Because the heating principle of microwave oven is to use the microwave generated by magnetron to heat, but the microwave can't penetrate the metal, it will reflect the microwave and damage the magnetron. Moreover, when the microwave collides with the metal, the electrons in the metal will collide with other electrons, and the molecules will violently move to generate heat, which will spontaneously ignite when it reaches a certain temperature.

Tin foil is a kind of film-like metal paper, and its composition is actually aluminum, not tin. The resistance of tin foil is low, and the microwave oven can reflect metal, so it can't be easily heated in the microwave oven unless the barbecue function of the microwave oven is used. Ordinary microwave ovens do not have barbecue function, only intelligent micro-steaming and roasting integrated microwave ovens have barbecue function.

The role of tin foil paper

Tin foil paper has good heat insulation. In summer, if the roof is covered with a layer of reflective material similar to tin foil, the problem of 60% direct sunlight can be basically solved.

Tin foil paper has good smoothness and thermal reflectivity. With the protection of tin foil paper, the delicious taste of cigarettes will not be destroyed by external stimuli. More importantly, it will not be deteriorated by air and environmental humidity, and the cut tobacco in cigarettes will not deteriorate, making its shelf life longer! In addition, there are thermal insulation and aesthetic factors. So there is a layer of platinum paper in the cigarette case.

Tin foil can also be used for barbecue. Wrapped in the outer layer of food, it cooks quickly, has a strong flavor and is not easy to cool. There is usually a layer of tin foil outside the roast leg of lamb in the restaurant.

The above contents refer to Baidu Encyclopedia-Tin Foil Paper.