Patent attributes
In a flow sensor (1) including an anticorrosion metallic diaphragm; an insulating film formed on one surface of the metallic diaphragm; and a flow rate measuring sensor formed on the insulating film, the other surface of the metallic diaphragm being in contact with a fluid under measure, between the insulating film (122) on which sensor devices (25) are formed and the metallic diaphragm, a buffer layer (121) having an intermediate linear expansion coefficient between the linear expansion coefficient of the insulating film (122) and the linear expansion coefficient of an anticorrosion metal is interposed. Thereby, the sensitivity and response of the flow sensor are improved, and also the heat resistance is improved, by which the flow sensor is made especially suitable for measuring the flow rate of a corrosive fluid.