Kobaltkróm

Kobaltkróm, or cobalt-chromium alloy, refers to a family of cobalt-based metals in which chromium is the major alloying element. Typical compositions include cobalt around 60–70% and chromium about 20–30%, with smaller additions of molybdenum, tungsten, nickel and/or iron to improve strength, hardness and biocompatibility. Cast variants (often designated Co-Cr-Mo) are commonly used for dental crowns, bridges and implant frameworks, while wrought variants serve orthopedic implants. Modern manufacturing also employs additive processes, such as powder-bed fusion, to produce complex Co-Cr components.

Properties of cobalt-chromium alloys include high yield and tensile strength, excellent wear resistance, and good corrosion resistance in physiological environments. They have a relatively high elastic modulus, typically around 200–230 GPa, and are radiopaque, aiding imaging after implantation. Fatigue strength is favorable for long-term load-bearing applications. Densities generally range from 8.3 to 8.8 g/cm3, and performances can vary with heat treatment and processing.

Processing and manufacturing methods encompass casting, forging and finishing for traditional components, as well as additive manufacturing techniques such as selective laser melting or electron beam melting for complex geometries. Surface finishing and post-processing are important to minimize ion release and optimize biocompatibility.

Applications span medical devices including dental restorations (crowns, bridges and implant bars) and orthopedic implants (hip and knee components, spinal hardware) as well as surgical instruments. Standards for Co-Cr alloys used in implants are covered by ISO 5832 series, including wrought and cast variants, which address mechanical properties and biocompatibility. While generally biocompatible, cobalt sensitivity can occur in some individuals, and ion release under wear remains a consideration in long-term implants.