Due to the very thin thickness of aluminized layer on vacuum aluminizing film, therefore can’t be used conventional thickness measurement instrument for the detection of the thickness, Nowadays, the detection of aluminum film thickness uniformity of special instrument is densitometer. The principle of the optical density meter is to detect the optical properties of the thin film through the densitometer.
Aluminized layer thickness testing is now known as the following 4:
1: Powerful electron microscopy direct measurement, precision to 10E-10M, also is 0.1 nm(1 M = 1000mm, 1mm = 1000 microns, 1 micron = 1000 nm, 1 nm = 10 Amy). Aluminized layer thickness is between 30 to 800 Amy. This method requires extreme transect sampling technique on aluminized layer thickness, the precision influence is bigger, but the obtained data is the most direct physical measurement.
2: Sheet resistance measurement, the state standard: 15717-1995 GB/T "vacuum metal coating thickness test method resistance method". This standard has a detailed description of the method, If you are interested, can download to study. - this is an simulate detection means, has a certain error, especially for the detection of translucent aluminized film, almost can’t be processed.
3: With a spectrodensitometer to measure: at present the instrument in terms of the principles of physics is the same, but strange is even in the United States there are two companies producing spectrodensitometer, actually the difference is large, One is production of Tobias, another is production of X-Rite. The famous domestic one is Linshang manufactured of LS117 spectrodensitometer. it is by optical perspective method to convert aluminized layer thickness, it’s a simulation method. The instrument can be applied to a translucent film, also can be used for opaque metalized film.
4: With light transmission meter for testing: there are many instruments, but global standards are not unified, is also a kind of simulation method for detection in translucent aluminium plating film.
From the above comparison, spectrodensitometer is the most appropriate detector to test coating thickness of aluminizer film.