ZrO2-SiO2膜的制备和结构研究

以正硅酸乙酯和氧氯化锆为原料,用溶胶－数胶法制备了无支撑ＺｒＯ２－ＳｉＯ２膜。应用ＤＴＡ－ＴＧ、ＸＲＤ－ＳＥＭ和ＢＥＴ等测试技术对无支撑ＺｒＯ２－ＳｉＯ２膜结构、表面形貌和孔径进行了表征,结果ＺｒＯ２－ＳｉＯ２凝胶膜虽在４６７℃开始出现少量单斜ＺｒＯ２,但在５００℃和１２００℃热处理后的晶相均为四方ＺｒＯ２显然ＳｉＯ２的存在的ＺｒＯ２－ＳｉＯ２膜具有比ＺｒＯ２膜同的热稳定性,在９５０℃欧下发人头发     

Ultrafine particles of the ZrO2-SiO2 system prepared by the spray-ICP technique

Ultrafine powders of the ZrO₂-SiO₂ system prepared by spraying aqueous mixed solutions of ZrO(NO₃)₂·2H₂O and silicone oil into an ultrahigh temperature inductively coupled plasma (the spray-ICP technique) have been investigated in connection with particle growth and phase change caused by heat treatment. The prepared powders were composed of roundish ultrafine particles 10 to 20 nm in size, and their components were tetragonal ZrO₂ (t-ZrO₂) and amorphous SiO₂ (a-SiO₂).a-SiO₂ alone did not crystallize below 1400° C, though the particles grew above 900° C.t-ZrO₂ converted to monoclinic ZrO₂ (m-ZrO₂) above 400° C, also followed by particle growth. On the other hand composite powders oft-ZrO₂ anda-SiO₂ exhibited no particle growth below 1200° C. Above 1200° Ct-ZrO₂ converted tom-ZrO₂, and its amount decreased with an increase in SiO₂ content. At 1400° C particle growth occurred, and the round particles of ZrO₂ were dispersed in ana-SiO₂ glass medium. These results indicate that ZrO₂ and SiO₂ mutually block particle growth, and that SiO₂ contributes to the quenching oft-ZrO₂ by keeping the particles of ZrO₂ within the critical particle size oft-ZrO₂.     

非晶ZrO2-SiO2系薄膜及微细图形的制备

采用溶胶－凝胶与化学修饰相结合的方法制备了ZrO2-SiO2系薄膜，研究了这种凝胶薄膜的FT－IR光谱特性及随紫外线照射时的变化，发现在1600－1400cm^-1之间有一些与含锆螯合物相关的峰，这些峰值随紫外线照射而减弱，表明这些螯合物发生分解，伴随着螯合物的分解，薄膜的乙醇中的溶解能力也发生变化，利用这特性，紫外光通过掩膜照射凝胶薄膜，用有机溶剂溶洗后，获得凝胶薄膜的微细图形，再进行热处理，消除薄膜中的有机物就可得到非晶质ZrO2-SiO2系薄膜的微细图形。     

Cathodoluminescence from crystalline phases in a ZrO2-SiO2-CeO2 ceramic

The chemical composition of crystalline phases in a ZrO₂-SiO₂-CeO₂ ceramic was determined by electron probe x-ray microanalysis, and the luminescent properties of these phases were studied. The valence state of Ce in these phases was determined from cathodoluminescence data.     

Crystal growth of tetragonal ZrO2 in the glass system ZrO2-SiO2 prepared by the sol-gel process from metal alkoxides

Glasses in the system ZrO₂-SiO₂ containing 40 to 60 mol % ZrO₂ were prepared by the sol-gel process from metal alkoxides. Tetragonal ZrO₂ was precipitated by heat treatment at 800 and 1200° C, and its crystal growth was measured by differential thermal and X-ray diffraction analyses. At 800 to 900° C, tetragonal ZrO₂ crystals grew three-dimensionally and the activation energy for growth was calculated as about 680 kJ mol⁻¹. On the other hand, the secondary growth of tetragonal ZrO₂ at 1000 to 1200° C followed the cube-root-of-time law. The activation energy for secondary growth was about 380 kJ mol⁻¹. It is suggested that the diffusion of Zr⁴⁺ ions is the rate-limiting process for the secondary crystal growth of tetragonal ZrO₂.     

