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
1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of e...1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of eordierite bricks for ceramic burner of blast furnace and hot blast stove.展开更多
In this paper,cordierite-based porous ceramics with magnetic properties have been firstly in-situ synthesized by using MgO,Al_(2)O_(3),and SiO_(2) powders as raw materials and Fe_(3)O_(4) as a functional additive.Comb...In this paper,cordierite-based porous ceramics with magnetic properties have been firstly in-situ synthesized by using MgO,Al_(2)O_(3),and SiO_(2) powders as raw materials and Fe_(3)O_(4) as a functional additive.Combining with the foam freeze casting method,near net size fabrication(total linear shrinkage<2.86%)of the magnetic porous materials was realized by adjusting the amount of Fe_(3)O_(4).The porosity,compressive strength,and saturation magnetization of the prepared materials were 83.9%-87.8%,1.51-2.65 MPa,and 1.2-5.8 emu/g,respectively.The phase composition and microstructure evolutions during sintering were investigated briefly.The results showed that the synthesis temperature of cordierite was lowered about 100℃ due to the addition of Fe_(3)O_(4).Except for the main phase-cordierite,Mg-Al-Fe spinel and α-Fe_(2)O_(3) also existed in the final materials.The lattice parameters of the Mg-Al-Fe spinel and the amount of α-Fe_(2)O_(3) changed obviously with the change in the sintering temperature and Fe_(3)O_(4) amount,which mainly influenced the magnetic properties of the prepared materials.Thus,a facile fabrication method of the cordierite-based porous ceramics with the magnetic properties has been put forward in this paper.展开更多
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.
文摘1 Scope This standard specifies the classification, brand, technical requirements, shape and dimension, test method, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of eordierite bricks for ceramic burner of blast furnace and hot blast stove.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.2020YJS148 and 2022JBZY025)State Key Laboratory of New Ceramics and Fine Processing Tsinghua University(Grant No.KFZD201902)+1 种基金Beijing Natural Science Foundation(Grant No.2182059)the Beijing Government Funds for the Constructive Project of Central Universities.
文摘In this paper,cordierite-based porous ceramics with magnetic properties have been firstly in-situ synthesized by using MgO,Al_(2)O_(3),and SiO_(2) powders as raw materials and Fe_(3)O_(4) as a functional additive.Combining with the foam freeze casting method,near net size fabrication(total linear shrinkage<2.86%)of the magnetic porous materials was realized by adjusting the amount of Fe_(3)O_(4).The porosity,compressive strength,and saturation magnetization of the prepared materials were 83.9%-87.8%,1.51-2.65 MPa,and 1.2-5.8 emu/g,respectively.The phase composition and microstructure evolutions during sintering were investigated briefly.The results showed that the synthesis temperature of cordierite was lowered about 100℃ due to the addition of Fe_(3)O_(4).Except for the main phase-cordierite,Mg-Al-Fe spinel and α-Fe_(2)O_(3) also existed in the final materials.The lattice parameters of the Mg-Al-Fe spinel and the amount of α-Fe_(2)O_(3) changed obviously with the change in the sintering temperature and Fe_(3)O_(4) amount,which mainly influenced the magnetic properties of the prepared materials.Thus,a facile fabrication method of the cordierite-based porous ceramics with the magnetic properties has been put forward in this paper.