Metal-metalloid glasses

Metals Some metal alloys can be vitrified to give metallic glasses they are classified in two classes metal-metalloid glasses such as Pd-Si, Fe-B, Fe-Ni-P-B, and metal-metal glasses such as Ni-Nb and Cu-Zn. 

E24.14 Transition metal and rare earth sulfides ate typically non-glass-forming sulfides, many of which have crystalline and layered phases. Any metal sulfide glasses would involve metalloid and non-metal sulfides. 

The various metallic glasses reported in the literature [4.9] fall into a few well-defined categories (i) late transition metal + metalloid (ii) early transition metal + late transition metal or group IB metal (iii) earth alkali metal + group IB metal (iv) early transition metal + alkali metal and, (v) Actinide + early transition metal. In catalysis research, exclusively metallic glasses of categories (i) and (ii) have been used so far. Table 4.1 lists glassy metals which have been used in catalytic studies. Note that metal-zirconium alloys and Ni, Fe, and mixed Ni-Fe alloys with P and/or B as metalloid have been used most frequently. 

Another readily glass-forming system involves metal-metalloid alloys. The most common ones use iron or nickel with phosphorus or boron. Their frequent use results from the catalytic properties of the metals for the widely studied hydrogenation of CO. Alloys prepared with all possible combinations of these four elements in different compositions have been studied. Additionally, some of these alloys, Ni-B, Ni-P, and Fe-Ni-(Cr)-P-B, as well as Pd-Si and Pd-Ge alloys, have been studied in the hydrogenation of hydrocarbons containing multiple bonds. 

The numerous glass-forming binary alloys may be divided into two main categories metal-metal alloys and metal-metalloid alloys. The former category may again be subdivided into three subgroups comprising alloys of transition metals (3d, 4d, 5d), alloys of simple metals and alloys of transition metals with either rare earths... 

Metallic Glasses. Under highly speciali2ed conditions, the crystalline stmcture of some metals and alloys can be suppressed and they form glasses. These amorphous metals can be made from transition-metal alloys, eg, nickel—2irconium, or transition or noble metals ia combination with metalloid elements, eg, alloys of palladium and siUcon or alloys of iron, phosphoms, and carbon. 

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