SURFACE MODIFICATION ON THE STEM OF A TOTAL HIP JOINT REPLACEMENTINTRODUCTIONTitanium and its alloys are used in various applications due to their desirable properties. One of the main sectors in which titanium is widely used is that of biomedical applications where both implants and surgical instruments make use of this element due to its biocompatibility, low modulus and excellent resistance to corrosion. However, titanium shows poor tribological properties and is therefore generally alloyed and undergoes surface modification to obtain the optimal requirements. Biomedical implants are subject to high clinical requirements, so a surface modification process is carried out before implantation into the human body. The purpose of making such changes includes; sterilize the implant surface from contaminants before implantation, increase bioactivity, increase hardness, and thus promote the reduction of the wear rate of the implant and the introduction of a passive layer to minimize the release of ions into the body .1 For this purpose of this assignment, the study of the surface modification of a titanium alloy stem, used in a hip joint implant, will be studied. A total hip joint implant consists of a joint that basically supports the head, femur cup, and stem. The stem is made of titanium alloy - Ti- 6Al- 4V where the titanium is alloyed with aluminum and vanadium. When titanium is alloyed with these materials, excellent properties such as a high strength-to-weight ratio and exceptional corrosion resistance are achieved.2 However, this alloy imparts poor tribological properties and tends to seize when subjected to sliding motion due to its low hardness of 36HRC.3 Different surface modification techniques are performed on ti...... half of the paper ...... Advanced surface modification technology in the biomedical sector has the ability to offer not only a improvement of tribological properties but also to improve clinical requirements before and after implantation. Such properties include cell growth and antibacterial effect.1-(pg4 doc.pdf)2-http://www.arcam.com/wp-content/uploads/Arcam-Ti6Al4V-Titanium-Alloy.pdf3- (reference ta lpdf twil )4- http://www.news-medical.net/whitepaper/20130903/Hydroxyapatite-Coating-for-Titanium-Implants.aspxTable 1 ghandek min http://www.azom.com/properties.aspx? ArticleID=1547 u l-pdf hi twil5- http://emedicine.medscape.com/article/2085501-overview6-http://www.intechopen.com/books/titanium-alloys-towards-achieving-enhanced-properties- for-diversified -surface-modification-applications/techniques-for-oxidation-carburization-of-biomedical-grade-titanium-alloys-