Study on the release of copper ion and corrosion for intrauterine contraceptive device with two kinds of Cu-containing stent / 中国医疗器械杂志

Two kinds of Cu-containing intrauterine contraceptive device (Cu-IUD) has been evaluated through the study on the release of copper ion and corrosion of copper surface in artificially formulated fluid. The result showed that the copper ions were released profusely from the stainless steel stents Cu-IUD in the first week of soak (25-12 microg/d), and then it became slowly and steady. The release of the copper ions from the titanium nickel shape memory alloy stents Cu-IUD were always slowly and steady in two months (0.5-5 microg/d). It obviously shows that the corrosion on copper surface of stainless steel stents Cu-IUD were more serious than titanium nickel shape memory alloy stents Cu-IUD by using 200 times microscope testing before and after soaking in formulated fluid.

The uncertainty of different vickers-hardness test force in medical device testing / 中国医疗器械杂志

Vickers hardness is widely used in the performance testing of the metallic medical devices. It discusses the relationship between different test force and the uncertainty by mathematical simulation and experiment. With the increase of test force its uncertainty becomes smaller at 400 times magnification. If you can, you should try to choose a large test force, in order to improve the accuracy and repeatability. In the actual testing process, it is best not to use the micro vickers hardness test.