高压喷涂偶联剂对氧化锆表面微观形貌及粘接效果的影响

探讨使用不同压力气体喷涂偶联剂对氧化锆表面形貌及氧化锆-树脂粘合剂粘接强度的影响。烧结、喷砂后的氧化锆瓷片,按偶联剂种类(CP;ZP)和喷涂气体压力的高低(L 0.1 MPa;H 0.3 MPa)随机分为CPL、CPH、ZPL、ZPH 4个实验组及无偶联剂处理的对照组NP(n=15)。各组处理后的氧化锆瓷片利用激光共聚焦显微镜观察5组氧化锆表面形貌并测量粗糙度,并与树脂粘合剂(SA luting)粘接并测试微剪切强度。激光共聚焦显微镜观察显示,CPL和ZPL组中氧化锆表面光滑平坦,CPH、ZPH组的氧化锆表面则保留了高低不平的微观形貌,平均粗糙度明显高于低压气体喷涂组。CPH组的微剪切粘接强度最高(24.82±7.34)MPa,其次为CPL组(17.93±1.53)MPa、ZPL组(15.67±3.39)MPa和ZPH组(9.59±5.97)MPa,对照组最低(8.77±3.12)MPa。偶联剂喷涂压力显著影响氧化锆-树脂粘合剂的粘接强度。,,     

Effect of different ceramic primers on shear bond strength of resin-modified glass ionomer cement to zirconia

Purpose: This study evaluated and compared the effect of different ceramic primers on the shear bond strength of RMGIC to zirconia with and without air-particle abrasion. Material and Methods: 120 zirconia square specimens (5 mm × 5 mm × 2 mm) were fabricated. Half of the specimens were air-particle abraded (A) and the other half were left untreated (NA). Both groups were further divided into six subgroups (n = 10). Composite cylinders (2.9 mm × 3.0 mm) were fabricated and bonded to the zirconia samples with RMGIC (RelyX Plus) after different priming methods: no ceramic primer (group NS); Z-Prime (group ZP); Clearfil ceramic primer (group CP); cleaned with Ivoclean then Monobond plus (IV/MS); Monobond plus (group MS); and Rely X ceramic primer (group RX). Specimens were rinsed, stored in distilled water, and thermocycled (TC) for 10,000 cycles between 5 and 60 °C with a dwell time of 15s. Data were analyzed with two-way ANOVA and the Tukey–Kramer method test (a = .05). Results: air-particle abrasion significantly affected bond strength of RMGIC to zirconia regardless of the primer used (p < 0.001 for all primers and the control). After TC, A-ZP (11.1 ± 0.6 MPa), A-CP (11.9 ± 0.6 MPa), and A-MS (11.9 ± 0.5 MPa) revealed the highest shear bond strength values, while NA-NS (2.9 ± 0.3 MPa) and NA-RX (4.7 ± 0.5 MPa) had the lowest. Failure modes were primarily adhesive. Conclusion: air-particle abrasion with aluminum oxide and application of MDP-based ceramic primers provide the highest bond strength of RMGIC to zirconia.     

Fracture strength and fractographic analysis of zirconia copings treated with four experimental silane primers

