Alumina tool applications

Ceramics Based on Alumina Increasing the Hardness for Tool Applications... 

This reaction, based on the classic water-gas reaction, takes place in excess hydrogen, at an optimum temperature of 1050°C and at low pressure (ca. 1 Torr).bH3] It is the preferred reaction for tool coatings and electronic applications. The formation of alumina is... 

Whiskers are short fibers, usually a single crystal with an aspect ratio of 10/1 or greater. They have high strength but are difficult to process. Their applications so far has been limited SiC whiskers are reported as random reinforcement for ceramics and in alumina cutting tools. CVD is a common production method.O Beside SiC, the following whiskers have recently been produced by CVD ... 

Adsorption and ion exchange chromatography are well-known methods of LC. In adsorption, one frequently selects either silica or alumina as stationary phase for separation of nonionic, moderately polar substances (e.g. alcohols, aromatic heterocycles, etc.). This mode works best in the fractionation of classes of compounds and the resolution of isomeric substances (J). Ion exchange, on the other hand, is applicable to the separation of ionic substances. As to be discussed later, this mode has been well developed as a tool for analysis of urine constituents (8). 

In view of catalytic potential applications, there is a need for a convenient means of characterization of the porosity of new catalyst materials in order to quickly target the potential industrial catalytic applications of the studied catalysts. The use of model test reactions is a characterization tool of first choice, since this method has been very successful with zeolites where it precisely reflects shape-selectivity effects imposed by the porous structure of tested materials. Adsorption of probe molecules is another attractive approach. Both types of approaches will be presented in this work. The methodology developed in this work on zeolites Beta, USY and silica-alumina may be appropriate for determination of accessible mesoporosity in other types of dealuminated zeolites as well as in hierarchical materials presenting combinations of various types of pores. 

In order to extend applications of cBN to include machining of medium-hardness steels, modifications of the cBN were introduced. An example is the fabrication of sintered cBN tools by the same HP—HT process, but using binder and second phase (either metallic or nonmetallic) such as TiN or TiC to increase toughness (171). In regard to phase distribution, cBN tools resemble cemented-carbide or alumina—TiC ceramic tools, but are tougher and have greater chemical stability. 

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