放电等离子烧结和快速热压工艺制备具有低或负热 膨胀系数钨酸锆块体(英文)

采用快速热压工艺(放电等离子烧结和感应加热热压),利用ZrW2O5粉料制备了负热膨胀系数(coefficient of thermal expansion,CTE)钨酸锆 (ZrW2O8)陶瓷体材料.这两种工艺可在烧结过程中保留负CTE材料钨酸锆所需的结构和相组成.结果表明:改变工岂参数,如热压温度和保温时间, 可以调节ZrW2O8陶瓷的CTE从-9×10-6/K到+9×10-6/K变化.首次采用ZrW2O8作为填料与轻金属钛复合制备了零膨胀复合材料.     

掺铝钙钛锆石基玻璃陶瓷的结构和抗浸出性能

采用熔融–热处理工艺制备钙钛锆石–钡硼硅酸盐玻璃陶瓷固化体,研究了不同Al_2O_3含量对玻璃陶瓷中玻璃网络体、晶相和显微结构的影响,用产品一致性测试法(PCT法)对玻璃陶瓷固化体的抗浸出性能进行评价。结果表明:随着Al_2O_3含量的增加,更多的Al~(3+)和自由氧形成[AlO_4],使[BO_4]相对减少,[BO_3]增多。在不含Al_2O_3的样品中,只有钙钛锆石和榍石晶相。当掺入2%(质量分数)Al2O3时,开始出现钛酸钙晶相,其含量随着Al_2O_3含量的增加而增加。当Al2O3含量达到6%时,榍石晶相基本消失,只有条状钙钛锆石和方形钛酸钙晶体。产品一致性测试结果表明:掺入Al_2O_3对玻璃陶瓷固化体抗浸出性能影响不明显,玻璃陶瓷中B、Ca、Nd元素的归一化浸出率(LRB、LRCa、LRNd)在28 d后基本保持不变,其中,LR_B、LR_(Ca)与硼硅酸盐玻璃固化体处于同一数量级[约为10–3 g/(m~2·d)],LRNd[约为10–6 g/(m~2·d)]比硼硅酸盐玻璃固化体低1个数量级。     

富锆PZT陶瓷热释电性能的研究

介绍了富锆PZT陶瓷F_(RL)和F_(RH)的相变,并测试具有不同锆钛比PZT陶瓷的热释电性能,探索相变温度与锆钛比的关系,找出室温下热释电性能最好的PZT陶瓷锆钛比。通过测试,结果表明当锆钛比为97/3时,PZT陶瓷室温下的热释电性能最好,为30×10~(-4)C/m~2℃,符合热释电探测器的性能要求。     

安徽省淮北市及周边地区陶瓷原料工业化生产适用性及储量评估

1 前言今年二至三月份,佛山市陶瓷研究所、佛山市陶瓷学会等一行人应邀对淮北市在烈山区成立陶瓷工业园区进行了各方面的考察评估,现将主要情况介绍如下,供国内外陶瓷同行参考。2陶瓷原料概况2.1确定陶瓷原料选择标准考察范围:当地储量丰富而优质的陶瓷矿点,毗邻外市、外省矿点(包括有陶瓷生产的地区和有优质原料的矿点:安徽宿州、凤阳,河南永成、禹州等)。陶瓷原料初步选择取样标准:(1)储量大:软质粘土在数十万吨以上,硬质粘土百万吨以上,长石类瓷土在千万吨以上,石英百万吨以上。(2)品位高:主要要求含铁钛有害杂质少,化学成份和矿物成份稳…     

放电等离子烧结制备金刚石/钛铝碳复合材料

以金刚石微粉和钛铝碳微粉为原料,采用放电等离子烧结制备金刚石/钛铝碳陶瓷复合材料。研究结果表明:在温度1100℃~1200℃、30 MPa和金刚石含量为(30~60)wt.%条件下,制得金刚石/钛铝碳陶瓷复合材料。当金刚石含量大于40wt%时,制得样品的微观结构中存在大量的空隙;当金刚石含量为(30~40)wt.%时,制得样品微观结构较致密。钛铝碳与金刚石作用分解为碳化钛和少量的碳化铝,金刚石能够被反应产物表面包覆,包覆后镶嵌于陶瓷基体中,复合材料密度达到3.7g/cm3,磨耗比约为1550。     

