In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructure...In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructures were studied by XRD and SEM. The results indicate that the samples have a wide firing temperature range. The main crystal phases are CaA12SizOs, a-Al203, Fe203, which distribute uniformly in the samples. The sample have the best properties in the series ＇Ca-A1-Si＇, and water absorption （Wa）, porosity （Pa）, bulk density （D）, bending strength and compressive strength are 7.24%, 15.82%, 2.19 g.cm＂3, 45.57 MPa and 56.81 MPa respectively, when the addition amount of East-lake sediment is 80% and the firing temperature is 1 100 ~C. In the series ＇K-A1-Si＇, the sample with the best properties was obtained when addition amount of East-lake sediment was 70% and firing temperature was 1 060 ~C. The water absorption, porosity, bulk density, bending strength and compressive strength are 7.62%, 16.37%, 2.15 g ~ cm＂3, 39.26 MPa, and 50.81 MPa respectively. They all come up to the national standardization, and meet the needs of manufacturing production.展开更多
Mullite and corundum co-bonded SiC-based composite ceramics(SiC-mullite-Al2O3)were prepared by using SiC,calcined bauxite and kaolin via pressureless carbon-buried sintering.The low-cost SiC-based composite ceramics d...Mullite and corundum co-bonded SiC-based composite ceramics(SiC-mullite-Al2O3)were prepared by using SiC,calcined bauxite and kaolin via pressureless carbon-buried sintering.The low-cost SiC-based composite ceramics designed in this study are expected to be used as thermal storage materials in solar thermal power generation based on the high density and excellent thermal shock resistance.The influences of calcined bauxite addition and sintering temperature on the microstructures,phase compositions,and physical properties of the samples were investigated.Results demonstrated that the introduction of calcined bauxite containing two bonding phases greatly reduced the lowest sintering temperature to 1400℃.The SiC-mullite Al2O3 composite with 40 wt%calcined bauxite sintered at 1500℃exhibited optimum performance.The density and bending strength were 2.27 g·cm^-3 and 77.05 MPa.The bending strength increased by 24.58%and no cracks were observed after 30 thermal shock cycles,while general clay would reduce the thermal shock resistance of SiC.The SiC-mullite-Al2O3 composites with satisfied performance are expected to be used as thermal storage materials in solar thermal power generation systems.展开更多
For improving the properties of SiC-mullite composite ceramics used for solar sensible thermal storage, MnO2 was introduced as sintering additive when preparing. The composite ceramics were synthesized by using SiC, a...For improving the properties of SiC-mullite composite ceramics used for solar sensible thermal storage, MnO2 was introduced as sintering additive when preparing. The composite ceramics were synthesized by using SiC, andalusite, a-Al2O3 as the starting materials with non-contact graphite-buried sintering method. Phase composition and microstructure of the composites were investigated by XRD and SEM, and the effect of MnOz on the properties of SiC composites was studied. Results indicated that samples SM1 with 0.2 wt% MnO2 addition achieved the optimum properties： bending strength of 70.96 MPa, heat capacity of 1.02 J.（g.K）-1, thermal conductivity of 9.05 W-（m.K）-1. Proper addition of MnO2 was found to weaken the volume effect of the composites and improve the thermal shock resistance with an increased rate of 27.84% for bending strength after 30 cycles of thermal shock （air cooling from 1 100 ℃ to RT）. Key words： SiC-mullite composite ceramics; MnO2; solar sensible thermal storage; non-contact graphite-buried sintering; thermal shock resistance展开更多
Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abunda...Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insuffi cient encapsulation effi ciency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required fi ne size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.展开更多
To efficiently utilize the kaolin, an economical way of preparing cordierite ceramic with high performance for electric heater supports was put forward. In this study, sintering process, phase transformation, microstr...To efficiently utilize the kaolin, an economical way of preparing cordierite ceramic with high performance for electric heater supports was put forward. In this study, sintering process, phase transformation, microstructure evolutions were systematically studied by heating microscope, X-ray diffraction, scanning electronic microscope and thermal analysis. Properties（physical properties, electrical properties and coefficient of thermal expansion（CTE）） were tested for comprehensive performance evaluation. The results showed that the utilization of poor quality kaolin broadened the firing range of cordierite ceramic which was from 1 200 to 1 380 ℃. Microstructure becomes loose with increasing of the pore size, which had significant influence on bending strength and electrical properties. High content of K2 O in poor quality kaolin was the reason for liquid phase generation in sintering process, which further leads to microstructural changes. The cordierite ceramic sintered at 1 320 ℃ had the properties as follows： CTE of 1.98×10^（-6） ℃^（-1）（500 ℃）, bending strength of 90 MPa, apparent porosity of 15.1%, dielectric constant of 7.5（100 Hz）, and volume resistivity of 1.05×109 Ω·cm（100 Hz）. The comprehensive properties are very suitable for use as electric heater supports.展开更多
文摘In order to utilize solid wastes, ceramic facing brick was made form East-lake sediment and some additives. The strength and freeze-thaw resistance of the samples were tested, and the crystal phases and microstructures were studied by XRD and SEM. The results indicate that the samples have a wide firing temperature range. The main crystal phases are CaA12SizOs, a-Al203, Fe203, which distribute uniformly in the samples. The sample have the best properties in the series ＇Ca-A1-Si＇, and water absorption （Wa）, porosity （Pa）, bulk density （D）, bending strength and compressive strength are 7.24%, 15.82%, 2.19 g.cm＂3, 45.57 MPa and 56.81 MPa respectively, when the addition amount of East-lake sediment is 80% and the firing temperature is 1 100 ~C. In the series ＇K-A1-Si＇, the sample with the best properties was obtained when addition amount of East-lake sediment was 70% and firing temperature was 1 060 ~C. The water absorption, porosity, bulk density, bending strength and compressive strength are 7.62%, 16.37%, 2.15 g ~ cm＂3, 39.26 MPa, and 50.81 MPa respectively. They all come up to the national standardization, and meet the needs of manufacturing production.
