Oriented Barium Titanate Thick Films by Reactive Coating on Rutile

A mechanically stable [110] oriented tetragonal barium titanate layer of ≤50 μm thickness on a rutile substrate has been obtained by reactive coating of screen printed barium titanate submicrometer powder on the substrate and following a two-step firing cycle at 1400°C for 6 min and 1310°C for 60 min. The results have been explained taking into account the BaTiO₃–TiO₂ equilibrium phase diagram.     

Reactive Coating of Zircon on Mullite and Mullite—Alumina Substrates

A stable zirconia coating of 20–30 pm thickness on a mullite substrate with a different alumina/silica ratio was obtained by reactive coating of zircon. It is shown that the Al₂O₃/ SiO₂ ratio of the mullite substrate drastically affects the morphology of the zirconia coating. The results are explained on the basis of the Al₂O₃–SiO₂–ZrO₂ phase equilibria.     

Synthesis of Lead Zirconate Titanate Stannate Antiferroelectric Thick Films by Sol-Gel Processing

The effects of different sintering procedures on the preparation of antiferroelectric thick films and the structure–property relations in these films were studied. An acetic acid-based sol–gel processing with multistep annealing and suitable lead oxide overcoat layers was developed to fabricate both niobium-doped and lanthanum-doped lead zirconate titanate stannate antiferroelectric thick films. The 5-μm-thick Pb_0.99Nb_0.02(Zr_0.85Sn_0.13Ti_0.02)_0.98O₃ films demonstrate typical square hysteresis loops with a maximum polarization of 40 μC/cm², zero remanent polarization, an antiferroelectric-to-ferroelectric phase transition field of 153 kV/cm, and a ferroelectric-to-antiferroelectric phase transition field of 97 kV/cm. The dielectric constant and dielectric loss are 283 and 1.7%, respectively. The 5-μm-thick Pb_0.97La_0.02(Zr_0.65Sn_0.31Ti_0.04)O₃ films display typical slanted hysteresis loops with very small hysteresis, a maximum polarization of 35.0 μC/cm², and zero remanent polarization. The dielectric constant and dielectric loss are 434 and 2.0%, respectively.     

Hydroxyapatite Coating on Thermally Oxidized Titanium Substrates

Titanium substrates were oxidized in oxygen or air at temperatures of 600°–800°C, then immersed in solutions of 2.0m M – 20.7m M CaCl₂ and 1.2m M –12.4m M KH₂PO₄ for aging periods of 0.5–10 d. The titanium surface was successfully coated with hydroxyapatite (HAP) when the substrates were oxidized in oxygen gas at 610°C for 1 h and then aged in a solution of 2.00m M Ca²⁺ and 1.20m M PO₄³⁻. The Ca/P ratio of the surface coating increased toward its stoichiometric HAP value (return 10/6) as the aging time increased; the Ca/P ratio attained a value of 1.66 after 10 d.     

金红石型钛白锆铝包膜工艺的改进

针对金红石型钛白锆铝包膜过程中,在酸性体系中易降低浆料分散性的特性,分析了pH值、包膜剂含量等包膜条件,以及TiO2落窑品中硫含量对包膜过程浆料分散性的影响,得出了较佳的TiO2包膜工艺。该工艺具有过程控制较并流包膜工艺简单、包膜过程中浆料的分散性好、产品的综合性能佳等特点。     

Fabrication and Electrical Properties of Lead Zirconate Titanate Thick Films

Thick films of lead zirconate titanate of the morphotropic phase boundary composition, Pb(Zr_0.52Ti_0.48)O₃, have been fabricated on platinum-buffered silicon using a modified sol–gel spin-coating technique. Crack-free films of 12-μm thickness can be uniformly deposited on 3-in.-diameter wafers with high yield and properties comparable to those of bulk ceramics. The thickness dependence of film structure and the dielectric, ferroelectric, and piezoelectric properties have been characterized over the thickness range of 1–12 μm. A strong (100) texture develops as film thickness increases above 5 μm; the films were marked by saturation values of longitudinal piezoelectric coefficient d ₃₃, 340 pC/N; remanent polarization, 27 μC/cm²; and dielectric permittivity, 1450. PZT films in this thickness range are extremely well-suited to application as electromechanical transduction media in silicon-based microelectromechanical systems (MEMS).     

