下载后只包含 1 个 DOC 格式的文档，没有任何的图纸或源代码，查看文件列表
Standard of People’s Republic of China
Paints and Varnishes –
Determination of Resistance to Neutral Salt Spray
This standard is identical to the international standard ISO 7253 – 1984 Paints and Varnishes – Determination of Resistance to Neutral Salt Spray.
Subject Contents and Application Scope
This standard defines the method for the measurement of coating resistance to the neutral salt spray.
The methods specified in this standard may be taken as the inspection means for the paints and varnishes system quality.
GB 1266 Sodium Chloride
GB 1764 Paint Film Thickness Measurement Method
GB 1765 Paint Film Preparation for Measurement of Wet Heat Resistance, Salt Fog Resistance, and Weather Resistance (Manual Accelerated Method)
GB 3186 Sampling of Coated Products
GB 6682 Laboratory Water Specification
GB 9271 Paint and Varnish - Standard Specimen
GB 9278 Status Adjustment of Coated Specimen and Test Temperature and Humidity
GB 9286 Paint and Varnish – Grid Test for Paint Film
The test solvent should be prepared in such manner to dissolve the chemically pure sodium chloride that met with GB1266 into the grade 3 water that met with GB 6682, with the concentration of 50±10g/L1].
The pH measurement of the test solvent (3.1) at 25ºC should be 6.5~7.2 when measured with pH meter (with 0.1 pH precision). When beyond such scope, it may add the pure hydrochloric acid or sodium hydroxide to adjust. The precision test paper calibrated by the pH meter can be used for daily inspection.
The test solvent should be filtered before filling into the reservoir of the equipment so as to avoid the jamming of nozzle by the solid substances.
The equipment is salt spray test chamber, which should include ponents.
Salt Spray Chamber: Made of or cushioned with the material with anti corrosion performance to the salt water solvent, with the cover or cap inclines upward, of which the angle with the level plane should be above 25º so that the drop condensate collected in the cover will not drop to the test sheet.
The size and shape of the salt spray chamber should guarantee that the solvent volume collected in the chamber is within the range specified in clause 8.2.
In order to ensure the uniformity of salt spray, the volume of the salt spray chamber should not be less than 0.4m3. For the water spray chamber with the volume exceeded 2m3, the careful considerations in design and structure
should be taken to facilitate the operation, of which the factors to be taken into consideration are listed in Annex A.
1] Value in ISO standard is 50±5 g/L.
Thermostat Control Unit: Attached inside of the salt spray chamber in such position that at least 100 mm reach from the chamber wall, or attached in the water jacket of the chamber interior, capable of making all por