Does acid pickling of Mg-Ca alloy enhance biomineralization?

The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environment.In the present work,surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored.The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests.In vitro degradation behaviour was studied using immersion test in simulated body fluid(SBF).The sample surfaces were characterized using scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate(Ca P)coating on the sample surfaces.In addition,the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples.Thus,acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.

A new acid pickling process for copper alloys

The cleaning process of removing oxides on the surface of copper alloy sheetswas investigated systematically. Through optimizing, a perfect process was selected that is fit forremoving oxides on the surface. By acid pickling, all kinds of copper oxides are removedcompletely, furthermore, no poisonous gases are given out and a smooth and clean surface of copperalloys is obtained. At present, the process is applied successfully in the copper-processingindustry.

Surface processing for iron-based degradable alloys:A preliminary study on the importance of acid pickling

The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.

Multicomponent synthesis and designing of tetrasubstituted imidazole compounds catalyzed via ionic-liquid for acid steel corrosion protection:Experimental exploration and theoretical calculations

Five new tetrasubstituted imidazoles were designed with outstanding yields(83%-92%) in the occurrence of ionic liquid-based-pyridinium as a catalyst. The constructions of all synthesized derivatives were established by spectral tools and their purities were verified using thin-layer chromatography(TLC), displaying single-spot. The performance of corrosion protection of the prepared imidazole derivatives was examined theoretically and practically for acid steel corrosion. The experimental study was conducted by electrochemical(electrochemical impedance spectroscopy(EIS) and Tafel polarization(PPS)) tools.The findings from the used approaches concluded that the synthesized compounds were wellorganized inhibitors with an efficiency of 90.7%-98.5% at 50℃ and 0.7 mmol·L^(-1). The Tafel polarization results indicate the protective action of the additives was under mixed-monitoring. The additive adsorption on the electrode interface performed as a distinguished aspect for protection. The surface exploration on the blank and protected metal was completed by field emission scanning electron microscopy(FESEM). Computational studies by Monte Carlo(MC) simulation and quantum chemical calculation(DFT)were related to practical findings. The corrosion protection adsorption mechanism was reinforced by the preferable fitted Langmuir isotherm model. All findings from the applied-inspected approaches alternately confirm each other.