Method for improving anti-reduction performance of PTC thermosensitive element

A method for improving anti-reduction performance of a PTC thermosensitive element, comprising coating an inorganic protective layer, organic protective layer, or organic and inorganic composite protective layer coated with a mixture of an inorganic substance and an organic substance for blocking harmful reducing gases from entering an interior of a ceramic body of a PTC thermosensitive element through surface defects or grain boundaries of the ceramic body onto a surface of the ceramic body of the PTC thermosensitive element;

• wherein the inorganic protective layer is a glass film layer or a metal oxide film layer, and the glass film layer is formed by coating a slurry prepared from glass onto the surface of the PTC thermosensitive element that has undergone surface cleaning treatment through any one of spray-coating, printing, impregnation and sputtering, and then performing high-temperature sintering and infiltration;
• the metal oxide film layer is formed by sputtering an oxide of a metal oxide target onto the surface of the PTC thermosensitive element through a sputtering method, and then performing heat treatment;
• a method for the surface cleaning treatment comprises cleaning and drying after cleaning;
• the cleaning is performed by using a cleaning agent, and the cleaning agent is deionized water;
• the metal oxide is Al2O3, SiO2 or CaO2;
• the temperature for the heat treatment is 300-500° C., and the time for the heat treatment is 30-60 min;
• wherein the temperature for the high-temperature sintering and infiltration is 550-800° C., and the temperature is increased at speed of 250° C./h from room temperature to a softening point of the glass, is held for 10-30 min, and then is naturally decreased to room temperature;
• wherein the organic silicon sealing material layer is composed of the following raw materials in parts by weight:
• 1 part of organic silicon material, 1-5 parts of crosslinking agent, 0.05-0.5 parts of catalyst, and 0.05-0.5 parts of auxiliary agent;
• the organic silicon material is one or more of silicone oil, silicone gel, silicone rubber and silicone resin;
• the crosslinking agent is ethyl orthosilicate, propyl orthosilicate, perbenzoic acid, MEKP, acetylsilane or acylaminosilane;
• the catalyst is a dibutyltin dilaurate or vinyl platinum complex;
• the auxiliary agent is a nano inorganic filler, and the nano inorganic filler is silicon dioxide or aluminum oxide.

A method for improving anti-reduction performance of a PTC thermosensitive element, comprising coating an inorganic protective layer, organic protective layer, or organic and inorganic composite protective layer coated with a mixture of an inorganic substance and an organic substance for blocking harmful reducing gases from entering an interior of a ceramic body of a PTC thermosensitive element through surface defects or grain boundaries of the ceramic body onto a surface of the ceramic body of the PTC thermosensitive element;

• wherein the thickness of the organic and inorganic composite protective layer coated with the mixture of the inorganic substance and the organic substance is less than 5 microns;
• wherein the organic and inorganic composite protective layer coated with the mixture of the inorganic substance and the organic substance is formed by coating a prepared slurry onto the surface of the PTC thermosensitive element that has undergone surface cleaning treatment and drying after the surface cleaning treatment through spray-coating, printing, vacuum impregnation or isostatic pressing, and then performing drying and curing at 150-250° C., the organic and inorganic composite protective layer coated with the mixture of the inorganic substance and the organic substance is a mixture of a metal oxide and an organic silicon sealing material mixed in a weight ratio of 1:1, or a mixture of a metal oxide and insulating paint mixed in a weight ratio of 1:1;
• the metal oxide is Al2O3, SiO2, or TiO2, and the organic silicon sealing material is composed of the following raw materials in parts by weight:
• 1 part of organic silicon material, 1-5 parts of crosslinking agent, 0.05-0.5 parts of catalyst, and 0.05-0.5 parts of auxiliary agent;
• the insulating paint is acrylic paint, polyurethane paint, amino paint or epoxy resin paint;
• the organic silicon material is one or more of silicone oil, silicone gel, silicone rubber and silicone resin;
• the crosslinking agent is ethyl orthosilicate, propyl orthosilicate, perbenzoic acid, MEKP, acetylsilane or acylaminosilane;
• the catalyst is a dibutyltin dilaurate or vinyl platinum complex;
• the auxiliary agent is a nano inorganic filler, and the nano inorganic filler is silicon dioxide or aluminum oxide.