JP2019189896A - Insulation inorganic powder, method for producing the same, and powder treatment agent - Google Patents

Abstract

To provide an inorganic powder having excellent insulation properties and also having excellent press pressure resistance, a method for producing the same, and a powder treatment agent usable for the production method.SOLUTION: An insulating inorganic powder comprises a film at least including Ni, Al and P, and in which a P/(Ni+Al) molar ratio lies in the range of 0.5 to 15.0 on a surface of the inorganic powder.SELECTED DRAWING: None

Description

  The present invention relates to an inorganic powder having excellent insulating properties useful for electronic equipment and electronic parts, a method for producing the same, and a powder treating agent usable in the method for producing the same.

  In recent years, with the miniaturization of electronic devices and electrical devices, electronic components used for them are required to have excellent magnetic properties. For this reason, the magnetic powder used for electronic parts needs to have high insulation properties. Therefore, insulating magnetic powder having a coating on the surface has been developed.

  For example, Patent Document 1 discloses a coated soft magnetic iron-based powder having a plurality of coated soft magnetic iron-based particles in which an insulating coating is coated on the outer periphery of soft magnetic iron-based particles.

  In Patent Document 2, a phosphoric acid-based chemical conversion film is formed on the surface of the iron-based soft magnetic powder, the phosphoric acid-based chemical conversion film contains nickel element, and the phosphoric acid-based chemical conversion film contains An iron-based soft magnetic powder for a dust core is disclosed in which the aluminum element content is equal to or less than the aluminum element content in the powder.

JP2013-131676A JP2013-216964A

  However, since the coated soft magnetic iron-based powder described in Patent Document 1 is not sufficiently insulating, it may not be suitable for magnetic powder used in electronic parts. In addition, in the iron-based soft magnetic powder for dust core described in Patent Document 2, the insulation is reduced during dust molding when the powder is molded into an electronic component, and the molded electronic component has sufficient insulation. There is a possibility not to. Accordingly, the present invention provides an inorganic powder excellent in insulating properties and excellent in properties (hereinafter also referred to as press pressure resistance) capable of suppressing a decrease in insulating properties during compacting, a manufacturing method thereof, and a manufacturing method thereof. An object of the present invention is to provide a powder treating agent that can be used.

  As a result of intensive studies to solve the above problems, the inventor of the present invention contains Ni, Al and P on the surface of the inorganic powder using a predetermined powder processing agent, and the P / (Ni + Al) molar ratio is It has been found that inorganic powders having excellent insulation and press pressure resistance can be obtained by forming films each in a predetermined range, and the present invention has been completed.

That is, the present invention
(1) Insulating inorganic powder having a film containing at least Ni, Al and P on the surface of the inorganic powder and having a P / (Ni + Al) molar ratio in the range of 0.5 to 15.0;
(2) The insulating inorganic powder according to (1), wherein the Al / Ni molar ratio of the coating is in the range of 0.003 to 0.500;
(3) Mixing of a source of ions containing phosphorus with respect to a total of 100 parts by mass in terms of metals of Ni ions and Al ions, including at least Ni ions, Al ions, ions containing phosphorus, and an aqueous medium A powder treating agent having an amount in the range of 100 parts by mass to 3000 parts by mass and an amount of the aqueous medium in the range of 1000 parts by mass to 40000 parts by mass;
(4) The powder processing agent according to (3), wherein the free acidity (FA) of the powder processing agent is in the range of 0.3 point to 30.0 point;
(5) A film obtained by bringing the powder treatment agent according to any one of (3) and (4) into contact with the inorganic powder and then heating to evaporate the volatile matter of the powder treatment agent. Having an insulating inorganic powder;
(6) heating the composition containing the inorganic powder and the powder treating agent according to any one of (3) or (4) to evaporate volatile components in the composition; A method for producing an insulating inorganic powder having a film formed on the surface of the inorganic powder;
Etc.

  ADVANTAGE OF THE INVENTION According to this invention, the inorganic powder excellent in insulation and press pressure resistance, its manufacturing method, and the powder processing agent which can be used for the manufacturing method can be provided.

