Study On Amorphous Formation Ability And Performance Of Pt-Pd-Cu-P Alloys

Pt-based alloys possess high glass-forming ability(GFA) and Pt-based metallic glasses can be used in various fields. In this work, new Pt-based Pt-Pd-Cu-P and Pt-Pd-Cu-Ni-P bulk glassy alloys were developed and their GFA, thermal properties and mechanical as well as chemical properties were evaluated.The Pt-based alloys were prepared by rapid solification and copper mould casting methods. X-ray diffractometry (XRD), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and scanning electron microscope were employed to characterize the GFA and thermal properties of Pt-based glassy alloys. The main results are as followings:1) Glassy alloys in Pt-Pd-Cu-P system were developed. In the alloy system, Pt4oPd2oCu2oP2o has the highest glass-forming ability and the glass transition temperature (Tg) is 533K, the crystallization temperature (Tx) is 603K, the supercooled liquid regionΔTX(Tx-Tg) is 70K, the liquidus T1 is 823K and the reduced glass transition temperature Tg/T1 is 0.65, respectively. It was also found that theΔTx of Pt33Pd22Cu22P23 glassy alloys is up to 112K, which is the widest for the glassy alloys in the Pt-Pd-Cu-P system.2) The addition of Ni to the Pt-Pd-Cu-P alloys for replacing a portion of Cu enhanced the glass forming ability. In the Pt40Pd20Cu20-xNixP2o system, Pt40Pd20Cu15 Ni5P2o alloy possessed the highest GFA. For the Pt4oPd2oCui5 Ni5P2o glassy alloy, the Tg,ΔTx, T1 and Tg/T1 are 91K,784K,531K and 0.69, respectively.3) The Pt-Pd-Cu-P bulk glassy have good mechanical properties. The compressive fracture strength in the range of 1200-1400Mpa and the Young's modulus is around 80 Gpa. The Pt-based glassy alloys also exhibited high corrosion resistance 0.3 V in the corrosive 12 N HCl solution. The open circuit potential of the glassy alloy containing 23 at% P is up to 0.8V.