Composite cements composition

J. Chatterji, J.F. Heathman, D.W. Gray, and B.K. Waugh, Set retarder compositions, cement compositions, and associated methods, US Patent 7 004 256, assigned to Halliburton Energy Services, Inc. (Duncan, OK), February 28, 2006. 

Etude et realisation de sondes pour la caracterisation non destructive par courants de Foucault de couches de cementation des aciers. Les proprietes electromagnetiques des aciers dependent de leur composition, de leurs microstructures et des contraintes appliquees. II est done naturel d essayer d utiliser les parametres electriques et magnetiques des aciers pour evaluer leur microstructure. 

Cement clinker Cement-composites Cement copper Cemented carbide... 

Composite Gemstones. Many types of composite or assembled gemstones have been made (1). Some are shown in Figure 3. In the United States a doublet has two pieces combined using a colodess cement. If three pieces are used, or if two pieces are assembled using a colored cement, the gemstone is a triplet. The use of composite stones has declined rapidly with the rise of inexpensive synthetics. Frequendy seen are opal doublets, where precious opal is backed by a black material. In opal triplets a thin sHce of precious opal is cemented between a black backing and a clear cover, usually of quartz. Additionally, insects and even fish have been inserted into amber. 

In the case of refractory metals, coatings generaHy are sHicides, appHed by pack cementation or slurry processes. Typical sHicide compositions are... 

The cermet class of materials contains a large number of compositions (57). Most cermets are carbide-based, eg, WC and titanium carbide [12070-08-5] TiC. Cemented tungsten carbides are widely used for cutting tools and car parts. 

Over time a large variety of materials have been used, including ivory, stainless steel, chromium—cobalt, and ceramics for the acetabular component. None proved sufficient. The implant material composition must provide a smooth surface for joint articulation, withstand hip joint stresses from normal loads, and the substance must disperse stress evenly to the cement and surrounding bone. 

Vitahium FHS ahoy is a cobalt—chromium—molybdenum ahoy having a high modulus of elasticity. This ahoy is also a preferred material. When combiaed with a properly designed stem, the properties of this ahoy provide protection for the cement mantle by decreasing proximal cement stress. This ahoy also exhibits high yields and tensile strength, is corrosion resistant, and biocompatible. Composites used ia orthopedics include carbon—carbon, carbon—epoxy, hydroxyapatite, ceramics, etc. 

The nitrate deposits are made up of several layers (Fig. 1). The ore bodies are very heterogeneous and variable in size, thickness, composition, and hardness. The overburden may include chuca a layer of unconsoHdated sand, silt, and clay, andpanqueque a layer of semiconsoHdated and porous material poody cemented by salts over poody cemented gravel. The ore composition has degraded considerably since the eady days of the industry, when it was reported that ores of up to 50% sodium nitrate were mined. There are stiU reserves that can be commercially mined well into the twenty-first century (1). 

In the softer grades (average carbon content ca 0.50%), the composition of the bar was uniform throughout. In the harder grades (average carbon content as high as 1.50%), the outside of a bar might have a carbon content of 1.50—2.00%, whereas the center contained 0.85—1.10%. Steels made by this method were called cement steels. 

Minor and potential new uses include flue-gas desulfurization (44,45), silver-cleaning formulations (46), thermal-energy storage (47), cyanide antidote (48), cement additive (49), aluminum-etching solutions (50), removal of nitrogen dioxide from flue gas (51), concrete-set accelerator (52), stabilizer for acrylamide polymers (53), extreme pressure additives for lubricants (54), multiple-use heating pads (55), in soap and shampoo compositions (56), and as a flame retardant in polycarbonate compositions (57). Moreover, precious metals can be recovered from difficult ores using thiosulfates (58). Use of thiosulfates avoids the environmentally hazardous cyanides. 

Table 7. Composition and Properties of Some Representative Grades of Cemented-Carbide Tools ...

There are at least four different classification systems for cemented carbides (7,12). The U.S. system is based on relative performance the U.K. system is based on properties, and the former USSR system on composition the fourth system, widely used in Europe and supported by the ISO, is based on apphcation and chip form. In this article, the U.S. system and the ISO system are briefly reviewed. 

The original objective of the ISO classification was to issue detailed standards for cemented carbides in terms of microstmcture, composition, and properties for quaUty control and performance rehabiUty. This objective, however, is yet to be realized. Increased emphasis on worldwide implementation of ISO 9000 standards and globalization of manufacturing, may lead the industry-at-large to adopt the ISO classification. 

Other. Vinyl acetate resins are useful as antishrinking agents for glass fiber-reinforced polyester mol ding resins (165). Poly(vinyl acetate)s are also used as binders for numerous materials, eg, fibers, leather (qv), asbestos, sawdust, sand, clay, etc, to form compositions that can be shaped with heat and pressure. Joint cements, taping compounds, caulks, and fillers are other uses. 

From the beginning of this century, the demand for asbestos fibers grew in a spectacular fashion for numerous applications, in particular for thermal insulation in steam engines and technologies (4). Moreover, the development of the Hatschek machine in 1900 for the continuous fabrication of sheets from an asbestos—cement composite opened an important field of industrial application for asbestos fibers. 

The reinforcing capacity of asbestos fibers in a cement matrix constitutes another key criteria for the evaluation of asbestos fibers. This property is assessed by preparing samples of asbestos —cement composites which, after a standard curing period, are tested for flexural resistance. The measured mpture modub are converted into a parameter referred to as the fiber strength unit (FSU) (34). 

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