化学修饰法制备的ZrO2-SiO2系凝胶薄膜的感光特性研究

本研究采用溶胶-凝胶与化学修饰相结合的方法制备了xZrO2@(100-x)SiO2系薄膜,进一步研究了这种薄膜的紫外光谱特性,发现了当x＞30时,这种凝胶薄膜在335nm附近有较强的吸收峰,这一吸收峰对应于与Zr形成配位体的BzAcH的π-π*迁移.当紫外光照射薄膜后,随着含Zr螯合物的分解,吸收峰也消失,并引起薄膜在有机溶剂中的溶解特性的显著变化,表现出明显的感光特性.这种薄膜经400℃、30min热处理以后,薄膜中的有机物消失,可获得非晶质的ZrO2-SiO2系薄膜,依据这一特性可以用紫外光对这类薄膜进行微细加工.     

Microstructure of plasma dissociated zircon and liquid immiscibility in the ZrO2-SiO2 system

The foam texture developed in plasma-dissociated zircon consists of plane surfaced interlocking grains which contain crystallites of dendritic zirconia embedded in amorphous silica. In the interstices of these grains silica has been segregated. This segregation appears to have come about mainly as the result of supercooling and liquid immiscibility. This accounts for the development of the almost pure silica phase and the formation of a zirconia-rich phase which crystallized to yield dendrites consisting of monoclinic zirconia at ambient temperature. Clear envelopes on the grains were found to consist of amorphous silica-rich material containing zirconia spherulites whose density of development is proportional to the zirconia content of the envelopes.     

Toughened glass-ceramics in the ZrO2-Al2O3-SiO2 system prepared by the sol-gel process

Monolithic glass-ceramics containing Al₂O₃ or TiO₂ were prepared in the ZrO₂-SiO₂ system by the sol-gel process from metal alkoxides. Tetragonal ZrO₂ was precipitated by heat treatment at 900–1200 °C and its crystal growth was increased by adding TiO₂ or Al₂O₃. Further heating at higher temperature resulted in the precipitation of zircon and monoclinic ZrO₂ which was transformed from tetragonal ZrO₂. The addition of Al₂O₃ had less effect on both the tetragonal-to-monoclinic ZrO₂ transformation and the precipitation of zircon. The fracture toughness increased as the size of tetragonal ZrO₂ particles increased and then decreased with the appearance of monoclinic ZrO₂ or zircon. The fracture toughness of the glass-ceramics was measured in the glass-forming regions of the ZrO₂-Al₂O₃-SiO₂ system. The fracture toughness was sensitively dependent on both Al₂O₃ and ZrO₂ content, of which the highest value achieved was 9 MPa m^1/2 for the 50ZrO₂·10Al₂O₃·40SiO₂ composition.     

Preparation of glass fibres of the ZrO2-SiO2 and Na2O-ZrO2-SiO2 systems from metal alkoxides and their resistance to alkaline solution

Glass fibres of the ZrO₂-SiO₂ and Na₂O-ZrO₂-SiO₂ systems containing up to 33 wt% ZrO₂ were prepared by a non-melting technique using zirconium n-propoxide, sodium methoxide and silicon tetraethoxide as raw materials. The mixed alkoxide solutions were exposed to moist air for hydrolysis. The fibrous gels were drawn from these solutions in the course of hydrolysis, and converted to the corresponding oxide glass fibres by heating at 500 to 700° C. It was found that chemical durability of the fibres toward alkaline solution increased with ZrO₂ content. The weight loss due to the corrosion by 2 N NaOH solution at 96° C for 4 h was around 14 mg dm^–2 for the fibres containing 17 to 26 wt% ZrO₂, which was comparable to the alkali-resistant glasses so far obtained by the conventional melting technique. The glass fibres containing 33 wt% ZrO₂ showed higher resistance.     

