碳化硅匣钵的研制

研制成功了ＳｉＣ匣钵,其性能已达到和超过了德国ＡｎｎａＷｅｒｋ和Ｎｏｔｏｎ公司同类产品考核水平,该匣钵经济效益显著,对ＳｉＣ的氧化,烟熏及损坏机理进行了研究。     

薄壁匣钵效益多

匣钵的厚薄对节能、隧道窑的烧成速度和产量关系很大,同时对匣钵的成本有很大的影响,薄壁匣钵具有很多的优点,陕西庄里瓷厂,利用薄壁匣钵装烧瓷器,获得了显著的经济效果。该厂匣钵采用粘土、熟料和滑石配方,系属堇青石质匣钵,在隧道窑中的使用寿命为30～35次。过去使用的厚壁匣钵采用摩擦压力机压制,现使用的薄壁匣钵采用机压成型。现以煅烧过的三大碗匣钵壁厚改变前后     

匣钵 脚钵 盖钵

日用陶瓷在尚未实现无匣钵烧成之前,匣钵仍是一种不可缺少的辅助工具。实践证明,匣钵质量的优劣,直接影响到陶瓷制品的质量及成本。从六十年代起,许多陶瓷厂家和科研单位的工程技术人员及工人,对匣钵进行了大量的研究工作和探索,在改进其材质、生产工艺、器型设计等方面均取得了可喜的成果。因此出现了山东淄博的高热稳定性匣钵、唐山的滚压成型无底匣钵、郑州的多曲面结构匣钵、湖南建湘的高铝匣钵和     

匣钵的破坏机理及启示

本文分析了匣钵的破坏机理,并提出了一个匣钵内部组成的较精细的宏观结构模型和引入了一个说明匣钵在高温下力学特性的公式,从而对匣钵破坏机理的认识和如何提高匣钵的使用性能获得了一些有益的启示.     

谈谈提高匣钵质量的途径

高温快速的烧成制度,对匣钵的质量和性能要求更高了。当前生产中使用的匣钵,特别是装小件的匣钵(即大匣钵),开裂、沉底较为严重,影响了瓷器的质量的进一步提高。匣钵使用次数少,破损大,相对来说,也就增加了瓷器产品的成本。为适应当前窑炉的操作制度,改善匣钵质量是当务之     

碳化硅质制品在景德镇日用陶瓷工业中的应用

前言碳化硅是一种人工合成的晶体,用它作为原料制成匣钵,具有很好的热传导性,高的耐火度和机械强度等特点。这些特点能赋于匣钵一系列优良性能,是粘土质匣钵所无法比拟的。景德镇市匣钵厂先后试制了14英寸鱼盘匣钵10(1/2),英寸平盘匣体,8英寸平盘匣钵,6英寸平盘匣钵等在瓷厂试烧,其试烧情况如表1。     

后司岙越窑窑址出土唐五代匣钵制作工艺初探

越窑是我国南方著名青瓷窑口。为了揭示后司岙越窑窑址匣钵的制作工艺,本文从科学技术的角度利用EDXRF、热膨胀仪等现代测试分析手段,对越窑出土的匣钵标本进行了胎元素组成、烧成温度的测试,并对实验数据进行多元统计分析,初步探讨了后司岙越窑窑址匣钵的制备工艺。研究表明:瓷质匣钵的化学组成与白洋湖泥土和后司岙窑址附近采集的泥土成分接近,这表明后司岙唐五代匣钵的主要原料可能来源于其窑址附近的沉积粘土,但在粗质匣钵中可见明显的粗颗粒。为了进一步探明这些粗颗粒的来源和特点,对其进一步分析发现,粗质匣钵中的粗颗粒主要是一些石英颗粒,为人工刻意掺入以提高匣钵的使用性能,粗质匣钵中粗颗粒的掺入也体现了粗质匣钵和瓷质匣钵在制作工艺上的差异。     

粘土—熔融石英匣钵损坏机理的探讨

本文利用SEM和EPA研究了粘土—熔融石英匣钵的微观结构随使用次数增加而产生的变化,分析了变化过程中匣钵内各相的受力状态及其对这种匣钵损坏的影响。要进一步改善这种匣钵的质量,应延缓骨料晶化及改变结合相组成。     

