Structure and Selected Properties of Si(C,N) Coatings on Ni-Cr Prosthetic Alloys

Metal alloys continue to be, and are expected to remain, essential materials for fabricating prosthetic elements due to their unique properties, particularly their high strength, durability, and appropriate modulus of elasticity, which make them well-suited for such applications. However, commonly used non-precious metal alloys exhibit lower corrosion resistance compared to precious metal alloys. This reduced resistance leads to the release of metal ions from the alloy into the oral environment. Adverse biological responses to metal alloys can be mitigated through various surface modifications, most commonly by applying coatings. These coatings are typically ceramic, including oxides, nitrides, and carbides. In this study, the mechanical properties (hardness, modulus of elasticity, adhesion, and thickness) of complex Si(C,N) coatings applied to a prosthetic Ni-Cr alloy were investigated. Depending on the proportions of N, C, and Si in the coating, the hardness ranged from 12 to 15 GPa, while the modulus of elasticity varied between 130 and 170 GPa. Adhesion strength, measured via the scratch test method, was within an acceptable range. Microscopic analysis revealed that the coatings had a thickness of 2 to 2.5 μm, exhibiting a homogeneous, columnar structure. In conclusion, the properties of the fabricated Si(C,N) coatings are deemed satisfactory for their intended use as protective layers for prosthetic and orthodontic components.