涂覆类cBN磨料性能研究

对比了几种涂覆类cBN磨料的性能及其应用于陶瓷结合剂磨具的性能,通过扫描电子显微镜(SEM)、差热—热重分析仪(DSC-TG)及力学性能测试仪对其进行表征,结果发现:刚玉涂覆cBN磨料的力学性能和热稳定性没有劣化,但与陶瓷结合剂制成磨具抗折强度降低;钛涂覆cBN磨料陶瓷结合剂磨具抗折强度提高,但钛涂覆后cBN磨料力学性能和热稳定性变差;玻璃涂覆cBN磨料的力学性能和热稳定性有所提高,其与陶瓷结合剂在界面处结合紧密,增强了二者之间的把持力,提高了其磨削性能.     

钙钛锆石-钡硼硅酸盐玻璃陶瓷的制备及表征

采用熔融–热处理工艺制备了Si O2–B2O3–Ba O–Na2O–Ca O–Zr O2–Ti O2体系钙钛锆石基钡硼硅酸盐玻璃陶瓷,研究了Ca O、Ti O2、Zr O2(记为CTZ,摩尔比为2:2:1)含量对玻璃陶瓷相结构、显微结构的影响,采用产品一致性测试法(PCT)测试了玻璃陶瓷样品的抗浸出性能。结果表明:样品的玻璃转变温度为615~650℃且随着CTZ含量增加而升高。CTZ含量为35%的样品和CTZ含量为45%的样品分别在900和850℃附近出现了明显的放热峰。当CTZ含量≥30%时,钙钛锆石晶相开始析出;CTZ含量为45%时,样品中出现大量均匀分布的柱状钙钛锆石晶相;CTZ含量达55%时,样品致密性较差,除钙钛锆石晶相外还有榍石和二氧化硅晶相析出。PCT测试表明:CTZ含量为45%的样品具有较好的抗浸出性能,B和Na在42 d后的归一化质量损失约为0.1 g/m2,Si和Ca约为0.01 g/m2,与硼硅酸盐玻璃固化体处于同一数量级。     

专利信息

提高陶瓷接头高温性能的方法本发明属于材料加工技术领域,采用铝、钛、铝,或铝、镍、铝,或钛、镍、钛构成多层金属中间层,其步骤为:(1)在被连接材料之间插入三层结构的多层金属中间层;(2)放入真空炉中,加压、加热、保温,冷却至室温即可形成耐高温性能较好的接头。本发明能在较低温度下使用(在此温度下陶瓷性能不受损伤),不使用贵金属合金,接头在600℃下有较高的力学性能,具有低成本、低消耗等优点。半固态连接材料制备与使用本发明属于材料加工技术领域,其制作方法包括在铝基合金中添加可与铝形成金属间化合物的合金元素,在低真空中或氩气保…     

钛粉对SHS陶瓷内衬复合管组织与性能的影响

在自蔓延离心法制备陶瓷内衬钢管过程中,用钛粉取代部分铝粉,研究了钛粉对燃烧过程、陶瓷层性能及组织的影响。利用XRD分析陶瓷层的相组成,利用SEM和EDS分析陶瓷层的微观组织。结果表明,加入钛粉后,反应的绝热燃烧温度不变,反应速度降低。当钛粉加入量为3.9%时,陶瓷层致密度最大,可达96.8%。加入钛粉后,复合钢管的压溃强度,压剪强度得到提高,陶瓷层硬度略有下降。陶瓷内衬层主要由α-Al_2O_3和少量的FeAl_2O_4,FeAlTiO_5组成,α-Al_2O_3晶粒为等轴晶。     

TiB2对无压烧结B4C–TiB2复相陶瓷结构和性能的影响

以碳化硼(B₄C)、二硼化钛(TiB₂)、碳化钛(TiC)为原料,采用无压烧结法在2 130℃制备了含20%(质量分数)和30%TiB₂的B₄C基复相陶瓷,分析所制样品的密度、硬度、弯曲强度和断裂韧性。结果表明:在2 130℃,直接加入30%的TiB₂亚微米颗粒,复相陶瓷的抗弯强度和断裂韧性分别达到277.6 MPa和5.38 MPa·m^1/2。陶瓷中颗粒拔出和裂纹微桥接对复相陶瓷增韧作用显著。B₄C–TiB₂复相陶瓷的增韧机理主要是由于TiB₂与B₄C热膨胀系数不匹配产生的残余应力导致的微裂纹增韧和裂纹偏转增韧。     

