标准编号：ISO 10070:2019
中文名称：金属粉末 在稳态流动条件下根据测量粉末层的透气性确定包线的表面积
英文名称：Metallic powders — Determination of envelope-specific surface area from measurements of the permeability to air of a powder bed under steady-state flow conditions
发布日期：2019-12
标准范围
This document specifies a method of measuring the air permeability and the porosity of a packed
bed of metal powder, and of deriving therefrom the value of the envelope-specific surface area. The
permeability is determined under steady-state flow conditions, using a laminar flow of air at a pressure
near atmospheric. This document does not include the measurement of permeability by a constant
volume method.
Several different methods have been proposed for this determination, and several test devices are
available commercially. They give similar, reproducible results, provided that the general instructions
given in this document are respected, and the test parameters are identical.
This document does not specify a particular commercial test device and corresponding test procedure.
However, for the convenience of the user, an informative annex has been included (see Annex A) which
is intended to give some practical information on three specific methods:
— the Lea and Nurse method, involving a test device which can be built in a laboratory (see A.1);
— the Zhang Ruifu method, using a similar test device (see A.2);
— the Gooden and Smith method, involving a test device which can be built in a laboratory but for
which a commercial test device also exists. (Two types of commercial test device exist; one of these
is no longer available for purchase, but is still being used, see A.3.)
These methods are given as examples only. Other test devices available in various countries are
acceptable within the scope of this document.
This testing method is applicable to all metallic powders, including powders for hardmetals, up to
1 000 µm in diameter, but it is generally used for particles having diameters between 0,2 µm and
75,0 µm. It is not intended to be used for powders composed of particles whose shape is far from
equiaxial, i.e. flakes or fibres, unless specifically agreed upon between the parties concerned.
This testing method is not applicable to mixtures of different metallic powders or powders containing
binders or lubricant.
If the powder contains agglomerates, the measured surface area can be affected by the degree of
agglomeration. If the powder is subjected to a de-agglomeration treatment (see Annex B), the method
used is to be agreed upon between the parties concerned.
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