生匣钵装烧对产品质量的影响

随着设备更新和技术进步,陶瓷产品的产量与质量也相应提高,但在现实工作中的确也存在一些容易忽视的技术问题,例如我厂用生匣钵装烧釉面砖产品既与技术有关又与生产相连,现就如何解决存在的问题,克服各种产品缺陷,提高产品质量,与同行们共同商讨。 一、生匣钵装烧产品的主要问题 1、生匣钵装产品在茂名是常见的事（因为匣钵是与生产釉面砖的窑同时烧成,只装生匣钵,生匣钵内不装产品）,这本就不符合匣钵生产工艺制度,有人却喜欢在生匣钵里装产品,名曰:一可烧好匣钵,二可得到产品,三则增加收入。然而事实上达不到以上目的,一是降低了匣钵的使用寿     

薄壁匣钵和余热利用

一、薄壁匣钵的使用我厂于一九七八年推广使用薄壁匣钵。现三条隧道窑共使用窑车179辆。若按厚壁匣钵计算,每辆窑车上需装匣钵辅料(柱脚等)1053.30公斤,而且每辆窑车上需装陶瓷坯子141.23公斤。匣钵和辅料重量:坯子重量=7.46,使用薄壁匣钵以后,每辆窑车上装匣钵和辅料854.60公斤。装陶瓷坯子261.70公斤。匣钵和辅料重量:坯子重量=3.27。从以上两个不同的比值来看,如     

镍-钨-碳化钨复合电极在盐酸介质中的阳极极化行为的研究

复事电极发展迅速,应用广泛。为节约资源,回收废弃复合镀层中的金属元素,以镍－钨碳化金属复合镀层为便,采用复合电沉积法制得镍－钨碳化乌复合电极。研究 烨微粒的共沉积量、温度及盐酸浓度对镍－钨碳化乌复合电极在盐酸溶液中的阳极极化行为的影响,分析了阳极钝化的原因并研究了采用电化学溶液法回收镍－钨碳化钨复合电极中的镍的工艺条件     

Alkaline treatment of clay minerals from the Alhambra Formation: Implications for the conservation of earthen architecture

Clay–water interactions result in damage and loss of earthen architecture. Natural and artificial additives were traditionally added to earth in order to increase its water resistance and mechanical strength. More recently, portland cement, ethyl silicates and synthetic resins have been applied to consolidate earthen structures, however often with limited success. Here, in an effort to design a more effective procedure for the in situ consolidation of earthen architectural remains, the alkaline reaction of clay-rich earth used in the construction of the Alhambra (Spain) was studied. Alhambra Formation clays were treated with diluted Ca(OH)₂, NaOH and KOH solutions. The most sensitive smectite fraction was rapidly destroyed after alkaline treatment. Furthermore, NaOH and KOH treatments resulted in the formation of interstratified illite–smectite, the partial destruction of both expandable and non-expandable clays, and their transformation into poorly-crystalline alkali aluminosilicates and calcium silicate hydrates, the latter two exhibiting cementing properties. These preliminary results suggest that alkaline activation might be efficient in stabilizing earthen architecture, as well as other clay-rich building and ornamental materials by reducing the intracrystalline swelling capacity of smectites, limiting osmotic swelling of both expandable and non-expandable clays, and producing gel-like silicate cements. However, further research and field tests will be necessary to study the effectiveness of the treatment in situ.     

Reaction of Iradium with Metal Carbides in the Temperature Range of 1923 to 2400 K

The reactions of titanium carbide and hafnium carbide with iridium have been studied in thin film couples fabricated by vapor deposition processes. The reaction product layers after exposure in the temperature range of 1923 to 2400 K are dependent on the stoichiometry of the metal carbide layers and range from simple solid solutions to MIr_x compounds. The observed microstructures are predictable from available thermochemical data. The morphology of residual carbon in the reacted metal carbide-iridium product layer varies from interfacial deposits to uniform carbon dispersion and depends upon exposure temperature and metal carbide stoichiometry.     

High-Temperature Creep and Microstructural Evolution of Chemically Vapor-Deposited Silicon Carbide Fibers

The creep behavior of three types of silicon carbide fibers that have been fabricated via chemical vapor deposition is described. The fibers exhibit only primary creep over the range of conditions studied (1200°–1400°C, 190–500 MPa). A transmission electron microscopy study of the microstructural development that is induced by the creep deformation of SCS-6 silicon carbide fibers at 1400°C is presented. Significant grain growth occurs in all silicon carbide regions of the fiber during creep, in contrast to the reasonably stable microstructure that is observed after annealing at the same temperature and time.     

