This invention is directed to a corrosion resistant permanent magnet, to a method for producing a corrosion resistant permanent magnet, and to an intravascular blood pump comprising the magnet. The magnet is corrosion resistant due to a composite coating comprising a metal layer, optionally a metal oxide layer, a layer formed from poly(2-chloro-p-xylylene), and a linker layer between the metal oxide layer and the poly(2-chloro-p-xylylene) layer.

A magnetic article with a corrosion resistant barrier formed from a poly(tetrafluoro-p-xylene) conformal coating or from a parylene conformal coating having a melting point of at least about 430° C. and a moisture vapor transmission less than about 0.5 g-mm/m.sup.2/day at 90% RH and 37° C., the conformal coating being covered with a polysulfone thermoplastic overlayer.

A rare earth magnet capable of reducing an eddy current loss by virtue of a low-cost, simple configuration, when mounted in a motor, is to be provided, where the rare earth magnet comprising: a magnet body comprising a rare earth element and iron; and a resistive layer formed on at least one surface of the magnet body, the resistive layer comprising a rare earth element, iron, and oxygen and having an average volume resistivity of 10.sup.3 Ωcm or more and a thickness of from 3 to 25 μm, as is shown in FIG. 2.

There is provided a compression-bonded magnet with a case, which can realize high magnetic properties, high corrosion resistance and high durability strength even at low cost. The compression-bonded magnet with a case is a compression-bonded magnet with a case 1, comprising: a compression-bonded magnet 2 comprising a rare earth magnet powder such as an isotropic Nd—Fe—B magnet powder and a resin binder of a thermosetting resin; a case 3 for inserting the compression-bonded magnet 2; and a sealing member 4, wherein the compression-bonded magnet 2 is formed by compression-molding a mixture comprising the rare earth magnet powder and the resin binder into a green compact and curing the resin binder contained in the green compact, the rare earth magnet powder is contained in a large amount with respect to the entire compression-bonded magnet (for example, in a volume ratio of 85% to 90%), the sealing member 4 is fixed at an insertion opening part 3a of the case 3, and the compression-bonded magnet 2 is hermetically sealed by the sealing member 4 and the case 3.

Embodiments of the disclosure pertain to methods of plating magnets with a stack of layers such that the resulting magnet assembly has improved corrosion resistance. Embodiments of the disclosure are also directed to magnet assemblies formed by such methods. Some embodiments include a High Phosphorus Electroless Nickel (HiPEN) layer with Phosphorus content greater than 11% by weight.

Disclosed is a surface modification technique for permanent magnetic materials. First, a sintered Nd—Fe—B magnet is immersed in a chlorine-containing solution to corrode its surface after the sintered Nd—Fe—B magnet is ground, polished and cleaned, so that atomic vacancies or gaps are produced at the grain boundaries in the surface layer of the corroded sintered Nd—Fe—B magnet; then, compound nanopowders coated on the surface of the sintered Nd—Fe—B magnet are implanted into the grain boundaries by laser shock peening to obtain a gradient nanostructure layer along the depth direction; at the same time, the surface nanocrystallization of the sintered Nd—Fe—B magnet and a residual compressive stress layer are induced by laser shock peening which remarkably improves the corrosion resistance of the sintered Nd—Fe—B magnet.

Disclosed is a surface modification technique for permanent magnetic materials. First, a sintered Nd—Fe—B magnet is immersed in a chlorine-containing solution to corrode its surface after the sintered Nd—Fe—B magnet is ground, polished and cleaned, so that atomic vacancies or gaps are produced at the grain boundaries in the surface layer of the corroded sintered Nd—Fe—B magnet; then, compound nanopowders coated on the surface of the sintered Nd—Fe—B magnet are implanted into the grain boundaries by laser shock peening to obtain a gradient nanostructure layer along the depth direction; at the same time, the surface nanocrystallization of the sintered Nd—Fe—B magnet and a residual compressive stress layer are induced by laser shock peening which remarkably improves the corrosion resistance of the sintered Nd—Fe—B magnet.

A method for protecting a watch magnet against corrosion, wherein a magnet is provided, and that a surface preparation operation is carried out on the magnet, before subjecting it to an ion implantation treatment, in order to create an impervious surface layer acting as a barrier against oxidation with all of the surface bonds saturated by the implanted ions, in order to prevent the corrosion of the magnet in a humid environment, under the usual conditions for wearing watches.

A rare earth magnet including a magnetic phase having the composition represented by (Nd.sub.(1−x−y)La.sub.xCe.sub.y).sub.2(Fe.sub.(1−z)Co.sub.z).sub.14B. When the saturation magnetization at absolute zero and the Curie temperature calculated by Kuzmin's formula based on the measured values at finite temperature and the saturation magnetization at absolute zero and the Curie temperature calculated by first principles calculation are respectively subjected to data assimilation. The saturation magnetization M(x, y, z, T=0) at absolute zero and the Curie temperature obtained by machine learning using the assimilated data group are applied again to Kuzmin's formula and the saturation magnetization at finite temperature is represented by a function M(x, y, z, T), x, y, and z of the formula in an atomic ratio are in a range of satisfying M(x, y, z, T)>M(x, y, z=0, T) and 400≤T≤453.

A method for producing an insulator-coated soft magnetic powder includes: a mixing step of mixing a soft magnetic powder and a ceramic powder to obtain a mixture; a first compression bonding step of pulverizing the ceramic powder by applying mechanical energy to the mixture; and a second compression bonding step of fusing, by applying to the mixture mechanical energy larger than the mechanical energy in the first compression bonding step, the pulverized ceramic powder to surfaces of particles of the soft magnetic powder and obtaining an insulator-coated soft magnetic powder, after the first compression bonding step.