Cobalt-boron alloy

The method with azomethine H has been used for determining boron in plant materials [75], biological samples [76], plants [77], soils [77-79], water [80], sewage [4,81], rocks and bituminous [22,55,82], steel [47], copper, nickel, and cobalt alloys [9], boron nitride [83], and fertilisers [84]. Azomethine H has been utilized in automatic determination of boron [81] and in flow injection analysis (FIA) [75]. Boron has also been determined in plants and soils with the use of 4-methoxyazomethine H [85],... 

Weld hardfacing coatings, for example, high-carbon iron-chromium alloys, tool steels, nickel-chromium-boron alloys, cobalt-base alloys, and austenitic manganese steels... 

Soft magnetic materials are characterized by high permeabiUty and low coercivity. There are sis principal groups of commercially important soft magnetic materials iron and low carbon steels, iron—siUcon alloys, iron—aluminum and iron—aluminum—silicon alloys, nickel—iron alloys, iron-cobalt alloys, and ferrites. In addition, iron-boron-based amorphous soft magnetic alloys are commercially available. Some have properties similar to the best grades of the permalloys whereas others exhibit core losses substantially below those of the oriented siUcon steels. Table 1 summarizes the properties of some of these materials. 

A wide range of cutting-tool materials is available. Properties, performance capabilities, and cost vary widely (2,7). Various steels (see Steel) cast cobalt alloys (see Cobalt and cobalt alloys) cemented, cast, and coated carbides (qv) ceramics (qv), sintered polycrystalline cubic boron nitride (cBN) (see Boron compounds) and sintered polycrystalline diamond tbin diamond coatings on cemented carbides and ceramics and single-crystal natural diamond (see Carbon) are all used as tool materials. Most tool materials used in the 1990s were developed during the twentieth century. The tool materials of the 1990s... 

In recent years, the spraying process has been adapted for hard facing, using the chromium-nickel-boron alloys which have become known as Colmonoy. More recently still, the cobalt-base Stellite alloys have also been used. These materials in powder form are sprayed on to the surface in the usual way. The deposit is afterwards heat treated by a torch, so that fusion takes place. The process is often known as spray-welding. Such coatings are primarily used for hard facing under wear conditions, but as the Anal surface is nickel-chromium or cobalt-chromium they exhibit very high anticorrosive properties. 

The reduction diffusion process has also been used for the production of powders of the magnetic neodymium-iron-boron alloy (Nd15Fe77B8). The reaction involves use of a powder mix of neodymium oxide, iron, ferroboron and calcium. The reaction is conducted by heating the powder charge mixture at 1200 °C for 4 h under vacuum. Neodymium-iron-boron alloys are much more prone to oxidation than samarium-cobalt alloys and a proprietary leaching procedure is used for the separation of the alloy and calcium oxide. 

Creaies a diffused hum (boron compoundsl case. Base nieials are alloy and tool steels cobalt- and nickel-base alloys Process temperature range is 400-1150 C (750-2100nFi. 

New permanent magnet materials, such as samarium-cobalt and, a fortiori, neodymium-iron-boron alloys, are also of special interest in the design of static devices with specific magnetic-field configurations. Apart from high remanence and coercive force values of magnets made of these materials, Chavanne et al. (1987) emphasize the presence of large anisotropy fields in the conception of these devices. 

---