This study evaluated and compared the effect of new four experimental silane coupling agents on the fracture strength of zirconia copings. The findings were supported with fractographic and finite element analyses. All together 125 zirconia copings with a ?wall thickness of 0.6?mm were fabricated on identical nickel-chromium master dies and then divided randomly into five groups (n?=?25). Four test groups were prepared according the experimental silane primer (labeled: OIWA1, OIWA2, OIWA3 and OIWA4) ?and one control group without silanization. The silane monomers used were: ?3-methacryloxypropyltrimethoxysilane (in OIWA1), ?3-acryloxypropyltrimethoxysilane (in OIWA2), ?3-?isocyanatopropyltriethoxysilane (in OIWA3) and styrylethyltrimethoxysilane (in OIWA4). Tribochemical sandblasting (silica-coating) treatment was performed to the inner surface of the copings in the ?test groups. All the specimens were silanized at the inner surfaces of the zirconia copings. Self-?adhesive universal resin cement was used to cement the copings to ?the underlying master die. Zirconia copings were vertically loaded on the ?cusp ?area until the first crack failure was occurred using Precision Universal Tester ?at a ?constant crosshead speed of 1?mm/min. Then, the machine ?was manually controlled to cause more failure ?to further determine the texture of fracture. Three dimensional finite element analysis and fractography were performed to support the fracture strength findings. Based on the finite element analysis results, zirconia silanized with ?3-acryloyloxypropyltrimethoxysilane showed the highest fracture strength with a mean of ?963.75??N (SD 4.5?N), while zirconia copings silanized with ?3-methacryloyloxypropyltrimethoxysilane showed a mean fracture strength value of ?925.65?N (SD 2.4?N). Styrylethyltrimethoxysilane-silanised zirconia showed mean fracture strength of 895.95?N (SD 3.5?N). Adding silane coupling agents to the resin-zirconia interface increased the fracture strengths significantly (ANOVA, p?<?0.05). Silanization with four new experimental silane primers in vitro produced significantly ?greater fracture strength than the control group not treated with the test silane.?     

Adhesion to zirconia as a function of primers/silane coupling agents,luting cement types,aging and test methods

This study evaluated the adhesion of resin cements to zirconia with different primers/silane coupling agents using two test methods with and without aging. Zirconia discs (Cercon) (N = 900, n = 15 per group) were ground finished to 2000 grit silicone carbide and randomly divided into seven groups: (a) C: No treatment (Control), (b) SG: Signum, (c) CL: Clearfil Ceramic Primer, (d) AP: Alloy Primer, (e) Monobond Plus, (f) ES-R: ESPE-Sil after Rocatec and (g) ES-C: ESPE-Sil after CoJet. Methacrylate (Variolink II-VL) and MDP based (Panavia F2.0-PN) dual-polymerized and self-adhesive resin cements (RelyX Unicem-RX) were adhered and polymerized accordingly. The specimens were further randomly divided into two groups to be tested after (a) 24-h dry storage at 37 °C and (b) thermocycling (×5000, 5–55 °C). Macroshear (MSB) and macrotensile bond tests (MTB) were conducted in an universal testing machine (crosshead speed: 1 mm/min) and failure types were analyzed after debonding. Data were analyzed using Univariate analysis and Tukey’s tests (α = 0.05). Two-parameter Weibull modulus, scale (m) and shape (0) were calculated. While primer/silane (p < 0.001), cement type (p < 0.001) and aging (p < 0.001) significantly affected the bond results, test method did not show significant difference (p = 0.237). In MSB test, Weilbul moduli were more favorable for MP-VL (4.2) and AP-PN (6) combinations and after aging for MP-VL (4.2) and AP-PN (5.66). In MTB test, after aging, Weilbul moduli were more favorable for AP-PN (5.41). Bond strength results mostly decreased with SG (24–92%) after aging. Cohesive failures in the cement were more frequent with PN (252) compared to VL (83).     

Influence of zirconia surface treatments on resin cement bonding and phase transformation

