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通过对40℃时、不同pH值和不同过饱和度下磷酸二氢钾(KDP)晶体{100}面生长的原子力显微镜(AFM)的非实时研究,发现在低过饱和度下,{100}面台阶化明显,台阶形貌差异较大;高过饱和度下,KDP晶体生长以二维成核机制为主.对于pH=4.2和pH=2.5,在过饱和度较低时,位错生长机制控制晶体的生长;当σ≥0.05时,二维成核机制起主导作用.而pH=5.0时,在低过饱和度下同样是由位错机制控制生长,但当σ≥0.03晶体生长即以二维成核机制为主.通过对25℃时、不同pH值、低过饱和度下KDP晶体{100}面台阶推移的原位实时AFM的研究,估算了KDP晶体{100}面的法向生长速度,发现pH=5.0时生长速度最快,晶体生长主要受螺旋位错生长机制控制.另外,发现随着过饱和度的降低,台阶的密度也随之减少,宽度变大.最后,通过原位实时AFM,观察到一种各向异性生长的台阶推移现象.
Through the non-real-time study of atomic force microscopy (AFM) at 40 ℃, the growth of {100} plane of potassium dihydrogen phosphate (KDP) crystal under different pH values and different supersaturations, it was found that under low supersaturation, {100} The surface of KDP is obviously different, and the difference of the step topography is significant. Under high supersaturation, the crystal growth of KDP is dominated by two-dimensional nucleation mechanism.For pH = 4.2 and pH = 2.5, dislocation growth Mechanism controls the growth of crystal, while when σ≥0.05, two-dimensional nucleation mechanism plays a leading role.While pH = 5.0, it is also controlled by dislocation mechanism under low supersaturation, but when σ≥0.03 crystal growth Dimensional (2D) nucleation mechanism is adopted.The in-situ real-time AFM of {100} plane transition of KDP crystal at 25 ℃, different pH value and low supersaturation is used to estimate the {100} plane of KDP crystal It is found that the growth rate is the fastest when pH = 5.0 and the growth of crystal is controlled by the mechanism of helical dislocation growth.In addition, it is found that with the decrease of supersaturation, the density of the step decreases and the width becomes larger.Finally, By in situ real-time AFM, an anisotropic growth step was observed.