Diamond abrasive properties

Mining work requires specialized tools to perform work under the harshest and most aggressive conditions. This is when diamond abrasive properties combined with the hardness properties of other materials become crucial to drilling or cutting action that is subjected to extreme loading during prolonged periods. 

Uses Surfactant, o/w emulsifier, thickener, pigment grinding aid in hair, skin, and makeup prods., household polishes, cleaners, silicone-based lubricants emulsifier, lubricant, and softener for textile processing oils and finishes component of diamond abrasive pastes antigel agent in starch sol ns. for paper industry internal antistat for PS Properties Wh. soft solid sol. in methanol, ethanol, acetone, ethyl acetate, toluol, naphtha, min. and veg. oils disp. in water sp.gr. 1.0 m.p. 30 C min. HLB 11 acid no. 3 max. sapon. no. 83-94 pH 5 (5% aq.) nonionic 100% cone. 

Hardness. The hardness (qv), or related property abrasiveness, is an important filler property. Hardness is determined by comparison to materials of known hardness on the Mohs scale. On this nonlinear scale, diamond is rated 10, quartz 7, calcite 3, and talc 1. The abrasiveness of a filler is also dependent on psd and the presence of impurities, eg, ka olin clay (Mohs hardness of 3) can be quite abrasive because of the presence of quartz impurities. 

In diamond, each carbon atom is sp3 hybridized and linked tetrahedrally to its four neighbors, with all electrons in C C cr-bonds (Fig. 14.30). Diamond is a rigid, transparent, electrically insulating solid. It is the hardest substance known and the best conductor ol heat, being about five times better than copper. These last two properties make it an ideal abrasive, because it can scratch all other substances, yet the heat generated by friction is quickly conducted away. 

Plasma Synthesis The use of plasma methods has lead to a new range of materials having unique properties. An example is the family of amorphous elemental hydrides (eg cr-C H Of -Si H or-P H) which contain a variable proportion of H from almost zero to 50 atomic %. The carbon films, known variously as "hard carbon", "diamond-like carbon", " a-carbon" etc (9 ) - These layers are of considerable interest because of their optical and abrasion-resistant properties etc (Table I). The properties of these Gr-carbon films, can be tailored by modifying the plasma parameters. 

HARDNESS. The significance of this tern) as applied to solids lias various interpretations. Commonly, it refers to the resistance of the substance to. surface abrasion, so thut of two solids, the one that will scratch the other, as diamond scratches glass. is the harder. Again, it may denote rigidity, or lack of plasticity, or even strength in some cases a combination of several such properties. The original Mohs Scale of Hardness is delineated in Table I and further described under Mineralogy. 

The product thus obtained consists of sharp iridescent crystals which are extremely inactive chemically. The most notable property of this material, however, is its hardness. Carborundum is almost as hard as diamond and is generally as an abrasive (i.e., in the manufacture of grinding stones and wheels, polishing papers and cloths, etc.). A lesser use lies in the incorporation of coarse Carborundum crystals into concrete or terrazzo floors to render them slipproof. 

AH = 2.9 kJ mol-1 at 300 K and 1 atm. Diamond is the hardest material known, although a compound containing boron and nitrogen, borazon, has almost equal hardness. Because of this property, diamond has a great many industrial uses in tools and abrasives. Because gem quality diamonds are prohibitively expensive for such uses, there has been a great deal of interest in producing diamonds synthetically. Industrially, this process is carried out under extreme conditions (3000 K and 125 kbar) to produce several tons of diamond annually. 

A wide variety of materials have been implemented as abrasive particles in CMP processes. They include alumina, silica, ceria, zirconia, titania, and diamond. The effectiveness and suitability of these particles in CMP with particular applications are greatly influenced by their bulk properties (density, hardness, particle size, crystallinity etc.) and the surface properties (surface area, isoelectric electric point (lEP), OH content, etc.). This section will focus on the evaluation of alumina, silica, diamond, and ceria as the major abrasives used for the CMP of metals. 

Abrasive particle properties can be attributed to the method or process used to generate the particles. The surface properties can be altered or modified by varying the physical conditions (temperature, pressure, time) or chemical composition of the initial reactants. This section will survey the various preparation techniques for silica, alumina, and diamond. 

Abrasive particles are a key component in CMP slurry. The most commonly used abrasive particles include silica, alumina, ceria, zirconia, titania, and diamond. Table 21.1 listed a set of information on each type of abrasive particles such as density, microhardness, and isoelectric points (lEP). It is important to point out that the specific values for these properties depend highly on the preparation techniques and the specific states of the samples. The values listed in the table represent an average of the most commonly reported data. For example, the isoelectric point for silica is a function of the number of hydroxyl groups, type and level of adsorbed species, metal impurity in the solid matrix, and the treatment history of the materials [1]. There are three major types of silica according to their preparation methods fumed, colloidal, and precipitated. The common sources for obtaining these abrasive particles are listed in Table 21.2. As examples, some of the more specific information on... 

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