It evaluated the effects of different zirconia surface treatments on the bond strength of a resin cement to Y-TZP (yttria-stabilized tetragonal zirconia) ceramics, as well as their phase-transformations. 75 blocks (5 mm × 5 mm × 4 mm) of Y-TZP were assigned into five groups (n = 15): (tribochemical silica coating - TBS) zirconia surface was abraded by silica coated alumina particles followed by silanization; (GLZ₁) zirconia surface received the application of a thin layer of low-fusing porcelain glaze, followed by hydrofluoric acid (HF) etching for 1 min; (GLZ₅) glaze application + HF etching by 5 min; (GLZ₁₀) glaze application + HF etching by 10 min; (GLZ₁₅) glaze application + HF etching by 15 min. After etching, all the specimens were washed, dried and silanized. Cylinders of composites (diameter: 3.25 mm; height: 3 mm) were cemented to the Y-TZP blocks using a resin cement. All the specimens were subjected to aging (10,000 thermal cycles and 90 days storage), tested under shear conditions, and finally analyzed by a stereomicroscope (failure analysis). In addition, we also performed topographical and phase transformation analyses of the treated zirconia surfaces. The TBS group presented the highest bond strength value (23.34 MPa). The glazed groups presented low bond values and high prevalences of pretest failures. X-ray diffraction analysis showed a phase transformation for the TBS group (13.14%); however, there was no clear phase change observed for the GLZ groups. From our results, we concluded that tribochemical silica coating is the main Y-TZP surface conditioning for resin bond improvements.     

Effect of hot-etching treatment on shear bond strength of zirconia to resin cement

ABSTRACT

The purpose of this study was to evaluate the effect of hot-etching surface treatment on the shear bond strength between zirconia ceramics and resin cement. Ceramic cylinders were divided randomly into 10 groups (n?=?10) according to different surface treatments (blank control; airborne particle abrasion; hot-etching for 10?min; hot-etching for 30?min; hot-etching for 60?min) and whether or not performed thermal cycling fatigue test. Flat enamel surfaces, were prepared from human permanent incisors and were bonded to the zirconia discs. All specimens were subjected to shear bond strength test by a universal testing machine. All data were statistically analysed using one-way analysis of variance and multiple comparison least significant difference tests (α?=?0.05). Hot-etching for 60?min treatment produced higher bond strengths than the other treatment. Surface treatment of zirconia with a hot-etching solution might enhance surface roughness and bond strength between zirconia and resin cement.     

Effect of thermal cycling and low pressure sandblasting on the bond strength of a self-adhesive cement to Y-TZP zirconia

The aim of this investigation was to assess the influence of several surface treatments on the shear bond strength (SBS) of a self-adhesive resin cement containing 10-methacryloxydecyl-dihydrogenphosphate monomer to densely sintered zirconia ceramic, before and after thermal cycles. Hundred densely sintered zirconia cylinders were divided into five groups (n = 20). Each of them received a different surface treatment: (1) control [No_T], with the zirconia surface unconditioned, (2) low pressure air abrasion [Sand_S], (50 μm, 1 bar), (3) standardized air abrasion [Sand_H], (50 μm, 2.8 bar), (4) standardized Rocatec? Plus (silica-coated alumina oxide) air abrasion (2.8 bar) and silanization [Roc_H], (5) low pressure Rocatec? Plus (silica-coated alumina oxide) air abrasion (1 bar) and silanization [Roc_S]. Five more surface-treated specimens were addressed to scanning electron microscope for qualitative observations. After specimen fabrication, subgroups of 10 bonded samples were stored in water either for 24 h (T1) or subjected to 5000 thermal cycles (T2); SBSs were determined with a universal testing machine at a crosshead speed of 1 mm/min. At T1, mean SBSs (MPa) obtained for the examined groups were: [Sand_H] 16.24 ± 2.95; [Sand_S] 16.01 ± 2.68; [Roc_H] 17.17 ± 1.64; [Roc_S] 15.92 ± 1.99. All surface treatments positively affected (p < 0.05) the initial self-adhesive cement adhesion to zirconia with respect to No_T (13.29 MPa). Artificial aging decreased the bond strength in all test groups significantly, but no spontaneous debonding was observed in [No_T]: at T2, SBS values ranged from 7.76 ± 2.37 (No_T) to 8.89 ± 1.74 (Sand_S), with no statistically significant difference between groups (p = 0.5293). Both air abrasion with alumina oxide and Rocatec? universal bonding system, used with hard or low air pressure, produced comparable effects on cement–zirconia interface before and after thermal cycles. After artificial aging, minimal differences in bond strength values between sandblasted and control groups were not of statistical significance.     