原材料与钛酸铝陶瓷性能之间关系的研究

用不同纯度的二氧化钛粉体和不同晶型的氧化铝粉体为原料进行钛酸铝合成研究。结果表明:引入稳定剂和烧结助剂,在一定的烧结温度条件下,这些原材料均可生成具有良好力学性能的钛酸铝陶瓷;在相同的烧成条件下,钛黄粉反应生成的钛酸铝陶瓷比钛白粉反应生成的陶瓷具有更好的力学性能;采用钛黄粉与工业氧化铝粉合成的钛酸铝陶瓷,由于生产成本低,在耐火材料领域具有广泛的应用潜力。     

溶胶-凝胶法制备Na1/2La1/2Cu3Ti4O12粉体及陶瓷的结构与巨介电性研究

采用溶胶-凝胶法制备Na1/2La1/2Cu3Ti4O12 (NLCTO)粉体和陶瓷样品,探讨不同Ti4+浓度、pH值和水含量对NLCTO粉体和陶瓷结构的影响.结果表明在Ti4+浓度为0.75~1.0 mol/L,pH=0.3~1.3,[H2O]/[Ti4+]=11∶1的条件下制备的干凝胶在800 ℃预烧后,粉体分散程度较好,颗粒均匀.在获得优越NLCTO粉体基础上制备的陶瓷材料介电常数约可达到1.9×104以上,介电损耗降低到0.039.     

Preparation of Undoped Lead Titanate Ceramics via Sol-Gel Processing

Crack-free, undoped PbTiO₃ ceramics were fabricated successfully using sol–gel-synthesized powder prepared from chelated titanium alkoxide and lead acetate. The sintered ceramics, 8.3 mm in diameter and 6–8 mm thick, were 96% dense. In the present study, PbTiO₃ ceramics with excess lead (Pb:Ti = 1.1:1.0) had large grains, averaging 14.3 μm. Lower-lead ceramics (Pb:Ti = 1.0:1.0 and 0.9:1.0) had smaller grains, averaging 1.8 μm. The PbTiO₃ ceramics with a high lead content cracked during sintering at 1150°C, whereas the other ceramics did not crack. Excess lead, in a more-than-stoichiometric ratio, promoted grain growth and caused disintegration of the ceramics. Therefore, uncracked PbTiO₃ ceramics apparently can be fabricated by avoiding excess lead, possibly because restricted grain growth in low-lead ceramics causes low residual stress over many small grains during transition. The electrical properties measured in the present study for PbTiO₃ ceramics with a Pb:Ti ratio of 1:1 are d ₃₃= 35 pC/N, K ₃= 64, k _p= 0.59, and k _t≈ 0.     

La_2O_3掺杂(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_3陶瓷的介电和压电性能的研究

用固相反应法制备La2O3掺杂的铁电陶瓷(Bi0.5Na0.5)0.94Ba0.06TiO3(BNBT6)。X射线衍射曲线表明掺杂0-0.6wt%La2O3的BNBT6为钙钛结构。研究了La2O3掺杂对BNBT6陶瓷介电性能和压电性能的影响。结果表明La2O3掺杂量为0.3wt%的BNBT6陶瓷综合性能最佳,其中介电常数为1981.4,介电损耗为0.0625和压电常数为145pc/N。SEM图象表明La2O3掺杂提高了陶瓷的致密度。     

Zn2+离子掺杂对负载TiO2薄膜光催化活性的影响

以钛酸丁酯和ZnSO₄·7H₂O为原料，采用溶胶-凝胶法在钛片、玻璃、釉面瓷砖、陶瓷、不锈钢和铝片六种载体上制备了Zn²⁺掺杂TiO₂薄膜，讨论了不同Zn²⁺掺杂浓度下不同载体表面上制备的TiO₂薄膜对甲基橙脱色率的影响。结果表明，Zn²⁺对TiO₂薄膜的掺杂效果与载体的类型密切相关，并且不同载体其Zn²⁺掺杂的最佳浓度也不同。Zn²⁺掺杂后，TiO₂薄膜光催化活性提高最大的是釉面瓷砖，其次是钛片、玻璃、陶瓷。不锈钢和铝片上TiO₂薄膜的光催化活性不但没有升高，反而降低了。     

