The Effect of Grit Blasting on Surface Roughness and Hardness of Magnesium Alloy AZ31B: A Statistical Study

Magnesium alloys are known for their lightweight and high specific strength properties and being used as bio-degradable implant material. Materials' surface roughness and surface hardness play a major role when coating has to be applied and may subject to wear and abrasion. Grit blasting is one of the common techniques to remove surface impurities, corrosion products and modify the surface characteristics for better adhesion of protective coatings, as well as, surface hardness. In the present study, the effect of grit blasting media and blasting pressure on the surface characteristics and surface hardness of magnesium alloy is investigated. The surface characteristics such as mean surface roughness (Ra), highest peak values (Rp), deepest valley values (Rv) are measured using atomic force microscopy (AFM) and show a linear relation with blasting pressure. The surface topography is observed using scanning electron microscopy (SEM). The surface hardness results indicate 41% increase in hardness with blasting pressure. The statistical findings using analysis of variance (ANOVA) shows that both blasting pressure and blasting media contribute to final surface roughness and surface hardness. The blasting pressure imparts major contribution to it.