Enhancement of ionic conductivity and thermal stability of CaO-stabilised zirconia (CSZ) with MgO addition by scavenging effects

The effects of magnesia (MgO) addition on the ionic conductivity and thermal stability of CaO-stabilised zirconia (CSZ) was investigated by structural and morphological analysis. MgO was added to CSZ using a solid-state reaction, and a secondary phase was not observed via XRD of all specimens sintered at 1600°C. However, Mg₂SiO₄ and Mg-rich phases were detected in the microstructure of CSZ doped with 5 and 10?mol-% MgO, respectively. Ionic conductivity increased with an increase in MgO content, and CSZ doped with 5?mol-% MgO exhibited a maximum value of 0.819?S?cm^?1 measured at 1500°C due to the scavenging of Si impurities. The thermal diffusivity increased from 0.517 (CSZ) to 0.649?mm^2?s^?1 (5?mol-% doped CSZ), and the thermal expansion coefficient of 0.5?mol-% doped CSZ was maximal at 9.855?μm/m°C. The value of mol-% doped CSZ decreased to 8.937?μm/m°C as it was affected by the Mg–Si phase formation.     

Effect of monolithic zirconia on the degree of conversion of two resin cements analyzed by FT-IR/ATR spectroscopy

Objective: This study aimed to evaluate the degree of conversion (DC) of two different resin cements polymerized under the monolithic zirconia specimens in different thicknesses and colors.

Material and methods: Partially stabilized monolithic zirconia blocks (inCoris TZI) were cut into three different thicknesses (0.5, 1.0, and 2.0 mm) and the specimens were divided into four color groups (A1, A2, A3, and A4). The light transmittance of each specimen was measured. Panavia F 2.0 or Variolink N resin cement was applied into teflon mold and irradiated using the light emitting diode curing unit for 20 s under monolithic zirconia specimen (n = 10). The resin cement specimens were stored at room temperature under dry conditions. The DC of each specimen was measured by Fourier transform infrared-attenuated total reflection (FT-IR/ATR) spectroscopy after the 1st and 10th day. Data were analyzed with two-way analysis of variance (ANOVA), two-way repeated measures ANOVA, three-way repeated measures ANOVA, and the Tukey least significant difference (LSD) tests (α = 0.05).

Results: The light-cure resin cement groups showed higher DC than the dual-cure resin cement groups (p < 0.05). The DC of both resin cements reduced with an increase in the thickness and darkening of the color of monolithic zirconia specimens. There was a statistically meaningful increase in the 10th-day values for dual-cure resin cement (p < 0.05), whereas there were no significant differences between the 1st- and 10th-day values for light-cure resin cement (p > 0.05).

Conclusion: The use of light-cure resin cement can be suggested for the luting of monolithic zirconia restorations.     

添加氧化锆对钢渣微晶玻璃显微结构的影响

采用熔融法制备微晶玻璃材料,探讨了钢渣微晶玻璃中引入ZrO2对其显微结构以及性能的影响。用X衍射仪和扫描电镜分析了微晶玻璃的主晶相和显微结构。实验结果表明:引入质量分数为1%的ZrO2时,微晶玻璃的晶粒最小,抗弯强度最大;当ZrO2的添加量进一步增多,晶粒无法发育完全且晶相含量下降,导致微晶玻璃的抗弯强度降低。在该钢渣微晶玻璃中,ZrO2最佳添加量的质量分数为1%。     

Investigation on the phase stability of yttria-stabilized zirconia electrolytes for high-temperature electrochemical application

