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本文探讨了不同SiO2/Al2O3摩尔比对碱-硼-硅(ABS)系统无毒低温熔剂耐蚀性、光泽度、热膨胀系数等性能的影响规律;并采用SEM、FT-IR分析技术,对熔剂进行表征,从结构方面阐释了其性能变化的原因.结果表明:当n(SiO2)/n(Al2O3)取值范围为8~8.5时,熔剂的耐蚀性强、光泽度好、热膨胀系数低,原因是在此取值范围内熔剂结构中[BO3]伸缩振动峰和弯曲振动峰比较窄,即此时熔剂中的[BO3]数量较少,试样的显微结构更致密所致. 相似文献
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对具有不同Al2O3/SiO3比的双相铝硅凝胶的烧结行为及陶瓷材料的显微结构进行了研究,结果表明,少量液相的存在对先驱粉末的致密率和材料显微结构有显著的影响。富硅莫来石先驱粉末成型体能在较低的温度下常压烧结,相对密度高达98%以上,试样有柱状莫来石晶粒存在。 相似文献
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本文研究了镧系硼酸盐玻璃的基础组成对近紫外-可见波段光吸收的影响规律,并从玻璃结构网络强度讨论了硼硅比和不同的二价阳离子对本征吸收的影响以及从配位场理论讨论了基质玻璃的阳离子场强变化对着色杂质(铁离子)光吸收的影响。 相似文献
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B2O3—Y2O3添加剂对AlN陶瓷显微结构及性能的影响 总被引:7,自引:1,他引:7
研究了以B2O3-Y2O3作为助烧结剂的AlN陶瓷的烧结特性及显微结构。结果表明,晶界处存在YAlO3,Y4Al2O3及Y3Al5O12等各种铝酸钇结晶物,B2O3可固溶到铝酸钇中形成固溶体。 相似文献
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ZnO—B2O3—SiO2系统的介电性能研究 总被引:4,自引:0,他引:4
对ZnO-B2O3-SiO2三元系统进行了XRD和介电性能研究,提出系统的主晶相为方石英,另外还存在Zn2SiO4相。Zn2SiO4的ε为7.7,tgδ≤5×10^-4,αc(介电常数温度变化率)为+90×10^-5/℃。调整各组分,获得一系列αc〉0的超低介电常数的介质陶瓷,其中介电性能为:ε≤5,Ri≥10^13Ω,αc=0±30×10^-5/℃的组分,其烧结温度为1140℃,可用来制造高频低 相似文献
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n(B2O3)/n(SiO2)对硼硅酸盐玻璃结构和性能的影响 总被引:3,自引:0,他引:3
采用热膨胀仪、扫描电镜和红外光谱仪研究了硼硅酸盐玻璃的结构与性能随n(B2O3)/n(SiO2)和n(B2O3)/n(Na2O)的变化规律,深入探讨了结构对分相、热膨胀系数和膨胀软化温度的影响规律。结果表明:热膨胀系数取决于玻璃中[BO3]、[BO4]和[SiO4]的数量变化;玻璃的转变温度和软化温度主要由SiO2决定;[BO3]对玻璃的分相有着重要的影响;不论n(B2O3)/n(Na2O)比值多少,玻璃结构中均存在[BO3]和被破坏的[SiO4]。 相似文献
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《Ceramics International》2021,47(24):34396-34404
The effect of C/A ratio (abbreviation of w(CaO)/w(Al2O3)) on the crystallization characteristics was investigated. With an increase in C/A ratio from 1.1 to 1.8, the crystallization ability first decreased and then increased; the crystallization ability is weakest and strongest with C/A ratios of 1.5 and 1.8, respectively. Increasing C/A ratio, the crystalline phase changed from LiAlO2 and CaO·Al2O3 to LiAlO2 and 3CaO·Al2O3. The Li+ ions in the slag took precedence over Ca2+ ions to participate in charge compensation because the mold flux contains Al3+ which is more advantageous for a monovalent cation, and LiAlO2 formed preferentially over CaO·Al2O3. With a further increase in C/A ratio, 3CaO·Al2O3 formed from the combination of Ca2+ ions and QAl2 units, and the precipitated amount of 3CaO·Al2O3 increased. 相似文献
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H3BO3对Zn2SiO4:Mn绿色荧光粉性能的影响 总被引:4,自引:2,他引:2
采用溶胶-凝胶法,通过选择合适的助熔剂、调整助熔剂添加比例等手段,制备了发光强度高、颗粒形貌良好的Zu2SiO4:Mn绿色荧光粉.结果表明:选择H3BO3作为助熔剂,经800℃预烧2h,900℃煅烧4h的二次煅烧,样品中形成了α-Zn2SiO4相,有效地控制了颗粒的形貌,并改善了发光性能.通过改变H3BO3的加入量,可控制颗粒形状和大小.光致发光测试表明:添加H3BO3作为助熔剂对Zu2SiO4:Mn的光谱未产生不利的影响,但添加助熔剂样品的发光强度较未添加助熔剂样品有很大的提高,且添加助熔剂样品的发光强度与商用荧光粉相当. 相似文献
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Sm2O3掺杂对BaO-B2O3-Al2O3-SiO2玻璃形成及结构的影响 总被引:2,自引:2,他引:0
借助魔角旋转核磁共振技术,探讨掺Sm2O3后BaO-B2O3-Al2O3-SiO2(BBAS)玻璃(BBASS玻璃)的形成、结构及热处理条件下玻璃结构的变化情况.研究表明:随着稀土掺量的增加,BBASS玻璃的形成区域先扩大后缩小.在Sm2O3外掺摩尔分数为30%时BBASS玻璃具有最大的形成区域.在BBAS玻璃结构中,随着BaO含量的增加,硼氧三角体[BO3]逐渐向[BO4]转变,原先[AlO4],[AlO5],[AlO6]共存的铝氧多面体结构逐渐转变为大量[AlO4]和少量[AlO5]共存的结构.在BBASS玻璃结构中,随着5m2O3掺入量的增加,Sm2O3对铝氧多面体结构变化的影响与BaO类似;对硼氧多面体而言,Sm3 强大的积聚作用使玻璃结构中硼氧多面体形成了巨大的网络.以上差异说明了Al3 比B3 更容易进入稳定的四面体结构.热处理对玻璃结构影响甚微. 相似文献
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将烧结的Al2O3/PSZ(3Y)陶瓷材料在不同温度和时间下进行热处理,对不同热处理制度下的试样致密性能和力学性能进行了测试,用X射线衍射分析了热处理前后材料中的各晶相的变化情况。结果表明:1560℃烧结的Al2O3/PSZ(3Y)陶瓷材料,经1100℃热处理6小时后其抗弯强度达到680MPa,比未处理试样的强度提高了近30%。热处理后基体中出现的不同晶格常数的四方氧化锆晶相对提高材料的力学性能有利。 相似文献
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The relationship between the viscosity and structure of B2O3-containing calcium-silicate-based mold fluxes and the effects of fluidizers including CaF2, CaO, and B2O3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy. The viscosity decreased with increasing CaF2 addition up to 28 wt% at a fixed CaO/SiO2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca2+ and O2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol. With regard to the B2O3-melt, polymerization of the network structure was observed by comparing the B2O3-free to 4.4 wt% B2O3 content. However, the viscosity was relatively constant with increasing B2O3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt% B2O3. The break temperature decreased with greater B2O3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt% B2O3. 相似文献