How to medical titanium plates in the real sea change in galvanic corrosion

Galvanic corrosion behavior of electrochemical measurement parameter is the open circuit potential and galvanic current characterization of the two materials in contact titanium wire. The so-called open-circuit potential refers to the two materials temporarily off the meter coupling circuit to the reference electrode corrosion potential of each material were measured in the time. Due to the different degrees of polarization after coupling of different materials, the potential to achieve the basic stability of the different time after disconnection. Usually 1-20 minutes, the potential is measured after the stable potential. With the development of corrosion, the surface state of the material is also changing, and while the potential changes caused by changes in the behavior of galvanic polarization, ie corrosion kinetics changes. So we can come to understand variation of galvanic corrosion over time and the different electrical characteristics even on the track by open circuit potential measurements.
In the study of galvanic corrosion of titanium alloy parts can, first to see the real potential of the sea from rot titanium and other alloys from a thermodynamic point of view - time curve. All of these materials in the electrical potential in the real sea change over time. Especially stainless steel potential fluctuations and changes not only with the titanium is opposite tendency. Potential of titanium in all 20 days are rapidly being shifted over time, moving a rate of 200-300mV, but instead of stainless steel 1Cr18Ni9Ti rapid negative shift, moving magnitude of approximately 250mV. Copper alloys in seawater more stable full-B30 small potential fluctuation is small, but the overall trend is also a potential positive shift.
Seen from the curve, titanium potential shifts and more stable, while the stainless steel potential negative shift over time, it seems that with the stainless steel in just three months time cause corrosion perforation are intrinsically linked. Gillber and potential shifts Hefny think titanium has excellent corrosion resistance is due to the success of dense stable raw surface mechanical damage have a strong self-healing ability of TiO2: passivation film. We titanium E-pH diagrams and literature reports of knowledge, titanium chloride medium when pH> 2 does not occur when the activation area. For natural seawater pH was neutral to slightly alkaline is completely consistent.
Even for galvanic corrosion characteristics between pairs of titanium and titanium and even copper alloy, stainless steel between our TA2/BT14, TA2/B30 and TA2/18-8-ss three typical galvanic be analysis.
Galvanic corrosion specimen dimensions are 100 × 50 × 2mm, even for each group of three pairs of parallel samples were taken, even on the area ratio of 1:1. 104 days of trial.
According TA2/BT14 coupling measured open circuit potential - time curve, and galvanic current - time curve. May know, the open circuit potential curve has been in almost two titanium overlapped. medical titanium plate This shows that the coupling due to the polarization of the potential difference between the reduced and even disappear, although their corrosion potential difference of up to 150mV, would not exist galvanic corrosion.
According TA2/B30 even on the open circuit potential - time curve, and galvanic current - time curve. After the coupling of these two materials, TA2 potential positive shift dramatically, and B30, but fluctuate within a certain range, and a significant galvanic current. Another case, the outer channel potential difference is small, the galvanic current is not large, but there is an increasing trend to increase with time. It seems that localized corrosion of stainless steel from corrosion perforation caused by aggravated galvanic effect, the galvanic current rapidly increases. Thus, when titanium or stainless steel in contact with the B30, when their anode area ratio increased, galvanic effects will also increase, resulting Laqne early work also shows that this view.