For the Fundamental studies on the phase stability of YSZ, we tried to approach the detailed influences of practical conditions through various hypotheses. The phase stability of cubic and tetragonal yttria-stabilized zirconia (YSZ) was studied in the specific electrochemical conditions of current loading and molten salt flux. The degradation of electrochemical performance in the cubic phase occurred more easily than in the tetragonal phase because of yttrium elution in the lattice. The fully stabilized cubic phase showed high electrical performance as an oxide ion-conducting electrolyte, but phase decomposition occurred more easily under applied currents or chemical loading conditions than for the partially stabilized tetragonal phase. When YSZ reacted with a molten salt fluoride flux in solid oxide membrane (SOM) processing, which is used for direct metal reduction, and high-temperature electrolysis in the molten salt, the electrical conductivity of cubic YSZ was decreased by ~37%, while that of tetragonal YSZ showed no change. Our findings have important implications for the use of YSZ as an oxygen conductor in various electrochemical devices.     

Optical properties of gadolinia-doped cubic yttria stabilized zirconia single crystals

Cubic zirconia single crystals stabilized with yttria and doped with Gd₂O₃ (0.10–5.00 mol%) were prepared by the optical floating zone method, and characterized by a combination of X-ray diffraction (XRD), and Raman, electron paramagnetic resonance (EPR), ultraviolet–visible (UV–Vis), photoluminescence excitation (PLE) and photoluminescence (PL) spectroscopic techniques. XRD and Raman spectroscopy showed that the crystal samples were all in the cubic phase, whereas the ceramic sample consisted of a mixture of monoclinic and cubic phases. The absorption spectrum showed four peaks at 245, 273, 308, and 314 nm in the ultraviolet region, and the optical band gap differed between samples with ≤3.00 mol% and those with >3.00 mol% Gd₂O₃. The emission spectrum showed a weak peak at 308 nm and a strong peak at 314 nm, which are attributed to the ⁶P_5/2 → ⁸S_7/2 and ⁶P_7/2 → ⁸S_7/2 transitions of Gd³⁺, respectively. The intensities of the peaks in the excitation and emission spectra increased with Gd³⁺ concentration, reached a maximum at 2.00 mol%, then decreased with higher concentrations. This quenching is considered to be the result of the electric dipole-dipole interactions, and this interpretation is supported by the Gd³⁺ EPR spectra, which showed progressive broadening with increasing Gd³⁺ concentration throughout the concentration range investigated.     

Optimisation on the stability of CaO-doped partially stabilised zirconia by microwave heating

Partially stabilised zirconia has advantages for the applications in the metallurgical processes which have special requirements in corrosion resistance and high-temperature performance. In the present work, controllable microwave heating was used for the uniform thermal field and consequent microstructure improvement to further improve the stability of partially stabilised zirconia, which was 88.14% prepared by electric arc melting. Analyses including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (Raman) were used to study the effect of temperature change on the phase composition and structure of the samples. After heating at temperatures of 900 °C, 1000 °C, 1100 °C, 1200 °C and 1300 °C for 1h, the stabilities of the heated product were 88.51%, 95.02%, 95.17%, 96.31% and 97.64%, respectively. From the phase transformations based on the experimental results, the discussion indicates that the martensitic transformation temperature of zirconia from m-ZrO₂ to t-ZrO₂ during the heating stage was reduced under the radiation of microwave energy.     

Dual cure (UV/thermal) primers for composite substrates—Effect of surface treatment and primer composition on adhesion

It can be concluded by the study of UV primer formulations on sheet molding compound (SMC) substrates that all studied formulation parameters affect adhesion. Moreover, the dual cure approach can result in acceptable adhesion of UV primers on SMC substrates if the coating procedure and composition are well designed. Adhesion of UV cure primers as determined by the cross-cut test is significantly improved in formulations containing solvent. This is a result of enhanced wetting and interaction of the solvent with the SMC substrate, confirmed by contact angle and gravimetric swelling studies. Furthermore, sanded SMC surfaces demonstrated superior UV primer adhesion. This results from the increased surface area of the topography, confirmed by CSLM and the exposure of more oxygen moieties such as pigments and silanols at the air-substrate interface as confirmed by AFM and XPS. The UV films have a higher modulus with increasing resin functionality and resulting cross-link density which correlated with reduced adhesion in formulations without an added isocyanate functional UV monomer. This indicates that cure shrinkage may play a role in the adhesion of UV cure primers and will be investigated further. Also, the added adhesion that an isocyanate functional UV monomer provides results in a significant increase in the glass transition temperature (T_g) giving a glassier film at room temperature.     