The insulating inorganic powder according to one embodiment of the present invention includes at least Ni, Al, and P on the surface of the inorganic powder, and the P / (Ni + Al) molar ratio is in the range of 0.5 to 15.0. It has a film that is inside.
The inorganic powder used as the raw material is not particularly limited to the particle size, shape, composition, etc., as long as it is a powder made of an inorganic substance. The raw material inorganic powder is preferably an inorganic powder having magnetism because it is useful as a material for electronic components, for example, and the inorganic powder having magnetism is preferably one containing iron. In addition, the inorganic powder is preferably a conductor, and for example, the conductor may have an electric conductivity of 1 × 10 ⁶ S / m or more, or 1 × 10 ⁵ S / m or more.

Examples of the inorganic powder containing iron include Fe (pure iron powder), Fe—Si, Fe—Si—Cr, Fe—Ni, Fe—Si—Al, Fe—Cr, and Fe—Co. And metal compounds such as Fe amorphous. Examples of other inorganic powders include inorganic compounds such as metal oxides, nitrides, borides, etc., for example, barium titanate (BaTiO ₃ ),
Boron nitride (BN), ferrite (MFe ₂ O ₄ ; M represents a divalent metal element), lead zirconate titanate (Pb (Zr, Ti) O ₃ ), aluminum oxide (Al ₂ O ₃ ), carbonized Silicon (S
iC), zinc oxide (ZnO), zirconia (ZrO ₂ ), zircon (ZrO ₂ · SiO ₂ )
, Forsterite (2MgO · SiO _2), mullite _{(3Al 2 O 3 · 2SiO 2} ), steatite (MgO · SiO _2), cordierite _{(2MgO · 2Al 2 O 3 ·} 5SiO 2), aluminum nitride (AlN) , Silicon nitride (Si ₃ N ₄ ), and the like.

The particle size of the inorganic powder is not particularly limited, but the 50 volume% particle size (D ₅₀ ) of its cumulative distribution is usually 0.1 μm or more, 0.5 μm or more, or 1 μm or more, Moreover, it is 1000 micrometers or less normally, may be 500 micrometers or less, may be 200 micrometers or less, and may be 100 micrometers or less.
The shape of the inorganic powder is not particularly limited, and the aspect ratio is usually 50 or less, 20 or less, 10 or less, and usually 1 or more.

  The film which the insulating inorganic powder has includes at least Ni, Al and P, and may include other elements. Examples of other elements include components contained in inorganic powders. In addition, moisture and raw material-derived H and O, elements included in an ion supply source containing phosphorus described later, and the like can be given.

In this embodiment, the molar ratio of P to the total of Ni and Al in the film (P / (N
i + Al)) is in the range of 0.5 to 15.0. When these molar ratios are within a certain range, it is possible to uniformly form a film having excellent insulating properties that is hardly affected by the pressing pressure on the surface of the inorganic powder.
The molar ratio of (P / (Ni + Al)) is preferably 0.9 or more, and more preferably 1.3 or more. Moreover, it is preferable that it is 10.0 or less, and it is more preferable that it is 7.5 or less.

  Further, the molar ratio of Al to Ni (Al / Ni) in the film is preferably in the range of 0.003 to 0.500, more preferably in the range of 0.004 to 0.400. Preferably, it is in the range of 0.005 or more and 0.300 or less.

  The contents of Ni, Al and P in the film can be determined by the following method. First, a mixture of an insulating inorganic powder and a curable resin (may be a composition of a resin and a curing agent) is cured. Next, after mechanically polishing the cured product, thin pieces are produced using ion milling. Subsequently, the insulating inorganic powder coating on the flakes is subjected to elemental analysis using energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) attached to a transmission electron microscope (TEM). The content of each element can be calculated from the elemental analysis value (strength) of each element obtained.

  The film thickness of the film is not particularly limited, but is preferably in the range of 1 nm to 50 nm, more preferably in the range of 2 nm to 40 nm, and in the range of 4 nm to 30 nm. It is particularly preferred that

  The film thickness can be measured by observing the produced flakes with a transmission electron microscope (TEM).

The powder treating agent for forming the film is not particularly limited as long as it contains at least Ni ions, Al ions, ions containing phosphorus, and an aqueous medium. It may be included. The amount of the ion supply source containing phosphorus, which is blended in the powder treatment agent, is preferably in the range of 100 parts by mass or more and 3000 parts by mass or less with respect to 100 parts by mass in terms of metal of Ni ions and Al ions. . Moreover, it is preferable that the aqueous medium contained in a powder processing agent exists in the range of 1000 mass parts or more and 40000 mass parts or less with respect to 100 mass parts of metal conversion total of Ni ion and Al ion.
In addition, components other than the ion containing Ni ion, Al ion, and phosphorus may be contained in the powder processing agent, and may not be contained. “Not included in the powder treatment agent” means that the powder is not intentionally blended, and does not exclude the inevitable mixing.

