Ceramic for grinding bodies with low firing temperature

Translated from Stekli i Keramika, No. 9, p. 19, September, 1988.     

纳米AlN对低温陶瓷结合剂金刚石磨具结构与性能的影响

文章探讨了纳米AlN对Na2O-B2O3-SiO2硼硅酸盐玻璃体系陶瓷结合剂金刚石磨具结构与性能的影响.在不同气氛条件下烧结的陶瓷结合剂金刚石磨具试样,利用万能压力试验机、洛氏硬度计、扫描电子显微镜等仪器,测试磨具试样的抗折强度、洛氏硬度、耐磨性,以及显微结构等.结果表明:纳米AlN含量为6wt%时,结合剂的开始熔融温度为670℃,比纯结合剂低10℃,且烧结温度范围增大;在氩气气氛下烧成,金刚石磨具试样的抗折强度、洛氏硬度、耐磨性等,比在大气气氛下烧成磨具的均有所提高,其中折强度为60.46MPa,洛氏硬度为88;由SEM图谱可以看出,加入纳米AlN后,结合剂与磨粒间结合良好,且组织均匀.     

烧结温度对低温陶瓷结合剂性能的影响

文章研究了不同烧成温度下低温结合剂的烧结范围、强度、硬度,用XRD和SEM对不同烧成温度下陶瓷结合剂金刚石的结构进行了分析.结果发现:试验陶瓷结合剂在开始软化点725℃最适合陶瓷结合剂金刚石磨具的烧成,在该温度下烧成结合剂呈比较均匀的玻璃状态,对金刚石磨粒的润湿性好;在725℃烧成,结合剂的流动性为120%;结合剂试样的弯曲强度和洛氏硬度最大,分别为58.5MPa和93.5(HRA).     

霞石改性聚烯烃材料的研究

研究了聚烯烃／霞石复合材料的拉伸性能、弯曲性能和表面硬度,并采用扫描电镜直接观察其冲击断面的形态结构以及霞石在基体材料中的分布状态和被包裹状态。研究结果表明：采用硅烷偶联剂可以增进霞石与基体材料间的相互作用,有效地改善材料的力学性能,其处理效果优于只能作为分散剂使用的磷酸酯和聚乙二醇;霞石可以在ＨＤＰＥ、ＰＰ中使用,提高材料的综合性能     

Variations in structure and properties of vitrified bonds and vitrified diamond composites prepared by sol-gel and melting methods at different sintering temperature

Differences in structure and properties of Na₂O–Al₂O₃–B₂O₃–SiO₂ vitrified bonds and vitrified diamond composites prepared by sol-gel and melting methods were methodically discussed. Results showed that the vitrified bond prepared by sol-gel method contained more [AlO₄] tetrahedron and owned higher bending strength, with the maximum value reaching 137 MPa, 31.73% higher than that prepared by melting method (104 MPa). As the sintered temperature rose, coefficient of thermal expansion of the vitrified bond prepared by sol-gel method increased first and then decreased, acquiring a maximum value of 5.75 × 10⁻⁶ °C ⁻¹ at 720 °C, which was still much lower than the minimum value of vitrified bond prepared by melting method (7.02 × 10⁻⁶ °C ⁻¹). The vitrified diamond composite prepared by sol-gel method possessed lower sintering shrinkage than that prepared by melting method, and could be applicable to the production of grinding tools with high dimensional accuracy. What's more, the maximum bending strength of vitrified diamond composites obtained by sol-gel method was 106 MPa, 24.7% higher than that of vitrified diamond composites prepared by melting method (85 MPa).     

霞石正长岩对碱-硅酸反应的影响

以霞石正长岩为代表,研究了含碱集料对碱-硅酸反应膨胀的影响。研究结果表明,80℃或150℃蒸汽养护条件下可快速检测出霞石正长岩对碱-硅酸反应的影响;霞石正长岩在混凝土中的分解反应在增加混凝土可溶碱含量的同时,反应本身还将降低孔溶液OH-浓度,因此由霞石正长岩分解析出的碱与水泥中的碱对碱-硅酸反应影响不同,只有在适当的条件下才能显著增大碱-硅酸反应膨胀。     

霞石在陶瓷工业的应用

文章介绍了霞石在陶瓷工业的独特应用,并阐述了其使用方法、作用原理。     

Use of Nepheline Syenite Tailings in Sewer-Pipe Bodies

Small additions of ground nepheline syenite tailings were incorporated into various sewer-pipe bodies. The lost-cost tailings contained 2 to 3% Fe₂O₃ and significantly improved the physical properties of the sewer-pipe bodies.     