Effect of zirconia particle size on the properties of alumina-spinel castables

The industrial application of alumina-spinel refractory castables has crucial requirements on the service performance. Thus, the effects of different sized desilicated zirconia particles on the castables microstructure, thermal-mechanical properties and high temperature elastic modulus have been investigated. The zirconia particle sizes were varied from 1000 µm to 2.5 µm (d₅₀). It was observed that the finer (below 88 µm) zirconia particles were beneficial to improve the cold modulus of rupture (CMOR) and the hot modulus of rupture (HMOR), but could not effectively enhance the thermal shock resistance. Fine zirconia particles can homogeneously disperse in the matrix and significantly promote the sintering process. Accompanied with the phase transformation of zirconia, both the high density of matrix cracks and the strong ceramic bonding (between the coarse grains and the matrix) were found in the refractory castables, which was responsible for an increase of CMOR. However, the binding characteristic could also give rise to the high stored elastic energy that was adverse to the thermal shock resistance, and the excessive amount of preexisting matrix cracks could induce more microdamage during the thermal shock. Additionally, it was proposed that the second-phase dispersion reinforcement and the highly ceramics bonding resulted in the superior HMOR when introducing fine ZrO₂ particles.     

新型橡塑硫化助剂的合成

以九水硫化钠、硫粉、γ-氯丙基三乙氧基硅烷为原料,甲苯、乙醇作溶剂,合成了双-(γ-三乙氧基硅丙基)二硫化物。讨论了反应物比例、溶剂用量、反应温度和时间等因素对产率的影响。结果表明,最佳工艺条件:硫与九水硫化钠的物质的量比为1.05:1,甲苯与九水硫化钠的物质的量比为36:1,γ-氯丙基三乙氧基硅烷与过硫化钠的物质的量比为2.1:1,无水乙醇与过硫化钠的物质的量比为5.0:1,反应温度为80℃,反应时间为4 h。最终制得的产品外观为淡黄色,类乙醇香味,产率为95.63%,含硫量达13.8%,产品贮存时间长。     

Effects of sandblasting distance and angles on resin cement bonding to zirconia and titanium

ObjectivesThe aim of this study was to evaluate effects of sandblasting distance and angles resin to zirconia and titanium bonding.MethodsDensely sintered zirconia and cp2 titanium specimens were prepared and randomly divided into groups, and then sandblasted with various distance (5 mm, 10 mm and 15 mm) and angles (45°, 60°, 75° and 90°). After surface treatment, each specimen surface underwent a silane primer application (RelyX, 3M ESPE), followed by bonding of a resin cement (RelyX Unicem Aplicap, 3M ESPE). Then, each cylindrical resin stub (diameter 3.6 mm×2 mm) underwent a shear adhesive (bond) strength test and surface roughness evaluation. SEM evaluation and EDX analysis were used to observe surface properties of both zirconia and titanium samples. Results were statistically analyzed using analysis of variance (ANOVA) and Turkey test (α=0.05).ResultsSurface roughness showed a significant difference amongst the different distances and angles for both the zirconia and titanium materials and these changes in surface roughness were evident in the SEM imaging photos. As for the adhesive strength, there was a significant difference in the adhesive strength for the titanium and zirconia with different angles. In general, 75° gives the best results although this is not significantly different from 90°. However, no significant difference was observed in changes of sandblasting distance for both materials. EDX analysis at the surface revealed elements carbon, oxygen, silicon, aluminum, and zirconia on the surface.ConclusionsSandblasting at various distance and angles contributes differences in surface roughness when it comes to both zirconia and titanium materials. Despite both 75° or 90° sandblasting angle could yield a sufficiently high adhesive strength for resin to titanium or zirconia bonding, sandblasting at 75° seems to be optimal to increase the adhesive strength.     

