共查询到19条相似文献,搜索用时 93 毫秒
1.
2.
采用注凝成型技术研究了HfB2-Si3N4复合材料浆料的流变性能.主要讨论了pH值、分散剂、固相含量、球磨时间等对HfB2-Si3N4复合材料浆料粘度的影响.结果表明:当分散剂用量为8%(体积分数),pH值为10.9,球磨时间控制在15~20 h时,可制得固相体积含量为38%,粘度为600 mPa·s的HfB2-Si3N4复合浆料. 相似文献
3.
几种因素对刚玉-尖晶石复合浆料粘度的影响 总被引:1,自引:0,他引:1
研究了分散剂 (包括AN - 2 0 0 0、聚丙烯酸铵、三聚磷酸钠以及质量比为 1 1的三聚磷酸钠和六偏磷酸钠 )、浆料固相体积含量及助烧剂电熔镁砂细粉对刚玉 -尖晶石浆料粘度的影响。研究结果显示 :AN - 2 0 0 0对该复合浆料具有最佳的分散效果 ;添加 0 .5 %的AN - 2 0 0 0可制得固相体积含量为 5 7%的刚玉 -尖晶石浆料 ,该浆料在剪切速率为 5 0s- 1时粘度为 0 .37Pa·s ;为制备高固相体积分数的刚玉 -尖晶石浆料 ,电熔镁砂的添加量以小于 0 .7%为宜 相似文献
4.
研究了分散剂对纯氮化硅及氮化硅和助烧结剂(氧化铝及氧化钇)多元粉料高固相含量浆料(大于50%)流变性的影响。根据胶体特性的研究结果,选取Al(OH)3溶胶及柠檬酸铵改善高固相含量浆料的流变特性,得到适用于直接凝固注模成型的高固相体积分数、低粘度氮化硅浆料。此外,还研究了固相体积分数对浆料粘度及流变性的影响 相似文献
5.
主要研究了分散剂、pH、颗粒级配等因素对SiC水基浆料流变性能的影响,并分析了其原因。结果表明,各分散剂对SiC浆料粘度影响效果的大小顺序依次为:四甲基氢氧化铵(TMAH)>六偏磷酸钠(SHMP)>聚乙二醇(PEG)。TMAH、SHMP、PEG三种分散剂的最佳用量分别为0.8wt.%、0.6wt.%、1.0wt.%,最佳pH为13,最佳颗粒级配(F220/F1200,下同)为1.5,当固相体积分数超过50%后SiC浆料的粘度急剧增加。通过优化工艺参数,制备出了流动性较好,固相体积分数为50%、粘度为500mPa.s的SiC陶瓷浆料。 相似文献
6.
7.
高固相含量Si3N4浆料的研究(II)——浆料的流变特性 总被引:8,自引:1,他引:8
研究了分散剂对纯氮化硅及氮化硅和助烧结剂(氧化铝及氧化钇)多元粉料高固相含量浆料(大于50%)流变性的影响。根据胶体特性的研究结果,选取Al(OH)3溶胶及柠檬酸铵改善高固相含量浆料的流变特性,得到适用于直接凝固注模成型的高固相体积分数、低粘度氮化硅浆料。此外,还研究了固相体积分数对浆料粘度及流变性的影响。 相似文献
8.
9.
10.
11.
Maomao Ding Ying Shi Jianjun Xie Ding Zhou Yu Wang Fang Lei Lei Zhang 《International Journal of Applied Ceramic Technology》2020,17(1):285-295
Aluminum nitride (AlN) ceramic substrates have been fabricated using non-aqueous tape casting and pressureless densification under flowing N2 atmosphere. Considering the economic and environmental impact, a new strategy of solvent and dispersant system was adopted to prepare AlN slurries with high solid loading. According to the viscosity characteristics of AlN slurries, dispersant content was adjusted to be 0.5 wt% of AlN powder in order to optimize the rheological behavior of AlN slurries. The addition contents of binder and plasticizer were both optimized as 5 wt% of AlN powders by combining the viscosity of slurries and tensile strength of green tapes. Green AlN tapes were fabricated with an optimized tape casting process such as dry temperature. The exclusion process of organic additives was investigated by employing thermogravimetric analysis. Flat and dense AlN ceramic substrates with a relative bulk density over 99.75 % were achieved after being sintered under 1800°C for 6 hours, which had a maximum size of 110 × 110 mm. The thermal conductivity of the AlN substrate could reach 145 Wm−1K−1. 相似文献
12.
13.
