Dielectric Properties of Alkoxy-Derived BaTiO3 Films on LaNiO3/Pt/TiOx/Si(100)
BaTiO3 films with higher degrees of (100) orientation were deposited using both of the heterogeneous LaNiO3 nucleation layer and homogeneous BaTiO3 buffer layer. The microstructure and dielectric properties are characterized. The temperature dependence of the dielectric properties is additionally discussed. The alkoxy-derived 1-mum thick BaTiO3 had the unique microstructure and showed predominant (100) orientation. The film showed ferroelectric to paraelectric transition around at 105degC, and improved dielectric properties. The improvement is considered to be due to the simultaneous control of crystallographic and microstructural characteristics by using the double nucleation and buffer layers.
Grain Size Effect on Dielectric and Piezoelectric Properties of Alkoxy-Derived BaTiO3-Based Thin Films
Lead- and bismuth-free Ba(Ti1-xZrx)O3 (BTZ) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by the chemical solution deposition (CSD) process. The BaTiO3 and BTZ005 thin films fabricated by the conventional process were observed to have a remarkable difference in grain size along the depth of the thin film. The microstructure of the BaTiO3 and BTZ005 thin films was improved by additional sintering process, and their grain sizes were increased to about 60 and 40 nm, respectively, by additional sintering at 800°C for 1 h. The dielectric constant εr and piezoelectric constant d33 of the BaTiO3 thin film consisting of large grains by the additional sintering at 800°C for 1 h were found to be about 375 and 14.5 pm/V. But, εr and d33 of the BTZ005 thin film changed negligibly with increasing of the grain size.
Influence of filler addition, storage medium and evaluation time on biaxial flexure strength and modulus of adhesive systems
Abstract Objective. This study evaluated the effects of filler addition, storage medium and time on biaxial flexural strength and flexural modulus of six adhesive systems. Materials and methods. The adhesives were either unfilled resins: Single Bond, Prime&Bond 2.1 and One-Step; or filled resins: Single Bond Plus, Prime&Bond NT and One-Step Plus. Resin discs of each product (0.5 mm thick × 6.0 mm diameter) were prepared using silicon molds (n = 10). The discs were stored dry, in water, mineral oil or ethanol for 1 week or 3 months before biaxial flexural testing. Data were statistically analyzed by 3-way ANOVA and Tukey's post-hoc test (α = 0.05). The specimens were tested in a universal testing machine at 1.27 mm/min until failure occurred. Results. In general, the storage in ethanol led to significantly lower flexural strength and flexural modulus values than the other storage conditions for all adhesives in both storage periods. Filler addition increased flexural strength and flexural modulus for Prime&Bond NT, when it was stored dry or in water for 1 week. For Single Bond Plus, the filler addition resulted in higher flexural modulus, when it was stored for 1 week in oil and in ethanol. No significant differences in flexural modulus were observed between One-Step and One-Step Plus in any storage medium. Conclusions. Results suggested that filler addition does not necessarily have to increase the flexural strength and flexural modulus. Ethanol and oil storages tended to yield opposite effects.