Examples of Ni ions contained in the powder processing agent include nickel ions and complex ions containing nickel. The supply source of Ni ions contained in the powder processing agent is not particularly limited, and a commercially available reagent can be used. Specific examples include nickel sulfate hexahydrate, nickel chloride hexahydrate, basic nickel carbonate tetrahydrate, nickel acetate tetrahydrate, nickel nitrate hexahydrate, and the like. . In addition, these reagents can be used individually by 1 type or in combination of 2 or more types.
The Ni ion concentration contained in the powder treatment agent is not particularly limited as long as the Ni concentration in the film is satisfied, but the Ni ion concentration per kg of the powder treatment agent is usually 1 g or more in terms of metal concentration. It may be 2 g or more, usually 75 g or less, and 60 g or less.

Examples of Al ions contained in the powder treatment agent include aluminum ions and complex ions containing aluminum. The supply source of Al ions contained in the powder treatment agent is not particularly limited, and a commercially available reagent can be used. Specific examples include aluminum oxide, aluminum chloride hexahydrate, aluminum sulfate 14-18 hydrate, aluminum nitrate nonahydrate, and the like. In addition, these reagents can be used individually by 1 type or in combination of 2 or more types.

  Examples of the phosphorus-containing ions contained in the powder treatment agent include phosphate ions, hypophosphite ions, polyphosphate ions, and phosphonate ions. The source of ions containing phosphorus contained in the powder treatment agent is not particularly limited, and any of inorganic phosphorus compounds and organic phosphorus compounds can be used. Inorganic phosphoric acid, organic phosphoric acid, and salts thereof (for example, Metal salts such as alkali metal salts, ammonium salts, etc.). Specific examples include phosphoric acid, hypophosphorous acid (phosphinic acid), polyphosphoric acid, phosphonic acid, and salts thereof, and phosphoric acid esters. In addition, you may use the supply source of these ions containing phosphorus individually by 1 type or in combination of 2 or more types.

  As the phosphoric acid, for example, an arbitrary mass percent phosphoric acid aqueous solution or sodium phosphate aqueous solution such as 75% or 85% can be used. As hypophosphorous acid (phosphinic acid), for example, a 50% hypophosphorous acid aqueous solution, sodium phosphinate monohydrate, phenylphosphinic acid and the like can be used. As the polyphosphoric acid, for example, tripolyphosphoric acid, tetraphosphoric acid, sodium tripolyphosphate, sodium tetrapolyphosphate and the like can be used. The phosphate ester is preferably a (poly) oxyethylene alkyl ether phosphate ester having a hydrophilic group, for example, an epoxy group, for water-solubilization. As the phosphonic acid, for example, water-soluble phenylphosphonic acid can be used.

  The combination of the Ni ion source, the Al ion source, and the phosphorus-containing ion is not particularly limited. Specifically, the nickel sulfate hexahydrate, aluminum oxide, and 85% phosphoric acid are used. In addition to the combination, a combination of nickel chloride hexahydrate, aluminum chloride hexahydrate and 50% hypophosphorous acid, basic nickel carbonate tetrahydrate and aluminum sulfate 14-18 hydrate Combination with sodium tripolyphosphate, combination of nickel nitrate hexahydrate, aluminum nitrate 9 hydrate and phenylphosphonic acid, combination of nickel acetate tetrahydrate, aluminum oxide and 85% phosphoric acid, nitric acid Combination of nickel hexahydrate, aluminum chloride hexahydrate and 50% hypophosphorous acid, nickel chloride hexahydrate and aluminum sulfate 14-1 Combination of hydrate and sodium tripolyphosphate, combination of nickel sulfate hexahydrate and aluminum nitrate 9 hydrate and phenylphosphonic acid, basic nickel carbonate tetrahydrate and aluminum sulfate 14-18 Combination of hydrate and 85% phosphoric acid, combination of nickel sulfate hexahydrate and aluminum nitrate 9hydrate and 85% phosphoric acid, nickel chloride hexahydrate and aluminum sulfate 14-18 Combination of hydrate and 85% phosphoric acid, combination of basic nickel carbonate tetrahydrate, aluminum chloride hexahydrate and 85% phosphoric acid, nickel nitrate hexahydrate and aluminum oxide 85 Combination of% phosphoric acid, combination of nickel acetate tetrahydrate and aluminum oxide and 85% phosphoric acid, nickel nitrate hexahydrate and aluminum oxide Combination with 5% phosphoric acid, combination of basic nickel carbonate, tetrahydrate, aluminum chloride, hexahydrate and 85% phosphoric acid, nickel chloride, hexahydrate and aluminum sulfate, 14-18 hydration Combination of hydrate and 85% phosphoric acid, combination of nickel sulfate hexahydrate and aluminum nitrate 9 hydrate and 85% phosphoric acid, nickel sulfate hexahydrate and aluminum sulfate 14-18 hydration A combination of a product and 85% phosphoric acid, a combination of nickel sulfate hexahydrate and aluminum sulfate 14-18 hydrate and 50% hypophosphorous acid, nickel sulfate hexahydrate and aluminum sulfate 14 -18 hydrate and sodium tripolyphosphate, nickel sulfate hexahydrate, aluminum sulfate, 14-18 hydrate and phenylphosphonic acid, etc. The

