Papers by Keyword: Solid Content

Abstract: Zirconium sol was prepared using precipitation method. In the process, ZrO(OH)₂ precipitate was firstly obtained through the addition of strong base into the zirconium ions, and then was washed to remove the chloride ion. Lastly, the obtained ZrO(OH)₂ precipitate was dissolved in nitric acid solution to obtain the white mixed solution. The clear and transparent zirconium sol can be obtained after heated the white mixed solution in a water bath. In this study, the effects of three precipitating agents on the properties of zirconium sol were studied. Zirconium sol prepared by using ammonia as precipitating agent is easy to peptize, while its viscosity is very high. On the other hand, zirconium sol prepared by using urea as precipitating agent exhibits low solid content. Notably, the performance of zirconium sol prepared using ammonia and NH₄Cl solution as precipitating agent is best due to its low viscosity and high solid content. In addition, zirconium sol, xerogel and zirconium dioxide powder prepared using ammonia and NH₄Cl solution as precipitating agent were systematically characterized by SEM, viscometer, XRD, FTIR. The optimal zirconium sol was synthesized using a peptizing time of 8 h under a peptizing temperature was 80 °C, and the dried amorphous xerogel was converted to tetragonal ZrO₂ after calcined at 600 °C, while monoclinic at 1000 °C.

Abstract: The piezoelectric ceramic of PMN-PZT was prepared by gelcasting using N-hydroxymothl acrylamide(NMAM) as monomer. The green bodies with different microstructure and properties were obtained by changing solid contents of slurry. The effects of solid volume fraction in slurries on properties of PMN-PZT green bodies were investigated. The results that green shrinkage reduced from 5.95% to 1.47%, the green density increased from 3.51g/cm3 to 4.69g/cm³, and green bending strength increased firstly then decreased when solid content of slurry changed from 45vol% to 60vol%. SEM photographs revealed that^{Superscript text} the green body had a uniform microstructure and few agglomerates when the solid loading was 50vol%.

Abstract: M-AlN (surface modified aluminum nitride powder) suspensions for aqueous gelcasting were prepared Using NH4PAA as dispersant. The effects of pH value, NH4PAA amount and solid content on the rheological behavior of M-AlN suspensions were investigated. The results showed that low viscosity M-AlN aqueous suspensions with high solid content up to 55vol.% were obtained under the condition that the amount of NH4PAA was 0.9 wt. % of M-AlN powder, and pH value was about at 6.8. In spite of this, these suspensions still show a viscosity lower than 0.12 Pa•s at 100s-1, suggesting a good fluidity which can satisfy the requirement of gelcasting.

Abstract: Porous alumina ceramic was prepared using sodium dodecyl benzene sulfonate (SDBS) as foaming agent by the combination method of gel casting and foaming. The effect of solid content on the line shrinkage rate, the porosity, the fracture strength and the microscopic structure of porous aluminum ceramic were studied. The result showed that when solid content increased, the line shrinkage rate of porous alumina ceramic decreased form 20% to 1.2%, the total porosity first increased and then decreased from 43% to 57%, the fracture strength first decreased and then increased from 23MPa to 41MPa. SEM indicated that alumina ceramic had more open pores when solid content was too low, the number of closed pore increased along with solid content rising, when solid content was too high, pore size distribution uniformity decreased.

Abstract: The aeration-vacuum dewatering method is a new kind of solid-liquid separate technique. The filter clogging problem in the routine vacuum dewatering procedure of sludge can be solved by the method. This method is used to dewater the sewage sludge in this paper. Through the dewatering model test of the sewage sludge with this method, the change law of the solid content and the volume of the sewage sludge are studied. The dewatering effect of sewage sludge is got further more. The test results indicate that there is a great promotion for improving the solid content and reducing the volume by using the aeration-vacuum method.

Abstract: This study was triggered by our experience on electrophoretic deposition (EPD) with different suspension systems showing evidence of a particle concentration threshold, below which no deposit was formed. In this study, the role of particle concentration in the mechanism of EPD was investigated with a model system, consisting of isopropanol suspensions with TiO2 nanosized particles (d50 = 130 nm). The investigated concentration range was 0.01 - 0.4 vol% TiO2. Constant voltage EPD tests with variable particle concentration were performed for 1 min under different applied voltages (25 - 300 V corresponding to 62.5 - 750 V/cm). A longer deposition time (30 min) was tested for a lower concentration value (0.003 vol% TiO2). The deposition process was evaluated in situ by means of the current measured during EPD. The deposits obtained were characterized by weight and profile measurements and scanning electron microscope (SEM). The results confirmed the finding of a lower limit value of particle concentration, determining a threshold in the formation of an EPD coating. Above this threshold, proportionality between deposited mass and particle concentration was observed, in agreement with the equation of Hamaker. Below this threshold, the proportionality was lost with evidence of a lack of coating formation. A possible interpretation for this experimental finding was provided.