SAE J2334 （涂料盐雾腐蚀试验四）

2.1.4.1 Reproducibility and Repeatability information concerning this test method is discussed in SAE Paper 970734. See Reference 14.

3. Definitions
3.1 Cosmetic Corrosion－Corrosion that occurs as a result of the breakdown or damage to a coating system. Typically, this type of corrosion does not impact functiong but does compromise appearance.

3.2 General Corrosion－Corrosion of a component that is typically bare(no organic coating). Corrosive attack is uniform in nature and distributed over "large" areas.

3.3 Scribe Creepback－Coating creepback resulting from corrosion and undercutting from the scribe line. A scribe is a controlled simulated damage site designed to represent a scratch or chip.

3.4 Corrosion Coupons－Samples of bare metals, that are used to monitor and compare the corrosivivty of laboratory corrosion tests in terms of mass-loss.

3.5 Test Controls－Components(i.e., test panels,coupons,parts,etc.) which have been previously tested and/or correlated. They can be used to control the test conduct and compare the test results(also assist in evaluating reproducibility and repeateability).

4. Equipment and Test Materials
4.1　Test Cabinets－Test cabinet(s) with the ability to obtain and maintain the following environmental conditions (Reference SAE J1563, ASTM D 1735, and ASTM D 2247).

a. 50℃±2℃ and 100% Relative Humidity－The 100% relative humidity wet-stage condition can be achieved by use of one of the three methods shown as follows. Whichever method is employed, test samples and controls are required to be visibly moist/wet.

1. Wet-bottom method according to ASTM D 2247-except that the temperature shall be 50℃±2℃.
2. Water fog method according to ASTM D 1735, except that the collection rate is reduced from a range of 1.5 to 3 mL/h to 0.75 to 1.5 mL/h. The use of this method requires that the collection rates be documented.
3. Steam (vapor) generator method.

NOTE— The majority of the development of this specification was performed using the Wet-bottom method of humidity generation. This method was used as the basis when comparing other methods of humidity generations as well as other variables.

b. 60℃±2℃ and 50% Relative Humidity ±5%. Additional equipment will be required to maintain the 50% relative humidity condition.

Air circulation must be sufficient to prevent temperature stratification and allow drying of test parts during the dry-off portion of the test cycle.

Air circulation can be obtained through the use of a fan or forced air.

4.2 Salt Solution Application－The samples must be subject to an application of salt solution by use of one of the three methods shown as follows. Whichever method is employed, test samples and controls are required to be visibly moist/wet during the entire 15-minute interval of each test cycle.

   0.5% NaCl
   0.1% CaCl2
   0.075% NaHCO3