Controlling corrosion rate of Magnesium alloy using powder mixed electrical discharge machining

3rd International Conference on Science, Technology, and Interdisciplinary Research

自然科学;工业技术

Razak, M.A.^1,2 ; Rani, A.M.A.^1,3 ; Saad, N.M.^3 ; Littlefair, G.^4 ; Aliyu, A.A.^1,5

Mechanical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak

32610, Malaysia^1

Manufacturing Section, Universiti Kuala Lumpur, Malaysian Spanish Institute, Kulim Hi-Tech Park, Kedah

09000, Malaysia^2

Biomedical Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak

32610, Malaysia^3

School of Engineering, Faculty of Science, Engineering and Built Environment, Deakin University, Geelong

VIC

3220, Australia^4

Department of Mechanical Engineering, Faculty of Engineering, Bayero University Kano, Gwarzo Road, Nigeria^5

关键词: Biomedical implants;    In-vitro corrosions;    Localized temperature;    Machined surface quality;    Magnesium and its alloys;    Powder mixed electrical discharge machining;    Spark erosion process;    Surface characteristics;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/344/1/012010/pdf
DOI  :  10.1088/1757-899X/344/1/012010

来源: IOP

【 摘 要 】

Biomedical implant can be divided into permanent and temporary employment. The duration of a temporary implant applied to children and adult is different due to different bone healing rate among the children and adult. Magnesium and its alloys are compatible for the biodegradable implanting application. Nevertheless, it is difficult to control the degradation rate of magnesium alloy to suit the application on both the children and adult. Powder mixed electrical discharge machining (PM-EDM) method, a modified EDM process, has high capability to improve the EDM process efficiency and machined surface quality. The objective of this paper is to establish a formula to control the degradation rate of magnesium alloy using the PM-EDM method. The different corrosion rate of machined surface is hypothesized to be obtained by having different combinations of PM-EDM operation inputs. PM-EDM experiments are conducted using an opened-loop PM-EDM system and the in-vitro corrosion tests are carried out on the machined surface of each specimen. There are four operation inputs investigated in this study which are zinc powder concentration, peak current, pulse on-time and pulse off-time. The results indicate that zinc powder concentration is significantly affecting the response with 2 g/l of zinc powder concentration obtaining the lowest corrosion rate. The high localized temperature at the cutting zone in spark erosion process causes some of the zinc particles get deposited on the machined surface, hence improving the surface characteristics. The suspended zinc particles in the dielectric fluid have also improve the sparking efficiency and the uniformity of sparks distribution. From the statistical analysis, a formula was developed to control the corrosion rate of magnesium alloy within the range from 0.000183 mm/year to 0.001528 mm/year.