The aqueous medium contained in the powder treatment agent is particularly limited as long as it is water or a mixture of water and a water-miscible organic solvent (containing 50% by mass or more of water based on the volume of the aqueous medium). It is not a thing. The water-miscible organic solvent is not particularly limited as long as it is miscible with water. Examples thereof include ketone solvents such as acetone and methyl ethyl ketone; amide solvents such as N, N′-dimethylformamide and dimethylacetamide. Alcohol solvents such as methanol, ethanol and isopropanol; ether solvents such as ethylene glycol monobutyl ether and ethylene glycol monohexyl ether; pyrrolidone solvents such as 1-methyl-2-pyrrolidone and 1-ethyl-2-pyrrolidone Is mentioned. One of these water-miscible organic solvents may be mixed with water, or two or more thereof may be mixed with water.

  The powder treatment agent may have a free acidity (FA) usually in the range of 0.3 to 30.0 points, but preferably in the range of 0.4 to 20.0 points. More preferably, it is in the range of not less than 0.5 points and not more than 10.0 points. The free acidity can be adjusted using a commercially available acidic solution or alkaline solution. Examples of the acidic solution include aqueous solutions of phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, formic acid, succinic acid, hydrofluoric acid, and examples of the alkaline solution include ammonia, ammonium hydrogen carbonate, sodium hydroxide, and hydroxide. An aqueous solution of potassium or the like can be given.

  The free acidity (FA) was measured by collecting 10 ml of the powder treatment agent, adding 2-3 drops of “D-11” manufactured by Nihon Parkerizing Co., Ltd., and then titrating with “T-11” manufactured by Nihon Parkerizing Co., Ltd. It means what expressed the amount (ml) of “T-11” as a point (1 ml = 1 point).

  Examples of other components other than the components contained in the powder processing agent described above include additives such as surfactants and lubricants. This additive component may be contained in the powder processing agent to the extent that the effects of the present invention are not impaired.

  The method for preparing the powder treatment agent is not particularly limited, and the powder treatment agent can be obtained by blending the components to be blended with the above-described powder treatment agent into water at once or sequentially. The order of compounding is not particularly limited.

Insulating inorganic powder is produced by bringing the powder treatment agent into contact with the inorganic powder and then heating to evaporate the volatile matter of the powder treatment agent to form a film on the inorganic powder. ,It can be carried out. More specifically, it may be carried out by heating a composition containing a powder treating agent and inorganic powder to evaporate volatile matter in the composition (volatile matter in the powder treating agent). it can. The contact between the powder treating agent and the inorganic powder may be performed by a mixing method, but other contact methods may be employed. In order to stably and efficiently produce the insulating inorganic powder, the composition is air or inert gas (nitrogen, carbon dioxide, helium, neon, argon, krypton, xenon, radon, etc.). It is preferable to evaporate volatile components in the composition by heating. The evaporation of volatile components can be performed using, for example, a spray dryer.
In the production of the insulating inorganic powder, a step of forming a lubricating film by evaporating the volatile matter and then bringing a lubricant into contact with the surface of the inorganic powder having the film may be provided. The contact method is not particularly limited, and examples thereof include a method of dipping in a lubricant and a method of mixing with a lubricant. The production of the insulating inorganic powder may further include a step of drying the surface of the insulating inorganic powder contacted with the lubricant after the contact with the lubricant. Although it does not restrict | limit especially as a drying method, For example, although the method of heating in air or inert gas is mention | raise | lifted, it is not restrict | limited to this method. Insulating inorganic powder having a lubricating film can be obtained by the above-described manufacturing method of insulating inorganic powder.

