The expansion mechanism of hydroxide expanding phase for oil well cement slurry are discussed on the basis of principle of chemical thermodynamics and topochemical reaction model.

要基于膨胀剂原地反应模型和化学热力学原，了晶体生长压源动力及泥浆体体积膨胀与结晶压。

It is shown that expansible ettringite forms in the topochemical reaction,and crystallizes in-situ on the surface of unhydrated aluminate minerals and orients radially.

发现能够产生膨胀钙矾石是由局部化学反应所生成；它们在未化铝酸盐矿物表面原地结晶，呈放射状生长。