Papers by Keyword: Mullite

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Authors: M.S. Başpınar, Wolfgang Schulle, Ferhat Kara
Authors: Gui Hua Hou, Zhan Hong Wang, Yui Chi Cui
Abstract: A new idea for improving heat fade performance of organic based friction materials was invented; the method is to dope high specific heat material to the matrix for increasing the specific heat capacity of matrix. In this paper, selecting mullite as additive, organic based friction samples doping mullite were prepared by thermoforming methods, the specific heat of samples were analyzed by TG-DSC, and its friction and wear were tested by GB/T 5764-1998 in China. The results show that doping mullite to matrix can dramatically improve the heat fade performance of organic based friction materials, the friction coefficient of samples can keep steady among 0.3-0.4 when the test temperature is from room temperature to 350°C,while the friction coefficient of the reference samples without mullite decline from 0.38 to 0.19.
Authors: Hai Hong Zhan, Jian Min Zeng, Ping Chen, Zhuo Yi Lin
Abstract: A new porous nozzles for refining molten aluminum were made from mullite,graphite powder, red mud and sodium silicate. The relationships between graphite content and permeability, sintering parameters and permeability, graphite content and compressive strength were investigated, respectively. The internal structures of the nozzle before and after sintering were observed by SEM. The experimental results show that the permeability of sample can be improved by sintering at temperature of 1000°C for 2 hours. As graphite content increases, the permeability of sample increases, yet the ultimate compressive strength decreases. The compressive strength can be enhanced by using combination of different sizes of mullite particles.
Authors: An Ran Guo, Jia Chen Liu, Yi Bing Sun, Wen Jun Lian, Lu Yang
Abstract: A new technique of flyash utilization was presented and high-purity silica was prepared by alkali leaching. The flyash was added into sodium hydroxide solution, and then the suspension was heated to 115 °C for 30 min. After filtrated, the filtrate was collected and carbon dioxide was imported into the solution. Finally, the silica would precipitate from the solution. The silica was characterized by scanning electron microscopy, X-ray diffraction and X-ray fluorescence spectrometer. The high-purity silica prepared from flyash was qualified for the rubber reinforcing agent used in shoemaking.
Authors: Zhi Yu Liang, Gui Yang Yan, Liu Ping Zheng, Xing Hua Zheng, Yu Zhong Ruan
Abstract: A novel technique of Spent FCC equilibrium catalyst utilization is presented and mullite are prepared from it. The chemical composition, structure and thermal stability of the spent FCC equilibrium catalyst from oil refinery are characterized by XRD, FT-IR, DTA-TG, Fully chemical analysis technique, SEM. Mullite specimens are prepared by reaction sintering the spent FCC equilibrium catalyst at different temperatures. The result indicates that at 1300-1350°C, the spent FCC equilibrium catalyst could be used to prepare high purity mullite.
Authors: Kai Li, Hai Jian Li, Ping Wu
Abstract: This paper studied the problems met in the quantitative analysis of synthetic Mullite phase,which was based on the analysis of various typical Mullite composite scheme. A method of quantitative analysis of Mullite phase (excluding amorphous phase SiO2) by use X-ray diffraction was discussed. The error of the analysis can be verified by chemical analysis of Al2O3 content. The method can effectively improve the accuracy of quantitative analysis of the Mullite phase, the error analysis is less than 3%. The error range can meet the accuracy requirement of Mullite content in the production.Studies show that this method is preliminarily solved how to quantitative the content of mullite phase by X-ray diffraction method .
Authors: Tatiana V. Vakalova, Larisa P. Govorova, Antonina A. Reshetova, Anna Y. Tokareva, Ekaterina V. Shvagrukova
Abstract: It is found out that activation of the sintering process for refractory clay-containing raw materials (rusk kaolin and wocheinite) is provided using additives of 3d-transition elements oxides (Fe2O3 and MnO2) in the amount of 2 - 5 wt. % due to formation of defective solid solutions of mullite by isovalent substitution mechanism as well as fluxing additives of alkaline and alkaline-earth oxides (Na2O, MgO) in the amount of 2 wt. % by regulating rheological properties of silicate melts.
Authors: Pankaj N. Shrirao, Parvezalam I. Shaikh, Farazuddin Zafaruddin, A.N. Pawar
Abstract: Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3 .2SiO2 (mullite) (Al2O3= 60%, SiO2= 40%) over a 150 µm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on emission characteristics of diesel engine with and without mullite coating under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as29.41% and 24.35% decreasing on CO and HC emissions respectively for LHR (mullite coated) engine compared to conventional engine (without coating) at full load. The average decrease in smoke density in the LHR engine compared with the conventional engine was 13.82 % for full engine load. However, there was as much as 20% increasing on NOx emission for LHR engine compared to conventional engine at full load. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.
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