Comments on the Paper ‘‘Production of Zr55Cu30Ni5Al10 Glassy Alloy Rod of 30mm in Diameter by a Cap-Cast Technique’’

The authors of the title paper under discussion state the importance of low oxygen content in producing an amorphous top half in slowly cooled arc-melted buttons. Since the cooling rate does not favor the amorphous state in top half of the button, more evidence is needed to support the claim. Further, the authors made a liquid quenching machine to enhance the cooling speed to make larger ingots of the same alloy. It is not clear why a new machine with higher cooling rate is needed if the amorphous state can be achieved at lower cooling rates. Lack of essential details of the ‘‘cap-cast method’’ does not permit a critical assessment of the new process. The nature and quality of optical micrographs and HREM pictures are a cause of concern. [doi:10.2320/matertrans.M2009156]