GB/T 18880-2012 English PDF (GBT18880-2012)
GB/T 18880-2012 English PDF (GBT18880-2012)
GB/T 18880-2012: Materials for bonded neodymium iron boron permanent magnets
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
Replacing GB/T 18880-2002
Materials for bonded neodymium iron boron permanent
ISSUED ON: NOVEMBER 05, 2012
IMPLEMENTED ON: MAY 01, 2013
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Material classification and designation ... 6
5 Requirements ... 7
6 Test methods ... 8
7 Inspection rules ... 9
8 Marks, packaging, transportation, storage, quality certificate ... 10 Annex A (normative) Main anti-rust properties and adhesion properties of products for bonded neodymium iron boron permanent magnets ... 12
Annex B (informative) Additional magnetic properties and main mechanical and physical properties of materials for bonded neodymium iron boron permanent magnets ... 14
Annex C (informative) Dimensional and geometric tolerances of materials for bonded neodymium iron boron permanent magnets ... 15
Annex D (informative) Chemical composition, manufacturing process and application of materials for bonded neodymium iron boron permanent magnets ... 16
Materials for bonded neodymium iron boron permanent
This Standard specifies the requirements, test methods, inspection rules and marks, packaging, transportation, storage, and quality certificates for materials for bonded neodymium iron boron permanent magnets.
This Standard applies to isotropic bonded materials for bonded neodymium iron boron permanent magnets and products produced by powder compression molding and injection molding.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 2423.17, Environmental testing for electric and electronic products - Part 2: Test method - Test Ka: Salt mist
GB/T 2423.18, Environmental testing - Part 2: Test methods - Test Kb: Salt mist, cyclic (sodium chloride solution)
GB/T 2828, Sampling procedures for inspection by attributes
GB/T 3217, Permanent magnet (magnetically hard) materials -- Methods of measurement of magnetic properties (neq IEC 60404-5)
GB/T 6682, Water for analytical laboratory use -- Specification and test methods (neq ISO 3696:1987)
GB/T 8170, Rules of rounding off for numerical values and expression and judgement of limiting values
GB/T 9637, Electrotechnical terminology -- Magnetic materials and components GB/T 17803, Designation system for rare earth products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. 3.1 principal magnetic properties
Including the remanence (Br) of the permanent magnet material, the magnetic polarization intensity coercivity (intrinsic coercivity) (HCJ), the magnetic induction intensity coercivity (HCB), and the maximum magnetic energy product [(BH)max]. 3.2 additional magnetic properties
Including the relative recovery magnetic permeability (??rec), remanence temperature coefficient [??(Br)], magnetic polarization strength coercive force temperature coefficient [??(HCJ)], and Curie temperature (Tc) of the permanent magnet material. 4 Material classification and designation
4.1 Material classification
The products are isotropic materials for bonded neodymium iron boron permanent magnets produced by powder compression molding and injection molding processes, or permanent magnet products in shapes such as rings, cylinders, cuboids, and tiles directly made from this material. According to the intrinsic coercivity, it is divided into three categories: low coercivity L, medium coercivity M, and high coercivity H. Products can be produced directly with magnetic components in their final form. It can also be assembled with other magnetic or non-magnetic components into devices (assemblies) or components as the final form.
4.2 Material designation
Each type of product is divided into several designations according to the maximum magnetic energy product (see Table 1 for details). Its designation representation method complies with the regulations of GB/T 17803. Each designation of material can be directly made into permanent magnet products in the shapes of rings, cylinders, cuboids, tiles, etc.
4.3 Designation representation method
There are two types of designation representation methods: numeric type and character type. The representation method of digital designation is as follows:
Refer to Annex A for the inspection methods of product anti-rust performance and adhesion performance.
6.3 Additional magnetic properties and main mechanical and physical properties The additional magnetic properties and main mechanical and physical properties of the material are tested using measuring tools that meet accuracy requirements and comply with national metrology standards, see Annex B.
6.4 Product dimensions and geometric tolerances
The dimensional tolerance and geometric tolerance of the product are tested using measuring tools that meet the accuracy requirements and comply with national metrology standards, or with special inspection instruments confirmed by both the supplier and the purchaser. See Annex C.
6.5 Appearance quality
Use a 10x magnifying glass for product appearance quality inspection.
7 Inspection rules
7.1 Inspection and acceptance
7.1.1 Products are inspected by the supplier's quality and technical supervision department. Ensure product quality complies with the provisions of this standard. Fill out the quality certificate.
7.1.2 The purchaser shall inspect the received products in accordance with the provisions of this Standard. If the inspection results are inconsistent with the provisions of this Standard, it shall be reported to the supplier within 1 month from the date of receipt of the product. The matter shall be resolved through negotiation between the supplier and the purchaser. If arbitration is needed, an agency recognized by both parties can be entrusted to conduct it, and samples can be taken jointly by the purchaser. 7.2 Batching
Each batch of products shall be composed of materials of the same specifications and sizes made by the same designation and the same production process.
7.3 Inspection items
Each batch of products shall be inspected for magnetic properties, dimensional tolerances, geometric tolerances, appearance quality and other items. The sampling batches, methods, quantities, anti-rust performance index items and qualified quality levels for anti-rust performance inspection shall be agreed upon by both parties. When the anti-rust coating materials and processes are changed, inspections shall be carried out according to the anti-rust performance index items and qualified quality levels agreed between the supplier and the purchaser.
