Baino Francesco
Institute of Materials Physics and Engineering, Applied Science and Technology Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Interuniversity Center for the promotion of the 3Rs Principles in Teaching and Research, Italy.
Materials (Basel). 2019 May 30;12(11):1754. doi: 10.3390/ma12111754.
Deposition of bioactive glass or ceramic coatings on the outer surface of joint prostheses is a valuable strategy to improve the osteointegration of implants and is typically produced using biocompatible but non-bioactive materials. Quantifying the coating-implant adhesion in terms of bonding strength and toughness is still a challenge to biomaterials scientists. In this work, wollastonite (CaSiO)-containing glass-ceramic coatings were manufactured on alumina tiles by sinter-crystallization of SiO-CaO-NaO-AlO glass powder, and it was observed that the bonding strength decreased from 34 to 10 MPa as the coating thickness increased from 50 to 300 µm. From the viewpoint of bonding strength, the coatings with thickness below 250 µm were considered suitable for biomedical applications according to current international standards. A mechanical model based on quantized fracture mechanics allowed estimating the fracture toughness of the coating on the basis of the experimental data from tensile tests. The critical strain energy release rate was also found to decrease from 1.86 to 0.10 J/m with the increase of coating thickness, which therefore plays a key role in determining the mechanical properties of the materials.
在关节假体的外表面沉积生物活性玻璃或陶瓷涂层是一种改善植入物骨整合的有效策略，通常使用生物相容性但无生物活性的材料来制备。从结合强度和韧性方面量化涂层与植入物之间的附着力，对生物材料科学家来说仍是一项挑战。在这项工作中，通过对SiO-CaO-NaO-AlO玻璃粉末进行烧结结晶，在氧化铝瓷砖上制备了含硅灰石（CaSiO）的玻璃陶瓷涂层，并且观察到随着涂层厚度从50μm增加到300μm，结合强度从34MPa降至10MPa。从结合强度的角度来看，根据当前国际标准，厚度低于250μm的涂层被认为适用于生物医学应用。基于量化断裂力学的力学模型能够根据拉伸试验的实验数据估算涂层的断裂韧性。还发现临界应变能释放率随着涂层厚度的增加从1.86J/m降至0.10J/m，因此它在决定材料的力学性能方面起着关键作用。