Processing and Properties of Screen-Printed Lead Zirconate Titanate Piezoelectric Thick Films on Electroded Silicon

The printing of lead zirconate titanate (PZT, Pb(Zr,Ti)O₃) piezoelectric thick films on silicon substrates is being studied for potential use as microactuators, microsensors, and microtransducers. A fundamental challenge in the fabrication of useful PZT thick-film devices on silicon is to sinter the PZT to high density at sufficiently low temperature to avoid mechanical or chemical degradation of the silicon substrate. The goal of the present study is to develop and implement suitable electrodes and PZT sintering aids that yield attractive piezoelectric properties for devices while minimizing reactions between the silicon, the bottom electrode, and the PZT thick film. A B₂O₃-Bi₂O₃-CdO sintering aid has been found to be superior to borosilicate glass, and the use of a gold/platinum bilayer bottom electrode has resulted in better thermal stability of the electrode/film structure. Films sintered at 900°C for 1 h have relative permittivity of 970 (at 1 kHz), remnant polarization of 20 μC/cm², coercive field of 30 kV/cm, and weak-field piezoelectric coefficient d ₃₃ of 110 pm/V.     

有机硅包膜剂在金红石型钛白生产中的应用

对有机硅包膜剂产品JY-T-01应用于金红石钛白粉的有机包膜处理进行了详细研究。利用JY-T-01有机包膜剂处理金红石钛白粉,亮度高,流动性良好,产品具有很高的耐温性和加工性能,处理后的钛白粉能够在油性体系中良好稳定地分散,使得颜料性能得以全面发挥,在水性体系中颜料特性表现不明显,但也无排斥现象,是一种性价比较高的钛白粉有机处理剂。     

Lead Zirconate Titanate Films on Nickel–Titanium Shape Memory Alloys: SMARTIES

Thin films of 52/48 PZT have been deposited on Ni–Ti shape memory alloys using a sol–gel spin-on method. Micrometer-thick PZT films adhere well to the alloy for strains as large as 0.4%, and they retain their ferroelectric properties during repeated cycling through the shape memory transformation.     

Fabrication and Electrical Properties of Lead Zirconate Titanate Thick Films on Si Substrate by Using Lanthanum Nickelate Buffer Layer

Lead zirconate titanate PbZr_0.53Ti_0.47O₃ (PZT) thick films have been deposited on silicon substrate by modified metallorganic decomposition process. Crack-free PZT films of 8 μm thickness can be obtained by using lanthanum nickelate LaNiO₃ (LNO) as buffer layer. The greater LNO thickness, the greater thickness of crack-free PZT can be obtained. The X-ray diffraction measurements show the films exhibit a single perovskite phase with (110) preferred orientation. SEM measurements showed the PZT thick films have a columnar structure with grain size about 60–200 nm. The thickness dependence of ferroelectric, dielectric, and piezoelectric properties of PZT thick films have been characterized over the thickness range of 1–8 μm. For PZT with thickness of 8 μm, P _r and E _c are 30 μC/cm² and 35 kV/cm, and dielectric constant and dielectric loss are 1030 and 0.031, respectively. The piezoelectric coefficient ( d ₃₃) of PZT with 8 μm thickness is obtained to be 77 pm/V. PZT thick films on LNO-coated Si substrate are potential for MEMS applications.     

