Effect of plasma gas atmosphere on hydroxyapatite-coated titanium-based implants Ravindra Kotian, Madhu Keshava Bangera, Karen Boaz and Prashanthi S. Madhyastha Metall. Res. Technol., 118 1 (2021) 103 Published online: 30 November 2020 DOI: 10.1051/metal/2020072