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Material Properties for Biomedical Applications
Published in Savaş Kaya, Sasikumar Yesudass, Srinivasan Arthanari, Sivakumar Bose, Goncagül Serdaroğlu, Materials Development and Processing for Biomedical Applications, 2022
D. Ajith, K.G. Ashok, K. Aravind
Therefore, corrosion in biomaterials is also attributed by chemical or electrochemical degradation of a material through interactions with its environment. Galvanic corrosion occurs when two dissimilar materials are present in a solution and one becomes cathode and the other becomes anode and the electrons will move from one to another causing the dissolution of the metal. Relative micromotion between two mating surfaces causes fretting corrosion. For example, SS 316L is also prone to wear and various corrosions such as crevice corrosion, intergranular corrosion, pitting corrosion, and fretting corrosion. Other widely used implants, Co-Cr alloys, are subjected to inter-granular corrosion, etching, selective dissolution of cobalt, etc. The corrosion behavior of various biomaterials including metals, metallic glasses, and biodegradable metals are comprehensively discussed in [31]. Implant failure mechanisms, retrieval and failure analysis are highlighted in that study. Table 3.4 shows the concentration of ions in blood plasma extracellular fluid and is compared with Ringer’s solution.
Corrosion: Introduction
Published in Hatem M.A. Amin, Ahmed Galal, Corrosion Protection of Metals and Alloys Using Graphene and Biopolymer Based Nanocomposites, 2021
Anjali Peter, Sanjay K. Sharma
This process happens in the electrically conductive environment. Deformation comes into existence due to the potential difference between the metals. If the active noble metal acts as the cathode with higher surface area and the less noble metal acts as the anode with less surface area, in this case, a large cathodic reaction takes place with the combination of higher anodic reaction. This process upsurges the corrosion rate with major harm to metal. The electromagnetic series (Galvanic series) is used to predict the tendency of metal to galvanic corrosion.
Surface Failure
Published in Ansel C. Ugural, Youngjin Chung, Errol A. Ugural, Mechanical Engineering Design, 2020
Ansel C. Ugural, Youngjin Chung, Errol A. Ugural
Corrosion can also allude to materials other than metals, such as polymers; however, in this context, the term degradation is more proper. Ceramic materials are almost entirely immune to corrosion. Usually, corrosion can be concentrated locally to form a pit or crack, or it can extend across a wide area. Galvanic corrosion occurs when two different materials contact one another and are immersed in any substance that is capable of conducting an electric current. It is of major interest to the marine industry and also anywhere where water contacts metal structures, such as pipes. It is frequently possible to chemically remove the corrosion to produce a clean surface. For instance, phosphoric acid is often applied to ferrous surfaces of tools to remove rust. Materials (typically metals) also chemically deteriorate when subjected to a high-temperature atmosphere containing oxidizing compounds.
Effect of hydrostatic pressure on galvanic corrosion of low-alloy steel in simulated deep-sea environments
Published in Corrosion Engineering, Science and Technology, 2022
Yuxin Wang, Fulei Yan, Bo Wu, Jianhua Wu, Kefeng Hu, Xianbin Hou, Leyang Dai
The increase in hydrostatic pressure causes the corrosion potential of the three low-alloy steels to shift negatively, thus facilitating the conversion process of the intermediate product γ-FeOOH to , accelerating the process of cathodic reaction, and the generated can be used as a large cathode to accelerate corrosion. The increase in hydrostatic pressure will also change the morphology of corrosion products. The corrosion products under high pressure are more likely to form crack defects, making it easier for corrosion ions to contact the substrate surface and accelerate corrosion.Although the potential difference between the three low-alloy steels is slight (<60 mV), severe galvanic corrosion still occurs after coupling. Under different hydrostatic pressure conditions, 907A is used as the anode of the 907A/921A1# system, and the protection current is output to the 921A steel and 1# steel (cathodes), and the corrosion is aggravated., while 921A steel and 1# steel are used as cathodes, corrosion will slow down. Therefore, in engineering applications, the galvanic corrosion of metals with low potential differences cannot be ignored, and coatings and cathodic protection must be used for total protection.
Galvanic corrosion of aluminium alloy members of bridge guiderails under severe atmospheric exposure conditions
Published in Corrosion Engineering, Science and Technology, 2019
Emmanuel Mrema, Yoshito Itoh, Akira Kaneko
Aluminium alloy guiderails are commonly used on bridges constructed in marine environments due to the proven durability of aluminium alloy materials. However, to ensure a higher structural strength at key points, the fasteners in these aluminium alloy structures continue to be made of steel. The contact between the aluminium alloy and the steel fasteners can trigger galvanic corrosion in the aluminium alloy under severe atmospheric conditions [2]. Galvanic corrosion is an electrochemical deterioration of a metal occurring when two dissimilar metals (electrodes) with a potential difference between them come in contact in an electrolytic environment. For galvanic corrosion to occur, three conditions have to be met: the metals must be far apart in the galvanic series, they must be in an electrolytic environment and they must be electrically in contact [5]. Normally, the more anodic metal dissolves in the electrolyte and the dissolved particles migrate to the more cathodic metal. In this sense, the more anodic metal is considered to have undergone galvanic corrosion. The severity of the corrosion increases with the increase of the area in contact with the cathodic metal [6]. One of the most common triggers of galvanic corrosion is a combination of stainless or mild steel fasteners with aluminium alloy members, as illustrated in Figure 1. Galvanic corrosion can be inhibited by preventing the electric flow between the two dissimilar metals through proper insulation or through some appropriate surface treatment on either metal.
Galvanic corrosion analysis of a Bi–Zn solder alloy coupled to Ni and Cu substrates
Published in Corrosion Engineering, Science and Technology, 2020
Rudimylla S. Septimio, Maria A. Arenas, Ana Conde, Amauri Garcia, Noé Cheung, Juan de Damborenea
Galvanic corrosion, also known as ‘dissimilar metal corrosion’, occurs when two (or more) dissimilar metals are electrically coupled under the presence of an electrolyte. In this context, the noblest metal will act as a cathode leading the less noble metal to degrade; in other words, it increases the corrosion of the anode. Galvanic corrosion has been one of the major concerns for industry since the modern engineering structures are commonly created by joining dissimilar materials [1,2]. This kind of corrosion is very common in aircraft [3–7], petroleum [8–10], civil engineering and architecture [11,12] and shipping industries [13,14], resulting a great economic and safety burden [2].