Effects of manganese oxide addition and reductive atmosphere annealing on the phase stability and microstructure of yttria stabilized zirconia

The effects of Mn₃O₄ addition and reductive atmosphere (N₂:H₂ = 97:3) annealing on the microstructure and phase stability of yttria stabilized zirconia (YSZ) ceramics during sintering at 1500 °C for 3 h in air and subsequent annealing in a reductive atmosphere were investigated. Mn₃O₄ added 6 mol% YSZ (6YSZ) and 10 mol% YSZ (10YSZ) ceramics were prepared via the conventional solid-state reaction processes. The X-ray diffraction results showed that a single cubic phase of ZrO₂ was obtained in 1 mol% Mn₃O₄ added 6YSZ ceramic at a sintering temperature of 1500 °C for 3 h. A trace amount of monoclinic ZrO₂ phases were observed for 1 mol% Mn₃O₄ added 6YSZ ceramics after annealing at 1300 °C for 60 cycles in a reductive atmosphere by transmission electron microscopy. Furthermore, a single cubic ZrO₂ phase existed stably as Mn₃O₄ added 10YSZ ceramics was annealed at 1300 °C for 60 cycles in reductive atmosphere.     

Effect of optical basicity on the stability of yttria‐stabilized zirconia in contact with molten oxy‐fluoride flux

Solid oxide membrane (SOM) electrolysis process can produce high‐purity silicon from SiO₂ dissolved in molten oxy‐fluoride flux at elevated temperatures. Yttria‐stabilized zirconia (YSZ), the preferred material for the oxygen‐conducting membrane for this application, is found to degrade over time upon exposure to the silica‐containing molten oxy‐fluoride flux. This YSZ degradation is caused by the acidity of the dissolved silica, especially when the optical basicity of the molten flux is lower than that of the yttria present in the YSZ membrane. To counteract this mismatch, the addition of CaO, a basic oxide, to the flux can adjust the optical basicity of the flux and successfully mitigate the YSZ membrane degradation. The detailed correlation between the rate of YSZ membrane degradation and the optical basicity of the flux is investigated by systematically testing a series of flux compositions. It is found that as the oxide optical basicity in the flux approaches that of the yttria in the YSZ, the degradation of the YSZ membrane is mitigated and essentially vanishes when the flux acidity with respected to the yttria is neutralized. This approach provides a guideline for eliminating membrane degradation during the production of silicon using the SOM electrolysis process.     

Microstructure and thermal properties of nanostructured gadolinia doped yttria-stabilized zirconia thermal barrier coatings produced by air plasma spraying

In this article, the nanostructured 2 mol% Gd₂O₃-4.5 mol% Y₂O₃-ZrO₂(2GdYSZ) coating was developed by the atmospheric plasma spraying technique. And the microstructure and thermal properties of plasma-sprayed 2GdYSZ coating were investigated. The result from the investigation indicates that the as-sprayed coating is characterized by typical microstructure consisting of melted zones, nano-zones, splats, nano-pores, high-volume spheroidal pores and micro-cracks. The 2GdYSZ coating shows a lower resistance to destabilization of the metastable tetragonal (t′) phase compared to the yttria stabilized zirconia(YSZ). The thermal diffusivity and thermal conductivity of the nano-2GdYSZ coating at room temperature are 0.431 mm² s⁻¹ and 1.042 W/m K, respectively. Addition of gadolinia to the nano-YSZ can significantly reduce the thermal conductivity compared to the nano-YSZ and the conventional YSZ. The reduction is mainly attributed to the synergetic effect of gadolinia doping along with nanostructure.