目前国内生产的录音、计测和录像磁带的涂层大多是采用γ-Fe_2O_3磁粉。不论采用何种涂布方式,其涂层厚度大多利用磁层透光度(用目测或光电)来控制。这种控制方法会受到磁粉或磁浆颜色差异的限制,很难保证磁层厚度的一致性,从而造成磁带性能的不一致。如采用塞尺法来控制,也只能控制磁带初始的磁层厚度,且操作不方便,在生产上麻烦较多。 At present, domestic production of recording, measurement and video tape coatings are mostly used γ-Fe_2O_3 magnetic powder. Regardless of the coating method used, the coating thickness is mostly controlled by the permeability of the magnetic layer (visual or photoelectric). This control method will be subject to the magnetic powder or magnetic paste color differences, it is difficult to ensure the consistency of the thickness of the magnetic layer, resulting in inconsistent tape performance. Such as the use of plug-foot method to control, only the initial control of magnetic tape thickness of the magnetic layer, and the operation is not convenient, more trouble in the production.