###### Abstract  
In the field of surgery, bioresorbable magnesium is considered a promising candidate. Its low corrosion resistance, which is disadvantageous for technical application, is advantageous for surgery since the implant fully degrades in the presence of the water-based body fluids, and after a defined time the regenerating bone takes over its function again. Therefore, knowledge of the corrosion behavior over several months is essential. For this reason, an in vitro short-time testing method is developed to accelerate the corrosion progress by galvanostatic anodic polarization without influencing the macroscopic corrosion morphology. The initial corrosion rate of the magnesium alloy WE43 is calculated by detection of the hydrogen volume produced in an immersion test. In a corresponding experimental setup, a galvanostatic anodic polarization is applied with a three-electrode system. The application range for the polarization is determined based on the corrosion current density from potentiodynamic polarization. To correlate the initial corrosion rate, and accelerated dissolution rate, the corrosion morphologies of both test strategies are characterized by microscopy images, as well as energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. The results demonstrate that the dissolution rate can be increased in the order of decades with the limitation of a changed corrosion morphology with increasing polarization. With this approach, it is possible to characterize and exclude new unsuitable magnesium alloys in a time-efficient manner before they are used in subsequent preclinical studies. bioresorbable implants; magnesium alloys; WE43; immersion test; galvanostatic anodic polarization; corrosion process; corrosion morphology 2021112  
animal experiments are ethically questionable, many studies focus on in vitro corrosion investigations [9; 10; 11], which can be divided into electrochemical [12; 13; 14] and immersion investigations [15; 16; 17]. In the field of electrochemical testing, potentiodynamic polarization (PDP) measurement is often used due to the short test duration. However, owing to the negative difference effect (NDE), it leads to inaccurate values of the corrosion rate. According to current studies, the applied anodic polarization leads to a cathodic activation of the sample resulting in a surface layer with a persistent cathodic effect reducing by a cathodic value the anodic current density falsifying the results [18; 19; 20]. Hence, PDP measurement should mainly be used to estimate the corrosion rate and for the qualitative comparison of different material conditions. The current method to determine the in vitro corrosion rate and evaluate the corrosion behavior is the immersion test with detection of the hydrogen volume produced and or the mass loss [11; 15; 16; 17]. The corrosion rate can be determined immediately via the mass loss; however, it does not allow in situ measurements, and the removal of the corrosion layer by--e.g., the carcinogenic chronic acid--is another disadvantage. In contrast, hydrogen detection allows an indirect calculation of the corrosion rate by using the reaction equation of Mg corrosion. It enables an in situ measurement [21], allowing the evaluation of a time-dependent corrosion behavior, which is of advantage compared to PDP. Due to the formation of an inhibiting corrosion layer, Mg alloys usually exhibit a time-dependent corrosion behavior. The uncorroded surface is more reactive, resulting in a high hydrogen evolution rate (HER). The arising corrosion layer is porous and allows the electrolyte to access the surface. With increasing immersion time, a thicker, more protective corrosion layer is formed, leading to a decrease in accessibility and thus to a decrease in HER [11; 22; 23]. This effect can be enhanced by alloying elements that change the nature of the corrosion layer [24]. An adverse effect can be observed due to corrosion pit formation.