Photonic Sintering of Aerosol Jet Printed Lead Zirconate Titanate (PZT) Thick Films

Lead Zirconate Titanate (PZT) is a commonly used piezoelectric material due to its high piezoelectric response. We demonstrate a new method of printing and sintering micro‐scale PZT films with low substrate temperature increase. Self‐prepared PZT ink was Aerosol‐Jet printed on stainless steel substrates. After drying for 2 h in vacuum at 200°C, the printed PZT films were divided into two groups. The first group was traditionally sintered, using a thermal process at 1000°C for 1 h in an Argon environment. The second group was photonically sintered using repetitive sub‐msec pulses of high intensity broad spectrum light in an atmospheric environment. The highest measured substrate temperature during photonic sintering was 170.7°C, enabling processing on low melting point substrates. Ferroelectric measurements were performed with a low‐frequency sinusoidal signal. The remanent polarization (P_r) and coercive field (E_c) for thermally sintered PZT film were 17.1 μC/cm² and 6.3 kV/cm, respectively. The photonically sintered film had 32.4 μC/cm² P_r and 6.7 kV/cm E_c. After poling the samples with 20 kV/cm electric field for 2 h at 150°C, the piezoelectric voltage constant (g₃₃) was measured for the two film groups yielding ?16.9 × 10^?3 (V·m)·N^?1 (thermally sintered) and ?17.9 × 10^?3 (V·m)·N^?1 (photonically sintered). Both factors indicate the PZT films were successfully sintered using both methods, with the photonically sintered material exhibiting superior electrical properties. To further validate photonic sintering of PZT on low melting point substrates, the process and measurements were repeated using a polyethylene terephthalate (PET) substrate. The measured P_r and E_c were 23.1 μC/cm² and 5.1 kV/cm, respectively. The g₃₃ was ?17.3 × 10^?3 (V·m)·N^?1. Photonic sintering of thick film PZT directly on low melting point substrates eliminates the need for complex layer transfer processes often associated with flexible PZT transducers.     

Interfacial Reaction between Titanium Thin Films and Aluminum Nitride Substrates

Interdiffusion and reaction at the interface between titanium thin films and AlN have been studied by using Rutherford backscattering spectrometry and transmission electron microscopy. Ti₂AlN is formed as a result of reaction with titanium and AlN at temperatures of 800°-950°C. The activation energy for Ti₂AlN formation in the temperature range of 800°-850°C is 224 kJ/mol, which is similar to that of nitrogen diffusion in titanium. Therefore, the formation of Ti₂AlN is believed to be controlled by the diffusion of nitrogen in titanium.     

Piezoelectric Properties of Ink‐Jet–Printed Lead Zirconate Titanate Thick Films Confirmed by Piezoresponse Force Microscopy

An ink consisting of Pb(Zr_0.53Ti_0.47)O₃ (PZT) particles with a median size of 170 nm and a narrow size distribution, in a dispersion of water and glycerol, and with a low viscosity and surface tension, was used for the fabrication of thick films by piezoelectric ink‐jet printing. This study reports the printing conditions, the subsequent thermal treatment of the as‐deposited layers, and the properties of the sintered PZT thick film. The film, sintered at 1100°C, had a locally dense microstructure and consisted of grains that are a few 100 nm across, as revealed by scanning electron microscopy. A local piezoelectric response of 15 pm/V was measured in the ink‐jet–printed PZT thick film by piezoresponse force microscopy.     

Stress Modulation and Ferroelectric Properties of Nanograined PbTiO3 Thick Films on the Different Substrates Fabricated by Aerosol Deposition

Nanograined PbTiO₃ (PT) thick films were deposited on Si, yttria‐stabilized zirconia (YSZ), and Ni substrates using an aerosol deposition (AD) method at room temperature. The AD PT thick films on each different substrate were annealed at 500°C and 700°C for 1 h to increase the crystallinity. The stresses in the PT film were modulated by controlling the difference in the coefficient of thermal expansion (CTE) between the films and substrates during the thermal annealing process. The morphology of the AD PT films was examined from the polycrystalline dense structure (thickness ~8 μm), and the changes in the crystallographic phase, in‐plane stresses, and ferroelectric properties in annealed films were investigated. In‐plane stress analysis showed that the PT films annealed at 500°C and 700°C on each substrate exhibited compressive stress. Owing to the effects of compressive stress in the PT film, the film showed less tetragonality (c/a ratio) and enhanced ferroelectric behaviors. The change in the polarization–electric field (P–E) hysteresis loop of the PT films was explained by the stress induced from CTE mismatch between the films and substrates.     