Negative permittivity in titanium nitride-alumina composite for functionalized structural ceramics

The study on novel physical properties of structural ceramics or ceramic composites could make them more conducive to be function- and structure-integrated materials. Herein, titanium nitride-alumina (TiN–Al₂O₃) duplex ceramics were prepared and the dielectric spectra of the ceramics were studied from 10 MHz to 1 GHz. Negative permittivity appeared when TiN content exceeded 40 wt% due to the induced plasmonic state of massive delocalized electrons in connected TiN grain networks. Meanwhile, alternating current conduction behaviors of the duplex ceramics were discussed with percolation theory. Furthermore, the analysis of reactance by equivalent circuit models indicated that negative permittivity ceramics exhibited inductive character. This work realized negative dielectric behaviors in TiN–Al₂O₃ duplex ceramics and would promote the study of electromagnetic functionalization in wave shielding or attenuation for structural ceramics.     

Utilization of gold tailings for the construction of foamed ceramics used in external insulation buildings

The utilization of gold tailings and bentonite as raw materials for prepared foamed ceramic was studied. The effects of boric acid and titanium dioxide content on the properties and microstructures of foamed ceramic were studied from the aspects of bulk density, compressive strength, bending strength, phase composition, and micromorphology. These results show that the synergistic effect of boric acid and titanium dioxide leads to the crystallization of quartz, which enhanced the compressive strength and bending strength and decreased the thermal conductivity of foamed ceramics, while the bulk density increases gradually with the addition of titanium dioxide. Taking into account all of these properties, the optimal results are as follows: bending strength of 1.111 MPa, compressive strength of 1.165 MPa, bulk density of 0.258 g/cm³, the porosity of 81.89%, the thermal conductivity of 0.088 (W/(m⋅K)). This study indicated that gold tailings are a promising candidate for the preparation of foamed ceramics used as external insulation building materials.     

Fabrication and Mechanical Properties of Titanium Boride Ceramics

Dense TiB ceramics (99.6% of theoretical) with a grain size of ∼5 µm have been fabricated by reaction hot pressing of TiB₂ and titanium for 2 h at 1900°C and 28.5 MPa. The TiB ceramics exhibit a fracture toughness ( K_IC ) of 4.5 MPa·m^1/2 and a bending strength (sigma_b) of 360 MPa. Electrical resistivity (rho) is 3.4 × 10^-7 Omega·m at room temperature.     

Effects of SnCl2 concentration and Ti source on the phase composition,sinterability, and microwave dielectric properties of Zr0.8Sn0.2TiO4 ceramics by choline chloride-malonic acid deep eutectic solvent

Zr_0.8Sn_0.2TiO₄ (ZST) ceramics were prepared by choline chloride-malonic acid deep eutectic solvent (Cm-DES) route using analytical-grade raw materials such as Zr(CH₃COO)₄, SnCl₂·2H₂O, titanium isopropoxide, and so on. The effects of SnCl₂ concentration and Ti source on phase composition, sinterability, and microwave dielectric properties of ZST ceramics processed by Cm-DES routes were investigated. Single-phase ZST powders were processed by Cm-DES routes calcined at 450 °C, and no second phase was detected in all the ceramics. The sintering temperature of ZST ceramics processed by Cm-DES routes was seriously decreased to 1350 °C. Excellent dielectric properties (ε_r = 38.0, Q×f = 44,500 GHz, and τ_f = 1.9 ppm/°C) were obtained when 0.6 mol/L SnCl₂ and titanium isopropanol were employed. These results give the underlying enlightenments needed for cost-saving and low energy consumption fabrication of microwave dielectric ceramics.     

AlN陶瓷表面钛金属化沉积的动力学研究

利用融盐热歧化反应进行了氮化铝陶瓷表面钛金属化沉积的动力学研究.结果表明,氮化铝陶瓷表面钛膜的厚度随着反应温度和反应时间的增加而增加,膜的厚度与反应时间成很好的线性关系,沉积速率与融盐中K2TiF6的起始浓度成线性关系,沉积过程是受融盐与氮化铝陶瓷基体之间的界面反应控制.其沉积过程的活化能为130kJ/mol.