Institute for Color Science and Technology (ICST) Progress in Color, Colorants and Coatings 2008-2134 19 2 2026 05 01 Coating Ti13Nb13Zr Alloy with Hydroxyapatite Using Pyrolysis Spray Improves Corrosion and Osseointegration Characteristics for Biomedical Applications (In-vitro study) 113 133 82113 10.30509/pccc.2025.167501.1376 EN G. Hamed Farhan Department of Biomedical Engineering, College of Engineering, Al-nahrain University, P.O. Box: 62021, Baghdad, Iraq J. Abduljabar Hassan Department of Biomedical Engineering, College of Engineering, Al-nahrain University, P.O. Box: 62021, Baghdad, Iraq A. H. Al-helli Department of Unmanned Aerial Vehicle (UAV) Engineering, College of Engineering Al-nahrain University, P.O. Box: 62021, Baghdad, Iraq Journal Article 2025 03 19 Titanium and its alloys are widely used in biomedical applications. There are two essential uses in the biomedical field: dental and orthopedic. Ti13Nb13Zr has been predominantly used in orthopedic surgery over the last decade. In this research, Ti13Nb13Zr was coated with hydroxyapatite (HAP) to enhance osseointegration and improve corrosion characteristics. The pyrolysis spray technique was used to apply layers of HAP (2, 3, 4 and 5) on the Ti13Nb13Zr alloy, with a 2-minute interval between each layer to allow for drying. The coating was characterized using XRD, FESEM, and EDX, and its electrochemical corrosion properties were also investigated. The coated samples were immersed in simulated body fluid (SBF) for one month and then  tested using the same methods to evaluate the improvement in corrosion  and osseointegration characteristics. The results show that coating before immersing in SBF solution was uniform, and the corrosion rate improved, reaching 5.779 × 10-5 mmpy compared with 1.741 × 10-3 mmpy for the uncoated sample, while the protection efficiency reached 96.68 %. After immersing in the SBF solution, the XRD, FESEM, and EDX test results confirm the formation of a new hydroxyapatite layer, and the corrosion rate and protection efficiency reached 3.498 × 10-5 mmpy and 98.27 % respectively.  https://pccc.icrc.ac.ir/article_82113_730795b30f76ad37c56ad34c449f8d86.pdf