The composition may be heated gradually to reach a predetermined temperature, or may be stepwise to finally reach a predetermined temperature. The upper limit of the predetermined temperature is not particularly limited.
It is preferably 0 ° C. or lower, more preferably 300 ° C. or lower, and particularly preferably 200 ° C. or lower. Moreover, the drying temperature on the surface of the insulating inorganic powder in contact with the lubricant is not particularly limited, but is preferably 200 ° C. or less, and more preferably 100 ° C. or less.

The insulating inorganic powder is compacted when used as an electronic component. The insulating inorganic powder of the present embodiment has excellent insulating properties even in a thin film under a pressure of 13 MPa, and has a volume resistivity under a pressure of 64 MPa. It also has excellent performance in terms of press pressure resistance, which is a value divided by volume resistivity under conditions. Therefore, the insulating inorganic powder of this embodiment is useful as a material for various electronic devices and electronic components manufactured by pressure molding.
In particular, by using the insulating inorganic powder of this embodiment, it is possible to realize downsizing and high performance of various electronic devices and electronic components such as inductors, capacitors, thermistors, varistors, and the like after press molding. However, since good insulation can be maintained, it is extremely useful in practice. In addition, the insulating inorganic powder of the present embodiment is not limited to one having a film on the surface of the inorganic powder, but one or more films (for example, an oxide film or the like) between the inorganic powder and the film. ) Are also included.

  Next, examples of the actual processing and comparative examples will be shown to specifically explain the effects of the present invention. In addition, an Example does not restrict | limit this invention at all.

"Inorganic powder"
Commercial atomized pure iron powder (Heganes, ABC 100.29, volume average particle size (D ₅₀ ) = 106 μm, hereinafter referred to as “pure iron powder”), or Fe-5.5% Si-4% Cr Insulating inorganic powder was produced as described later using atomized powder (soft magnetic powder manufactured by Nippon Atomizing Co., Ltd., volume average particle size = 10 μm, hereinafter referred to as “alloy powder”).

(Preparation of powder processing agent)
As shown in Table 1, each component and pure water were mixed in predetermined amounts to prepare powder treating agents of Examples 1 to 22 and Comparative Examples 1 to 7. The free acidity was adjusted with phosphoric acid, sulfuric acid, sodium hydroxide and the like.
The symbols shown in the “component symbol” column in Table 1 are as follows.
A: Nickel sulfate hexahydrate B: Nickel chloride hexahydrate C: Basic nickel carbonate tetrahydrate D: Nickel nitrate hexahydrate E: Nickel acetate tetrahydrate F: Oxidation Aluminum G: Aluminum chloride hexahydrate H: Aluminum sulfate 14-18 hydrate I: Aluminum nitrate 9 hydrate J: 85% phosphoric acid K: 50% hypophosphorous acid L: sodium tripolyphosphate M : Phenylphosphonic acid

(Method for producing insulating inorganic powder)
20 g of each of the inorganic powders shown in Table 2 was weighed, and the weighed inorganic powder was added to ½ amount of the prepared powder treating agents of Examples 1 to 22 and Comparative Examples 1 to 7, and 25 ° C. For 10 minutes. Next, as a drying step, the stirred mixture was left standing in a thermostat kept at 100 ° C. and held for 5 minutes. Subsequently, the dried inorganic powder was added to the remaining powder treating agent, and the mixture was again stirred at 25 ° C. for 10 minutes. As a drying process, the stirring mixture was left still in a thermostat kept at 100 ° C. and kept for 5 minutes. Next, the mixture taken out from the thermostatic device was stirred again, and was left to stand in a thermostatic device maintained at 120 ° C. for 30 minutes to obtain insulating inorganic powders 1 to 29.

