This study numerically investigates the deposition behavior of cold-sprayed hydroxyapatite (HA) coatings on a 316L stainless steel substrate. The velocity of HA particles sprayed using a de Laval nozzle was estimated using the discrete phase mode (DPM) model in FLUENT. Particle retention was subsequently analyzed using the Coupled Eulerian Lagrangian (CEL) and Smoothed Particle Hydrodynamics (SPH) models. The critical or threshold particle velocity was determined to be 577 m/s. Higher particle retentions were observed for impacted velocities closer to this threshold. Various morphologies of the splat were observed depending on the impact velocity, ranging from cap-shaped to ring-like structures. At impact velocities exceeding 677 m/s, the central part of the splat detached due to high spring back force, leaving behind ring-like particle remnants on the substrate. Moreover, beyond this velocity, stripes surrounding the splat diameter and grooves around the cap were observed due to material fragmentation. The study emphasizes the significant role of particle velocity and mechanical interlocking in bonding and retaining HA coatings on the metal substrate, distinct from adiabatic shear instability prevalent in metal-on-metal coatings.

本研究对 316L 不锈钢基材上冷喷涂羟基磷灰石 (HA) 涂层的沉积行为进行了数值研究。使用 FLUENT 中的离散相模式 (DPM) 模型估算使用德拉瓦尔喷嘴喷射的 HA 颗粒的速度。随后使用耦合欧拉拉格朗日 (CEL) 和平滑粒子流体动力学 (SPH) 模型分析粒子保留。临界点或阈值颗粒速度测定为 577 m/s。对于接近该阈值的冲击速度，观察到较高的颗粒保留。根据撞击速度，观察到碎片的各种形态，从帽状结构到环状结构。当冲击速度超过 677 m/s 时，碎片的中心部分由于高回弹力而分离，在基材上留下环状颗粒残留物。此外，超过这个速度，由于材料破碎，会观察到围绕板直径的条纹和围绕帽的凹槽。该研究强调了粒子速度和机械联锁在金属基材上粘合和保留 HA 涂层中的重要作用，这与金属对金属涂层中普遍存在的绝热剪切不稳定性不同。