化学复合镀Ni—P—PTFE共沉积机理研究

通过测定钢试片上化学镀Ｎｉ－Ｐ－ＰＴＦＥ（聚四氟乙烯）复合镀层中ＰＴＦＥ粒子沉积量及分布特征，研究各种因素对ＰＴＦＥ粒子沉积的影响规律．试验表明，表面活性剂在化学镀Ｎｉ－Ｐ－ＰＴＦＥ过程中起着重要作用；同时，镀面状态及施镀工艺也有明显影响．提出了化学镀Ｎｉ－Ｐ－ＰＴＦＥ复合镀层的共沉积机理，即ＰＴＦＥ粒子通过机械碰撞及静电吸附的联合作用被试件表面俘获，实现与Ｎｉ－Ｐ共沉积

An Investigation on the Cellular Reaction of Cu 4%Ti Alloy

An investigation on the cellular reaction of Cu 4%Ti alloy aged at a lower temperature has been conducted by means of transmission electron microscope. It is found that the cellular reaction for the alloy aged at a lower temperature undergoes a series of transition processes, for example, spinodal decomposition, ordering and etc. The supersaturated Cu Ti alloy solid solution first decomposes into rich solute and depleted solute regions by spi nodal mechanism. Thereafter, the rich solute region undergoes ordering to form a metastable ordered phase Cu 4Ti with Dl a type. Finally, the cellular reaction takes place to make the ordered Cu 4Ti transform into a stable phase which is of the orthorhombic crystal lattice and same chemical composition as the former. The depleted solute region turns to the matrix with dilute solute. The cellular structure for the alloy aged at lower temperature is formed either from the modulated structure directly or by the coarsening of the modulated structure and the rearrangement of the precipitation phase. The latter, which is different from the classical cellular reaction, is a continuous transformation process.