GB/T 43489-2023Sintered neodymium iron boron permanent magnets - Steady state damp heat tests (English PDF)

1 Scope

This document describes a method for constant damp heat testing of sintered NdFeB permanent magnets:

Note: According to the steam pressure in the test chamber during the test, the constant damp heat test of sintered NdFeB permanent magnets is divided into ordinary constant damp heat test and high pressure steam constant heat test:

Damp heat test, among which, the high-pressure steam constant damp heat test is divided into HAST test and PCT test:

This document is applicable to the constant moist heat test of sintered NdFeB permanent magnets with covering layers, including metal protective layers, coatings, conversion

Film layer and composite protective layer; also suitable for constant damp heat test before measuring the irreversible loss of magnetic flux in the open circuit state of sintered NdFeB permanent magnets:

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text: Among them, the dated quotations

For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document:

GB/T 8170 Numerical rounding rules and expression and determination of limit values

GB/T 13560 Sintered NdFeB permanent magnet material

GB/T 34491 Sintered NdFeB surface coating

GB/T 38437 Method for measuring the magnetic dipole moment of ferromagnetic material samples by pulling or rotating

GB/T 40793 Sintered NdFeB surface coating

3 Terms and definitions

The following terms and definitions apply to this document:

3:1

Constant humidity and heat test of unsaturated steam in a humidity and heat chamber:

Note: The normal control range of temperature and humidity is: 30°C~95°C, 50%RH~95%RH (RH means relative humidity):

3:2

Constant hygrothermal test of unsaturated high-pressure steam in a pressure vessel:

Note: The normal control range of temperature and humidity is: 105°C~135°C, 75%RH~98%RH:

3:3

PCT testpressurecookertest

Constant hygrothermal test of saturated high-pressure steam in a pressure vessel:

Note: The normal control range of temperature and humidity is: 105°C~135°C, 100%RH:

3:4 conversion film conversion film

A compound film formed by chemical or electrochemical treatment on the surface of sintered NdFeB permanent magnets:

Note: Conversion coatings include phosphating coatings, zirconating coatings and various types of oxide coatings (such as passivation coatings): […]