Summary of the invention
The object of the present invention is to provide a kind of manufacture method of dry type anisotropy strontium ferrites, it uses synthetic wax as tackiness agent, can reduce because of use that camphor causes to the harm of the person with to the pollution of environment, can also improve sintered density, avoid product surface to produce bee-hole, form the dry type anisotropy strontium ferrites with superior magnetic property.
The technical solution adopted for the present invention to solve the technical problems is:
(1) preparation pre-burning fine powder material
Fe in molar ratio
2O
3: SrCO
3=5.7-5.9:1 takes raw material Fe
2O
3And SrCO
3, through mixing, oven dry, pre-burning, coarse breaking, obtain the meal material, then add the CaCO of the 0.8-1.25wt% of this meal material weight
3And the SiO of 0.08-0.3wt%
2, then, oven dry broken through fine powder, obtain the pre-burning fine powder material;
(2) prepare mixing concentrate feed
Take step (1) gained pre-burning fine powder material and mix with synthetic wax as tackiness agent, wherein synthetic wax accounts for 1-12wt%, and the pre-burning fine powder material accounts for 99-88wt%, drops into Banbury mixer after mixing, and is cooled to room temperature after adding hot milling, obtains mixing concentrate feed;
(3) preparation moulding fine powder
Take the mixing concentrate feed of step (2) gained and step (1) gained pre-burning fine powder material mixes with mass ratio 1:9, obtain the mixture that synthetic wax accounts for 0.1-1.2wt%, the moulding auxiliary calcium stearate that adds again the 0.05-1.2wt% of this mixture weight, through mixing, Crushing of Ultrafine, obtain the moulding fine powder;
(4) forming and sintering
Use fine powder through moulding, sintering, grinding step (3) gained moulding, obtain dry type anisotropy strontium ferrites of the present invention.
Described synthetic wax is the brown color blocks of solid, and molecular weight is that 200-600, carbonatoms are the hydrocarbon mixture of 4-26, and main component is straight-chain paraffin, also contains simultaneously naphthenic hydrocarbon, isoparaffin, aromatic hydrocarbon, unsaturated hydrocarbons or their mixture.
The density of described synthetic wax is 0.990-0.999g/cm
3, fusing point is 58-79 ℃, and is water insoluble, is dissolved in hot ethanol.
Preferably, in step (2), synthetic wax accounts for 1.5-8wt%.
More preferably, in step (2), synthetic wax accounts for 2-6wt%.
In step (1), the mean particle size of pre-burning fine powder material is 0.65-0.8 μ m, is preferably 0.7-0.75 μ m.
The time that adds hot milling in step (2) is 10-25min.
The synthetic wax tackiness agent that the present invention adds, it is a kind of brown color blocks of solid material, molecular weight is about the hydrocarbon mixture that 200-600, carbonatoms are about 4-26, and main component is straight-chain paraffin, also has simultaneously a small amount of naphthenic hydrocarbon, isoparaffin, aromatic hydrocarbon, unsaturated hydrocarbons or their mixture.Density is 0.990-0.999g/cm
3, fusing point is 58-79 ℃, and is water insoluble, is dissolved in the organic solvents such as hot ethanol, can help esterifying agent, slightly acidic esterifying catalyst, organic salt catalyzer etc. to make through techniques such as catalyzed oxidation, nitrogen esterifications by adding higher alcohols in the food-class high-purity Microcrystalline Wax.
Synthetic wax is as tackiness agent, and its addition in product (being content) is 0.1-1.2wt%.Addition is very few, can not bring into play effect, and particle and magnetocrystalline orientation degree are bad, the formability variation; Addition is too much, and organic carbonization in the time of can causing sintering and the density of sintered compact is descended makes Br equimagnetic degradation.
Also added the moulding auxiliary calcium stearate of 0.05-1.2wt% when adding the synthetic wax tackiness agent, addition is preferably 0.1-0.8wt%.Can effectively improve formability, improve mobility and the power of reducing friction by adding the moulding auxiliary, can further improve magnetic property.
The invention has the beneficial effects as follows:
Owing to replacing camphor as tackiness agent with synthetic wax in the manufacture method of dry type anisotropy strontium ferrites, have benefited from the characteristic of its difficult volatilization, so in reaction system, the addition of tackiness agent can not reduce along with the carrying out of whole technological process; Can reduce production costs, reduce to use camphor as tackiness agent cause to the harm of the person with to the pollution of environment; The heat decomposition temperature of synthetic wax is wider, slowly decompose in 100-500 ℃ of scope, final temperature of having decomposed is lower than the formation temperature of strontium ferrites, when it is in molten state, has good mobility, can penetrate into better in the powder gap, be conducive to the moulding of magnet and the raising of density, can also avoid green compact cracking and sintered compact surface bee-hole to occur; Synthetic wax also has good oilness simultaneously, then reduces the frictional force that in moulding process, ferrite particle rotates, and is conducive to improve the orientation degree of particle and magnetocrystalline.
Embodiment
Below in conjunction with specific embodiment, further set forth the present invention.