Low-Temperature Preparation of Anatase and Rutile Layers on Titanium Substrates and Their Ability To Induce in Vitro Apatite Deposition

Surface modification of titanium and its alloys to induce apatite deposition within a short period is of practical importance in clinical applications. In this study, titanium substrates were treated with hydrogen peroxide solutions at low temperatures to yield titania layers consisting of anatase and rutile. Those titania layers, regardless of the fraction of anatase and rutile, were bioactive to induce deposition of apatite in Kokubo's simulated body fluid within 24 h. The bioactivity was attributed to both the epitaxial effect and the abundant Ti–OH group of the titania layer.     

金红石型钛白粉后处理工艺技术研究

介绍了钛白粉基料的后处理工艺,以及目前国内处理工艺中的一些缺陷,并与国内外的钛白粉后处理工艺进行对比研究。然后针对国内工业生产的情况,提出了对处理工艺的改进方法,并展望了钛白粉后处理工艺的发展方向以及需要研究的重点。     

盐处理对金红石钛白粉的影响

硫酸法生产钛白粉的过程中,盐处理工序是非常重要的一道工序,文章以水洗后偏钛酸为原料,分别探讨了氧化锌、氢氧化钾及硫酸镁这三种盐处理剂的加入率对钛白粉颜色指标(光亮度L值和白度b值)及金红石转化率的影响。     

钛白粉及金红石中TiO2的置换配位滴定

本文提出了测定钛白粉和金红石中二氧化钛的简易置换配位滴定法，向含有钛离子和其它阳离子的溶液中加入过量的环己烷二胺四乙酸（ＤＣＴＡ），以二甲酚橙（ＸＯ）为指示剂，用乙酸锌标准溶液返滴定过量的ＤＣＴＡ，然后以氟化物分解Ｔｉ（ＩＶ）－ＤＣＴＡ配合物，释放出的ＤＣＴＡ，用乙酸锌标准溶液滴定，本法终点变化敏锐，具有很好的精密度和准确度。     

外添加晶种法制备金红石型钛白粉

<正> 金红石型涂料钛白粉(TiO_2)是一种极为优越的白色颜料,它具有遮盖率强、着色率高、颗粒微细及抗粉化、耐黄变等性能,是制备各种高档白漆及浅色漆不可缺少的白色颜料。近年来,对涂料用金红石型钛白粉的需要量增长很快,目前国内仅少数厂生产,年产量为500～1000吨,远远满足不了国民经济发展的需要。采用的工艺路线,大都用并流法晶种。但该方法由于烧结而不易破碎的颗粒,需采用设备条件要求较高的气流粉碎工艺,这对小型工厂生产带来一定的困难。     

Properties of Lead Zirconate Titanate Thick-Film Piezoelectric Actuators on Ceramic Substrates

Lead zirconate titanate (PZT) is a piezoelectric material that can sense or respond to mechanical deformations and can be used in ceramic electro-mechanical systems (C-MEMS). The microstructural, electrical, and piezoelectric characteristics of thick PZT films on low-temperature cofired ceramics (LTCC) and alumina substrates were studied. The PZT composition was prepared with low-melting-point additives in order to decrease the sintering temperature and to be compatible with thick-film technology. The integration of the PZT thick-film materials on ceramic substrates could lead to degradation of the PZT's characteristics due to the interactions between an active PZT layer and a substrate, particularly with glassy LTCC material. To minimize the interactions with LTCC substrates, an intermediate PZT barrier layer was integrated. The value of the piezoelectric coefficient d ₃₃ was found to be up to 120 pC/N on an alumina substrate and approximately 50 on an LTCC substrate. Based on these results, a cantilever-type actuator was designed and fabricated on alumina substrates. Under an applied voltage of 200 V, the maximum tip deflection was about 5 μm.