“Draft:Grain boundary dissolution”的意思、由来-开放百科全书

Grain boundary dissolution refers to the widely observed phenomena of enhanced solubility or solvation at grain boundaries in inorganic polycrystalline materials. This phenomena is analogous to Intergranular corrosion in alloys and has implications in biomaterials, pharmacology and water treatment.

Phenomenon

A polycrystalline material exhibiting a low solubility rate at crystalline surfaces, when immersed in an aqueous environment such as Simulated body fluid, will often exhibit the solvation of atomic or ionic species occurring predominantly at grain boundaries and triple points ^[1]. This preferential grain boundary dissolution manifests in a dissolution front with a pitted or mottled appearance. The phenomenon of grain boundary dissolution can be harnessed to enhance the solubility of implantable bioceramics such as hydroxyapatite. A similar effect occurs with preferential dissolution at other crystal defect sites.

Mechanistic explanations

The distortion of atomic packing at grain boundary and triple point regions in crystalline solids results in local disorder and weaker bonding energy in these regions, favoring dissolution processes. Amorphous solids in general dissolve more rapidly than analogous crystalline structures and this can be seen as a localised extension of this trend. In crystalline materials with high dissolution rates, preferential dissolution at grain intersections is not readily observable. The presence of dopant elements in crystalline solids is known to enhance phenomena of grain boundary dissolution, with potential applications in the design of crystalline biomaterials with enhanced bioactivity.

Significance in ceramics

In ceramic materials, grain boundary dissolution is of profound significance in governing the bioactivity of hydroxyapatite and other biomaterials.

References

1. ^{{cite journal | last1= Zhu | first1= H. |display-authors=etal| title= Nanostructural insights into the dissolution behavior of Sr-doped hydroxyapatite| journal = Journal of the European Ceramic Society | year=2018 | volume=38| issue=16| pages= 5554-5562|doi= 10.1016/j.jeurceramsoc.2018.07.056| url=https://www.sciencedirect.com/science/article/pii/S0955221918304837 | }}