SO4^2-／ZrO2-SiO2的制备及其催化性能研究

用共沉淀法制备了SO4^2-／ZrO2-SiO2固体酸催化剂，通过XRD、BET、IR、SEM等综合实验手段考察了SiO2的加入量不同对固体酸的晶体结构的影响，并以乙酸正丁酯的酯化反应为探针实验考察了SO4^2-／ZrO2-SiO2的催化性能。结果表明，SiO2的加入抑制了ZrO2晶型的转变，提高了催化剂的活性。     

ZrO2/钙铝硅系微晶玻璃复合材料热处理制度研究

采用Sol-gel法制备ZrO2/CaO-Al2O3-SiO2系微晶玻璃复合材料,通过差热分析、X射线衍射和扫描电镜等对材料进行表征.结果表明:烧结温度范围为1035～1065℃,晶化温度约为870℃条件下所制得的复合微晶玻璃材料主晶相为t-ZrO2和β-CaSiO3,具有较高的抗折强度,可以用于制备高强度牙科材料.     

The infrared and Raman spectra of ZrO2-SiO2 glasses prepared by a sol-gel process

Infrared and Raman spectra were measured and interpreted on the basis of structure for various ZrO₂-SiO₂ glasses that were prepared by a sol-gel process involving zirconium nitrate. Interpretation of the spectra indicates the presence of both Zr-O-Si and Si-O-H linkages depending upon heat treatment conditions, and the evidence of zirconium atoms with eight fold coordination for glasses with high ZrO₂ contents. The crystalline products formed during glass devitrification were monitored by vibrational spectra. The formation and detection of tetragonal ZrO₂, zircon, monoclinic ZrO₂ and -cristobalite depended upon the conditions of devitrification.     

Estimation of formation mechanism of spherical fine ZrO2-SiO2 particles by ultrasonic spray pyrolysis

Spherical fine ZrO₂-SiO₂ (11) particles were synthesized from a hydrolysed mix-solution of Si(OC₂H₅)₄ and ZrOCI₂ · 8H₂O by ultrasonic spray pyrolysis, and the formation mechanism of the particles discussed. All of the resultant particles identified as t-ZrO₂ and amorphous SiO₂ with an atomic order dispersion were spherical, and mainly of diameter 0.8 to 1.0m. It was estimated that the three-dimensional ladder siloxane chains containing an equimolar Zr⁴⁺ homogeneously dispersed were formed by hydrolysis, and an atomized droplet itself converted into an isolated ZrO₂-SiO₂ (11) particle without aggregation.     

ZrO2-SiO2薄膜对离子交换增强玻璃的光学和力学性能影响

采用溶胶-凝胶法在玻璃表面制备出ZrO₂-SiO₂薄膜, 然后通过离子交换形成镀膜增强玻璃, 研究了薄膜组成对离子交换增强玻璃的力学和光学性能的影响。利用紫外可见分光光度计、激光椭偏仪、纳米压痕、三点抗弯和能谱(EDX)分析了薄膜结构及性能。结果表明: 所有薄膜均连续均匀, 纯ZrO₂薄膜为四方相结构, 含Si薄膜为无定形结构; 薄膜具有较高弹性恢复率(>60%)以及H/E比(>0.1), 有利于强度增强; 随Si含量增加, 可见光透过率增大, 但表面硬度和杨氏模量随之降低; 0.5ZrO₂-0.5SiO₂薄膜综合性能最佳: 表面硬度为18 GPa, 抗弯强度为393 MPa, 厚度~45 nm时可见光透过率大于85%。