1. USING ALUMINA IN CERAMIC IMPLANTS FOR PROSTHETICS Osteoplastic surgeries are not a revolutionary new development in the medical field. However making alumina composite a key ingredient of ceramic prosthetics is a clear indication that engineers and medical professionals are developing new ways to refurbish the human body effectively. Ceramics are generally made with a powder and often resemble cement before being exposed to extreme heat and pressure to form hard solid substances. 1.CaO and Al 2 O 3 powders are mechanically mixed 2.The powders undergo calcification (a process in which more complex gas–solid reactions) at 1200°F for 48 hours 3.The resulting partially sintered compact was reground in a mortar and pestle, mixed with a small amount of distilled water, cold pressure into the required shape 4.This mixture is then sintered for 16 hours at 1225°C to produce a durable ceramic implant [4] With these conditions in mind, ceramics with alumina composite exhibit optimal structural arrangement and hardness. In Vivo Bone-Bonding Study of Bioglass ® -Coated Titanium Alloy studies the applications of specific glasses (know as Bioglass) as a coating for titanium alloy implants. Glasses such as these are able to chemically bond to bone without a porous surface or cement. Bioglasses are brittle, and are therefore most useful as coating for harder materials, such as titanium alloy or stainless A bioactive silicate glass would be capable of bonding with both metal and bone, although 2-3 graded layers are required to bind the surfaces. Ceramic materials with alumina composite are the most structurally sound material for prosthetic replacement for reasons that include: a)Hardness b)Physical molecular structure c)Durability Though plastic and metal prosthetics are generally the most commonly used in vivo, ceramic implants are unsurpassed in strength and see high rates of success in numerous studies testing qualities such as strength and biocompatibility. The core structure of Al 2 O Non-conducting material Less likely to release ions of aluminum or oxygen into the body Metallic and ionic bonding properties are due to the stable structure of alumina [Figure 1] Very little decomposition over time Good biocompatibility in vivo (porous material) PropertyAl 2 O 3 Mg-PSZY-TZPZTACoCrBone (cortical) Composition99.9% Al 2 O 3 ZrO 2 - 8 mol% MgO ZrO 2 - 3 mol% Y 2 O 3 Al 2 O 3 - 20 vol% ZrO 2 -- Density (g/cm 3 )>3.975.756.054.408.51.7-2.0 Grain size (μm)1-5500.1-1.01-2-- Fracture toughness K IC (MPa.m 1/2 ) 4-56-106-126-1050-1002-12 Fracture threshold K IO (MPa.m 1/2 ) 2.0-2.53.0-3.54-- Elastic Modulus (GPa) 400-450200-250 300-350210-2503-30 Hardness (Vickers) (GPa) 14-1610-1212-1412-153-4- Hardness (Vickers) (HV) 1800- 2000 1200 1600- 1800 300-400- Thermal expansion coefficient (10 -6 K -1 ) 87-10118.514- Thermal conductivity (Wm -1 K -1) 3022171000- Kaylene Kowalski and Margot Shore Table 1: Comparison of Alumina vs. Other Materials Figure 2: Structure of Alumina (Al 2 O 3 ) Figure 1: Crystalline Structure of Alumina (Al 2 O 3 ) The recurring problems in ceramic prosthetics remain pressing issues that affect both the popularity and effectiveness of joint implants. Squeaking and shattering in vivo of alumina ceramic implants has resulted in increased research into improvements and alternate designs for hip prosthetics. The Nanomaterials and Nanotechnology Research Center has recently produced an alumina-zirconia nanocomposite that is expected to have a lifespan of over 70 years in vivo. The Changzhou Institute of Light Industry Technology (CIT) has developed a method of strengthening traditional materials, and they believe that irradiating ceramic prosthetics with gamma radiation before implantation will further toughen the joints. The short burst of gamma radiation breaks the long polymer strands inside the plastic into small pieces called radicals which relink to form a tougher material that does not propagate stress throughout the structure. USING ALUMINA IN CERAMIC IMPLANTS ALUMINA INNOVATIONS ADVANAGES OF ALUMINA