Evaluation of room temperature Tribocorrosion behaviour of Al-4.5Cu/SiC Particulate Composite in Natural Sea Water

Room  temperature  tribocorrosion behaviour  of  Al-4.5%Cu/SiC particulate composite  was  evaluated against  stainless  steel  ball  in natural  sea  water.  Ab-initio,  the          Al-4.5%Cu  was  reinforced  with  5,10,15  and  20  %  SiC  reinforcements  to  produce  the Al-4.5%Cu/SiC  particulate  composite  by  stir  casting  method.  The  tribocorrosion  test  was carried  out  with  an  Anton  Paar  Tribometer  at  applied  loads  of  5  and  7  N.  The  surfaces  of  the control  and  worn  out  surfaces  were  characterized  by  scanning  electron  microscopy  (SEM);  the navigation  camera  of  the  SEM  machine  was  used  to  capture  the  exposed  areas  of the  composite that  were  subjected  to  tribocorrosion  prior  to  the  SEM.  From  the  results,  it  was  found  that  the control  sample  (Al-4.5%Cu)  was  more  susceptible  to  corrosion  and  wear  in  sea  water  than  the reinforced  (Al-4.5Cu%/SiC)  sample  under  the  loadings  considered  in  this  work.  The susceptibility  to  corrosion  and  wear  decreased  as  the  percent  composition  of  the  reinforcement was  increased;  the  synergistic  action  of  corrosion  and  wear  (tribocorrosion)  decreased  as  the reinforcement  was  increased.  The  pre  and  post-tribocorrosion  scanning  electron  microscopy (SEM)  images  of  the  test  samples  obtained  at  magnifications  of  2000x  and  2500x  revealed white  patches  of  SiC  particulates  embedded  in  dark  areas  of  Al-Cu  matrix  regions  and  appears to  be  fairly  distributed  throughout  the  matrix.  It  was  concluded  that  the  tribocorrosion  rate  of the  test  samples  decreased  with  increase  in  percentage  volume  fraction  of  the  SiC  particulate reinforcement.

Key  words:  Al-4.5%Cu/SiC;  seawater;  tribocorrosion;  room  temperature;  synergism;  SEM.