Mechanical alloying of biocompatible Co-28Cr-6Mo alloy.
We report on an alternative route for the synthesis of crystalline Co-28Cr-6Mo alloy, which could be used for surgical implants. Co, Cr and Mo elemental powders, mixed in an adequate weight relation according to ISO Standard 58342-4 (ISO, 1996), were used for the mechanical alloying (MA) of nano-structured Co-alloy. The process was carried out at room temperature in a shaker mixer mill using hardened steel balls and vials as milling media, with a 1:8 ball:powder weight ratio. Crystalline structure characterization of milled powders was carried out by X-ray diffraction in order to analyze the phase transformations as a function of milling time. The aim of this work was to evaluate the alloying mechanism involved in the mechanical alloying of Co-28Cr-6Mo alloy. The evolution of the phase transformations with milling time is reported for each mixture. Results showed that the resultant alloy is a Co-alpha solid solution, successfully obtained by mechanical alloying after a total of 10 h of milling time: first Cr and Mo are mechanically prealloyed for 7 h, and then Co is mixed in for 3 h. In addition, different methods of premixing were studied. The particle size of the powders is reduced with increasing milling time, reaching about 5 mum at 10 h; a longer time promotes the formation of aggregates. The morphology and crystal structure of milled powders as a function of milling time were analyzed by scanning electron microscopy and XR diffraction.
Sánchez-De Jesús
F
F
Area Académica de Ciencias de la Tierra y Materiales, UAEH, Carr. Pachuca-Tulancingo Km. 4.5, 42184 Pachuca, Hidalgo, México.
Bolarín-Miró
A M
AM
Torres-Villaseñor
G
G
Cortés-Escobedo
C A
CA
Betancourt-Cantera
J A
JA
D002858:Chromium Alloys / Q000138:chemical synthesis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008982:Molybdenum / Q000737:chemistry*; D010316:Particle Size; D011208:Powders; D014961:X-Ray Diffraction
D002858:Chromium Alloys; D011208:Powders; D008982:Molybdenum