共查询到19条相似文献,搜索用时 109 毫秒
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采用高温熔融法制备了MgO-Al2O3-SiO2 (MAS)系堇青石基微晶玻璃.借助X射线衍射仪(XRD)、扫描电镜(SEM)及热膨胀系数仪研究了晶化热处理工艺、MgO/Al2O3质量比以及晶核剂种类(TiO2/ZrO2)与含量对MAS系堇青石基微晶玻璃理化性能和晶化特性的影响.结果表明:在核化温度750℃、保温时间1h,晶化温度1050℃、保温时间2.5h,升温速率5 ℃/min时,微晶玻璃中堇青石含量最高,析晶性能最好;当MgO/Al2O3质量比为1左右时,在30 ~ 700℃温度范围内,平均热膨胀系数最小,在4.4 ~4.8×10-6K-1范围内可调;TiO2是MAS系堇青石基微晶玻璃的有效晶核剂,而ZrO2的加入并不利于基础玻璃的晶化. 相似文献
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本文利用天然矿物原料,采用烧结法制备具有结晶花纹,透明度高的微晶玻璃大理石,探讨了玻璃的熔制,碎玻璃的烧结等工艺,指出了合理的配方组成和适宜的玻璃颗粒组成是制造微晶玻璃大理石的关键。 相似文献
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采用熔融法制备了含有不同晶核剂的非化学计量比堇青石微晶玻璃,通过DSC、XRD、FE-SEM、UV-VIS-NIR等测试方法研究了不同晶核剂对微晶玻璃析晶与性能的影响,并用经典动力学方程(Johnson-Mehl-Avrami)分析了微晶玻璃的析晶动力学。结果表明,以P2O5和P2O5+ZrO2为晶核剂的微晶玻璃晶化机制均为表面晶化,而以P2O5+ZrO2+TiO2为晶核剂的微晶玻璃则倾向于整体析晶。三组微晶玻璃在950℃晶化时主晶相为μ-cordierite,当温度升高到980℃时开始转变为α-cordierite,引入TiO2使α-cordierite的含量增加,析出的晶体更加复杂致密。随着晶化时间延长,与其他晶核剂相比,P2O5+ZrO2+TiO2组合晶核剂微晶玻璃在相同晶化时... 相似文献
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添加氧化铈对堇青石基微晶玻璃的烧结和性能的影响 总被引:6,自引:0,他引:6
采用X射线衍射、扫描电镜和差热分析等手段研究了稀土氧化铈对由熔融淬冷法制备的非化学计量组成的堇青石基微晶玻璃的相变、烧结特性和性能的影响。研究结果表明:添加氧化铈能够明显抑制μ-堇青石相的形成和促进μ-堇青石向α-堇青石的转变。氧化铈的加入降低了微晶玻璃的烧结活化能和堇青石微晶玻璃的烧结温度,添加氧化铈质量分数为4%的微晶玻璃的μ-堇青石转变为α-堇青石的最低温度约为900℃,此时烧结样品几乎完全致密化,但氧化铈加入量太多将会阻止微晶玻璃的烧结和晶化。微晶玻璃的抗折强度随氧化铈含量的增加而增加,当氧化铈为4%时样品的抗折强度达到最大值。微晶玻璃的热膨胀系数随着氧化铈含量的增加变化不大。该微晶玻璃可望应用于微电子封装领域,能够与高导电率、低成本的金属如铜、银/钯低温共烧制成电子基板材料。 相似文献
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堇青石粉末合成及其烧结特性的研究 总被引:3,自引:2,他引:1
以热喷雾法制备的MgAl2.6(OH)x粉末、水玻璃和MgCb为原料,用沉淀包裹法制备堇青石前躯体粉末。通过控制沉淀过程中体系的pH值,在MgAl2.6(OH),粉末粒子上形成无定形连续包裹层。烧结过程中,在700℃之前,包裹层与被包裹粒子反应形成无定形相;在850℃,从无定形体系中析出的纳米尖晶石对致密化烧结过程没有影响,相反,方石英的析出将阻碍烧结。堇青石的烧结属液相烧结,其致密化过程发生在堇青石合成之前。700℃煅烧的堇青石前躯体在1250℃烧结2h,其相对密度可达96.4%。 相似文献
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Preparation of Mullite Cordierite Composite Powders by the Sol-Gel Method: Its Characteristics and Sintering 总被引:4,自引:0,他引:4
Mohamed G.M.U. Ismail Hideo Tsunatori Zenjiro Nakai 《Journal of the American Ceramic Society》1990,73(3):537-543
Mullite/cordierite composite powders containing different proportions of cordierite were prepared by the sol-gel method using boehmite, colloidal silica, and Mg(NO3 )2 ·6H2 O. Mullite and cordierite sols were prepared separately and mixed to form the composite sol. Mullitization temperature depends on the cordierite content in the composite. Also, α-cordierite crystallizes at a lower temperature in a mullite-rich (MC20) composite. The XRD patterns of the powders calcined at 1450°C for 12 h showed that mullite and cordierite exist as two different phases, and no additional phases were observed. The IR absorbance spectra of composites showed characteristic peak corresponding to both mullite and cordierite. The sintered density of the powders increases with temperature up to 1450°C and decreases beyound the melting point of cordierite (1455°C). The microstructure of MC30 sintered at 1440°C for 3 h consisted of acicular grains, whereas in MC40 and MC50 equiaxed grain morphology was observed under similar sintering conditions. The flexural strength and Vickers hardness decreases with the increase of cordierite content in the composite. Dielectric constant and thermal expansion showed a similar behavior. 相似文献
