Investigation of Spherical Al₂O₃ Magnetic Abrasive Prepared by Novel Method for Finishing of the Inner Surface of Cobalt-Chromium Alloy Cardiovascular Stents Tube

In this investigation, spherical Al₂O₃ magnetic abrasive particles (MAPs) were used to polish the inner surface of ultra-fine long cobalt-chromium alloy cardiovascular stent tubes. The magnetic abrasives were prepared by combining plasma molten metal powder and hard abrasives, and the magnetic abrasives prepared by this new method are characterized by high sphericity, narrow particle size distribution range, long life, and good economic value. Firstly, the spherical Al₂O₃ magnetic abrasives were prepared by the new method; secondly, the polishing machine for the inner surface of the ultra-fine long cardiovascular stent tubes was developed; finally, the influence laws of spindle speed, magnetic pole speed, MAP filling quantities, the magnetic pole gap on the surface roughness (Ra), and the removal thickness (RT) of tubes were investigated. The results showed that the prepared Al₂O₃ magnetic abrasives were spherical in shape, and their superficial layer was tightly bound with Al₂O₃ hard abrasives with sharp cutting; the use of spherical Al₂O₃ magnetic abrasives could achieve the polishing of the inner surface of ultra-fine cobalt-chromium alloy cardiovascular bracket tubes, and after processing, the inner surface roughness (Ra) of the tubes decreased from 0.337 µm to 0.09 µm and had an RT of 5.106 µm.