Cast magnets

Magnetic anisotropy. In conjunction with slip casting, magnetic alignment of anisotropic particles may be used to produce polycrystalline materials with a preferred orientation, or texture. 

The casting method can also be applied to Nd-Fe-B and Nd-Fe-C systems (Eisses et al. 1991). Since the magnetic properties and the shape homogeneity of small and thin magnets, however, are better in sintered magnets, the industrialization of the cast magnets has not been yet realized. 

NONDESTRUCTIVE MAGNETIC METHID OF INSPECTION OF THE MECHANICAL PROPERTIES OF CAST STEELS. 1. CONSTRUCTION OF CORRELATION MODELS and II. PRACTICAL APPLICATION OF CORRELATION... 

The standard analytic treatment of the Ising model is due to Landau (1937). Here we follow the presentation by Landau and Lifschitz [H], which casts the problem in temis of the order-disorder solid, but this is substantially the same as the magnetic problem if the vectors are replaced by scalars (as the Ising model assumes). The themiodynamic... 

Typically, dry potassium nitrate is pulverized in a ball mill. Sulfur is milled into cellular charcoal to form a uniform mix in a separate ball mill. The nitrate and the sulfur—charcoal mix are screened and then loosely mixed by hand or in a tumbling machine. Magnetic separators may be used to ensure the absence of ferrous metals. The preliminary mix is transferred to an edge-mimer wheel mill with large, heavy cast iron wheels. A clearance between the pan and the wheels is required for safety purposes. The size of this gap also contributes to the density of the black powder granules obtained. Water is added to minimize dusting and improve incorporation of the nitrate into the charcoal. The milling operation requires ca 3 to 6 h. 

The matte can be treated in different ways, depending on the copper content and on the desired product. In some cases, the copper content of the Bessemer matte is low enough to allow the material to be cast directly into sulfide anodes for electrolytic refining. Usually it is necessary first to separate the nickel and copper sulfides. The copper—nickel matte is cooled slowly for ca 4 d to faciUtate grain growth of mineral crystals of copper sulfide, nickel—sulfide, and a nickel—copper alloy. This matte is pulverized, the nickel and copper sulfides isolated by flotation, and the alloy extracted magnetically and refined electrolyticaHy. The nickel sulfide is cast into anodes for electrolysis or, more commonly, is roasted to nickel oxide and further reduced to metal for refining by electrolysis or by the carbonyl method. Alternatively, the nickel sulfide may be roasted to provide a nickel oxide sinter that is suitable for direct use by the steel industry. 

Fig. 3. Magnetic susceptibility of plutonium metal as a function of temperature where represent initially high density plutonium and , cast plutonium...

Tellurium also improves the properties of electrical steels by aiding in the magnetic anisotropy, malleable cast iron (77), and spheroidal (graphitic) cast irons (see also Metal surface TiiEATiffiNTs). 

Magnetizing losses, however, as the name implies, are a phenomenon in electromagnetic circuits only. They are absent in a non-magnetic circuit. A motor is made of steel laminates and the housing is also of steel, hence these losses. Some manufacturers, however, use aluminium die-cast stator frames in smaller sizes, where such losses will be less (the bulk of the losses being in the laminations). 

In addition to nickel alloys, nickel also forms an important alloying element in stainless steels and in cast irons, in both of which it confers additional corrosion resistance and improved mechanical and engineering properties, and in Fe-Ni alloys for obtaining controlled physical and magnetic properties (see Chapter 3). With non-ferrous metals nickel also forms important types of alloys, especially with copper, i.e. cupro-nickels and nickel silvers these are dealt with in Section 4.2. 

Many other devices for use by hand have been invented. Mention may be made of limpet charges which usually employ magnets to make them adhere to the metal sides of tanks or ships. The explosive filling for such charges is a high velocity high power explosive such as cast RDX/TNT. 

Permanent magnets, ferrites as, 11 58 Permanent mold castings, aluminum alloys, 2 326t... 

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