A new direct coagulation casting process for alumina slurries prepared using poly(acrylate) dispersant 总被引:1,自引:0,他引:1
Direct coagulation casting (DCC) of concentrated aqueous alumina slurries prepared using ammonium poly(acrylate) dispersant has been studied using MgO as coagulating agent. Addition of small amounts of MgO increased the viscosity of the concentrated alumina slurries with time and finally transformed it in to a stiff gel. Sufficient working time for degassing and casting could be achieved by cooling the slurries to a temperature of ∼5 °C after proper homogenization after the addition of MgO. The DCC slip with alumina loading in the range of 50–55 vol% showed relatively low viscosity (0.12–0.36 Pa s at shear rate of 93 s−1) and yield stress (1.96–10.56 Pa) values. The wet coagulated bodies prepared from slurries of alumina loading in the range of 50–55 vol% had enough compressive strength (45–211 kPa) for handling during mould removal and further drying. The coagulated bodies prepared from slurries of alumina loading in the range of 50–55 vol% showed linear shrinkage in the range of 4.8–2.3 during drying and 17.1–16.2 during sintering respectively. Near-net-shape alumina components with density >98% TD could be prepared by the DCC process. 相似文献
14.
Owing to low density, hollow glass microspheres (HGMs) float on common media such as water, ethanol, and tertiary butanol. As a result, HGMs are not suitable to prepare slurries and ceramics by gel, slip, and freeze castings. In this paper, polyacrylamide (PAM) was used as dispersant and thickener agent to prepare homogeneous HGM aqueous slurries with controlled solid loadings and subsequent lightweight HGM porous ceramics were prepared by gel casting. Effects of PAM content on the stability of aqueous slurries as well as effects of solid (i.e., HGM) loading on density, porosity, pore size distribution, and compressive strength of porous ceramics were investigated. Increasing the viscosity of the slurry resulted in HGMs with significantly lower floating rates and more stable HGM aqueous slurries. HGM porous ceramics with densities and compressive strengths of 0.127–0.219?g/cm3 and 0.74–1.71?MPa, respectively, were prepared by gel casting. 相似文献
15.
Preparation of alumina by aqueous gelcasting 总被引:6,自引:0,他引:6
The alumina ceramic was prepared by aqueous gelcasting. The effects of zeta potentials, solid loading, dispersant content and milling time on the alumina suspension were studied systematically. The dispersant content has remarkable effects on the viscosity of the suspension. The appropriate dispersant concentration for alumina aqueous slurry with the solid loading of 55 vol.% is 0.6 wt.%. It can be seen that all suspensions (50–56 vol.% solid loading) exhibited a shear-thinning behavior and relatively low viscosity, which was suitable for casting. The degree of shear thinning and the viscosity at high shear rates increased with increasing volume fraction of solid. As the milling time prolongs, viscosity of the suspension decreases first, then the plateau appears and the average diameter keeps changeless. When the milling time was shorter than 20 h, the viscosity of slurries decreased gradually as the time of milling increased. After 20 h milling, the viscosity of the slurry tended to be consistent. Therefore, the ball milling time should be equal to or more than 20 h to obtain a stable suspension at equilibrium. The time available for casting the slurry (idle time) can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing temperature. Micrograph of the gelcast green body was homogeneous. 相似文献
16.
Si3N4—MgAl2O4—ZrO2系陶瓷凝胶注模成型的研究 总被引:1,自引:0,他引:1
本文对Si_3N_4-MgAl_2O_4-ZrO_2系陶瓷料浆注凝成型工艺进行了较系统的研究,着重分析了复合分散剂、PH值及固相含量对粘度的影响,最终获得了固相含量为47vol%,粘度为455mPa·s,注模性能良好的注凝料浆,使用该料浆已制备了多种复杂形状的氮化硅基陶瓷制品。 相似文献
17.
《Journal of the European Ceramic Society》2007,27(7):2671-2677
The condition for the preparation of stable hydroxyapaptite (HA) slurries by aqueous tape casting was identified. To acquire stable low-viscosity slurries, the influences of dispersant, binder and plasticizer on the rheological properties were investigated. The slurries of submicron sized HA behaved as near Newtonian up to a solid loading of 56.1 vol%. Films of HA had very good qualities, such as homogeneity, surface quality, and so on. Results indicated that slurries at selected conditions met the needs of tape casting process. 相似文献
18.
Kuo-Yang Lee Chih-Cheng Chen Hsing-I Hsiang Fu-Su Yen Chi-Yuen Huang 《International Journal of Applied Ceramic Technology》2019,16(4):1493-1500
The dispersant (commercial ammonium polyacrylate), sintering additive (Mg2+), and chelating agent (EDTA) effects on the Zeta potential and rheological behavior of alumina slurry with high solid content were investigated. The alumina ceramic green microstructures and sintered microstructures prepared using slurries with different additives using the gel-casting process were also studied. It was observed that the dispersion deteriorated after adding Mg2+. Slurry simultaneously added with dispersant and EDTA-chelated Mg2+ produced higher absolute Zeta potential value and low viscosity due to EDTA chelating with Mg2+. The sample added with dispersant and EDTA-chelated Mg2+ exhibited a uniform green microstructure, high relative sintered density (99.5% theoretical density), and a nearly pore-free microstructure with an average grain size of about 1.5 μm. For the first time to our knowledge, the maximum Vickers hardness (22 GPa) was obtained for alumina simultaneously added with Mg2+ and EDTA, pressureless sintered at 1500°C in air. 相似文献
19.
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