the inorganic powder may contain rare earth or ferromagnetic elements the rare earth elements include the lanthanide elements having atomic numbers from 57 to 71 inclusive and the element yttrium atomic number 39 ferromagnetic metals for purposes of this invention include iron nickel cobalt and numerous alloys containing one or more of these metals in another embodiment the metals are present as alloys of two or more of the aforementioned elements in particular prealloyed powders such as low alloy steel bronze brass and stainless steel as well as nickel cobalt based super alloys may be used as inorganic powders the inorganic powders a may comprise inorganic compounds of one or more of the above described metals the inorganic compounds include ferrites titanates nitrides carbides borides fluorides sulfides hydroxides and oxides of the above elements specific examples of the oxide powders include in addition to the oxides of the above identified metals compounds such as beryllium oxide magnesium oxide calcium oxide strontium oxide barium oxide lanthanum oxide gallium oxide indium oxide selenium oxide etc specific examples of oxides containing more than one metal generally called double oxides include perovskite type oxides such as nanbo 3 srzro 3 pbzro 3 srtio 3 bazro 3 batio 3 spinel type oxides such as mgal 2 o 4 znal 2 o 4 coal 2 o 4 nial 2 o 4 nicr 2 o 4 fecr 2 o 4 mgfe 2 o 4 znfe 2 o 4 etc illmenite types oxides such as mgtio 3 mntio 3 fetio 3 cotio 3 zntio 3 litao 3 etc and garnet type oxides such as gd 3 ga 5 o 12 and rare earth iron garnet represented by y 3 fe 5 o 12 an example of.