Embodiment 1
Adopt following steps to make product of the present invention:
(1) preparation pre-burning fine powder material
Fe in molar ratio
2O
3: SrCO
3=5.7:1 takes raw material Fe
2O
3And SrCO
3Mixing, oven dry and pre-burning obtain Preburning material.Use vibromill to become mean particle size to be the meal material of 2-6 μ m above-mentioned Preburning material coarse breaking, add the CaCO of the 0.8wt% of this meal material weight
3And the SiO of 0.3wt%
2After, fine powder is broken into the fine powder post-drying that mean particle size is 0.8 μ m, obtains the pre-burning fine powder material.
(2) prepare mixing concentrate feed
Take step (1) gained pre-burning fine powder material and mix with synthetic wax, wherein synthetic wax accounts for 1wt%, and the pre-burning fine powder material accounts for 99wt%, and mixed material is dropped into Banbury mixer, carries out mixing in the time of heating.When temperature rises to 75 ℃, open cooling water circulationly, control temperature 80 ℃ of left and right, mix 15min, mix being cooled to room temperature after completing, obtain mixing concentrate feed.
(3) preparation moulding fine powder
Take the mixing concentrate feed of step (2) gained and step (1) gained pre-burning fine powder material mixes with mass ratio 1:9, obtain the mixture that synthetic wax accounts for 0.1wt%, the moulding auxiliary calcium stearate that adds again the 0.8wt% of this mixture weight, use double worm mixer mixing 15min, then by mechanical dispersion equipment Crushing of Ultrafine, obtain the moulding fine powder.
(4) forming and sintering
Use 45T semi-automatic liquid press that step (3) gained moulding is molded into fine powder
Right cylinder, and carry out sintering, grinding, obtain dry type anisotropy strontium ferrites of the present invention.
Embodiment 2
Adopt following steps to make product 4 of the present invention:
(1) preparation pre-burning fine powder material
Fe in molar ratio
2O
3: SrCO
3=5.8:1 takes raw material Fe
2O
3And SrCO
3Mixing, oven dry and pre-burning obtain Preburning material.Use vibromill to become mean particle size to be the meal material of 2-6 μ m above-mentioned Preburning material coarse breaking, add the CaCO of the 1.1wt% of this meal material weight
3And the SiO of 0.2wt%
2After, fine powder is broken into the fine powder post-drying that mean particle size is 0.72 μ m, obtains the pre-burning fine powder material.
(2) prepare mixing concentrate feed
Take step (1) gained pre-burning fine powder material and mix with synthetic wax, wherein synthetic wax accounts for 6wt%, and the pre-burning fine powder material accounts for 94wt%, and mixed material is dropped into Banbury mixer, carries out mixing in the time of heating.When temperature rises to 75 ℃, open cooling water circulationly, control temperature 80 ℃ of left and right, mix 15min, mix being cooled to room temperature after completing, obtain mixing concentrate feed.
(3) preparation moulding fine powder
Take the mixing concentrate feed of step (2) gained and step (1) gained pre-burning fine powder material mixes with mass ratio 1:9, obtain the mixture that synthetic wax accounts for 0.6wt%, the moulding auxiliary calcium stearate that adds again the 0.4wt% of this mixture weight, use double worm mixer mixing 20min, then by mechanical dispersion equipment Crushing of Ultrafine, obtain the moulding fine powder.
(4) forming and sintering
Use 45T semi-automatic liquid press that step (3) gained moulding is molded into fine powder
Right cylinder, and carry out sintering, grinding, obtain dry type anisotropy strontium ferrites of the present invention.
Embodiment 3
Adopt following steps to make product of the present invention:
(1) preparation pre-burning fine powder material
Fe in molar ratio
2O
3: SrCO
3=5.9:1 takes raw material Fe
2O
3And SrCO
3Mixing, oven dry and pre-burning obtain Preburning material.Use vibromill to become mean particle size to be the meal material of 2-6 μ m above-mentioned Preburning material coarse breaking, add the CaCO of the 1.25wt% of this meal material weight
3And the SiO of 0.1wt%
2After, fine powder is broken into the fine powder post-drying that mean particle size is 0.65 μ m, obtains the pre-burning fine powder material.
(2) prepare mixing concentrate feed
Take step (1) gained pre-burning fine powder material and mix with synthetic wax, wherein synthetic wax accounts for 12wt%, and the pre-burning fine powder material accounts for 88wt%, and mixed material is dropped into Banbury mixer, carries out mixing in the time of heating.When temperature rises to 75 ℃, open cooling water circulationly, control temperature 80 ℃ of left and right, mix 25min, mix being cooled to room temperature after completing, obtain mixing concentrate feed.
(3) preparation moulding fine powder
Take the mixing concentrate feed of step (2) gained and step (1) gained pre-burning fine powder material mixes with mass ratio 1:9, obtain the mixture that synthetic wax accounts for 1.2wt%, the moulding auxiliary calcium stearate that adds again the 0.1wt% of this mixture weight, use double worm mixer mixing 25min, then by mechanical dispersion equipment Crushing of Ultrafine, obtain the moulding fine powder.
