3. Product quality standards There are currently no national standards for Chinese mica products, only two standards: (2) Mica film standard for electronic tubes JC52-82 Direct-acting Electric Proportional Pressure Reducing Valve Guangdong Heidler Technology Co., Ltd , https://www.hyhemit.com
(1) Standard for industrial raw material mica JC49-82
This standard is applicable to the processing of raw materials for electrical and telecommunication mica insulation materials. It is divided into five categories according to the largest effective area of ​​either side of the mica crystal. See Table 6. 
This standard applies to high quality natural muscovite tablets. The diameter of the effective area is divided into ten specifications: Ñ„15, 17, 19, 21, 25, 30, 35, 40, 45, 50 mm. The percentage of the effective area to the total area should be in accordance with Table 7. The thickness, tolerance and thickness difference between any two points in the effective area shall comply with Table 8.