Corrosion Resistance of Stainless Steels Intended to Come into Direct or Prolonged Contact with the Skin

Abstract

The biocompatibility of materials in contact with a living tissue becomes a puzzle in the overall picture of assessing the toxic effects of chemicals that come into contact with us. Allergic reactions to substances are a significant and growing health problem affecting large parts of the population in Europe. Wristwatches are objects worn in prolonged contact with the skin, being subject to localized corrosion, especially pitting and crevice types, in sulfide-chloride medium, and high wear in the bracelets joints. Watches of medium quality are usually made of stainless steels. The X2 CrNiMo 17-12-2 316L grade as well as X1 CrNiMo 20-25-5 Cu 1 or 904L are commonly used, having good resistance to generalized corrosion. The passive layer is nevertheless insufficient to ensure complete immunity in all cases of localized corrosion encountered during wear. For this reason, a high-corrosion-resistant steel: X1 CrNiMo 18-15-4 N 0.15 or 317LMN, from three different suppliers was evaluated. Metallographic characterization was carried out. The corrosion behavior evaluation was performed for the generalized corrosion, pitting and crevice corrosion and galvanic corrosion. Galvanic couples steel 317LMN-gold 18K alloy 3N and gold 18K 5M were used. The results of the generalized and pitting corrosion test indicated three basic groups. All of the 317LMNs were similar. The 316L variants tested noticeably worse. The 904Ls were difficult to discern, but certainly easier than the 316Ls and, possibly, at least comparable to the 317LMNs.

Multicomponent Alloys for Biomedical Applications

“…The exposure to a variety of chemicals is known as the "cocktail effect" and expresses the way in which different chemicals are released from different sources and affect humans [7,21]. Individual chemicals can become more dangerous when mixed together and act as an aggravating factor [22].…”

“…It is estimated that 15-20% of Europe's population are sensitized to allergens. Allergic reactions are a significant and growing health problem affecting large parts of the European population [7,13].…”

“…The degradation of metallic devices in a biological environment is accompanied by the release of cations such as Cr, Co, Ni, and Ti. Therefore, we deal with a cumulative effect: allergic, irritating, mutagenic, and toxic [7].…”

Comportamiento electroquímico de los aceros 316L, 316L nitrurado y F1586 en fluido corporal simulado

“…Si bien este acero presenta una alta resistencia a la corrosión general, es susceptible a la corrosión por picadura (Guo, Kwok and Chan, 2019), (Laleh et al, 2019), (Man et al, 2019). La corrosión por picadura se manifiesta como pequeños huecos en áreas defectuosas de la capa pasiva, y es atribuida a la interacción con iones agresivos, como Cl -, presentes en el medio (Ziegenhagen et al, 2019). En términos generales, estos huecos no son visibles a simple vista y son altamente peligrosos puesto que conllevan a la corrosión bajo tensión, lo que conduce a la falla catastrófica del implante biomédico (Eliaz, 2019), (Sivakumar and Rajeswari, 1995).…”

“…Por otro lado, con la corrosión se liberan iones metálicos que son transportados y acumulados en diferentes tejidos corporales. Dosis elevadas de estos iones, especialmente níquel, pueden desencadenar efectos tóxicos y carcinógenos en las células (Ziegenhagen et al, 2019) (Yang and Ren, 2010). Debido a los efectos adversos que trae consigo la corrosión en el cuerpo humano, variados esfuerzos se están orientando a la fabricación de otras aleaciones e implementación de procesos industriales que permitan mejorar la resistencia a la corrosión del acero 316L.…”