(4) forming and sintering
Use 45T semi-automatic liquid press that step (3) gained moulding is molded into fine powder
Right cylinder, and carry out sintering, grinding, obtain dry type anisotropy strontium ferrites of the present invention.
Embodiment 4
Adopt the method for embodiment 2, when wherein the pre-burning fine powder material mixes with synthetic wax in step (2), synthetic wax accounts for 2wt%, prepares product 1 of the present invention.
Embodiment 5
Adopt the method for embodiment 2, when wherein the pre-burning fine powder material mixes with synthetic wax in step (2), synthetic wax accounts for 3wt%, prepares product 2 of the present invention.
Embodiment 6
Adopt the method for embodiment 2, when wherein the pre-burning fine powder material mixes with synthetic wax in step (2), synthetic wax accounts for 4wt%, prepares product 3 of the present invention.
Embodiment 7
Adopt the method for embodiment 2, when wherein the pre-burning fine powder material mixes with synthetic wax in step (2), synthetic wax accounts for 8wt%, prepares product 5 of the present invention.
Below for replace the Comparative Examples of synthetic wax with camphor.
Comparative Examples 1
Adopt following steps to make comparative sample 1:
(1) preparation pre-burning fine powder material
Fe in molar ratio
2O
3: SrCO
3=5.8:1 takes raw material Fe
2O
3And SrCO
3Mixing, oven dry and pre-burning obtain Preburning material.Use vibromill to become mean particle size to be the meal material of 2-6 μ m above-mentioned Preburning material coarse breaking, add the CaCO of the 1.1wt% of this meal material weight
3And the SiO of 0.2wt%
2After, fine powder is broken into the fine powder post-drying that mean particle size is 0.72 μ m, obtains the pre-burning fine powder material.
(2) preparation concentrate feed
Take step (1) gained pre-burning fine powder material and mix with camphor, wherein camphor accounts for 4wt%, and the pre-burning fine powder material accounts for 96wt%, and mixed material is dropped into Crushing of Ultrafine in mechanical dispersion equipment, obtains concentrate feed.(because the physical property of camphor highly volatile does not need to heat banburying, its concentrate feed also can mix uniformly with the pre-burning fine powder material)
(3) preparation moulding fine powder
Take step (2) gained concentrate feed and step (1) gained pre-burning fine powder material mixes with mass ratio 1:9, obtain the mixture that camphor accounts for 0.4wt%, the moulding auxiliary calcium stearate that adds again the 0.4wt% of this mixture weight, use double worm mixer mixing 20min, then by mechanical dispersion equipment Crushing of Ultrafine, obtain the moulding fine powder.
(4) forming and sintering
Use 45T semi-automatic liquid press that step (3) gained moulding is molded into fine powder
Right cylinder, and carry out sintering, grinding, obtain comparative sample 1.
Comparative Examples 2
Adopt the method for Comparative Examples 1, wherein camphor accounts for 8wt% in step (2), prepares comparative sample 2.
Comparative Examples 3
Adopt the method for Comparative Examples 1, wherein camphor accounts for 12wt% in step (2), prepares comparative sample 3.
The performance test methods of above embodiment and Comparative Examples products obtained therefrom is:
A) density of product is tested with drainage.
B) aspect magnetic property, the remanent magnetism Br of product, magnetic strength coercivity H b, HCJ Hcj adopt the B-H tester test of Loudi, Hunan electronics institute, exportable J-H loop line, BH loop, demagnetizing curve etc.Testing method: use the plane grinding machine to polish in sample, guarantee that the upper and lower surfaces of cake are all smooth smooth, and upper and lower surface is parallel to each other, then use the B-H tester to test under the 1500KA/m magnetic field condition, the test environment temperature is 23 ℃ of left and right.The repeatability of test result is: Br, Hcb, Hcj be ± and 0.2%.
Adopt above-mentioned testing method to carrying out performance test with the synthetic wax (product 1-5 of the present invention) of the present invention's employing and the camphor (comparative sample 1-3) of prior art employing as the dry type anisotropy strontium ferrites product that tackiness agent prepares respectively, the results are shown in following table 1.
Table 1 synthetic wax and camphor are as the product performance test result of tackiness agent
By finding out in table, as tackiness agent, at its product 1-5 of the present invention that more preferably adds (0.2-0.8wt%) in scope, follow with the comparative sample 1-3 of camphor as tackiness agent and compare: both have close density with synthetic wax; Produce bee-hole with camphor as the comparative sample 2,3 of tackiness agent, and all do not produced bee-hole with synthetic wax as the product 1-5 of the present invention of tackiness agent; Aspect magnetic property, with synthetic wax as the remanent magnetism Br of the product 1-5 of the present invention of tackiness agent, magnetic strength coercivity H b, HCJ Hcj than comparative sample 1-3, can reach substantially equal or slightly high level.
Should be understood that these embodiment only to be used for explanation the present invention and be not used in and limit the scope of the invention.After the content of having read the present invention's instruction, those skilled in the art can do various conversion or modification to the present invention with any same or similar means, within these equivalent form of values fall into protection scope of the present invention equally.