(Measurement of Al / Ni molar ratio, P / (Ni + Al) molar ratio and film thickness)
After embedding resin was prepared using Epomount A set (Refinetech Co., Ltd .; 27-770), the embedding resin and insulating inorganic powders 1 to 29 were mixed. Each mixture was poured into molds and allowed to cure. After mechanically polishing each cured product, a flake was prepared by ion milling (IM-4000 type manufactured by Hitachi High-Technologies Corporation). Using a transmission electron microscope (TEM, JEM-2100 type, manufactured by JEOL Ltd.), EDS and EELS attached thereto were used for elemental analysis of the insulating inorganic powder coating on the flakes. From the obtained elemental analysis values of each element, the content of each element was determined, and then converted into a molar amount to calculate a molar ratio of Al / Ni and a molar ratio of P / (Ni + Al), respectively. . The film thickness was measured by TEM observation.
These results are shown in Table 2.

(Insulation evaluation)
Using a powder resistance measurement system MCP-PD51 manufactured by Mitsubishi Chemical Analytech Co., Ltd. and Hiresta UX or Lorester GX, pressure was applied to a predetermined amount of insulating inorganic powder to measure volume resistivity (Ω · cm). . The pressure was varied from 13 MPa to 64 MPa, and the volume resistivity at a predetermined pressure was measured. The evaluation criteria were as follows.
-Compared to the volume resistivity at a pressure of 13 MPa of pure iron powder not forming a film, the volume resistivity at a pressure of 13 MPa of pure iron powder forming a film is
1.0 × 10 ⁵ times more than “○”,
1.0 × 10 ⁴ times or more and less than 1.0 × 10 ⁵ times “△”,
Less than 1.0 × 10 ⁴ times was defined as “×”.
-Compared to the volume resistivity at a pressure of 13 MPa of the alloy powder not forming the film, the volume resistivity at a pressure of 13 MPa of the alloy powder forming the film is
1.0 × 10 ⁸ times more than “○”,
1.0 × 10 ⁷ times or more and less than 1.0 × 10 ⁸ times “△”,
Less than 1.0 × 10 ⁷ times was defined as “x”.
These results are shown in Table 3. In addition, “◯” was judged to be a practical level. Moreover, the volume resistivity at a pressure of 13 MPa of pure iron powder not forming a film was 1.51 × 10 ⁻² Ω · cm. The volume resistivity of the alloy powder not forming a film at a pressure of 13 MPa was 1.12 × 10 ¹ Ω · cm.

(Evaluation of press pressure resistance)
Using the volume resistivity when the pressure is 13 MPa and 64 MPa obtained by the evaluation of insulation, the rate of decrease in volume resistivity is calculated by the following formula (1), and the press pressure resistance is determined according to the following evaluation criteria. evaluated. As evaluation criteria,
Decrease rate of less than 85% is “○”,
“△” means a reduction rate of 85% or more and less than 90%.
A reduction rate of 90%
It was. In addition, “◯” was judged to be a practical level. These results are shown in Table 3.
Decrease rate (%) = (1− (Volume resistivity at 64 MPa / Volume resistivity at 13 MPa)) × 100 (Formula 1)

  Since the insulating inorganic powder according to the embodiment of the present invention has excellent insulating properties and press pressure resistance, it can be applied to any application that requires these performances. Further, by using the powder treating agent according to the embodiment of the present invention, a film containing Ni, Al, and P can be formed on the surface of the inorganic powder, and the performance of the film (insulation and press pressure resistance). ) Can be imparted to the inorganic powder. As described above, the powder treating agent according to the embodiment of the present invention is useful for producing insulating inorganic powder applicable to various uses.

Claims (5)

  An insulating inorganic powder having a film containing at least Ni, Al and P on the surface of the inorganic powder and having a P / (Ni + Al) molar ratio in the range of 0.5 to 15.0.   The insulating inorganic powder according to claim 1, wherein the Al / Ni molar ratio of the coating is in the range of 0.003 to 0.500.   It contains at least Ni ions, Al ions, ions containing phosphorus, and an aqueous medium, and the compounding amount of the source of ions containing phosphorus is 100 parts by mass with respect to 100 parts by mass in terms of metals of Ni ions and Al ions. The powder processing agent which exists in the range of mass part or more and 3000 mass parts or less, and the quantity of an aqueous medium exists in the range of 1000 mass parts or more and 40000 mass parts or less.   The powder processing agent according to claim 3, wherein a free acidity (FA) of the powder processing agent is in a range of 0.3 to 30.0 points.   A film on the surface of the inorganic powder, comprising a step of heating a composition containing the inorganic powder and the powder treating agent according to claim 3 or 4 to evaporate volatile components in the composition. The manufacturing method of the insulating inorganic powder which formed A.