Abstract: A coil is provided radially outside a housing. Each of a stator and a moving core is formed from a magnetic material and substantially in a tubular shape. The stator and the moving core are located radially inside the housing and opposed to each other in an axial direction. The moving core is configured to move toward the stator when being drawn by magnetic attractive force caused between the moving core and the stator in response to energization of the coil. A valve element is movable together with the moving core in the axial direction and configured to open and close a nozzle hole for controlling fuel injection. The moving core and the valve element are separate components. The moving core has an inner periphery defining a through hole in which the valve element is slidable in the axial direction. The inner circumferential periphery has a surface-hardened layer.

Abstract: A method of production of an inexpensive corrosion-resistant heat exchanger made of stainless steel including the steps of electroplating chrome to a thickness of 15 &mgr;m on at least one of the end faces of a plurality of first and second shaped plates made of stainless steel alternately stacked in the thickness direction so as to form a chrome-based brazing filler metal layer, then electrolessly plating or electroplating Ni-P to a thickness of 35 &mgr;m on the chrome-based brazing filler metal layer to form a nickel-based brazing filler metal layer. The first and second shaped plates are brazed together through the chrome-based brazing filler metal layer and the nickel-based brazing filler metal layer to obtain a high corrosion resistant heat exchanger. Due to this, a high corrosion resistance brazing filler metal containing an Ni-Cr28-P8-etc. alloy composition is obtained at the two end faces of the first and second shaped plates.