Effect of ultrafine carbon precursors on the morphology of silicon carbide nanoparticles

A comparative analysis of carbon precursors used for the synthesis of silicon carbide nanoparticles has been carried out. Phenol-formaldehyde resin, colloidal graphite, poly(vinyl alcohol), carbon black obtained as a byproduct of fullerene synthesis, and multiwall carbon nanotubes have been used as carbon sources in the synthesis of the starting ultrafine composition nC + mSiO₂. After carbothermic synthesis, the morphology of silicon carbide nanoparticles was studied by scanning and transmission electron microscopy. The morphologic features and particle-size distribution of the materials were comparatively studied.     

Synthesis of Novel (Polymer Blend-Ceramics) Nanocomposites: Structural,Optical and Electrical Properties for Humidity Sensors

Fabrication of novel nanocomposites films of (PVA–CMC) blend and (PVA–CMC) blend doped by niobium carbide nanoparticles has been investigated. The structural, optical and electrical properties of (PVA–CMC–NbC) nanocomposites for humidity sensors have been studied. The (PVA–CMC–NbC) nanocomposites were prepared with different concentrations of (polyvinyl alcohol and carboxyl methyl cellulose) and Niobium carbide nanoparticles. The experimental results of optical properties for (PVA–CMC–NbC) nanocomposites showed that the absorbance, absorption coefficient, extinction coefficient, refractive index, real and imaginary dielectric constants and optical conductivity of (PVA–CMC) blend increase with increase in Niobium carbide nanoparticles concentrations. The transmittance and energy band gap decrease with increase in Niobium carbide nanoparticles concentrations. The DC electrical properties of (PVA–CMC–NbC) nanocomposites showed that the electrical conductivity of the blend increases with increase in NbC nanoparticles concentrations. The experimental results of novel (PVA–CMC–NbC) nanocomposites applications showed that the (PVA–CMC–NbC) nanocomposites have high sensitivity for relative humidity.     

电沉积镍-钴-碳化钨复合镀层的研究

研究了在镍钴合金镀液中加入碳化钨微粒形成镍－钴－碳化钨得合镀层的共沉积过程。分析了镀液中碳化钨微粒的悬浮量、镀液温度及阴极电流密度对镀层中碳化钨含量的影响,并进一步通过正交试验优选出一种较佳的操作条件。     

宁夏碳化硅产业发展现状与对策

碳化硅陶瓷材料因具有多种优异性能已成为应用非常广泛的新材料。宁夏基于自身丰富优质的太西煤资源,在中国乃至全球碳化硅产业中都占据重要的地位。根据文献调研与实地走访,研究了宁夏碳化硅产业近几十年的发展历程,梳理出产量大但产值低、份额高但分量轻、企业群庞大但市场话语权不足的独特现状。基于此现状及碳化硅材料发展趋势,建议宁夏碳化硅产业在政策扶持下建立并增强高校、企业、市场间产—学—研—用的创新合作模式,在已有优势基础上瞄准高技术陶瓷产品和半导体电子信息材料领域,加快产业的高质量发展。     

High-Temperature Thermal Expansion Behavior of Refractory Materials: I, Selected Monocarbides and Binary Carbides

An apparatus for absolute thermal expansion measurements has been developed and operated to 2843°C. Thermal expansion characteristics have been measured for niobium carbide, zirconium carbide, tantalum carbide, and the carbide solutions 8TaC·ZrC, 4TaC·ZrC, TaC·ZrC, and TaC·4ZrC. Supporting evidence for a high temperature inversion in the monocarbides of zirconium and tantalum has been observed. Evidence of analogous behavior for other carbides is also reported.     

Carbide phases formed in WC–M (M = Fe/Ni/Cr) systems

The effect of composition in the formation of carbides in the WC–M (M = Fe/Ni/Cr) system has been studied. Three conventional compositions have been prepared with 10 wt.% of metallic binder. Fe as a metallic binder was first studied and its partial substitution by Ni and Cr was also investigated. A WC powder coated with a similar binder (Fe/Ni/Cr) amount was also investigated. The XRD results, after thermal treatment at 1400 °C, reveal that the substitution of half percent of the iron content by Ni stabilized the austenite Fe(γ) formation. The introduction of Cr in the binder composition induces the formation of Cr₂C carbide. With the decrease of Cr amount in the binder composition of the coated powder, Cr₂C carbide was not formed, but instead other carbide, M₆C, was detected. In order to eliminate this carbide a small excess of carbon (3.6 wt.%) was added to the coated powder. The results are discussed in terms of the phases formed, the binder composition and the final carbon content.