JPH0439206B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing polymer composite magnets, typically rubber magnets or plastic magnets, and particularly relates to a method for manufacturing polymer composite magnets, typically rubber magnets or plastic magnets. The present invention relates to a method for manufacturing a polymer composite rare earth magnet obtained by combining R ₂ T ₁₄ B-based rare earth magnet powder containing transition metal (T) and boron (B) as main components with a polymer resin. [Prior art] Regarding the manufacturing method of R/Fe/B magnets, see 2.
It is broadly divided into two methods. One is liquid quenching fine crystallization, which is obtained by adjusting the quenching rate to contain a moderate amount of precipitated fine crystal grains (generally about 0.05 to 0.1 μm) when super-quenching a molten alloy. This is a liquid quenched magnet obtained by producing a thin ribbon and then compounding it with a polymer resin or the like, or by press-molding it at high temperature. One is a sintered magnet, which is manufactured by finely pulverizing an ingot of a crystallized magnetic alloy (crystal grains are 10 μm or more) obtained by melting, molding in a magnetic field, and then sintering. The latter manufacturing method allows for more anisotropy than the former, and is therefore suitable for obtaining high magnetic properties. On the other hand, polymer composite magnets are made by dispersing magnetic powder in polymer resin, and have various characteristics not found in cast magnets or sintered magnets, such as elasticity and ease of processing. It is used in various fields. [Problems to be solved by the invention] However, since polymer composite magnets are made of magnet powder and non-magnetic resin, they have the disadvantage that their magnetic properties are lower than that of sintered magnets. There is. Therefore, attempts are generally made to achieve high magnetic properties by making the magnetic powder anisotropic, such as by orienting it in a magnetic field. However, in the microcrystalline R ₂ / T ₁₄ / B liquid quenched ribbons that have been obtained so far, the direction of easy magnetization of the crystals is disordered, so it is difficult to make them anisotropic by magnetic field orientation, etc. It was hot. Therefore, there is a drawback that high magnetic properties cannot be achieved. In general, the alloy powder used for liquid quenched magnets is
In an inert atmosphere such as Ar, the alloy is melted using high-frequency waves, etc., and is injected onto a roll made of Fe or Cu that rotates at high speed to crush a thin ribbon with a thickness of several tens of micrometers. By changing the rotation speed of this roll, the cooling rate of the molten alloy can be controlled.
At this time, the quenched ribbon with the highest magnetic properties is
It consists of fine crystal grains of about 0.05 to 0.1 μm, and the circumferential speed of the roll can be achieved within a very limited range of about 20 m/sec. This quenched ribbon is pulverized into particles of several to several hundred micrometers depending on the purpose, and then composited with a polymer resin. At this time, the powder particles are composed of a large number (several tens or more) of fine crystal grains, and the directions of easy magnetization of these crystal grains are disordered. Therefore, even if this powder is subjected to treatments such as molding in a magnetic field, it is difficult to make the magnet anisotropic. Therefore, as a result of various experiments in view of the above-mentioned drawbacks, the present inventor crystallized a liquid-quenched amorphous alloy ribbon while hot rolling it, and then pulverized it.
We discovered that by forming in a magnetic field, anisotropy can be achieved and high magnetic properties can be obtained. In the present invention, the hot rolling temperature of the liquid-quenched amorphous ribbon varies depending on the composition (for example, it also varies depending on the melting point and crystallization temperature of the alloy), but ranges from 450°C to 1100°C. A range of is desirable. 450℃
In the following, the crystallization rate during roll rolling is significantly reduced, so that the anisotropy of the magnet and the hard magnetic properties of the magnet are insufficient, and high magnetic properties cannot be obtained. On the other hand, if the temperature is 1100°C or higher, the fluidity of the alloy increases, and the effect of crystal grain orientation due to roll rolling is significantly reduced. Furthermore, when hot roll rolling is performed at 850°C or higher, the decrease in _I H _C may become significant depending on the composition. In that case, heat treatment at a temperature of about 500° C. to 750° C. after hot rolling can produce a magnet powder with a high _I H _C. The relationship between the compression ratio ((thickness before rolling) - (thickness after rolling) / (thickness before rolling)) due to hot roll rolling and the magnetic properties is that up to a compression ratio of about 70%, the magnetic properties are However, at higher compression ratios, the elongation rate of property improvement tends to decrease. [Means for solving the problem] According to the present invention, a polymer composite rare earth magnet consisting of R ₂ T ₁₄ B-based components containing Nd, Fe, and B as main components (where R is Y, Ce, Pr, Nd,
Rare earth metals such as Gd, Tb, Dy, Ho, T is Al and
Represents transition metals such as Cr, Mn, Fe, Co, and Ni. ), the R ₂ T ₁₄ B-based amorphous alloy is hot-rolled into a crystallized alloy, and then a polymer resin is mixed with the powder of the crystallized alloy, and the mixture is molded in a magnetic field. A method for manufacturing a polymer composite rare earth magnet is obtained. [Example] An example according to the present invention will be described. Example 1 Nd with a purity of 95wt% (the remainder is other rare earth elements mainly consisting of Ce and Pr), ferroboron (purity of B approximately 20wt%)
%) and electrolytic iron, Nd is 28.0wt%, B is
In an Ar atmosphere, the balance was 1.0wt% Fe.
It was melted by high frequency heating to obtain an alloy ingot. Next, using this ingot, after remelting it by high frequency heating in an Ar atmosphere, the circumferential speed was approximately 50.
m/sec to a copper roll to obtain an amorphous alloy ribbon with a width of about 5 mm and a thickness of 50 μm by the single roll method. Next, this amorphous alloy ribbon was hot rolled at 700° C. to crystallize it to a thickness of 5 to 50 μm. At this time, the particle size of the precipitated crystals was 0.5 μm or less. After coarsely pulverizing the alloy of each thickness,
It was ground to an average particle size of about 15 μm using a ball mill. As shown in the figure, after mixing 2.5 vol% of epoxy resin with these magnet powders, they were mixed in a magnetic field of 25 KOe.
It was molded at a pressure of 3 tons/cm ² . After holding this at 110° C. for 1 hour, a magnetic field of 30 KOe was applied to measure the magnetic properties. As a result, it was found that the magnetic properties were significantly improved by crystallizing the amorphous alloy ribbon at a compression ratio exceeding 0 while hot rolling it. Example 2 5wt% Ce, 15wt% Pr, balance Nd (however,
Other rare earth elements were included as Nd. ), 10 at% Dy was added as a substitution element, ferroboron, electrolytic iron, and electrolytic cobalt were used, and in the same manner as in Example 1, R (rare earth element) was 28.5 wt% and B was 28.5 wt%. 1.0wt%, Co 7wt%,
After obtaining an ingot having a composition of balance Fe, an amorphous alloy ribbon having a width of about 5 mm and a thickness of 50 μm was produced. Next, this alloy ribbon was hot-rolled at 750° C. to crystallize it to a thickness of about 30 μm (compressibility: 40%). The particle size of the crystals precipitated at this time was 1 μm or less. This was pulverized in the same manner as in Example 1 to an average particle size of about 10 μm. Next, add 40vol% polyethylene to this magnet powder.
After mixing, the mixture was injection molded into a mold at about 100° C. while applying a magnetic field of 20 KOe to obtain a polymer composite magnet. The magnetic properties measured by applying a magnetic field of 30KOe to this sample were compared to a sample with a rolling reduction of 0% (thickness 50μ
A comparison with m) is shown in the table. As a result, it was found that the magnetic properties were significantly improved by crystallization during hot rolling.

