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含有α-氮化硅晶须的氮化硅流延浆料的制备 总被引:2,自引:0,他引:2
通过分析粘度、ζ-电位等参数,研究烧结助剂、分散剂、粘结剂等对含有α-氮化硅晶须陶瓷浆料的粘度的影响,并确定了最佳的工艺参数。结果发现:Si3N4悬浮粒子的等电点在pH=4.3,其最佳的ζ-电位在pH=11附近。分散剂的引入有效地提高悬浮粒子的ζ-电位等电点,改善浆料的分散性,最佳分散剂用量在1.9%~2.1%(质量分数)之间。制备了具有一定固相含量,流动性和稳定性良好的适合于流延工艺的陶瓷浆料,成型的膜片具有一定的柔韧性。 相似文献
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通过沉降实验、Zeta电位的测定及粘度和流变性能测量的方法研究了制备高固相含量TiB2泡沫陶瓷浆料的工艺条件;通过挂挂浆量的测定及烧结体的扫描照片分析研究了浸渍工艺的条件。研究表明:浆料最佳pH值为9,分散剂的引入有效提高了悬浮粒子的Zeta电位,改善浆料的分散性,最佳的分散剂含量为0.3wt%,最佳固相含量为77wt%。 相似文献
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不同颗粒尺寸α-A12O3粉体制备稳定浆料的研究 总被引:9,自引:2,他引:9
通过改变pH值和分散剂的浓度,对不同颗粒尺寸的α—A12O3粉体制得浆料的稳定性、分散性以及流变特性进行研究.结果表明。pH值和分散剂用量对α—A12O3浆料的稳定性和分散性有显著影响.用不同颗粒尺寸的α—A12O3粉体制备高稳定、高分散的陶瓷浆料,其量适pH值和量佳分散剂用量各不相同.α—A12O3浆料的流变特性呈剪切稀化特点,悬浮浆料的粘度随固含量的增加而上升,而最佳分散剂用量不随浆料固含量的变化而改变. 相似文献
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阳离子松香中性施胶剂 总被引:6,自引:0,他引:6
以松香、环氧氯丙烷及三乙胺为原料,按照物质的量比1∶0-7∶0-7 投料,搅拌下恒温90℃回流4 ~6h,合成出自身阳离子型的松香胶(SCR) 。将上述胶料在强烈机械搅拌下加水及其它辅助助剂配成质量分数为1% 的白色乳液,用电泳法测其在pH 值为4 ~9 时的Zeta 电位值,波动范围均在+ 25mV~+52mV之间。同一乳液在中、碱性条件下(pH=6~9) ,Zeta 电位几乎为恒定值且略高于酸性条件下的Zeta 电位,因此SCR胶料更适于用作中性及弱碱性条件下的纸张施胶剂。杂质盐CaCl2 、MgCl2 会明显降低SCR胶料的Zeta 电位。造纸业中常用的CaCO3 填料也会使SCR胶料的Zeta 电位略有降低,但变化并不明显。分别添加含有少量CaCl2 、MgCl2 及CaCO3 的胶料乳液到纤维悬浮液中,控制体系的pH值为6-5 ~8-5,胶料在纤维上的吸附显微照片显示,在此条件下胶料均可以在纤维上较好地吸附。 相似文献
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通过对影响氮化硅浆料流变性因素的研究发现:不同的氮化硅粉体具有不同的等电点(isoelectric poing,简称IEP)。分散剂的引入明显改善浆料的流动性。对于粉体A,当分散剂用量达1.2wt%时浆料具有最佳的流动性。颗粒尺寸及其形貌对浆料的流动性均有较大的影响:颗粒尺寸越大,颗粒形貌越不规则,浆料的流动性就越差。 相似文献
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氮化硅粉体水基悬浮液电动特性的研究 总被引:1,自引:0,他引:1
通过测量氮化硅粉体在水溶液中的Zeta电位和颗粒大小j研究了不同条件下氮化硅水基悬浮液的电动特性。结果表明,溶液的pH值以及引入的聚合电解质不同均会使氮化硅颗粒表面的荷电状态发生变化,进而导致粉体在水溶液中的分散状况发生改变.在碱性条件下添加适量的阴离子聚电解质有利于氮化硅水基悬浮液的稳定分散。 相似文献
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《Ceramics International》2016,42(3):4347-4353
A direct coagulation casting method for silicon nitride suspension via dispersant reaction was reported. Tetramethylammonium hydroxide (TMAOH) was used as dispersant to prepare silicon nitride suspension with high solid loading and low viscosity. Influences of TMAOH and pH value on the dispersion of silicon nitride powder were investigated. Glycerol diacetate (GDA) was used to coagulate the silicon nitride suspension. Influences of the concentration of glycerol diacetate on the viscosity and pH value of the suspension were investigated. It was indicated that high viscosity sufficient to coagulate the suspension was achieved by adding 1.0–2.0 vol% glycerol diacetate at 40–70 °C. The coagulation mechanism was proposed that the silicon nitride suspension was destabilized by dispersant reacting with acetic acid which was hydrolyzed from glycerol diacetate at elevated temperature. Coagulated samples could be demolded without deformation by treating 50 vol% silicon nitride suspensions with 0.2 wt% tetramethylammonium hydroxide and 1.0–2.0 vol% glycerol diacetate at different temperatures. Dense silicon nitride ceramics with relative density above 98.8% had been prepared by this method using glycerol diacetate as coagulating agent sintered by different methods. 相似文献
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This work focuses on the optimization of the rheological properties of silicon suspensions by changing the concentration of a dispersant and the pH value of the dispersing medium. The zeta potential and rheological properties of silicon suspensions as a function of tetramethyl ammonium hydroxide (TMAH) concentration were carried out. The results show that the isoelectric point of the silicon particles was at pH 1.6. A silicon suspension with 46 vol.% particles displayed a minimum viscosity at pH 9.6. The results also show that TMAH is an efficient dispersant by enhancing the absolute value of the zeta potential of silicon particles. The optimum dosage of the dispersant was 0.4 wt.% of silicon particles. 相似文献
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分散剂用量对碳化硅浆料流变性能的影响 总被引:13,自引:3,他引:10
使用四甲基氢氧化铵(TMAH)作为分散剂,研究了分散剂用量对SiC浆料流变性能的影响,并分析了其原因。结果表明:TMAH能够显著提高SiC粉体的zeta电位,降低浆料粘度,从而显著优化浆料的流变性能。在pH为10左右,加入质量分数为0.3%和o.6%NTMAH后zeta电位分别提高了11.7mV和21mV。实验中,在不同体积分数SiC浆料中,加入0.6%TMAH时能够达到最优性能,浆料粘度都达到最低。过量的分散剂则会增加浆料中的离子浓度而导致双电层厚度减小,从而恶化浆料的流变性。 相似文献
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通过测定超重力法制备的纳米钛酸钡悬浮体的Zeta电位和团粒尺寸分布,确定了纳米BaTiO3在水中稳定分散的基本条件,制备了不同体积分数的悬浮体并研究了其流变学特性. 该纳米BaTiO3在水中的等电点约为pH 2.8,加入分散剂PAA-NH4后,颗粒零电点向更低pH值移动;当分散剂用量为干粉量的1.2%(w)时,悬浮体中平均团粒尺寸最小,分散效果最佳. FT-IR分析证明颗粒表面上PAA-NH4的吸附为物理化学吸附. 制备了体积分数高达45%的纳米BaTiO3悬浮体,其流变特性表现为剪切变薄行为,流延成型的BaTiO3陶瓷生坯片具有较高的相对密度(55.4%). 相似文献
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Electrostatic and electrosteric stabilization of aqueous suspensions of barite nanoparticles were investigated. The state of dispersion was evaluated in terms of zeta potential, apparent viscosity and the mean particle size of solid phase in the solution. Zeta potential, apparent viscosity and the mean particle size as a function of pH were performed in absence of dispersant. The result showed that electrostatic stabilization of the aqueous suspension of barite nanoparticles can be accomplished in low acidic and high basic range of pH. In presence of sodium polyacrylate (PAA-Na) dispersant, the isoelectric point (IEP) of the barite nanoparticles was shifted to lower pH and the negative zeta potential was increased in a large range of pH above the (IEP). The optimum amount of PAA-Na dispersant is discussed in the light of zeta potential and viscosity. It is found that the adsorption of PAA is correlated to the net surface charge of the barite nanoparticles and the fraction of dissociated polymer at pH 4, 8.5 and 10. At pH 4, the state of dispersion was achieved at higher amount of electrolyte due to the low fraction of negatively charged dissociated polymer and the positively charge particles. At basic pH, the fraction of dissociated polymer was high and the surface charge of particle was highly negative, therefore, the lowest viscosity was obtained at a small amount of PAA. In addition, the optimum amount of polymer decreased with the increase in pH of the suspension. 相似文献
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采用Zeta电位表征Al_2O_3粉在悬浮液中的分散特性,研究了超声波分散时间、不同粒度Al_2O_3粉以及分散剂六偏磷酸钠的浓度和Al_2O_3粉体悬浮液pH值对Al_2O_3粉体Zeta电位的影响.研究结果表明:Zeta电位绝对值随超声波作用时间发生明显变化,在一定条件下存在一个最佳分散时间为4~6 min;悬浮液中Al_2O_3粉体颗粒的粒度对悬浮液的Zeta电位有重要影响;在Al_2O_3粉体悬浮液中添加分散剂六偏磷酸钠,Zeta电位随其浓度发生变化,存在一个最佳浓度0.5%;在不同pH值下,Al_2O_3粉体悬浮液的Zeta电位不同,在碱性条件下,粉体的分散性较好,且碱性越强,分散性越好. 相似文献
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采用PAA—NH4作为分散剂制备了超细氧化铝悬桴液,通过沉降实验观察了PAA-NH4的添加量、pH值对α—Al2O3低固含量悬浮液的沉降性能的影响,并用Zeta电位仪测定了不同pH值条件下稀固相含量悬浮液的Zeta电位;同时对烧结坯体进行了微观分析。结果表明:分散剂PAA—NH4的最佳用量为1.0%左右,最佳pH值为9;对添加PAA—NH4前后的稀悬浮液Zeta电位进行了测定,发现等电势点左移,Zeta电位的绝对值变化显著。添加PAA-NH4后,pH值的变化对悬浮液的沉降性能和Zeta电位影响很大。 相似文献