Brown S A, Simpson J P
J Biomed Mater Res. 1981 Nov;15(6):867-78. doi: 10.1002/jbm.820150611.
Mechanisms of corrosion at the areas of contact between screw heads and plate holes were investigated using electrochemical potential recording techniques. Static crevice corrosion was studied with plates and screws in isotonic and hypertonic saline solutions (0.9 to 7.2% NaCl). Fretting corrosion was studied in vitro with plates screwed to tubular bone analogs which were subjected ty cyclic axial loads, and was studied in vivo with plates screwed on the tibia of sheep. Static tests showed that crevice corrosion does not occur in isotonic saline for periods up to one year, but can occur in hypertonic saline solutions. Dynamic loading tests demonstrated immediate potential changes which were related to the magnitude of the applied load, indicating fretting corrosion due to motion between screw head and plate, both in vitro and in vivo. A mechanism for screw-plate relative motion is proposed. It is hypothesized that corrosion seen in clinically retrieved implants is due to fretting corrosion which predisposes the contact area to crevice corrosion attack.
采用电化学电位记录技术研究了螺钉头部与钢板孔接触区域的腐蚀机制。在等渗和高渗盐溶液（0.9%至7.2%氯化钠）中使用钢板和螺钉研究了静态缝隙腐蚀。在体外，对拧在管状骨模拟物上的钢板施加周期性轴向载荷来研究微动腐蚀，在体内，则对拧在绵羊胫骨上的钢板进行研究。静态试验表明，在等渗盐水中长达一年的时间内不会发生缝隙腐蚀，但在高渗盐溶液中可能会发生。动态加载试验表明，电位会立即发生变化，这与所施加载荷的大小有关，表明在体外和体内，螺钉头部与钢板之间的运动都会导致微动腐蚀。提出了一种螺钉 - 钢板相对运动的机制。据推测，临床取出的植入物中出现的腐蚀是由于微动腐蚀，这种腐蚀使接触区域易于受到缝隙腐蚀的侵蚀。