The sampling quantity of the magnetic properties, dimensional tolerance, and geometric tolerance of the product shall be carried out in accordance with the provisions of GB/T 2828. Its acceptance qualified quality level (AQL) is level 1.5 of general inspection level II. The sampling quantity of product appearance quality shall be carried out in accordance with the provisions of GB/T 2828. Its acceptance quality level (AQL) is level 1.5 of general inspection level I. All are carried out according to a normal inspection sampling plan.
The principal magnetic properties of the material and the anti-rust performance of the product shall be determined by sampling quantity and qualified quality level as agreed upon by both parties.
7.5 Inspection result judgment
If the product's principal magnetic properties or anti-rust properties, dimensional tolerances, geometric tolerances, appearance quality and other inspection results are inconsistent with the provisions of this Standard, double samples will be taken from the batch of products to re-inspect the unqualified items. If there are still unqualified items, the batch of products will be judged as unqualified.
8 Marks, packaging, transportation, storage, quality certificate
8.1 Marks, packaging
8.1.1 If the purchaser requires the polarity of the product to be marked, it can be clearly stipulated in the contract.
8.1.2 Product packaging shall comply with the corresponding regulations on transportation and storage methods. Generally, foam plastic boxes are used as inner packaging. The outer packaging is in cartons or wooden boxes. Guarantee against damage during proper transportation and storage. Each outer packaging shall be marked with a mark on its surface, indicating:
a) Name of supplier;
b) Product name;
c) Batch number, specification size or product code;
d) Quantity, gross weight, exit-factory date.
8.2 Transportation, storage
In the constant temperature and humidity standard test chamber, put the coated product specimen. Store at 90% relative humidity and 80??? ??1??? test temperature for 240 h. After taking it out, place it at 23?????3??? for 2 h. Use a 10x magnifying glass to observe the coating surface of the specimen. If there is no rust or expansion phenomenon, it will be judged as qualified.
A.2.4 Acid resistance test
Put 10 mL of hydrochloric acid [(1+2), chemically pure] into a cleaned 200 mL plastic bottle. Then add 60 mL of laboratory grade 3 water to prepare hydrochloric acid (1+19). Then put in the coated product specimen. Cover and leave for 24 h. Then take out the product specimen. After cleaning, dry at 23??C ??3??C for 2 h. Observe with a 10x magnifying glass. When the coating film of the specimen (except for the electrode contacts during coating) does not have swelling, cracking, peeling, bubbles, softening, dissolution, and no major changes in color and brightness, it is judged to be qualified. A.2.5 Salt spray resistance test
In the salt spray standard test chamber, put the painted product specimen. The main conditions for the test must comply with the requirements of GB/T 2423.17 and GB/T 2423.18. The specimen can be properly cleaned before testing. However, abrasives and solvents with corrosive or inhibitory effects cannot be used for cleaning. The cleaning method must not damage the surface. After cleaning the specimen, wipe it dry with a clean cloth or absorbent paper, or blow it dry with oil-free dry air. Handprint contamination will cause serious adverse test results, so the specimen must not have any handprint contamination after cleaning. After the salt spray test is completed, the specimen is taken out and placed at 23??C ??3??C for 2 h. Observe with a 10x magnifying glass. When the coating film of the specimen (except for the electrode contacts during coating) does not have swelling, cracking, peeling, bubbles, softening, dissolution, and no major changes in color and brightness, it is judged to be qualified. A.2.6 Adhesion tape peeling test
Fix the coated product specimen on the table. Use a single-sided cutting blade to mark the "#" shape. Be sure to use the tip of the knife when cutting into the knife mark. Opposite the coating surface, the tip of the knife is perpendicular to the coating surface and penetrates the coating film. The intervals between each cut are about 1 mm. Then stick the 3M600 tape on the product specimen marked with the character "#". Lift up one end of the tape and pull instantly. If there is no defect in the coating film, it will be judged as qualified.
Chemical composition, manufacturing process and application of materials for bonded neodymium iron boron permanent magnets
D.1 Chemical composition of materials for bonded neodymium iron boron
Material for bonded neodymium iron boron permanent magnets is a permanent magnet product prepared by mixing and molding NdFeB permanent magnet powder and binder (including organic binder and low melting point metal). The main components are rare earth (RE), iron (Fe), boron (B) and binder. Among them, the rare earth is mainly the metal neodymium (Nd). In order to obtain different properties, some other rare earth metals such as praseodymium (Pr), lanthanum (La), and cerium (Ce) can be substituted. Iron can also be partially replaced by other metals such as cobalt (Co), zirconium (Zr), aluminum (Al), etc. The content of boron is small, but it plays an important role in forming the intermetallic compound R2Fe14B with a tetragonal crystal structure, giving the compound high saturation magnetization, high uniaxial anisotropy and high Curie temperature. Binders are usually polymer resins, such as thermosetting epoxy resin, thermoplastic nylon and polyphenylene sulfide (PPS).
D.2 Manufacturing process of materials for bonded neodymium iron boron
The material for bonded neodymium iron boron permanent magnets adopts powder metallurgy process and composite material process. The compression molding process usually uses thermosetting resin as the binder. The process is as follows: first, the smelted alloy is made into magnetic powder through a rapid solidification process, then mixed with a binder, and then formed into a compact through a compression method. The compact reaches a certain mechanical strength through curing. In order to increase the anti-oxidation ability of the product, it is usually necessary to perform surface anti- rust treatment on the product. The process flow is shown in Figure D.1. A: Smelting B: Powder preparation C: Mixing with binder D: Compression molding E: Solidifying F: Surface anti-rust treatment G: Magnetizing H: Final testing I: Finished product Figure D.1 -- Process flow of compression molded materials for bonded
neodymium iron boron permanent magnets
A B C D E F
G H I