〔Effect of the invention〕

As explained above, according to the present invention,
R ₂ T ₁₄ By hot rolling an amorphous alloy ribbon consisting of B-based components to a compression ratio of 0 or more, the alloy ribbon is crystallized while reducing its thickness, and then crystallized. A polymer composite rare earth magnet with high anisotropy and good magnetic properties is created by finely pulverizing the alloy ribbon into magnet powder, mixing polymer resin with the resulting magnet powder, and molding it in a magnetic field. can be provided.

[Brief explanation of drawings]

Figure 1 is a correlation diagram showing the relationship between the rolling rate of the amorphous alloy ribbon during hot rolling and the properties ((BH) _nax , Br, _{IHC )} of the polymer composite magnet in Example 1. be.

Claims (1)

[Claims] 1 Contains Nd, Fe, and B as main components
R ₂ T ₁₄ A polymer composite rare earth magnet consisting of B-based components (where R is Y, Ce, Pr, Nd, Gd, Tb,
Rare earth metals such as Dy and Ho, T is Al and Cr, Mn,
Represents transition metals such as Fe, Co, and Ni. ), the R ₂ T ₁₄ B-based amorphous alloy is hot-rolled into a crystallized alloy, and then a polymer resin is mixed with the powder of the crystallized alloy, and the mixture is molded in a magnetic field. A method for manufacturing a polymer composite rare earth magnet characterized by: