Iron crystal shape, usual

Good quality steel is used and electrozinc is preferred for washing machines. Steel is pretreated with iron phosphate for economy electrozinc with a fine crystal zinc phosphate. No primer is normally used 25-40/im of finish is applied direct to metal. The required properties are best obtained with a thermosetting acrylic or polyester/melamine-formaldehyde finish. Self-reactive acrylics are usually preferred these resins contain about 15 Vo 7V-butoxymethyl acrylamide (CH2=CH —CO —NH —CHj—O —C4H,) monomer and cure in a manner similar to butylated melamine-formaldehyde resins. Resistance or anti-corrosive properties may be upgraded by the inclusion of small amounts of epoxy resin. Application is usually by electrostatic spray application from disc or bell. Shapes are complex enough to require convected hot-air curing. Schedules of 20 min at 150-175°C are... 

Anisometric forms of Fe304 with the spinel structure or y-Fe203 with a tetragonal superlattice structure do not crystallize directly. They are obtained from iron compounds that form needle-shaped crystals (usually a- and y-FeOOH, see Section... 

Generally, the presence of various amounts of metal cations during the formation of iron oxides can yield the following results (a) incorporation of these cations into the crystal structure of an iron oxide [205,206,218,245,261,267, 269,279,316], (b) modification ofthe size and shape of obtained particles [233,240,243,257,284,285,295,326,333], (c) formation of iron oxides different from those in the pure system [243,293,295,302,313], (d) formation of ferrites or other mixed iron-metal oxide phases [265,269,274,285,291], (e) formation of separated iron oxide and metal oxide phases, usually with incorporated foreign cations into the structure [242,265,314], and (f) formation of an iron oxide along with the formation of metal by reduction of metal cations present in the system [307,308,310,334]. 

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