基金Funded by the National Key Research and Development Program of Science and Technology of China(No.2018YFB1501002).
文摘Mullite and corundum co-bonded SiC-based composite ceramics(SiC-mullite-Al2O3)were prepared by using SiC,calcined bauxite and kaolin via pressureless carbon-buried sintering.The low-cost SiC-based composite ceramics designed in this study are expected to be used as thermal storage materials in solar thermal power generation based on the high density and excellent thermal shock resistance.The influences of calcined bauxite addition and sintering temperature on the microstructures,phase compositions,and physical properties of the samples were investigated.Results demonstrated that the introduction of calcined bauxite containing two bonding phases greatly reduced the lowest sintering temperature to 1400℃.The SiC-mullite Al2O3 composite with 40 wt%calcined bauxite sintered at 1500℃exhibited optimum performance.The density and bending strength were 2.27 g·cm^-3 and 77.05 MPa.The bending strength increased by 24.58%and no cracks were observed after 30 thermal shock cycles,while general clay would reduce the thermal shock resistance of SiC.The SiC-mullite-Al2O3 composites with satisfied performance are expected to be used as thermal storage materials in solar thermal power generation systems.
基金Funded by the Major State Basic Research Development Program of China(973 Program)(No.2010CB227105)
文摘For improving the properties of SiC-mullite composite ceramics used for solar sensible thermal storage, MnO2 was introduced as sintering additive when preparing. The composite ceramics were synthesized by using SiC, andalusite, a-Al2O3 as the starting materials with non-contact graphite-buried sintering method. Phase composition and microstructure of the composites were investigated by XRD and SEM, and the effect of MnOz on the properties of SiC composites was studied. Results indicated that samples SM1 with 0.2 wt% MnO2 addition achieved the optimum properties： bending strength of 70.96 MPa, heat capacity of 1.02 J.（g.K）-1, thermal conductivity of 9.05 W-（m.K）-1. Proper addition of MnO2 was found to weaken the volume effect of the composites and improve the thermal shock resistance with an increased rate of 27.84% for bending strength after 30 cycles of thermal shock （air cooling from 1 100 ℃ to RT）. Key words： SiC-mullite composite ceramics; MnO2; solar sensible thermal storage; non-contact graphite-buried sintering; thermal shock resistance
文摘Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insuffi cient encapsulation effi ciency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required fi ne size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.
基金Funded by the Major State Basic Research Development Program of China(973 Program)(No.2010CB227105)
文摘To efficiently utilize the kaolin, an economical way of preparing cordierite ceramic with high performance for electric heater supports was put forward. In this study, sintering process, phase transformation, microstructure evolutions were systematically studied by heating microscope, X-ray diffraction, scanning electronic microscope and thermal analysis. Properties（physical properties, electrical properties and coefficient of thermal expansion（CTE）） were tested for comprehensive performance evaluation. The results showed that the utilization of poor quality kaolin broadened the firing range of cordierite ceramic which was from 1 200 to 1 380 ℃. Microstructure becomes loose with increasing of the pore size, which had significant influence on bending strength and electrical properties. High content of K2 O in poor quality kaolin was the reason for liquid phase generation in sintering process, which further leads to microstructural changes. The cordierite ceramic sintered at 1 320 ℃ had the properties as follows： CTE of 1.98×10^（-6） ℃^（-1）（500 ℃）, bending strength of 90 MPa, apparent porosity of 15.1%, dielectric constant of 7.5（100 Hz）, and volume resistivity of 1.05×109 Ω·cm（100 Hz）. The comprehensive properties are very suitable for use as electric heater supports.