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Sintering Behavior and Properties of Iron-Rich Glass-Ceramics 总被引:1,自引:0,他引:1
Alexander Karamanov Giuliana Taglieri Mario Pelino 《Journal of the American Ceramic Society》2004,87(8):1571-1574
Iron-rich glass-ceramics were obtained by the sintering of two glass powders, labeled G1 and G2, at heating rates of 5° and 20°C/min followed by an isothermal step in the 850°–1050°C temperature interval. The sintering process was evaluated by the linear shrinkage; the closed porosity was estimated by density measurements; the structure and the morphology of the glass ceramics were observed by scanning electron microscopy. The bending strength, the Young modulus, and Vickers hardness of the glass-ceramics materials were evaluated. The results showed that the sintering process and morphology of the glass-ceramics depends on the amount of magnetite and pyroxene formed. With a low percentage of crystal phase formed (25%–30% typical of G1) the structure is characterized by closed porosity; at higher crystallization (45%–50% typical of G2) open porosity is mainly formed. The properties of the glass-ceramics were not influenced by the heating rate but improved with an increase in the degree of crystallization. 相似文献
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以萤石尾矿和废玻璃为主要原料,硅酸钙为添加剂,采用烧结法制备微晶玻璃。利用X射线衍射仪、扫描电子显微镜等对微晶玻璃的析晶特性和微观形貌进行表征,利用Image Pro Plus统计晶粒的尺寸和数量,利用Factsage软件对不同配比下微晶玻璃制备过程中的物相和高温液相量的变化进行表征,并对微晶玻璃的抗折强度和耐酸碱性能进行测试。结果表明:通过废玻璃引入磷元素,可制备出主晶相为氟磷灰石(Ca5P3O12F)的微晶玻璃,且烧成温度范围宽,在1 060~1 180 ℃均可得到表现良好的微晶玻璃;随着添加剂硅酸钙配比的提高,主晶相种类并未改变,但氟磷灰石晶粒细化,有利于提升微晶玻璃的机械性能;当萤石尾矿质量分数为30%、废玻璃质量分数为60%、硅酸钙质量分数为10%时,制备的微晶玻璃具有良好的强度和耐酸碱性能。本研究设计的微晶玻璃为萤石尾矿的回收利用提供了新途径,对降低微晶玻璃生产成本和促进固废资源循环经济的发展具有重要的现实意义和经济效益。 相似文献
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Alexander Karamanov † Giuliana Taglieri Mario Pelino † 《Journal of the American Ceramic Society》2004,87(7):1354-1357
The sintering and the crystallization of two iron-rich glass compositions (45–75-μm powder fractions) were studied in air and nitrogen atmospheres. The phase formation was evaluated by differential thermal analysis, while the densification, by dilatometry; the crystalline phases were identified by X-ray diffraction and the structure observed by scanning electron microscopy. It was highlighted that, due to the absence of Fe2+ oxidation and lower viscosity of the parent and residual glasses, the sintering in nitrogen atmospheres occurs at 100°–200°C lower temperature. In the same time the higher amount of crystal phase, formed during sinter–crystallization in inert atmosphere, improves the mechanical properties. A value of 120 MPa for the bending strength was obtained after 1-h sintering at 960°C in N2 . 相似文献
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