Crystallization and Chemical Strengthening of Nepheline Glass-Ceramics

Electron micrographic and X-ray diffraction techniques were used to study the nucleation and growth of titania-nucleated nepheline in glass. On heating, the glasses phase-separated as a prelude to the crystallization sequence. The first crystalline phase identified was the metastable phase, carnegieite. With time, the equilibrium phase, nepheline, crystallized and the titania crystallized to anatase. The resulting materials were nonporous and largely crystalline. These nepheline glass-ceramics were chemically strengthened by treatments in molten potassium salts. A K⁺→ Na⁺ exchange took place and effected transformation of nepheline to kalsilite. This transformation was a function not only of the exchange treatment, but of the composition of the initial nepheline crystals. Confining the kalsilite surface against a volume increase during the phase transformation created a surface compressive stress. Glass-ceramics containing nepheline crystals with an appropriate structure were chemically strengthened in this manner to yield bulk, abraded modulus of rupture values above 200,000 psi.     

Effect of composition and annealing temperature on the mechanical properties of a vitrified waste

The microhardness and indentation fracture toughness of a vitrified industrial waste, in the form of ash, were characterized by the method of static indentation test. These properties were investigated as a function of composition and thermal treatment conditions. To further understand the influence of the constitutive oxides, additional measurements were made in a series of synthetic products, where a mixture of iron and lead oxides was used as a substitute for the ash. The underlying deformation mechanisms controlling the mechanical properties of such complex systems as determined by static indentation tests are discussed. It was found that plasticity, in the amorphous products, is mainly governed from the silica content, even in the cases where silica is not found in sufficient quantity in order to build an extended three-dimensional vitreous network. On the other hand, the morphology of the separated crystalline phases is the dominant factor affecting plasticity in the glass-ceramic products.     

霞石正长岩在绿色浮法玻璃中的应用研究

以霞石正长岩取代长石,按照绿色浮法玻璃的成分制备配合料并熔制玻璃。通过对熔化过程的观察和对玻璃样品有关性能测试结果的分析,讨论了霞石正长岩作为绿色浮法玻璃原料的可行性。     

个旧霞石综合利用的研究

介绍个旧霞石资源,重点阐述综合利用工艺、设备,对原材料、能源供应和产品销路进行论证,预测投资及效益。     

藻类与煤低温共炭化对低温煤焦油的影响

将不同配比的藻类与煤以低温干馏的方法进行低温共炭化,研究煤焦油的变化.结果表明,煤焦油中轻质油含量增加29.55％,萘类化合物含量增加9.15％,酚类化合物含量增加23.93％,实现一定程度的轻质化.     

Biodiesel usage at low temperature

This paper deals with numerical and experimental analysis of the influence of fuel temperature on the injection process. The tested injection system is the mechanically controlled diesel fuel injection M system of a bus diesel engine. The considered fuels are neat biodiesel from rapeseed oil and neat mineral diesel. All injection parameters, obtained with biodiesel, are compared to those of mineral diesel. At first, attention is focused on a single injection assembly (plunger-in-barrel assembly, high pressure tube, and injector). The flow through a single assembly to one cylinder is investigated numerically by using an one-dimensional mathematical model. The injection process is simulated at different operating regimes. On the basis of the numerical results, the influence of fuel temperatures on the injection characteristics, especially on fuelling at some stage of injection, mean injection rate, mean injection pressure, injection delay, and injection timing is investigated in view of harmful emissions reduction. Furthermore, the fuel flow through the whole injection system (all six injection assemblies) to all six cylinders is investigated experimentally with respect to fuel temperature. The pressure drop through the fuel filter and fuelling through each of six injection assemblies are analyzed.     

Enzymes for low temperature washing

The increasing use of synthetic fibers which cannot tolerate temperatures above 50–60 C has changed the washing habits during the past 5–10 years toward the use of lower washing temperatures. Furthermore, the energy crisis has focused interest on washing at ambient temperatures for the purpose of saving energy. In order to compensate for the lower washing efficiency at decreased temperatures, enzyme producers have devoted much R&D capacity to screen for new proteolytic enzymes which are more suitable for washing at lower temperatures. The result of a screening program carried out for several years, a new detergent protease with interesting characteristics, is discussed. Presented at ISF-AOCS World Congress, New York City, April 1980.     

霞石微晶玻璃热膨胀系数的研究

霞石微晶玻璃热膨胀系数的研究刘小波（湘潭矿业学院４１１２０１）ＳｔｕｄｙｏｎＴｈｅｒｍａｌＥｘｐａｎｓｉｏｎＣｏｅｆｆｉｃｉｅｎｔｏｆＮｅｐｈｅｌｉｎｅＧｌａｓｓ－Ｃｅｒａｍｉｃｓ￥ＬｉｕＸｉａｏｂｏ（ＸｉａｎｇｔａｎＭｉｎｉｎｇＩｎｓｔｉｔｕｔｅ）...