung Yeo,Seung-Ryong Ha 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.1

PURPOSE This study investigated the effect of amount of thickness reduction on color and translucency of dental monolithic zirconia ceramics. MATERIALS AND METHODS One-hundred sixty-five monolithic zirconia specimens (16.3 mm × 16.3 mm × 2.0 mm) were divided into 5 groups (Group I to V) according to the number of A2-coloring liquid applications. Each group was then divided into 11 subgroups by reducing the thickness up to 1.0 mm in 0.1-mm increments (Subgroup 0 to 10, n=3). Colors and spectral distributions were measured according to CIELAB on a reflection spectrophotometer. All measurements were performed on five different areas of each specimen. Color difference (ΔE*ab) and translucency parameter (TP) were calculated. Data were analyzed using one-way ANOVA and multiple comparison Scheffé test (α=.05). RESULTS There were significant differences in CIE L* between Subgroup 0 and other subgroups in all groups. CIE a* increased (0.52<R2<0.73), while CIE b* decreased (0.00<R2<0.74) in all groups with increasing thickness reduction. Perceptible color differences (ΔE* ab>3.7) were obtained between Subgroup 0 and other subgroups. TP values generally increased as the thickness reduction increased in all groups (R2>0.89, P<.001). CONCLUSION Increasing thickness reduction reduces lightness and increases a reddish, bluish appearance, and translucency of monolithic zirconia ceramics

Ageing assessment of zirconia implant prostheses by three different quantitative assessment techniques

Phyu Phyu Kyaw,Pong Pongprueksa,Warangkana Anuchitolarn,Krongkarn Sirinukunwatta,Kallaya Suputtamongkol 대한치과보철학회 2019 The Journal of Advanced Prosthodontics Vol.11 No.5

PURPOSE. To evaluate the influence of cyclic loading on phase transformation of zirconia abutments and to compare the effectiveness of three different quantitative ageing assessment techniques. MATERIALS AND METHODS. Thirty two Y-TZP prostheses fabricated from two brands, InCoris ZI and Ceramill ZI, were cemented to titanium bases and equally divided into two subgroups (n=8): control group without any treatment and aged group with cyclic loading between 20 N and 98 N for 100,000 cycles at 4 Hz in distilled water at 37°C. The tetragonal-to-monoclinic phase transformation was assessed by (i) conventional x-ray diffraction (XRD), (ii) micro x-ray diffraction (μXRD), and (iii) micro-Raman spectroscopy. The monoclinic-phase fractions (M%) were compared by two-way ANOVA. RESULTS. InCoris Zi presented significantly higher M% than Ceramill Zi in both control and aged groups (P<.001). Both materials exhibited significant phase transformation with monoclinicphase of 1 to 3% more in aged groups than controls for all thre e assessment techniques. The comparable M% was quantified by both μXRD and XRD. The highest M% was assessed with micro-Raman. CONCLUSION. Cyclic loading produced significant phase transformation in tested Y-TZP prostheses. The micro-Raman spectroscopy could be used as an alternative to XRD and μXRD.