Bulina Natalia V, Baev Sergey G, Makarova Svetlana V, Vorobyev Alexander M, Titkov Alexander I, Bessmeltsev Victor P, Lyakhov Nikolay Z
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze Str. 18, 630128 Novosibirsk, Russia.
Institute of Automation and Electrometry, Siberian Branch of Russian Academy of Sciences, Academician Koptyug Avenue 1, 630090 Novosibirsk, Russia.
Materials (Basel). 2021 Sep 19;14(18):5425. doi: 10.3390/ma14185425.
Hydroxyapatite, being the major mineral component of tooth enamel and natural bones, is a good candidate for bone tissue engineering applications. One of the promising approaches for manufacturing of three-dimensional objects is selective laser sintering/melting which enables the creation of a dense structure directly during 3D printing by adding material layer-by-layer. The effect of laser irradiation with a wavelength of 10.6 μm on the behavior of mechanochemically synthesized hydroxyapatite under different treatment conditions was studied for the first time in this work. It was shown that, in contrast to laser treatment, the congruent melting is impossible under conditions of a relatively slow rate of heating in a furnace. Depending on the mode of laser treatment, hydroxyapatite can be sintered or melted, or partially decomposed into the more resorbable calcium phosphates. It was found that the congruent selective laser melting of hydroxyapatite can be achieved by treating the dense powder layer with a 0.2 mm laser spot at a power of 4 W and at a scanning speed of 700 mm/s. Melting was shown to be accompanied by the crystallization of a dense monolayer of oxyhydroxyapatite while preserving the initial apatite crystal lattice. The thickness of the melted layer, the presence of micron-sized pores, and the phase composition can be controlled by varying the scanning speed and laser power. This set of parameters permits the use of selective laser melting technology for the production of oxyhydroxyapatite biodegradable implants with acceptable properties by 3D printing.
羟基磷灰石作为牙釉质和天然骨骼的主要矿物质成分，是骨组织工程应用的理想候选材料。制造三维物体的一种有前景的方法是选择性激光烧结/熔化，它能够通过逐层添加材料在3D打印过程中直接创建致密结构。在这项工作中，首次研究了波长为10.6μm的激光辐照对不同处理条件下机械化学合成的羟基磷灰石行为的影响。结果表明，与激光处理不同，在炉中相对缓慢的加热速率条件下不可能实现完全熔化。根据激光处理模式，羟基磷灰石可以被烧结或熔化，或者部分分解为更易吸收的磷酸钙。研究发现，通过用功率为4W、光斑直径为0.2mm的激光光斑以700mm/s的扫描速度处理致密粉末层，可以实现羟基磷灰石的完全选择性激光熔化。结果表明，熔化伴随着致密的羟基磷灰石单层结晶，同时保留了初始磷灰石晶格。通过改变扫描速度和激光功率，可以控制熔化层的厚度、微米级孔隙的存在以及相组成。这组参数允许通过3D打印使用选择性激光熔化技术生产具有可接受性能的羟基磷灰石可生物降解植入物。
