Alumina Ceramic for Knee and Hip Prostheses

1. Alumina Ceramic for Alumina Ceramic for Knee Knee and and Hip Hip Prostheses Prostheses Alumina is one of the world's most popular industrial ceramic materials due to its combination of mechanical, electrical and thermal properties. Alumina finds particular application as an abrasive/cutting tool material as well as extrusions nozzles nozzles used in piston engines as friction parts; in addition it is utilized as medical implants and high vacuum systems due to its hermeticity and chemical resistance properties. Alumina ceramics are slightly soluble in hot acids such as sulfuric, acetic and hot HF acids, but remain resistant to chemical corrosion due to this characteristic. Pure alumina materials therefore make an ideal material choice when it comes to chemical protection against corrosion. Due to their outstanding characteristics, alumina ceramics are commonly utilized in load-bearing hip and knee prostheses. To properly function as a load-bearing surface material must be free from porosity with an ultrafine microstructure, be strong and possess excellent creep resistance properties. Quality in alumina ceramic production can be significantly influenced by impurity levels present in its initial powder. Commercially produced alumina powders typically contain silica, calcium, magnesium, and sodium oxides that absorb during sintering to form liquids that degrade ceramic structures. Impurities found in alumina ceramics can significantly alter their properties, particularly strength and thermal conductivity at higher temperatures, as well as creep resistance. Furthermore, such impurities may compromise creep resistance. To minimize these adverse reactions, alumina ceramic must be manufactured from high-purity feedstocks.